This document provides information on synchronized FM emissions (Isofrequency-Isomodulation-SFN). It discusses the benefits of this technology, including lower protection ratios and more efficient use of spectrum. It then details the requirements for synchronized FM emissions, including transmitting the same identical modulation content with precise delay compensation. Test results show significantly better protection ratios can be achieved with a digital implementation compared to older analog methods. Various implementation examples are discussed, outlining how delay differences impact required protection ratios. The document also notes additional benefits of the WaveArt-ABE digital solution for signal backhauling.
Design and simulation of an analog beamforming phased array antenna IJECEIAES
The document describes the design and simulation of a phased array antenna system consisting of a 4-element slotted waveguide antenna array fed by an analog RF front-end to enable analog beamforming. The antenna array is designed to operate at 9.6 GHz and simulation results show a maximum gain of 13.95 dB and beamwidth of 19 degrees or less. The RF front-end is also simulated to demonstrate its ability to receive signals from the antenna array, adjust the phase, and transmit amplified signals to realize analog beamforming.
The document discusses different types of phase shifters, including ferrite and semiconductor phase shifters. Ferrite phase shifters work by changing the permeability of ferrite material with a magnetic field, thus changing the guided wavelength and phase delay. Semiconductor phase shifters include switched line, loaded line, and switched path designs using PIN diodes or FETs. Digital phase shifters provide precise phase shifts in discrete increments. Phase shifters have applications in communication systems, radar systems, and industrial instrumentation due to their ability to electronically control the phase of RF signals.
Field trial with a gsmdcs1800 smart antenna base station marwaeng
The document summarizes the results of field trials conducted with a smart antenna base station equipped with an adaptive antenna array processor. Key findings include:
1) Measurements in a static line-of-sight scenario demonstrated the potential to suppress interference by 25dB.
2) Field measurements in a microcell setup confirmed the system's ability to track mobiles even in multipath environments.
3) In non-line-of-sight situations an average signal-to-noise gain of 7.4dB was achieved, increasing to 8.3dB in line-of-sight environments.
4) Angular diversity provided an additional 5.8dB diversity gain at a 1% bit-error ratio
This document presents the design of a phased array antenna system using phase shifters. A group of 4 students designed and simulated a 1x4 microstrip patch antenna array fed by a Wilkinson power divider in ADS software. They first designed a single rectangular patch antenna, then a 1:4 Wilkinson power divider and combined them into an antenna array. Phase shifters using varactor diodes were also designed and simulated for different voltage biases. The phase and insertion loss characteristics of the phase shifters were analyzed to verify their performance in the phased array system.
This document discusses GSM-GPRS antenna operation and related equipment. It covers various antenna types including omnidirectional and directional antennas. It describes key antenna properties such as gain, polarization, beamwidth, downtilt, front-to-back ratio and intermodulation. It also discusses antenna development trends and network elements like masthead amplifiers and boosters. The document provides an overview of important concepts regarding antennas and equipment used for GSM-GPRS networks.
This document discusses earth stations, which transmit and receive signals to and from satellites using dish-shaped antennas. It describes the key components of both analog and digital earth station setups. Analog setups transmit one program per channel and require high power, while digital setups can transmit many more programs using compression and more efficient modulation schemes. The components of a digital earth station include encoders, multiplexers, modulators, up/down converters, high power amplifiers, low noise amplifiers, and antennas.
1. The document describes a self-adjusting optical serrodyne loop frequency shifter that uses a DQPSK modulator to generate a spectrum of optical carrier frequencies for testing high data rate transmission.
2. A biasing technique was studied that uses asymmetric dither signals to monitor and optimize the bias points of the DQPSK modulator in order to produce a clean optical frequency shift. This technique was simulated and a system was designed using an FPGA to implement it.
3. Testing showed that optimizing the bias points reduced output power and suppressed unwanted frequencies when no RF was applied, and produced a single sideband shift when RF was on, enabling generation of multiple optical subcarriers.
Radar Systems- Unit-II : CW and Frequency Modulated RadarVenkataRatnam14
This document provides information about continuous wave (CW) and frequency modulated (FM-CW) radar systems. It discusses the Doppler effect and how CW radar uses the frequency shift caused by the Doppler effect to detect moving targets. The key components of a CW radar like the transmitter, receiver, and Doppler filter are described. Issues like isolation between the transmitter and receiver, limitations of zero intermediate frequency receivers, and receiver bandwidth requirements are also covered. Finally, the document introduces the concept of FM-CW radar and its use of frequency modulation to measure target range and velocity.
Design and simulation of an analog beamforming phased array antenna IJECEIAES
The document describes the design and simulation of a phased array antenna system consisting of a 4-element slotted waveguide antenna array fed by an analog RF front-end to enable analog beamforming. The antenna array is designed to operate at 9.6 GHz and simulation results show a maximum gain of 13.95 dB and beamwidth of 19 degrees or less. The RF front-end is also simulated to demonstrate its ability to receive signals from the antenna array, adjust the phase, and transmit amplified signals to realize analog beamforming.
The document discusses different types of phase shifters, including ferrite and semiconductor phase shifters. Ferrite phase shifters work by changing the permeability of ferrite material with a magnetic field, thus changing the guided wavelength and phase delay. Semiconductor phase shifters include switched line, loaded line, and switched path designs using PIN diodes or FETs. Digital phase shifters provide precise phase shifts in discrete increments. Phase shifters have applications in communication systems, radar systems, and industrial instrumentation due to their ability to electronically control the phase of RF signals.
