Make a comparative study and performance analysis of different modulation
techniques which shows graphically and comparatively results like Bandwidth,
Energy and Power Efficiency of AM, DSB-SC, SSB and SSB-SC
Comparison of Amplitude Modulation Techniques.pptxArunChokkalingam
This document discusses different types of amplitude modulation (AM) used in communication systems. It describes AM-DSB-FC, AM-DSB-SC, AM-SSB-SC, and vestigial sideband modulation (VSB), comparing their objectives to save transmitter power and bandwidth, transmission efficiency, bandwidth, number of channels supported, power consumption, difficulty of reconstruction, and applications. The key objectives of different AM techniques are to optimize power and bandwidth efficiency for various communication modes like radio, telegraphy, telephone and TV.
The document discusses various digital modulation schemes, their advantages, disadvantages, and applications. It covers schemes such as DSB-SC, SSB-SC, VSB-SC, FM, PM, PSK, ASK, PAM, QAM, and their uses in applications like analog and digital television broadcasting, radio broadcasting, satellite transmission, cable communication, and optical and telephone communications. Key aspects covered are power and bandwidth efficiency, complexity of generation and detection, immunity to noise, and ability to transmit multiple bits per symbol.
Microwave attenuators are electronic devices that reduce the power of signals without distorting their waveforms. They are the opposite of amplifiers in that they reflect and absorb energy through dissipative elements. There are fixed and variable types of attenuators. Fixed attenuators provide a set amount of power reduction and are used for impedance matching and where a fixed power level is required. Variable attenuators allow step-wise or continuous adjustment of attenuation through mechanisms like rotary wheels, flaps, or vanes made of lossy dielectric materials inserted into the signal path. Both types have characteristics like impedance, power handling, frequency response, and temperature dependence that are important to their performance.
Single Sideband Suppressed Carrier (SSB-SC)Ridwanul Hoque
Single-sideband suppressed carrier (SSB-SC) modulation improves spectral efficiency by transmitting only one sideband. It requires a bandwidth equal to the signal bandwidth. SSB-SC can be detected coherently using multiplication by the carrier. Quadrature amplitude modulation (QAM) transmits two baseband signals over the same bandwidth using in-phase and quadrature carriers that are 90 degrees out of phase. Vestigial sideband (VSB) modulation is a compromise between DSB and SSB that inherits advantages of both while requiring only slightly greater bandwidth than SSB. It is used for broadcast television transmission.
The document discusses radio receivers and their components and design. It describes the functions of radio receivers as intercepting modulated signals, selecting the desired signal, amplifying it, and demodulating it to recover the original signal. It explains the key components of receivers, including the RF amplifier, mixer, local oscillator, IF amplifier, and detector. It compares tuned radio frequency (TRF) receivers and superheterodyne receivers, noting that superheterodyne receivers overcome issues of TRF receivers like instability, bandwidth variation, and poor selectivity by downconverting RF signals to a lower intermediate frequency (IF). It also discusses characteristics of receivers like sensitivity, selectivity, and fidelity.
1. The document discusses various topics related to antenna parameters and radiation patterns. It describes the radiation mechanism of single wire, two wire, and dipole antennas.
2. Current distribution on thin wire antennas is explained. Parameters like radiation patterns, patterns in principal planes, main lobe and side lobes, beam widths, and polarization are discussed.
3. Key points about radiation patterns, coordinate systems, principal plane patterns, and definitions of main lobe, side lobes, half power beamwidth and first null beamwidth are provided.
Fir filter design (windowing technique)Bin Biny Bino
The window design technique for FIR filters involves choosing an ideal frequency-selective filter with the desired passband and stopband characteristics, and then multiplying or "windowing" its infinite impulse response with an appropriate window function to make it causal and finite. This windowing in the time domain corresponds to convolution in the frequency domain. Common window functions are used to truncate the ideal filter response while maintaining desirable filtering properties. MATLAB code can be used to implement windowed FIR filters.
This document discusses different types of waveguides, including rectangular waveguides, circular waveguides, coaxial lines, optical waveguides, and parallel-plate waveguides. It describes the different modes of wave propagation including TEM, TE, TM, and HE modes. Cutoff frequencies and wavelengths are defined for rectangular and parallel-plate waveguides. Dominant TE10 mode is described for rectangular waveguides.
Comparison of Amplitude Modulation Techniques.pptxArunChokkalingam
This document discusses different types of amplitude modulation (AM) used in communication systems. It describes AM-DSB-FC, AM-DSB-SC, AM-SSB-SC, and vestigial sideband modulation (VSB), comparing their objectives to save transmitter power and bandwidth, transmission efficiency, bandwidth, number of channels supported, power consumption, difficulty of reconstruction, and applications. The key objectives of different AM techniques are to optimize power and bandwidth efficiency for various communication modes like radio, telegraphy, telephone and TV.
The document discusses various digital modulation schemes, their advantages, disadvantages, and applications. It covers schemes such as DSB-SC, SSB-SC, VSB-SC, FM, PM, PSK, ASK, PAM, QAM, and their uses in applications like analog and digital television broadcasting, radio broadcasting, satellite transmission, cable communication, and optical and telephone communications. Key aspects covered are power and bandwidth efficiency, complexity of generation and detection, immunity to noise, and ability to transmit multiple bits per symbol.
Microwave attenuators are electronic devices that reduce the power of signals without distorting their waveforms. They are the opposite of amplifiers in that they reflect and absorb energy through dissipative elements. There are fixed and variable types of attenuators. Fixed attenuators provide a set amount of power reduction and are used for impedance matching and where a fixed power level is required. Variable attenuators allow step-wise or continuous adjustment of attenuation through mechanisms like rotary wheels, flaps, or vanes made of lossy dielectric materials inserted into the signal path. Both types have characteristics like impedance, power handling, frequency response, and temperature dependence that are important to their performance.
Single Sideband Suppressed Carrier (SSB-SC)Ridwanul Hoque
Single-sideband suppressed carrier (SSB-SC) modulation improves spectral efficiency by transmitting only one sideband. It requires a bandwidth equal to the signal bandwidth. SSB-SC can be detected coherently using multiplication by the carrier. Quadrature amplitude modulation (QAM) transmits two baseband signals over the same bandwidth using in-phase and quadrature carriers that are 90 degrees out of phase. Vestigial sideband (VSB) modulation is a compromise between DSB and SSB that inherits advantages of both while requiring only slightly greater bandwidth than SSB. It is used for broadcast television transmission.
The document discusses radio receivers and their components and design. It describes the functions of radio receivers as intercepting modulated signals, selecting the desired signal, amplifying it, and demodulating it to recover the original signal. It explains the key components of receivers, including the RF amplifier, mixer, local oscillator, IF amplifier, and detector. It compares tuned radio frequency (TRF) receivers and superheterodyne receivers, noting that superheterodyne receivers overcome issues of TRF receivers like instability, bandwidth variation, and poor selectivity by downconverting RF signals to a lower intermediate frequency (IF). It also discusses characteristics of receivers like sensitivity, selectivity, and fidelity.
1. The document discusses various topics related to antenna parameters and radiation patterns. It describes the radiation mechanism of single wire, two wire, and dipole antennas.