Field trial with a gsmdcs1800 smart antenna base station marwaeng
The document summarizes the results of field trials conducted with a smart antenna base station equipped with an adaptive antenna array processor. Key findings include:
1) Measurements in a static line-of-sight scenario demonstrated the potential to suppress interference by 25dB.
2) Field measurements in a microcell setup confirmed the system's ability to track mobiles even in multipath environments.
3) In non-line-of-sight situations an average signal-to-noise gain of 7.4dB was achieved, increasing to 8.3dB in line-of-sight environments.
4) Angular diversity provided an additional 5.8dB diversity gain at a 1% bit-error ratio
This document presents the design of a phased array antenna system using phase shifters. A group of 4 students designed and simulated a 1x4 microstrip patch antenna array fed by a Wilkinson power divider in ADS software. They first designed a single rectangular patch antenna, then a 1:4 Wilkinson power divider and combined them into an antenna array. Phase shifters using varactor diodes were also designed and simulated for different voltage biases. The phase and insertion loss characteristics of the phase shifters were analyzed to verify their performance in the phased array system.
This document discusses GSM-GPRS antenna operation and related equipment. It covers various antenna types including omnidirectional and directional antennas. It describes key antenna properties such as gain, polarization, beamwidth, downtilt, front-to-back ratio and intermodulation. It also discusses antenna development trends and network elements like masthead amplifiers and boosters. The document provides an overview of important concepts regarding antennas and equipment used for GSM-GPRS networks.
This document discusses earth stations, which transmit and receive signals to and from satellites using dish-shaped antennas. It describes the key components of both analog and digital earth station setups. Analog setups transmit one program per channel and require high power, while digital setups can transmit many more programs using compression and more efficient modulation schemes. The components of a digital earth station include encoders, multiplexers, modulators, up/down converters, high power amplifiers, low noise amplifiers, and antennas.
1. The document describes a self-adjusting optical serrodyne loop frequency shifter that uses a DQPSK modulator to generate a spectrum of optical carrier frequencies for testing high data rate transmission.
2. A biasing technique was studied that uses asymmetric dither signals to monitor and optimize the bias points of the DQPSK modulator in order to produce a clean optical frequency shift. This technique was simulated and a system was designed using an FPGA to implement it.
3. Testing showed that optimizing the bias points reduced output power and suppressed unwanted frequencies when no RF was applied, and produced a single sideband shift when RF was on, enabling generation of multiple optical subcarriers.
Radar Systems- Unit-II : CW and Frequency Modulated RadarVenkataRatnam14
This document provides information about continuous wave (CW) and frequency modulated (FM-CW) radar systems. It discusses the Doppler effect and how CW radar uses the frequency shift caused by the Doppler effect to detect moving targets. The key components of a CW radar like the transmitter, receiver, and Doppler filter are described. Issues like isolation between the transmitter and receiver, limitations of zero intermediate frequency receivers, and receiver bandwidth requirements are also covered. Finally, the document introduces the concept of FM-CW radar and its use of frequency modulation to measure target range and velocity.
This document provides an overview of installing and setting up an IPSTAR user terminal. It discusses the components of the user terminal including the antenna, low noise block downconverter (LNB), block upconverter (BUC), feed assembly, orthogonal mode transducer (OMT), and transmit reject filter (TRF). It also covers topics like polarization, antenna patterns, the effects of mispointing an antenna, and checking for sun outage times. The proper assembly and setup of each component is important to ensure optimal performance and avoid interference issues.
Introduction To Antenna Impedance Tuner And Aperture Switchcriterion123
This document discusses antenna tuning techniques for mobile devices. It describes two main antenna tuning methods: impedance tuning and aperture tuning. Impedance tuning optimizes power transfer between the RF front-end and antenna by adding a tunable matching network. Aperture tuning modifies the antenna structure and performance by integrating a switch to change the antenna's electrical length and resonance. The document provides examples of antenna tuners that use these techniques and discusses design considerations like losses to maximize performance.
The document describes experiments on digital communication lab including:
1. Pulse amplitude modulation and time division multiplexing where amplitude of pulses is varied according to modulating signal and samples from different signals are combined in time domain and transmitted over a common channel.
2. Pulse time modulation and demodulation (PWM and PPM) where pulse width or repetitive frequency is varied according to information signal to save transmitter power.
3. Analog to digital and digital to analog conversion where analog signals are sampled, quantized into discrete levels represented by binary codes, and reconverted to analog for transmission and reception.
The document discusses several methods for demodulating frequency modulated (FM) signals in radio receivers, including slope detectors, balanced slope detectors, Foster-Seeley discriminators, ratio detectors, and phase-locked loops (PLLs). Slope detectors and balanced slope detectors convert FM signals to amplitude modulation (AM) using a tuned circuit before detecting the signal. Foster-Seeley discriminators and ratio detectors provide a more linear demodulation of FM signals compared to slope detectors. PLL FM demodulators do not require tuned circuits and can automatically compensate for carrier frequency instability. The output of these various FM demodulator circuits provides a signal proportional to the frequency deviation of the input FM signal.
This talk will give an overview of the current phased array radar systems and its requirements for weather observations, performance in sensitivity, antenna design requirement for dual-polarized weather radars.
10.7mW, 2.1 sq mm, 0.13um CMOS GPS radioDavid Tester
This document summarizes a fully integrated GPS radio realized in a 0.13μm CMOS technology. The radio achieves the lowest reported power consumption of 10.7mW and smallest die area of 2.1mm2. Key features include an LNA, mixer, frequency synthesizer, configurable filters, gain stages, and ADC. It operates at 1.5GHz and provides 84dB of gain. The radio represents the current state-of-the-art for low power, small area GPS receivers suitable for consumer electronics applications such as cameras and phones.
BASK Generator using analog switch
BFSK Generator using analog switch
BPSK Generator using analog switch
MATLAB EXPERIMENTS
4.Mean square estimation of signals
5. BASK
6. BFSK
7. BPSK
MICROWAVE EXPERIMENTS
8.Klystron characteristics
9.Frequency and wavelength measurement
10.VSWR measurement
This document discusses the history and types of radio receivers. It describes how the earliest radio receiver was created in 1896 by Alexander Popov and was based on Maxwell's discovery of electromagnetic waves. There are three main types of receivers discussed - crystal radios, tuned radio frequency receivers, and superheterodyne receivers. Crystal radios require no power source beyond the radio waves themselves, while tuned radio frequency receivers have individually tuned amplifier stages and superheterodyne receivers mix signals to extract an intermediate frequency. The document also covers frequency ranges, sensitivity, selectivity and how radio waves propagate.
The document discusses beamforming antennas and their applications. It begins by outlining beamforming concepts and configurations like phased arrays and adaptive arrays. It then discusses applications of beamforming antennas in areas like radar, sonar, communications and imaging. Specific examples covered include phased array radar, neuronal spike sorting, and smart antenna systems for wireless networks. Vector antennas and their advantages over phased arrays are also summarized. Finally, the document discusses potential uses and challenges of beamforming antennas for wireless ad hoc networks.
IF and baseband repeaters are used in microwave radio systems to amplify and regenerate signals. IF repeaters down-convert signals to an intermediate frequency, amplify and reshape the signal, then up-convert it back to radio frequency. Baseband repeaters further demodulate signals to baseband before modulating onto a carrier frequency. Diversity techniques like frequency, space, polarization and hybrid diversity are used to increase reliability by providing redundant transmission paths. Key components of microwave radio systems include the transmitter, receiver, antennas, and repeaters used to establish line-of-sight links over long distances.
The document summarizes key components and concepts in AM radio receivers. It discusses AM demodulators like envelope detectors and product detectors. It then covers different receiver types like tuned radio frequency (TRF) receivers and superheterodyne receivers. For superheterodyne receivers, it describes the RF stage, mixer, local oscillator, intermediate frequency (IF) amplifier, detector, and audio frequency (AF) stage. It also defines important receiver parameters like selectivity, sensitivity, bandwidth improvement factor, and dynamic range.
Tech Vidhya is the premier IT and Telecom training institute of India that is running its quality training courses since last decade and we deliver what we promise. Tech Vidhya is the leading training institute in telecom and IT sector that offers various Telecom, telecommunication, Networking and IT/Software courses in an efficient and friendly manner. We are having the highly qualified and experienced trainers for all the courses. The trainers are updated with the latest technologies and they are working on various live projects on India’s top telecom/IT companies.
1. TRF receivers had all RF stages simultaneously tuned to the received frequency before detection. This made tracking between stages difficult and resulted in wider bandwidths at higher frequencies.
2. Superheterodyne receivers mix the received signal with a local oscillator signal to produce an intermediate frequency (IF) signal, which is then amplified. This allows easier tracking between stages and keeps the bandwidth constant regardless of frequency.
3. Integrating entire radio receivers onto a single chip is limited by the bandwidth of electronic components, which is narrower than that of optical components. All-optical networks using technologies like optical pulse generation and modulation could enable much higher speed networks.
This document summarizes the evolution of low-cost construction using surplus satellite TV LNBs (low noise block downconverters). It begins with an introduction to the author's history with analog satellite TV and fascination with stripping down LNBs. It then provides a detailed overview of the technology and design of early single-output Ku-band LNBs from the 1990s, followed by early dual-output and current single-output extended band LNB designs. The document concludes by listing 10 potential reuses for spare or unwanted LNBs, such as using their GaAsFETs and MMICs for microwave circuits, or converting them for use as antennas, amplifiers, or frequency converters.
This document contains questions and answers related to television fundamentals. It covers topics like the functions of camera tubes, aspect ratio, luminance, illuminance, characteristics of the human eye, necessity of scanning in television systems, flicker, interlaced scanning, vertical and horizontal resolutions, composite video signals, pedestals, blanking pulses, and more. The document is divided into multiple units covering topics such as monochrome and color camera tubes, transmission and reception, color television systems, and more.