2. Current distribution on thin wire antennas is explained. Parameters like radiation patterns, patterns in principal planes, main lobe and side lobes, beam widths, and polarization are discussed.
3. Key points about radiation patterns, coordinate systems, principal plane patterns, and definitions of main lobe, side lobes, half power beamwidth and first null beamwidth are provided.
Fir filter design (windowing technique)Bin Biny Bino
The window design technique for FIR filters involves choosing an ideal frequency-selective filter with the desired passband and stopband characteristics, and then multiplying or "windowing" its infinite impulse response with an appropriate window function to make it causal and finite. This windowing in the time domain corresponds to convolution in the frequency domain. Common window functions are used to truncate the ideal filter response while maintaining desirable filtering properties. MATLAB code can be used to implement windowed FIR filters.
This document discusses different types of waveguides, including rectangular waveguides, circular waveguides, coaxial lines, optical waveguides, and parallel-plate waveguides. It describes the different modes of wave propagation including TEM, TE, TM, and HE modes. Cutoff frequencies and wavelengths are defined for rectangular and parallel-plate waveguides. Dominant TE10 mode is described for rectangular waveguides.
The document discusses amplitude modulation (AM), which is the simplest and earliest form of modulation. AM involves varying the amplitude of a carrier signal based on the instantaneous amplitude of an information signal. It describes the basic principles of AM, including modulation index and different types of AM such as double sideband suppressed carrier AM and single sideband AM. Advantages of AM include its simplicity of implementation, while disadvantages include inefficiency in power and bandwidth usage and susceptibility to noise.
This document discusses the generation of frequency modulation (FM) using direct and indirect methods. The direct method uses a reactance modulator like a varactor diode or FET placed across an LC oscillator tank circuit to vary the capacitance or inductance in proportion to the modulating voltage. The indirect method generates FM through phase modulation using a crystal oscillator and phase modulator, then detecting the phase changes to create FM. Vector diagrams are also presented to illustrate phase modulation. Effects of frequency changing like multiplication and mixing on FM signals are explained.
This presentation will explain about the need for modulation in communication system. We made this presentation as our group assignment in Analog and Digital Communication System course in MIIT.
Generation of SSB and DSB_SC ModulationJoy Debnath
The document discusses two methods of single sideband (SSB) modulation and balanced modulator modulation. It explains that SSB modulation eliminates one sideband from an amplitude modulated wave. It then describes the balanced modulator method, which uses two balanced modulators and a 90 degree phase shift to cancel out one sideband. The document also provides a brief overview of double sideband suppressed carrier (DSB-SC) modulation and notes that it uses two methods: multiplier modulation and balanced modulator.
This document discusses half wavelength dipole antennas. It defines a dipole antenna as a linear metallic wire or rod with a feed point at the center and two symmetrical radiating arms. It explains that a dipole antenna cannot work in a conducting medium but can work in dielectric mediums, where some parameters will change due to the relative permittivity and permeability. The document then compares half and full wavelength dipole antennas and provides parameters for a half wavelength dipole at an operating frequency of 600MHz, including its wavelength, dimensions, directivity, effective aperture, and effective length. It concludes that half wavelength dipole antennas are commonly used because their radiation resistance of 73Ω closely matches the impedance of 75Ω transmission lines
This document discusses transmission line theory and analysis. It begins by explaining how power is delivered through wires at low frequencies versus through electric and magnetic fields at microwave frequencies, defining transmission lines. It then lists common types of transmission lines including two-wire, coaxial cable, waveguide, and planar lines. It analyzes the differences between analyzing circuits at low versus high frequencies. Finally, it provides details on metallic cable transmission media, including balanced vs unbalanced lines, equivalent circuits, wave propagation, losses, phasors, and characteristic impedance.
Impedance matching is a procedure for obtaining the maximum power transfer to a load. What is a goal for microwave design? If we can give maximum power to a load, we succeed in design. Impedance matching allows us to make that happen.
This document discusses dipole and monopole antennas. It notes that dipoles and monopoles are widely used across radio frequencies for applications like mobile communications. An infinitesimal dipole is introduced as a theoretical construct to model antennas like top-loaded designs. The document also provides an example calculation for determining the power density and radiation resistance of a 1 cm Hertzian dipole antenna operating at 100 MHz from a distance of 1 km. Key parameters for dipole antennas like their radiation patterns and the properties of half-wave dipoles are additionally summarized.
1) Rectangular waveguides can transmit electromagnetic waves above a certain cutoff frequency, acting as a high-pass filter. They support transverse electric (TE) and transverse magnetic (TM) modes of propagation.
2) For TM modes, the electric field is transverse to the direction of propagation, while the magnetic field has a longitudinal component. The modes are denoted TMmn, with m and n indicating the number of half-wavelength variations across the width and height.
3) For TE modes, the magnetic field is entirely transverse, while the electric field has a longitudinal component. These modes are denoted TEmn, with m and n having the same meaning as in the TM case.
This document provides an overview of digital filter design. It introduces finite impulse response (FIR) and infinite impulse response (IIR) filters. FIR filters are designed using window techniques like rectangular, Hamming, and Kaiser windows. IIR filters are designed using approximation methods like Butterworth, Chebyshev I, and Chebyshev II. MATLAB code is provided to design low pass, high pass, and other filters using different window and approximation techniques. Pros and cons of FIR and IIR filters are discussed along with references.
These lecture notes cover microwave engineering topics such as transmission line analysis, microwave networks, impedance matching, power dividers and couplers, noise and active components, and microwave amplifier design. The notes are based on the textbook Microwave Engineering by David M. Pozar and contain 7 main sections that describe key microwave engineering concepts and analysis methods. Contact information is provided for the author, Dr. Serkan Aksoy, for future versions or proposals related to the material.
S-parameters are a useful method for representing a circuit as a "black box" whose external behavior can be predicted without knowledge of its internal contents. S-parameters are measured by sending a signal into the black box and detecting the waves that exit each port. They depend on the network, source and load impedances, and measurement frequency. Common S-parameters include S11 for the reflected signal at port 1 and S21 for the signal exiting port 2 due to a signal entering port 1.
The chapter discusses various types of pulse modulation techniques including pulse amplitude modulation (PAM), pulse width modulation (PWM), pulse position modulation (PPM), and pulse code modulation (PCM). PAM varies the amplitude of pulses based on the analog signal, PWM varies the width of pulses, PPM varies the position of pulses, and PCM converts the analog signal to a digital code using sampling and quantization. Digital communication through pulse modulation offers advantages like easier reception, less signal corruption over distance, ability to clean up noise and amplify signals, security through coding, and ability to store signals.
1. Low-pass filters allow low frequencies to pass through but attenuate frequencies higher than the cutoff frequency. They are implemented using a resistor and capacitor in conjunction with an op-amp amplifier.
2. A first-order low-pass filter has a single RC pair and rolls off at -20dB per decade above the cutoff frequency. Higher-order filters use multiple RC stages to achieve steeper roll-offs such as -40dB per decade for a second-order filter.
3. The cutoff frequency is the frequency at which the gain is 3dB below the maximum and is inversely proportional to the product of the resistor and capacitor values in each stage.