Improvement of Phase Noise Compensation for Coherent OpticalOFDM via Data Ai...Raj Kumar Parihar
This document discusses using a data-aided phase equalizer (DAPE) to improve phase noise compensation in coherent optical orthogonal frequency-division multiplexing (OFDM) systems. DAPE utilizes both pilot symbols and receiver decisions to estimate channel factors and phase noise on a symbol-by-symbol basis. Simulation results show DAPE achieves a bit error rate of 10^-3 with 1-2.2 dB less required RF-pilot power compared to using RF pilots alone after 2000km fiber transmission at 40Gb/s. DAPE provides more accurate phase noise estimation, particularly for noisier scenarios, by averaging estimates across subcarriers.
The document discusses various types of signal analyzers including cathode ray oscilloscopes, wave analyzers, harmonic distortion analyzers, and spectrum analyzers. It provides details on the working principles, components, and applications of general purpose cathode ray oscilloscopes, dual beam oscilloscopes, sampling oscilloscopes, analog and digital storage oscilloscopes, frequency selective and heterodyne wave analyzers, and fundamental-suppression and heterodyne harmonic distortion analyzers.
This document summarizes a seminar presentation on distributed amplifiers. It begins with an introduction describing how distributed amplifiers were first introduced to overcome bandwidth limitations of vacuum tube amplifiers by using parasitic capacitances and inductors to form transmission lines. It then provides the basic design circuit of a distributed amplifier consisting of input and output transmission lines coupled by transistors. Next, it explains the operating principle where signals traveling on the gate and drain lines add in the forward direction. It also includes analysis of the gate and drain line transmission models and how to calculate the optimum number of stages to cascade for maximum power gain before the input signal decays exponentially.
This document discusses demodulation, or detection, which is the process of recovering the audio frequency (AF) signal from a modulated radio frequency (RF) carrier wave. It describes the basic operations involved in demodulating an amplitude modulated (AM) wave and a frequency modulated (FM) wave. Specifically for AM detection, it explains the essential process of rectification using a diode detector circuit to recover the AF signal envelope. For FM detection, it discusses converting frequency variations in the FM signal into voltage changes using a quadrature detector circuit.
A wave analyzer is an instrument designed to measure relative amplitudes of single frequency components in a complex waveform. Basically, a wave instrument acts as a frequency selective voltmeter which is tuned to the frequency of one signal while rejecting all other signal components.
Mobile Communication Academic Assignment
For B.Tech Electronics and Communication Engineering 7th Semester
Index:
1. Introduction
2. Techniques
3. Schemes
4. History
5. Digital an Analog Beamforming
6. Difference between Digital and Analog Beamforming
7. Analog Beamforming Working
8. Digital Beamforming Working with receiver and transmitter
9. Digital Beamforming Challenges with receiver and transmitter
10. Solutions to the Challenges
11. For Speech Audio
Source: Wikipedia, Research Papers etc
To meet the demands of high speed required by mobile communication of past generations ,one solution is to increase the number of antennas to the show and the reception of the wireless link this is called MIMO (Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same PCB is delicate because of the small volume that require some applications and electromagnetic antenna between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance frequency folling each with 20MHz offset this device is characterized by its original form that keeps is highly isolated antennas from the point of view electromagnetic coupling
This document provides an overview of installing and setting up an IPSTAR user terminal. It discusses the components of the user terminal including the antenna, low noise block downconverter (LNB), block upconverter (BUC), feed assembly, orthogonal mode transducer (OMT), and transmit reject filter (TRF). It also covers topics like polarization, antenna patterns, the effects of mispointing an antenna, and checking for sun outage times. The proper assembly and setup of each component is important to ensure optimal performance and avoid interference issues.
Introduction To Antenna Impedance Tuner And Aperture Switchcriterion123
This document discusses antenna tuning techniques for mobile devices. It describes two main antenna tuning methods: impedance tuning and aperture tuning. Impedance tuning optimizes power transfer between the RF front-end and antenna by adding a tunable matching network. Aperture tuning modifies the antenna structure and performance by integrating a switch to change the antenna's electrical length and resonance. The document provides examples of antenna tuners that use these techniques and discusses design considerations like losses to maximize performance.
The document describes experiments on digital communication lab including:
1. Pulse amplitude modulation and time division multiplexing where amplitude of pulses is varied according to modulating signal and samples from different signals are combined in time domain and transmitted over a common channel.
2. Pulse time modulation and demodulation (PWM and PPM) where pulse width or repetitive frequency is varied according to information signal to save transmitter power.
3. Analog to digital and digital to analog conversion where analog signals are sampled, quantized into discrete levels represented by binary codes, and reconverted to analog for transmission and reception.
The document discusses several methods for demodulating frequency modulated (FM) signals in radio receivers, including slope detectors, balanced slope detectors, Foster-Seeley discriminators, ratio detectors, and phase-locked loops (PLLs). Slope detectors and balanced slope detectors convert FM signals to amplitude modulation (AM) using a tuned circuit before detecting the signal. Foster-Seeley discriminators and ratio detectors provide a more linear demodulation of FM signals compared to slope detectors. PLL FM demodulators do not require tuned circuits and can automatically compensate for carrier frequency instability. The output of these various FM demodulator circuits provides a signal proportional to the frequency deviation of the input FM signal.
This talk will give an overview of the current phased array radar systems and its requirements for weather observations, performance in sensitivity, antenna design requirement for dual-polarized weather radars.