Pulse code modulation (PCM) is an analog-to-digital conversion technique used to represent sampled analog signals as digital data. PCM involves sampling the analog signal at regular intervals, quantizing the amplitude of the signal at each point to a few discrete levels, and coding it as digital data. The sampling rate must be greater than twice the highest frequency of the analog signal as per the Nyquist sampling theorem. PCM was invented in 1937 but was not widely adopted until the 1940s. It became the standard method for digital telephony due to its robustness and ability to efficiently regenerate and transmit signals.
This chapter discusses amplitude modulation and demodulation circuits. It covers the basic principles of amplitude modulation and describes different types of modulators including diode, transistor, and PIN diode modulators. It also discusses high-level modulation techniques like collector and series modulation. The chapter describes amplitude demodulation circuits like diode detectors and synchronous detectors. It explains how these circuits work to generate and recover amplitude modulated signals.
This document provides an overview of amplitude (linear) modulation techniques. It defines key concepts like modulation, baseband communication, and carrier communication. It then describes various amplitude modulation schemes including AM, DSB-SC, QAM, SSB, and VSB. Implementation and demodulation of these techniques is discussed. The document also covers frequency mixing, superheterodyne receivers, frequency division multiplexing, and carrier acquisition using phase-locked loops. Suggested problems are provided at the end.
This document discusses amplitude modulation and demodulation. It defines amplitude modulation as varying the amplitude of a carrier wave linearly with a message signal while keeping frequency and phase constant. Modulation is used to transmit signals over long distances and allow multiple signals over the same channel. Demodulation recovers the signal intelligence by reversing the modulation process through rectification and filtering. The document describes amplitude modulation and different types of AM demodulation techniques.
Phase modulation (PM) is a form of modulation where information is represented by variations in the instantaneous phase of a carrier wave. The phase angle of the complex envelope is changed in direct proportion to the message signal. PM can be considered a special case of FM where the carrier frequency modulation is given by the time derivative of the phase modulation. The bandwidth of PM for a single sinusoidal signal is approximately equal to the modulation index multiplied by the carrier frequency.
This document discusses attenuators and phase shifters. It describes how attenuators are used to reduce signal power without distortion, and includes fixed and variable types. Fixed attenuators are commonly used where a fixed amount of power is needed, while variable attenuators provide continuous or stepwise adjustable attenuation using methods like flap or vane designs. Phase shifters are also discussed, including ferrite and semiconductor types. Applications of phase shifters include communication systems, radar, and industrial uses. Key specifications for digital phase shifters are provided.
This document discusses types of amplitude modulation (AM) and power efficiency in AM. It describes three main types of AM: double sideband full carrier (DSB-FC), double sideband suppressed carrier (DSB-SC), and single sideband suppressed carrier (SSB-SC). DSB-FC transmits both sidebands and the carrier, while DSB-SC suppresses the carrier. SSB-SC transmits only one sideband and suppresses the carrier. The document also discusses modulation index and how only 33% of the total transmitted power in AM is useful for the signal, while the rest is wasted, making AM inefficient in terms of power usage.
This document provides an overview of analog modulation techniques. It discusses the basic concepts of signals, modulation, and communication systems. It covers various analog modulation schemes including amplitude modulation (AM) and angle modulation. AM techniques described include double sideband with carrier (DSB-FC), double sideband suppressed carrier (DSB-SC), single sideband with carrier (SSB-C), and single sideband suppressed carrier (SSB-SC). Modulation index, generation of AM signals using balanced and ring modulators, and AM demodulation are also covered. Angle modulation techniques of frequency modulation (FM) and phase modulation (PM) are introduced along with their advantages.
The document discusses amplitude modulation (AM), which is the simplest and earliest form of modulation. AM involves varying the amplitude of a carrier signal based on the instantaneous amplitude of an information signal. It describes the basic principles of AM, including modulation index and different types of AM such as double sideband suppressed carrier AM and single sideband AM. Advantages of AM include its simplicity of implementation, while disadvantages include inefficiency in power and bandwidth usage and susceptibility to noise.
This document discusses the generation of frequency modulation (FM) using direct and indirect methods. The direct method uses a reactance modulator like a varactor diode or FET placed across an LC oscillator tank circuit to vary the capacitance or inductance in proportion to the modulating voltage. The indirect method generates FM through phase modulation using a crystal oscillator and phase modulator, then detecting the phase changes to create FM. Vector diagrams are also presented to illustrate phase modulation. Effects of frequency changing like multiplication and mixing on FM signals are explained.
This presentation will explain about the need for modulation in communication system. We made this presentation as our group assignment in Analog and Digital Communication System course in MIIT.
Generation of SSB and DSB_SC ModulationJoy Debnath
The document discusses two methods of single sideband (SSB) modulation and balanced modulator modulation. It explains that SSB modulation eliminates one sideband from an amplitude modulated wave. It then describes the balanced modulator method, which uses two balanced modulators and a 90 degree phase shift to cancel out one sideband. The document also provides a brief overview of double sideband suppressed carrier (DSB-SC) modulation and notes that it uses two methods: multiplier modulation and balanced modulator.
This document discusses half wavelength dipole antennas. It defines a dipole antenna as a linear metallic wire or rod with a feed point at the center and two symmetrical radiating arms. It explains that a dipole antenna cannot work in a conducting medium but can work in dielectric mediums, where some parameters will change due to the relative permittivity and permeability. The document then compares half and full wavelength dipole antennas and provides parameters for a half wavelength dipole at an operating frequency of 600MHz, including its wavelength, dimensions, directivity, effective aperture, and effective length. It concludes that half wavelength dipole antennas are commonly used because their radiation resistance of 73Ω closely matches the impedance of 75Ω transmission lines
This document discusses transmission line theory and analysis. It begins by explaining how power is delivered through wires at low frequencies versus through electric and magnetic fields at microwave frequencies, defining transmission lines. It then lists common types of transmission lines including two-wire, coaxial cable, waveguide, and planar lines. It analyzes the differences between analyzing circuits at low versus high frequencies. Finally, it provides details on metallic cable transmission media, including balanced vs unbalanced lines, equivalent circuits, wave propagation, losses, phasors, and characteristic impedance.
Impedance matching is a procedure for obtaining the maximum power transfer to a load. What is a goal for microwave design? If we can give maximum power to a load, we succeed in design. Impedance matching allows us to make that happen.
This document discusses dipole and monopole antennas. It notes that dipoles and monopoles are widely used across radio frequencies for applications like mobile communications. An infinitesimal dipole is introduced as a theoretical construct to model antennas like top-loaded designs. The document also provides an example calculation for determining the power density and radiation resistance of a 1 cm Hertzian dipole antenna operating at 100 MHz from a distance of 1 km. Key parameters for dipole antennas like their radiation patterns and the properties of half-wave dipoles are additionally summarized.
1) Rectangular waveguides can transmit electromagnetic waves above a certain cutoff frequency, acting as a high-pass filter. They support transverse electric (TE) and transverse magnetic (TM) modes of propagation.