10.7mW, 2.1 sq mm, 0.13um CMOS GPS radioDavid Tester
This document summarizes a fully integrated GPS radio realized in a 0.13μm CMOS technology. The radio achieves the lowest reported power consumption of 10.7mW and smallest die area of 2.1mm2. Key features include an LNA, mixer, frequency synthesizer, configurable filters, gain stages, and ADC. It operates at 1.5GHz and provides 84dB of gain. The radio represents the current state-of-the-art for low power, small area GPS receivers suitable for consumer electronics applications such as cameras and phones.
BASK Generator using analog switch
BFSK Generator using analog switch
BPSK Generator using analog switch
MATLAB EXPERIMENTS
4.Mean square estimation of signals
5. BASK
6. BFSK
7. BPSK
MICROWAVE EXPERIMENTS
8.Klystron characteristics
9.Frequency and wavelength measurement
10.VSWR measurement
This document discusses the history and types of radio receivers. It describes how the earliest radio receiver was created in 1896 by Alexander Popov and was based on Maxwell's discovery of electromagnetic waves. There are three main types of receivers discussed - crystal radios, tuned radio frequency receivers, and superheterodyne receivers. Crystal radios require no power source beyond the radio waves themselves, while tuned radio frequency receivers have individually tuned amplifier stages and superheterodyne receivers mix signals to extract an intermediate frequency. The document also covers frequency ranges, sensitivity, selectivity and how radio waves propagate.
The document discusses beamforming antennas and their applications. It begins by outlining beamforming concepts and configurations like phased arrays and adaptive arrays. It then discusses applications of beamforming antennas in areas like radar, sonar, communications and imaging. Specific examples covered include phased array radar, neuronal spike sorting, and smart antenna systems for wireless networks. Vector antennas and their advantages over phased arrays are also summarized. Finally, the document discusses potential uses and challenges of beamforming antennas for wireless ad hoc networks.
IF and baseband repeaters are used in microwave radio systems to amplify and regenerate signals. IF repeaters down-convert signals to an intermediate frequency, amplify and reshape the signal, then up-convert it back to radio frequency. Baseband repeaters further demodulate signals to baseband before modulating onto a carrier frequency. Diversity techniques like frequency, space, polarization and hybrid diversity are used to increase reliability by providing redundant transmission paths. Key components of microwave radio systems include the transmitter, receiver, antennas, and repeaters used to establish line-of-sight links over long distances.
The document summarizes key components and concepts in AM radio receivers. It discusses AM demodulators like envelope detectors and product detectors. It then covers different receiver types like tuned radio frequency (TRF) receivers and superheterodyne receivers. For superheterodyne receivers, it describes the RF stage, mixer, local oscillator, intermediate frequency (IF) amplifier, detector, and audio frequency (AF) stage. It also defines important receiver parameters like selectivity, sensitivity, bandwidth improvement factor, and dynamic range.
Tech Vidhya is the premier IT and Telecom training institute of India that is running its quality training courses since last decade and we deliver what we promise. Tech Vidhya is the leading training institute in telecom and IT sector that offers various Telecom, telecommunication, Networking and IT/Software courses in an efficient and friendly manner. We are having the highly qualified and experienced trainers for all the courses. The trainers are updated with the latest technologies and they are working on various live projects on India’s top telecom/IT companies.
1. TRF receivers had all RF stages simultaneously tuned to the received frequency before detection. This made tracking between stages difficult and resulted in wider bandwidths at higher frequencies.
2. Superheterodyne receivers mix the received signal with a local oscillator signal to produce an intermediate frequency (IF) signal, which is then amplified. This allows easier tracking between stages and keeps the bandwidth constant regardless of frequency.
3. Integrating entire radio receivers onto a single chip is limited by the bandwidth of electronic components, which is narrower than that of optical components. All-optical networks using technologies like optical pulse generation and modulation could enable much higher speed networks.
This document summarizes the evolution of low-cost construction using surplus satellite TV LNBs (low noise block downconverters). It begins with an introduction to the author's history with analog satellite TV and fascination with stripping down LNBs. It then provides a detailed overview of the technology and design of early single-output Ku-band LNBs from the 1990s, followed by early dual-output and current single-output extended band LNB designs. The document concludes by listing 10 potential reuses for spare or unwanted LNBs, such as using their GaAsFETs and MMICs for microwave circuits, or converting them for use as antennas, amplifiers, or frequency converters.
This document contains questions and answers related to television fundamentals. It covers topics like the functions of camera tubes, aspect ratio, luminance, illuminance, characteristics of the human eye, necessity of scanning in television systems, flicker, interlaced scanning, vertical and horizontal resolutions, composite video signals, pedestals, blanking pulses, and more. The document is divided into multiple units covering topics such as monochrome and color camera tubes, transmission and reception, color television systems, and more.
Improvement of Phase Noise Compensation for Coherent OpticalOFDM via Data Ai...Raj Kumar Parihar
This document discusses using a data-aided phase equalizer (DAPE) to improve phase noise compensation in coherent optical orthogonal frequency-division multiplexing (OFDM) systems. DAPE utilizes both pilot symbols and receiver decisions to estimate channel factors and phase noise on a symbol-by-symbol basis. Simulation results show DAPE achieves a bit error rate of 10^-3 with 1-2.2 dB less required RF-pilot power compared to using RF pilots alone after 2000km fiber transmission at 40Gb/s. DAPE provides more accurate phase noise estimation, particularly for noisier scenarios, by averaging estimates across subcarriers.