2) For TM modes, the electric field is transverse to the direction of propagation, while the magnetic field has a longitudinal component. The modes are denoted TMmn, with m and n indicating the number of half-wavelength variations across the width and height.
3) For TE modes, the magnetic field is entirely transverse, while the electric field has a longitudinal component. These modes are denoted TEmn, with m and n having the same meaning as in the TM case.
This document provides an overview of digital filter design. It introduces finite impulse response (FIR) and infinite impulse response (IIR) filters. FIR filters are designed using window techniques like rectangular, Hamming, and Kaiser windows. IIR filters are designed using approximation methods like Butterworth, Chebyshev I, and Chebyshev II. MATLAB code is provided to design low pass, high pass, and other filters using different window and approximation techniques. Pros and cons of FIR and IIR filters are discussed along with references.
These lecture notes cover microwave engineering topics such as transmission line analysis, microwave networks, impedance matching, power dividers and couplers, noise and active components, and microwave amplifier design. The notes are based on the textbook Microwave Engineering by David M. Pozar and contain 7 main sections that describe key microwave engineering concepts and analysis methods. Contact information is provided for the author, Dr. Serkan Aksoy, for future versions or proposals related to the material.
S-parameters are a useful method for representing a circuit as a "black box" whose external behavior can be predicted without knowledge of its internal contents. S-parameters are measured by sending a signal into the black box and detecting the waves that exit each port. They depend on the network, source and load impedances, and measurement frequency. Common S-parameters include S11 for the reflected signal at port 1 and S21 for the signal exiting port 2 due to a signal entering port 1.
The chapter discusses various types of pulse modulation techniques including pulse amplitude modulation (PAM), pulse width modulation (PWM), pulse position modulation (PPM), and pulse code modulation (PCM). PAM varies the amplitude of pulses based on the analog signal, PWM varies the width of pulses, PPM varies the position of pulses, and PCM converts the analog signal to a digital code using sampling and quantization. Digital communication through pulse modulation offers advantages like easier reception, less signal corruption over distance, ability to clean up noise and amplify signals, security through coding, and ability to store signals.
1. Low-pass filters allow low frequencies to pass through but attenuate frequencies higher than the cutoff frequency. They are implemented using a resistor and capacitor in conjunction with an op-amp amplifier.
2. A first-order low-pass filter has a single RC pair and rolls off at -20dB per decade above the cutoff frequency. Higher-order filters use multiple RC stages to achieve steeper roll-offs such as -40dB per decade for a second-order filter.
3. The cutoff frequency is the frequency at which the gain is 3dB below the maximum and is inversely proportional to the product of the resistor and capacitor values in each stage.
Pulse code modulation (PCM) is an analog-to-digital conversion technique used to represent sampled analog signals as digital data. PCM involves sampling the analog signal at regular intervals, quantizing the amplitude of the signal at each point to a few discrete levels, and coding it as digital data. The sampling rate must be greater than twice the highest frequency of the analog signal as per the Nyquist sampling theorem. PCM was invented in 1937 but was not widely adopted until the 1940s. It became the standard method for digital telephony due to its robustness and ability to efficiently regenerate and transmit signals.
This chapter discusses amplitude modulation and demodulation circuits. It covers the basic principles of amplitude modulation and describes different types of modulators including diode, transistor, and PIN diode modulators. It also discusses high-level modulation techniques like collector and series modulation. The chapter describes amplitude demodulation circuits like diode detectors and synchronous detectors. It explains how these circuits work to generate and recover amplitude modulated signals.
This document provides an overview of amplitude (linear) modulation techniques. It defines key concepts like modulation, baseband communication, and carrier communication. It then describes various amplitude modulation schemes including AM, DSB-SC, QAM, SSB, and VSB. Implementation and demodulation of these techniques is discussed. The document also covers frequency mixing, superheterodyne receivers, frequency division multiplexing, and carrier acquisition using phase-locked loops. Suggested problems are provided at the end.
This document discusses amplitude modulation and demodulation. It defines amplitude modulation as varying the amplitude of a carrier wave linearly with a message signal while keeping frequency and phase constant. Modulation is used to transmit signals over long distances and allow multiple signals over the same channel. Demodulation recovers the signal intelligence by reversing the modulation process through rectification and filtering. The document describes amplitude modulation and different types of AM demodulation techniques.
Phase modulation (PM) is a form of modulation where information is represented by variations in the instantaneous phase of a carrier wave. The phase angle of the complex envelope is changed in direct proportion to the message signal. PM can be considered a special case of FM where the carrier frequency modulation is given by the time derivative of the phase modulation. The bandwidth of PM for a single sinusoidal signal is approximately equal to the modulation index multiplied by the carrier frequency.
This document discusses attenuators and phase shifters. It describes how attenuators are used to reduce signal power without distortion, and includes fixed and variable types. Fixed attenuators are commonly used where a fixed amount of power is needed, while variable attenuators provide continuous or stepwise adjustable attenuation using methods like flap or vane designs. Phase shifters are also discussed, including ferrite and semiconductor types. Applications of phase shifters include communication systems, radar, and industrial uses. Key specifications for digital phase shifters are provided.
This document discusses types of amplitude modulation (AM) and power efficiency in AM. It describes three main types of AM: double sideband full carrier (DSB-FC), double sideband suppressed carrier (DSB-SC), and single sideband suppressed carrier (SSB-SC). DSB-FC transmits both sidebands and the carrier, while DSB-SC suppresses the carrier. SSB-SC transmits only one sideband and suppresses the carrier. The document also discusses modulation index and how only 33% of the total transmitted power in AM is useful for the signal, while the rest is wasted, making AM inefficient in terms of power usage.
This document provides an overview of analog modulation techniques. It discusses the basic concepts of signals, modulation, and communication systems. It covers various analog modulation schemes including amplitude modulation (AM) and angle modulation. AM techniques described include double sideband with carrier (DSB-FC), double sideband suppressed carrier (DSB-SC), single sideband with carrier (SSB-C), and single sideband suppressed carrier (SSB-SC). Modulation index, generation of AM signals using balanced and ring modulators, and AM demodulation are also covered. Angle modulation techniques of frequency modulation (FM) and phase modulation (PM) are introduced along with their advantages.
This document discusses various amplitude modulation techniques including DSBSC, SSB, and VSB modulation. It provides explanations of how to generate DSBSC waves using balanced modulators and ring modulators. It also describes coherent detection of DSBSC waves using synchronous detection and Costas loops. Methods for generating SSB signals using frequency and phase discrimination are outlined. VSB modulation is also introduced along with comparisons of different AM techniques. Limitations of standard AM are discussed and how more advanced modulation methods aim to overcome these limitations.
The document discusses amplitude modulation (AM) and different types of AM including double sideband AM (DSBAM), single sideband AM (SSBAM), and their modulation, demodulation, bandwidth requirements, and power considerations. It provides equations, diagrams, and explanations for DSBAM, SSBAM, and synchronous demodulation. Key aspects covered include the carrier signal, message signal, sidebands, modulation depth, spectrum analysis, and transmitter power efficiency comparisons between DSBAM and SSBAM.
This document discusses amplitude modulation (AM) in communication systems. It defines AM as varying the amplitude of a high-frequency carrier wave based on an information-carrying signal. Key points include:
- AM represents the modulating signal as variations in the carrier wave amplitude while keeping frequency and phase constant.
- An AM signal has a frequency spectrum consisting of the original carrier frequency along with upper and lower sideband frequencies that contain the modulating signal.
- The modulation index m indicates the degree of amplitude variation as a ratio of carrier to modulating signal amplitude. Higher m provides stronger signals but can cause distortion.
Modulation involves modifying a carrier signal with a modulating signal to make it suitable for transmission. There are two main types of modulation: analog and digital. Analog modulation includes amplitude modulation (AM), where the amplitude of the carrier wave varies with the modulating signal. AM can take different forms such as double sideband suppressed carrier (DSBSC) and single sideband (SSB) to improve power and bandwidth efficiency.
The document discusses various types of amplitude modulation including double sideband full carrier (DSB-FC), double sideband suppressed carrier (DSB-SC), and single sideband suppressed carrier (SSB-SC). It also covers power in amplitude modulation, noting that the carrier contains most power while each sideband contains half the carrier power. Finally, it defines modulation index as the ratio of the modulating signal to the unmodulated carrier signal, which should not exceed 1 or 100% modulation to avoid signal distortion.
This document discusses amplitude modulation (AM) used in radio broadcasting. It describes the principles of AM including: imposing an information signal onto a carrier wave such that the carrier amplitude varies proportionally to the information signal. This creates sidebands above and below the carrier frequency. The bandwidth of an AM signal is equal to twice the highest modulating frequency. Circuits and examples are provided to illustrate AM modulation and demodulation.
This document discusses amplitude modulation (AM) used in radio broadcasting. It describes the principles of AM including: how the carrier amplitude changes proportionally to the modulation signal, its advantages of simple circuits and use for audio/video broadcasting, and its disadvantages of noise and inefficient power use. Key aspects of AM include: the carrier signal combined with the modulating signal in the modulator, which produces an AM envelope waveform and sidebands around the carrier frequency. The bandwidth of an AM signal is equal to twice the highest modulating frequency.
This document provides an overview of analog communications and amplitude modulation (AM). It discusses the key components of a communication system including the input/output transducers, transmitter, channel, and receiver. For AM, it describes how the input signal is used to vary the amplitude of the carrier signal. It also examines the frequency spectrum of AM signals and discusses different forms of AM including double sideband suppressed carrier modulation. Coherent detection requires synchronization of both frequency and phase between the transmitter and receiver for DSB-SC due to the absence of the carrier signal.
The document discusses baseband and modulated communication signals. It defines baseband signals as those that do not use modulation and transmit information in its original form within the baseband frequency range. Modulated signals use carrier waves to shift the information signal to higher frequencies suitable for transmission. The key types of modulation discussed are amplitude modulation (AM), which varies the amplitude of the carrier wave, and angle modulation including frequency modulation (FM) and phase modulation (PM), which vary the frequency or phase of the carrier. Common applications of baseband signals include telephony and digital data transmission over copper wires, while modulated signals are required for wireless transmission through free space using radio frequencies.
Business utiliity plan for business managementDhirajPatel58
This document describes the principles and mathematical representations of amplitude modulation (AM). It discusses:
1) AM modulation involves varying the amplitude of a high-frequency carrier signal proportionally to the instantaneous amplitude of a modulating signal. This translates the modulating signal to a higher frequency for long-distance transmission.
2) An AM signal contains the carrier signal as well as upper and lower sideband signals displaced from the carrier by the modulating frequency. It requires demodulation to recover the original signal.
3) Power in an AM signal is distributed between the carrier and sidebands. At 100% modulation, half the power goes to each sideband. Transmitter efficiency is limited to 33% with this
This document discusses analog communications and amplitude modulation (AM). It defines analog and digital signals, and describes the characteristics of analog signals. It then explains AM modulation, including its time-domain and frequency-domain descriptions. It discusses single-tone modulation of AM and power calculations. Methods for generating and detecting AM waves are covered, including square law modulation/detection and envelope detection. Applications of AM such as radio broadcasting are also mentioned.
This document discusses types of amplitude modulation including:
- Double sideband full carrier (DSB-FC) which transmits both sidebands and the carrier.
- Double sideband suppressed carrier (DSB-SC) which transmits both sidebands but suppresses the carrier.
- Single sideband suppressed carrier (SSB-SC) which transmits either the upper or lower sideband and suppresses the carrier.
It also discusses power utilization in amplitude modulation, noting that only 33% of transmitted power is used to carry information in the sidebands, while the rest is wasted in the carrier. Finally, it defines modulation index as the ratio of modulation signal amplitude to carrier amplitude, with
1) Modulation involves changing characteristics of a high-frequency carrier signal according to an information signal. This allows signal transmission over long distances and multiple signals over the same channel.
2) The main modulation types are amplitude modulation (AM), which changes amplitude; frequency modulation (FM), which changes frequency; and phase modulation (PM), which changes phase.
3) AM is the simplest form and varies the carrier amplitude by the information signal. It has advantages of simplicity but is inefficient in power and bandwidth usage, and susceptible to noise.
Amplitude modulation and Demodulation TechniquesRich171473
The document discusses amplitude modulation (AM) and its various types. It begins by defining AM as varying the amplitude of a carrier wave based on an information-bearing signal. It then covers the basic mathematical model of AM and discusses aspects like modulation index. The main types covered are:
1. Double sideband AM (DSB-AM) which consists of the carrier wave along with upper and lower sidebands. It is bandwidth inefficient.
2. Single sideband AM (SSB-AM) which suppresses either the upper or lower sideband, reducing bandwidth by half compared to DSB-AM.
3. Suppressed carrier AM (DSB-SC and SSB-SC) which suppress
Modulation is the process of putting information onto a high frequency carrier wave for transmission. The key reasons for modulation are:
- To allow for frequency division multiplexing and support multiple transmissions via a single channel.
- For practicality, as transmitting very low frequencies would require antennas with miles in wavelength.
There are different types of modulation including analogue modulation (AM, FM, PM), pulse modulation, and digital modulation. Amplitude modulation (AM) varies the amplitude of the carrier wave and produces sidebands at sums and differences of the carrier and modulating frequencies. Double sideband suppressed carrier (DSB-SC) modulation suppresses the carrier wave to improve power efficiency but requires a complex receiver for demodulation.
The document discusses various types of analog modulation techniques. It begins by defining analog modulation and describing the key components - the message signal, carrier signal, and modulated signal. It then covers amplitude modulation techniques like AM, DSB-SC, and SSB which vary the amplitude of the carrier signal. Key aspects like bandwidth, power distribution, and detection methods are explained for each technique. The document also touches on angle modulation like FM and discusses metrics for evaluating different modulation schemes.
Double side band suppressed carrier AM generationswatihalunde
This document discusses various analog modulation techniques including double sideband suppressed carrier (DSB-SC), single sideband suppressed carrier (SSB-SC), and vestigial sideband (VSB) modulation. It explains the generation and demodulation of DSB-SC signals using a balanced modulator or ring modulator. It also describes how SSB-SC is generated by filtering one sideband from a DSB-SC signal. Finally, it discusses how VSB modulation transmits one full sideband and part of the other to avoid phase distortion at low frequencies during video transmission.