The document discusses various types of signal analyzers including cathode ray oscilloscopes, wave analyzers, harmonic distortion analyzers, and spectrum analyzers. It provides details on the working principles, components, and applications of general purpose cathode ray oscilloscopes, dual beam oscilloscopes, sampling oscilloscopes, analog and digital storage oscilloscopes, frequency selective and heterodyne wave analyzers, and fundamental-suppression and heterodyne harmonic distortion analyzers.
This document summarizes a seminar presentation on distributed amplifiers. It begins with an introduction describing how distributed amplifiers were first introduced to overcome bandwidth limitations of vacuum tube amplifiers by using parasitic capacitances and inductors to form transmission lines. It then provides the basic design circuit of a distributed amplifier consisting of input and output transmission lines coupled by transistors. Next, it explains the operating principle where signals traveling on the gate and drain lines add in the forward direction. It also includes analysis of the gate and drain line transmission models and how to calculate the optimum number of stages to cascade for maximum power gain before the input signal decays exponentially.
This document discusses demodulation, or detection, which is the process of recovering the audio frequency (AF) signal from a modulated radio frequency (RF) carrier wave. It describes the basic operations involved in demodulating an amplitude modulated (AM) wave and a frequency modulated (FM) wave. Specifically for AM detection, it explains the essential process of rectification using a diode detector circuit to recover the AF signal envelope. For FM detection, it discusses converting frequency variations in the FM signal into voltage changes using a quadrature detector circuit.
A wave analyzer is an instrument designed to measure relative amplitudes of single frequency components in a complex waveform. Basically, a wave instrument acts as a frequency selective voltmeter which is tuned to the frequency of one signal while rejecting all other signal components.
Mobile Communication Academic Assignment
For B.Tech Electronics and Communication Engineering 7th Semester
Index:
1. Introduction
2. Techniques
3. Schemes
4. History
5. Digital an Analog Beamforming
6. Difference between Digital and Analog Beamforming
7. Analog Beamforming Working
8. Digital Beamforming Working with receiver and transmitter
9. Digital Beamforming Challenges with receiver and transmitter
10. Solutions to the Challenges
11. For Speech Audio
Source: Wikipedia, Research Papers etc
To meet the demands of high speed required by mobile communication of past generations ,one solution is to increase the number of antennas to the show and the reception of the wireless link this is called MIMO (Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same PCB is delicate because of the small volume that require some applications and electromagnetic antenna between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance frequency folling each with 20MHz offset this device is characterized by its original form that keeps is highly isolated antennas from the point of view electromagnetic coupling
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
STUDY OF ARRAY BI-CONICAL ANTENNA FOR DME APPLICATIONSijwmn
This document summarizes the study of a linear array bi-conical antenna designed for Distance Measuring Equipment (DME) applications. The antenna consists of multiple bi-conical elements arranged in a linear configuration. Simulation results show that increasing the number of elements from 1 to 10 increases the maximum gain from 2 dB to 10.2 dB. This high gain linear array bi-conical antenna design is suitable for use in terrestrial DME ground stations due to its large size. The antenna operates within the DME frequency band of 960-1215 MHz.
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- Machine learning can optimize 5G across all layers to dynamically improve spectrum efficiency based on conditions.
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1) How the USRP N200/N210 support plug-and-play 2x2 MIMO systems using a shared reference cable.
2) External references can be used to synchronize larger MIMO arrays, though additional equipment is required.
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Orthogonal frequency-division multiplexing (OFDM) is a digital multi-carrier modulation technique that partitions the available bandwidth into multiple orthogonal subcarriers. Each subcarrier is modulated with a conventional modulation scheme at a low symbol rate, maintaining high data rates over the entire bandwidth. OFDM has advantages over single-carrier schemes in coping with severe channel conditions without complex equalization filters. It is used widely in digital television and audio broadcasting, wireless networks including WiFi, and mobile phone networks including 4G LTE.
Multichannel Speech Signal Separation by Beam forming TechniquesIRJET Journal
This document discusses techniques for separating speech signals from noise using a multichannel microphone array. It compares two beamforming techniques: time-delay beamforming and Frost beamforming. Time-delay beamforming is a data-independent technique that applies time delays to microphone signals to enhance signals from a particular direction. Frost beamforming is an adaptive technique that aims to minimize noise energy by adjusting filter weights using an algorithm like least mean squares. The document presents a methodology for simulating speech and noise collection with a microphone array in MATLAB and applying the two beamforming techniques to extract the speech signal from the noise for applications like hearing aid development. It finds that Frost beamforming performs better than time-delay beamforming at producing a clearer speech signal
Orthogonal frequency-division multiplexing (OFDM)
[1] is a method of encoding digital data on multiple carrier
frequencies. OFDM[1] has developed into a popular scheme
for wideband digital communication, whether wireless or
over copper wires, used in applications such as digital television
and audio broadcasting, DSL Internet access, wireless networks,
powerline networks, and 4G mobile communications. In the
Several wireless standards such as IEEE 802.11a[2] and
HiperLAN2[3].The orthogonality of the subcarriers is no longer
maintained which results in ICI (Inter carrier Interference)[4]
.ICI reduction techniques achieve a better SNR and BER in
OFDM at zero phase noise variance . This technique will use a
large number of closely spaced orthogonal subcarriers to avoid
phase noise. It provides high data rates with sufficient robustness
to radio channel damages. A major problem in OFDM is carrier
frequency offset error between the transmitted and received
signals. Due to this the orthogonality of the subcarriers is no
longer maintained which results in ICI (Inter carrier
Interference). In this paper, we used the ICI self-cancellation
technique and reduced the ICI and improved the BER and SNR
we are also calculate the SNR=15db and 20db at different phase
noise variance.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This presentation demonstrate:
- Different RF receiver architectures.