The document discusses amplitude modulation (AM), which is a process of superimposing a low frequency signal on a high frequency carrier signal. AM varies the amplitude of the carrier wave based on the instantaneous value of the modulating signal. This allows information to be transmitted over long distances using radio waves. Key points include: AM produces an output signal with sidebands having frequencies that are the sum and difference of the carrier and modulating signal frequencies. The bandwidth of an AM signal is twice the frequency of the modulating signal. Modulation index indicates how much the carrier is modulated and must be less than 1. Power transmission efficiency of AM is low. Examples demonstrate calculating modulation index, frequencies, and bandwidth from given AM signals.
Similar to Comparative Study and Performance Analysis of different Modulation Techniques AM, DSB-SC, SSB and SSB-SC (20)
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Advanced control scheme of doubly fed induction generator for wind turbine us...
Comparative Study and Performance Analysis of different Modulation Techniques AM, DSB-SC, SSB and SSB-SC
1. Problem:
Make a comparative study and performance analysis of different modulation
techniques which shows graphically and comparative results like Bandwidth,
Energy and Power Efficiency of AM, DSB-SC, SSB and SSB-SC.
Write a report on your analysis and justification of your results.
Abstract:
Several studies have been dedicated to the analysis of different modulation techniques. This paper
details a performance analysis of various modulation techniques like AM, DSB-SC, SSB, SSB-SC.
The aim of this study is to analyse and compare various techniques based on various parameters such
as bandwidth, power, energy, efficiency etc. AM generation involves mixing of a carrier and an
information signal. In Low level modulation, the message signal and carrier signal are modulated at
low power levels and then amplified. The advantage of this technique is small is that a small audio
amplifier is sufficient to amplify the message signal.
Keywords:
Modulation, Power, Efficiency, Bandwidth, Amplitude Modulation (AM), Double Sideband
Suppressed Carrier (DSB-SC), Single Sideband Suppressed Carrier (SSB-SC), Single Sideband SSB.
Introduction:
Communication is the process of conveying message or exchanging information. It means that
transmission of the encoded symbols transmitted in the communication channel, at the receiver
information is decoded and which recreates the original data. A message carrying a signal has to get
transmitted over a distance and for it to establish a reliable communication, it needs to take the help of
a high frequency signal which should not affect the original characteristics of the message signal.
Fig 1: Layout of Basic Analog Communication System
Modulation technique is used in communication process which increases the range of communication,
multiplexing and improves quality of reception. It is defined as the process of superimposing the
information contents of a base band signal on a carrier signal (which is of high frequency) by varying
the characteristic of carrier signal according to the message signal.
Advantages of implementing modulation in communication system are:
Reduction of antenna size
Increased in communication range
Possibility of bandwidth adjustment.
Improved reception quality
2. The types of modulations are broadly classified into continuous-wave modulation and pulse modulation.
In continuous-wave modulation, a high frequency sine wave is used as a carrier wave. This is further
divided into amplitude and angle modulation. If the amplitude of the high frequency carrier wave is
varied in accordance with the instantaneous amplitude of the modulating signal, then such a technique
is called as Amplitude Modulation. If the angle of the carrier wave is varied, in accordance with the
instantaneous value of the modulating signal, then such a technique is called as Angle Modulation.
Angle modulation is further divided into frequency modulation and phase modulation. If the frequency
of the carrier wave is varied, in accordance with the instantaneous value of the modulating signal, then
such a technique is called as Frequency Modulation. If the phase of the high frequency carrier wave is
varied in accordance with the instantaneous value of the modulating signal, then such a technique is
called as Phase Modulation.
Fig 2: Types of Modulation in Analog Communication System
As we discussed earlier modulation is a very important process in communication systems,
because the voice signal is dynamically varying signal hence need a high speed DSP processor to
process the signals accurately .The modulation schemes are broadly classified into two categories such
as analog and digital modulations .The topic for implementation is Amplitude modulation followed by
Double Sideband Suppressed Carrier (DSB-SC), Single Sideband (SSB) and Single Sideband
Suppressed Carrier (SSB-SC).
3. Methodology:
Amplitude Modulation:
According to the standard definition, “The amplitude of the carrier signal varies in accordance with the
instantaneous amplitude of the modulating signal” Which means, the amplitude of the carrier signal
containing no information varies as per the amplitude of the signal containing information, at each
instant. A continuous-wave goes on continuously without any intervals and it is the baseband message
signal, which contains the information. This wave has to be modulated. This can be well explained by
the following figures.
Fig 3: Baseband Signal Fig 4: Carrier Signal
Fig 5: Amplitude Modulated (AM) Signal
The first figure shows the modulating wave, which is the message signal. The next one is the carrier
wave, which is a high frequency signal and contains no information. While, the last one is the resultant
modulated wave. It can be observed that the positive and negative peaks of the carrier wave, are
interconnected with an imaginary line. This line helps recreating the exact shape of the modulating
signal. This imaginary line on the carrier wave is called as Envelope. It is the same as that of the
message signal.
Let the modulating signal be: m(t)=Am cos (2πfmt).
The carrier signal be: c(t)=Ac cos (2πfct).
The modulated wave be: s(t) = [Ac + Amcos (2πfmt)] cos (2πfct) s(t)………Eq. 1
Ac and Am are the amplitudes of carrier and message signal respectively.
fc and fm are frequency of carrier and message signal respectively.
4. Modulating Index:
A carrier wave, after being modulated, if the modulated level is calculated, then such an attempt is
called as Modulation Index or Modulation Depth. It states the level of modulation that a carrier wave
undergoes.
Rearranging the Eq. 1 as below:
s(t) = Ac [1 + (Am/Ac) cos (2πfmt)] cos (2πfct) s(t)
⇒ s(t )= Ac [1 + μ cos(2πfmt)] cos (2πfct) ………Eq. 2.
Where, μ is Modulation index and it is equal to the ratio of Am and Ac. Mathematically, we can write
it as: μ=Am/Ac.
Bandwidth of AM Wave:
It is the difference between the highest and lowest frequencies of the signal. Mathematically, we can
write it as: BW = fmax - fmin.
Consider the following equation of amplitude modulated wave:
s(t)=Ac [1 + μ cos (2πfmt)] cos (2πfct) s(t)
⇒ s(t) = Ac cos (2πfct) + Ac μ cos (2πfct) cos (2πfmt)
⇒ s(t) = Ac cos (2πfct) + Ac μ/2cos [2π (fc + fm) t] + Ac μ/2cos [2π(fc−fm) t]
Hence, the amplitude modulated wave has three frequencies. Those are carrier frequency fc, upper
sideband frequency (fc + fm) and lower sideband frequency (fc - fm).