- Basics of Multi-Standard receivers.
- How to select receiver's specifications from the selected standard.
- Subsampling basics.
MIMO-OFDM (Multi Input Multi Output- Orthogonal Frequency Division Multiplexing) system is very popular technique for mobile communication. We found that Ergodic channel capacity has some limitation in MIMO-OFDM system. So Ergodic channel capacity optimization is necessary to improve the performance of MIMO-OFDM System.
The document discusses simulation and testing of antennas for 4G LTE-MIMO systems. It describes simulating a PIFA antenna in CST Studio Suite to compare matched and unmatched cases. Results showed improved return loss and far-field patterns when the antenna was matched. Testing of a MIMO antenna system involved measuring isolation between antennas and comparing performance with the enclosure open versus closed.
This document summarizes research on performance analysis of adaptive multi-user OFDM systems. It describes using adaptive modulation to maximize throughput by selecting modulation schemes on a per-subcarrier basis to maintain bit error rate while maximizing spectral efficiency. Adaptive user allocation is also analyzed to improve signal power by optimizing user-subcarrier combinations based on frequency selective fading differences between users. Simulation results show adaptive modulation providing 12-16dB SNR improvement over fixed modulation. Adaptive user allocation provides an additional 3-5dB average signal power gain. The document concludes these adaptive techniques allow OFDM systems to approach channel capacity limits given constraints of the radio channel, transmitter power and quality of service requirements.
This document discusses coherent optical orthogonal frequency division multiplexing (CO-OFDM) for visible light communications. It begins with an introduction describing increasing bandwidth demand and the benefits of CO-OFDM. It then explains the basic principles of coherent optical transmission and CO-OFDM. The document proceeds to describe simulations conducted using OptiSystem software to model a 4-QAM CO-OFDM system over varying transmission distances. The results show degradation of the signal constellation and optical signal-to-noise ratio as distance increases due to attenuation and chromatic dispersion. Finally, the document concludes with a review of the CO-OFDM fundamentals and simulation results.
Similar to WaveArt Tutorial on FM Synchronized Emissions (Isofrequency - Isomodulation - SFN) (20)
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Power Grid Model
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👉 Check out our full 'Africa Series - Automation Student Developers (EN)' page to register for the full program:
https://bit.ly/Automation_Student_Kickstart
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💻 Extra training through UiPath Academy:
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UiPath Business Automation Platform
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2. 2
Benefits of synchronized FM emissions
Using Synchronized FM transmitters operating on the same frequency («FM Isofrequency» - «FM
Isomodulation» - «FM SFN») it is possible to extend the coverage area of a main transmitter to
neighboring areas, with some limitations and precautions.
The advantages offered by this technology are considerable:
The need for significantly lower protection ratios than non-synchronized emissions (up to
be able to accept, under certain conditions, differences in level of less than 1dB!)
More efficient use of the electromagnetic spectrum having the ability to cover poorly served
areas at the limits of a main service area without having to use a different frequency, thus
optimizing the use of the frequencies themselves (Gap-Filler)
An additional powerful tool for planning and optimizing FM broadcast networks
3. 3
The protection ratio normally required
The ITU-R BS.412-9 recommendation, for the
purpose of FM service planning, defines the
necessary protection ratios between two different
frequency modulation signals and/or not synchronized
with each other, according to:
Frequency difference
Emission mode (mono or stereo)
Continuity of the interference (tropospheric or
steady)
You can see that, in case of steady interference and
same frequency (channel), the minimum protection
ratio required is 36dB for monophonic broadcasting
and 45dB for stereophonic broadcasting.
4. 4
Qualitative Levels of an Audio Signal
The ITU-R BS.562-3 recommendation, in order to define the acceptability of the quality level of
an audio signal, classifies the degradation (Impairment) with a 5-level scale: from the best (5) to
the worst (1).
Normally, in addition to level 5 (a perfect signal), level 4 is accepted (defined as «good» because
the impairment is described as «perceptible, but not annoying») and, at least, level 3 is
accepted, for example, for reception in cars (defined as «fair» because the impairment is only
«slightly annoying»).
5. 5
Protection ratios in Isofrequency
The ITU-R BS.412-9
recommendation defines the
necessary protection ratios
between two Isofrequency
and Isomodulation signals
as a function of the delay to
reach the receiving point
(path difference), the
emission mode (mono or
stereo) and the quality level
(degradation – Impairment
grade).
The ITU-R BS.412-9 recommendation specifies that the indicated
values are the worst detected during the tests.
6. 6
Protection ratios in Isofrequency
With reference to the data obtained from the
ITU-R BS.412-9 recommendation and as can
be deduced from the graph on the side,
Isofrequency and Isomodulation signals with
path difference (delay) of 4Km (13.2µs), need a
protection ratio of approximately 25 dB instead
of the 45dB normally required between
unsynchronized stereo signals.