BW = (fc + fm) − (fc - fm)
⇒BW=2fm
Power of AM Wave:
Consider the following equation of modulated wave:
s(t)=Ac cos (2πfct) + Ac μ/2cos [2π (fc + fm) t] + Ac μ/2 cos [2π (fc − fm) t]
Power of AM wave is equal to the sum of powers of carrier, upper sideband, and lower sideband
frequency components: Pt=Pc + PUSB + PLSB
We know that the standard formula for power of cos signal is: P=vrms
2
/R=(vm/√2)2
/2
Pc=(Ac/2√2)2
/R=AC
2
/2R
PUSB = (Ac μ/2√2)2
/R=Ac
2
μ2
/8R
PLSB = Ac
2
μ2
/8R.
Pt = AC
2
/2R+ Ac
2
μ2
/8R+ Ac
2
μ2
/8R=(Ac2
/2R) (1+μ2/4+μ2/4).
Pt = Pc (1+μ2/2)
5. Double Sideband Suppressed Carrier (DSBSC):
In the process of Amplitude Modulation, the modulated wave consists of the carrier wave and two
sidebands. The modulated wave has the information only in the sidebands. Sideband is nothing but a
band of frequencies, containing power, which are the lower and higher frequencies of the carrier
frequency. The transmission signals contain a carrier with two sidebands (known as Double Sideband
Full Carrier) as shown below:
Fig 6: Sidebands of Carrier Signal
However, such a transmission is inefficient. Because, two-thirds of the power is being wasted in the
carrier, which carries no information. If this carrier is suppressed and the saved power is distributed to
the two sidebands, then such a process is called as Double Sideband Suppressed Carrier system or
simply DSB-SC. It is plotted as shown in the following figure:
Fig 7: Suppressed Carrier Signal
Let the modulating signal be: m(t)=Am cos (2πfmt)
The Carrier Signal be: c(t) = Ac cos (2πfct)
Equation for DSB-SC modulated wave: s(t)=m(t)c(t)
⇒ s(t) = Am Ac cos (2πfmt) cos (2πfct)
Bandwidth of DSBSC Wave:
Bandwidth (BW): BW = fmax − fmin
Equation for DSB-SC modulated wave:
⇒ s(t) = Am Ac cos (2πfmt) cos (2πfct)
⇒ s(t) = Am Ac/2 cos [2π (fc + fm) t] + Am Ac/2cos [2π (fc−fm) t]
6. The DSBSC modulated wave has only two frequencies. So, the maximum and minimum frequencies
are (fc + fm) and (fc − fm) respectively.
fmax = (fc + fm) and fmin = (fc−fm)
BW = (fc + fm) − (fc−fm)
⇒ BW = 2fm.
Power of DSBSC Wave:
Equation for DSB-SC modulated wave:
s(t) = Am Ac/2cos [2π (fc + fm) t] + Am Ac/2cos [2π (fc−fm) t]
Power of DSBSC wave is equal to the sum of powers of upper sideband and lower sideband frequency
components.
Pt = PUSB + PLSB
P = vrms
2
/R=(vm√2)2
/R
PUSB = (Am Ac/2√2)2/R = Am
2
Ac
2
/8R
Similarly, we will get the lower sideband same power as that of upper sideband:
PLSB = Am
2
Ac
2
/8R
Now, let these two sideband powers are added in order to get the power of DSBSC wave:
Pt = Am
2
Ac
2
/8R+ Am
2
Ac
2
/8R
⇒ Pt = Am
2
Ac
2
/4R
7. Single Sideband Modulation (SSB):
The single-sideband modulation definition is a modulation which is used for transmitting information
like an audio signal through radio waves. This modulation is used in radio communications by using
transmitter power & more bandwidth efficiently for an alteration of AM (Amplitude Modulation).
There are many radio communication devices available in the market which use single sideband radio
like SSB Tx, SSB Rx, and SSB transceiver.
There are several variations are used for SSB modulation like lower sideband (LSB), upper sideband
(USB), double sideband (DSB), Single Sideband Suppressed Carrier (SSB SC), Vestigial Sideband
(VSB), and SSB reduced carrier.
Fig 8: Single Sideband Modulation (SSB)
Power of SSB Wave:
It is often necessary to define the output power of a single sideband transmitter or single sideband
transmission. Power measurement for an SSB signal is not as easy as it is for many other types of
transmission because the actual output power is dependent upon the level of the modulating signal. To
overcome this a measure known as the peak envelope power (PEP) is used. This takes the power of the
RF envelope of the transmission and uses the peak level of the signal at any instant and it includes any
components that may be present. Obviously, this includes the sideband being used, but it also includes
any residual carrier that may be transmitted. The level of the peak envelope power may be stated in
Watts, or figures quoted in dBW or dBm may be used. These are simply the power levels relative to 1
Watt or 1 milliwatt respectively.
8. Single Sideband Suppressed Carrier (SSBSC):
The DSBSC modulated signal has two sidebands. Since, the two sidebands carry the same information,
there is no need to transmit both sidebands. We can eliminate one sideband. The process of suppressing
one of the sidebands along with the carrier and transmitting a single sideband is called as Single
Sideband Suppressed Carrier system or simply SSBSC.
It is plotted as shown below:
Fig 9: Single Sideband Suppressed Carrier (SSBSC)
In the above figure, the carrier and the lower sideband are suppressed. Hence, the upper sideband is
used for transmission. Similarly, we can suppress the carrier and the upper sideband while transmitting
the lower sideband. This SSBSC system, which transmits a single sideband has high power, as the
power allotted for both the carrier and the other sideband is utilized in transmitting this Single
Sideband.
Let the modulating signal be: m(t) = Am cos (2πfmt)
The Carrier Signal be: c(t)=Ac cos (2πfct)
The equation for SSBSC is:
s(t) = Am Ac/2 cos [2π (fm + fm) t]; for the upper sideband
s(t) = Am Ac/2 cos [2π (f c− fm) t] s(t); for the lower sideband
Bandwidth of SSBSC Wave:
Since the SSBSC modulated wave contains only one sideband, its bandwidth is half of the bandwidth
of DSBSC modulated wave. i.e., Bandwidth of SSBSC modulated wave = 2fm/2 = fm
Therefore, the bandwidth of SSBSC modulated wave is fm and it is equal to the frequency of the
modulating signal.
Power of SSBSC Wave:
Let the SSBSC modulated wave be:
s(t) = Am Ac/2 cos [2π (fm + fm) t]; for the upper sideband
s(t) = Am Ac/2 cos [2π (f c− fm) t] s(t); for the lower sideband
Power of SSBSC wave is equal to the power of any one sideband frequency components.
Pt = PUSB = PLSB
The power of the upper sideband is: PUSB = (Am Ac/2√2)2
/R = Am
2
Ac
2
/8R
The power of the lower sideband is: PLSB = Am
2
Ac
2
/8R
9. Code for Output Waveforms of AM, DSBSC, SSB, SSBSC:
Amplitude Modulation (AM):
m = input(‘Modulation index = ‘);
t = linespace(0,0.2,1000);
Am = 5; % amplitude of message signal
fm = 10; % frequency of message signal
M = Am*cos(2*pi*fm*t); % message signal
figure;
subplot(4,1,1);
plot(t,M);
title(‘Message Signal’);
xlabel(‘time(t)’);
ylabel(‘Amplitude’);
%% Carrier Signal :
Ac = Am/m; % amplitude of carrier signal
fc = 20; % frequency of carrier signal
C = Ac*cos(2*pi*fc*t); % carrier signal
subplot(4,1,2);
plot(t, C);
title(‘Carrier Signal’);
xlabel(‘time(t)’);
ylabel(‘Amplitude’);
y = ammod(M, fc, 100, 0, Ac); % modulated signal
% ammod(M,fc,fs,INI_PHASE,CARRAMP)
subplot(4,1,3),plot(t, y);
title(‘Modulated Signal’);
xlabel(‘time(t)’);
ylabel(‘Amplitude’);
ylim([-20, 20]);
10. Double Sideband Suppressed Carrier (DSBSC):
function amplitude = dsbsc
fm = input(‘Enter the value of message signal frequency:’);
fc = input(‘Enter the value of carrier signal frequency: ‘);
Am = input(‘Enter the value of message signal amplitude:’);
Ac = input(‘Enter the value of carrier signal amplitude:’);
Tm = 1/fm;
Tc = 1/fc;
t1 = 0:Tm/999:6*Tm;
message_signal = Am*sin(2*pi*fm*t1);
subplot(3,1,1)
plot(t1, message_signal, ‘r’);
grid();
title(‘Message signal’);
carrier_signal = Ac*sin(2*pi*fc*t1);
subplot(3,1,2)
plot(t1, carrier_signal,’b’ );
grid();
title(‘Carrier Signal’);
amplitude = message_signal.*carrier_signal;
subplot(3,1,3)
plot(t1,amplitude,’g);
grid();
title(‘DSBSC’);
end
11. Single Sideband Modulation (SSB):
function SSBAM
td = input(‘n Enter the total Signal Durationnn ->’);
ts = input(‘n Enter the sampling time for this signal and it should be less than
1nn ->’);
fc = input(‘ n Enter the carrier frequency of the cosine wave nn ->’);
k = input(‘n Enter the constant diminishing factor nn->’ );
%fs = 1/ts ;
t = 0:ts:td;
t2 = int64( (t/ts) +1 );
m(t2) = input(‘ n Enter the msg signal as a function of time “t”; nn ->’);
w(t2) = hilbert(m(t2));
c = cos((2*pi*fc*t));
cp = sin((2*pi*fc*t));
s(t2) = (c.*(1+k*m(t2))+cp.*(1+k*w(t2)));
u(t2) = (1+k*m(t2)).*c;
subplot(2,1,1),plot(t,s(t2));
grid minor
title(‘Single SideBand Modulation’)
subplot(2,1,2),plot(t,u(t2));
title(‘DSB Signal’)
grid minor
d = input(‘ n IF FUNCTION OF FOURIER TRANSFORM IS NEEDED PRESS “1” nn ->’);
if d==1
syms t;
M = input(‘ n REENTER THE MESSAGE SIGNAL AS A FUNCTION OF TIME BUT FOR THE
INFINITE TIME PERIODnn ->’);
U = (1+k*M)*(1/2)*(cos(2*pi*fc*t) + abs(cos(2*pi*fc*t)));
FourierTransform = fourier(U)
end
12. Single Sideband Suppressed Carrier (SSBSC):
function am = ssbsc
Am = input(‘Enter the value of message signal Amplitude:’);
Ac = input(‘Enter the value of carrier signal Amplitude:’);
fm = input(‘Enter the value of message signal frequency:’);
fc = input(‘Enter the value of carrier signal frequency:’);
m = Am/Ac;
A = (m*Ac);
Tm = 1/fm;
Tc = 1/fc;
t = 0:Tm/999:6*Tm;
message_signal = Am*sin(2*pi*fm*t);
carrier_signal = Ac*sin(2*pi*fc*t);
x1 = cos(2*pi*fc*t).*cos(2*pi*fm*t);
x2 = sin(2*pi*fc*t).*sin(2*pi*fm*t);
x3 = x1+x2;
x4 = x1-x2;
SSBSC_lsb = A*(x3);
SSBSC_usb = A*(x4);
subplot(4,1,1)
plot(t, message_signal, ‘r’);
grid();
title(‘message signal’);
subplot(4,1,2)
plot(t, carrier_signal , ’g’);
grid();
title(‘Carrier signal’);
subplot(4,1,3)
plot(t, SSBSC_lsb,’b’);
grid();
title(‘LSB of SSBSC wave cutting off USB’);
subplot(4,1,4)
plot(t, SSBSC_usb, ‘r’);
grid();
title(‘USB of SSBSC wave cutting off LSB’);
end
13. Results:
The basic research work carried out in the field of communication lead to the development of new
modulation techniques, error performances analysis, having immunity to noise but the ever-increasing
demand of the faster communication system with large bandwidth requirements and transmitted power
has again generated a new requirement towards the development of newer techniques.
The comparison table for various parameters for AM, DSBSC, SSB, and SSBSC is shown below:
Parameters AM DSBSC SSB SSBSC
Variable
Characteristics
Amplitude Amplitude Amplitude Amplitude
Sideband
Suppression
No No
One Sideband
Completely
One Sideband
Completely
Carrier
Suppression
No Complete
Any One
Sideband
Complete
Modulating
Input
1 1 1 1
Bandwidth 2fm 2fm fm fm
Transmission
Efficiency
Low Moderate Maximum Maximum
Power High Medium Low Low
Complexity Simple Simple Complex Highly Complex
Performance
in presence of
noise
Low Average Average
Merits Easy detection
Low power
consumption,
simple
modulation
system
Bandwidth
efficiency,
reduction in
distortion
Low power
consumption,
Better frequency
use
Demerits
Poor reception
quality,
Complex
detection
Complex
detection
Complex
detection
Table 1: Comparison of various parameters of AM, DSBSC, SSB and SSBSC
Conclusion:
An analysis of the modulation techniques carried out in this article reveals that the selection of a analog
modulation technique is solely dependent on the type of application. This is because of the fact that
some of the technique provide lesser complexities in the design of the modulation and demodulation
system and prove to be economic. Single sideband modulation, (SSB) is the main modulation format
used for analogue voice transmission for two-way radio communication on the HF portion of the radio
spectrum. Its efficiency in terms of spectrum and power when compared to other modes means that for
many years it has been the most effective option to use. Now some forms of digital voice transmission
are being used, but it is unlikely that single sideband will be ousted for many years as the main format
used on these bands.
14. References:
1) Lathi, B.P., “Modern Digital and Analog Communication,” Oxford University Press, New York,
1998.
2) ANALOG AND DIGITAL COMMUNICATION LABORATORY by Prof Shaik Aqeel,
Electronics and Telecommunication Engineering, Sreyas Institute of Engineering and Technology,
February 24, 2021.
3) John G. Proakis and Masoud Salehi, “communication systems engineering”, 2nd Ed, prentice hall,
2001.
4) Chapter 5, Traditional Analog Modulation Techniques, Mikael Olofsson, 2002-2007.
5) K. Sharma, A. Mishra & Rajiv Saxena, „Analog & Digital Modulation Techniques: An overview‟,
international Journal of Computing Science and Communication Technologies, VOL. 3, NO. 1, July
2010.
6) Schwartz, M.: Information Transmission, Modulation and Noise, McGraw-Hill, New York, 1990.