Of course, with lower delays (path differences),
the protection ratio is further reduced, as seen
in the table on the previous slide.
7. 7
Protection ratios in Isofrequency
The ITU-R BS.412-9 Recommendation dates back to 1998. The tests were conducted in the previous
years using an "Analog“ implementation of the Isofrequency/Isomodulation emissions and with the FM
receivers available on the market at that time.
Protection ratios
[dB]
Time delay
[µs]
Monophonic mode Stereophonic mode
Impairment grade Impairment grade
3 4 3 4
2
5
10
20
40
80
160
N.C.
N.C.
0*
1
3
6
7
N.C.
0*
1
3
6
10
11
N.C.
0*
<1
1
3
6
10
0*
<1
1
3
6
10
13
0*: Read explanation in the next slide
The tests of the new WaveArt-ABE implementation
have been conducted in a similar way to those of the
ITU-R BS.412-9 Recommendation, but with “Digital"
Isofrequency/Isomodulation transmitters and with
current FM receivers: results were considerably
better than those reported in ITU Recommendation
(see table on the side).
The tests were conducted with receivers equipped
with stereo blend (as in almost all car radios) and with
a frequency difference between the transmitters of
0.13Hz (phase rotation between the signals of 360° in
about 7 seconds), in order to also evaluate the
disturbances due to phase difference.
8. 8
Protection ratios in Isofrequency
In the table of the previous slide, for some combinations of delay/impairment grade, a value of «0dB»
difference between the two signals in Isofrequency/Isomodulation has been assigned.
It is also specified that the tests were conducted with a frequency difference between the transmitters
equal to 0.13Hz, so to obtain a slow phase rotation (360° in about 7 seconds).
Obviously, when the two signals are perfectly identical (also in amplitude – 0dB), and they are perfectly
in phase opposition (difference of 180°), they cancel out each other causing a noise at the output of the
receiver, clearly audible, that would not allow the assignment of an impairment grade equal to 3 or 4.
However, even a minimal difference in level between the signals is sufficient to avoid such disturbance.
In practical field tests, this condition hardly ever occurs, since the receiving antenna, in addition to the
signals coming directly from the two transmitters in Isofrequency/Isomodulation (if they are in optical line
of sight) also receives a large quantity of replicas of the same signal (reflections of buildings, vehicles,
etc.), each one independently delayed and attenuated respect to the others. The sum of all these
signals is, in practice, impossible to be equal to zero (signal cancellation). See, for reference, the Rician
and Rayleigh distribution models.
For this reason, it was decided to define «0dB» the condition described above.
9. 9
As better specified in the previous slides, the results reported in the Racomandation ITU-R BS.412-9
(1998) with «analog» Isofrequency implementation and with transmission and reception technologies
available at the time are enormously different from the results obtained in the current tests by
adopting the WaveArt-ABE solution with the «digital» implementation described in this tutorial.
Comparison between different implementations
Protection ratios [Analog - ITU-R BS.412-9]
[dB]
Time delay
[µs]
Monophonic mode Stereophonic mode
Impairment grade Impairment grade
3 4 3 4
2
5
10
20
40
80
160
<1
1
1
N.A.
N.A.
N.A.
N.A.
1
2
3
11
20
N.A.
N.A.
4
10
14
N.A.
N.A.
N.A.
N.A.
6
12
16
N.A.
N.A.
N.A.
N.A.
N.A. = Not Available (Non Disponibile)
Protection ratios [Digital - WaveArt-ABE]
[dB]
Time delay
[µs]
Monophonic mode Stereophonic mode
Impairment grade Impairment grade
3 4 3 4
2
5
10
20
40
80
160
N.C.
N.C.
0*
1
3
6
7
N.C.
0*
1
3
6
10
11
N.C.
0*
<1
1
3
6
10
0*
<1
1
3
6
10
13
N.C. = Not Considered (Non Considerato)
10. 10
The requirements of Synchronized FM emissions
This point must be absolutely clear, as there are many partial implementations that, obviously,
do not give the desired results.
Synchronized FM emissions must meet ALL of the following requirements:
The transmitters must emit on the same channel and have precisely the same frequency (for
example, with GPS locked reference oscillators).
They must transmit the same IDENTICAL modulation content, meaning not only the
transmission of the same program, but the exact same modulation «footprint» (same
modulation peaks with same precise deviation to the Hz, in the same moment, etc.).
This result is practically impossible to obtain with two different analog modulators or, in any
case, with two FM modulators - even with digital processing - but fed by analog signals.
They must have a delay compensation to simultaneously deliver the signals emitted into the
double serviced area (the potentially interfered area) in order to benefit from this technology.
11. 11
A simple method to verify Isofrequency
By analyzing the spectrum of two transmitters with the summed RF output, one can easily verify
whether the emissions have been correctly generated in Isofrequency/Isomodulation.
It is sufficient to modulate the carriers with a mono audio tone (e.g.: 500Hz) and, depending on the
difference in delay and level of the two RF modulated signals, "holes“ (notches) can be observed in
the spectrum. Distance and depth of the notches are a function of the differences of delay and
amplitude (greater difference of delay generates closer notches, while the smaller the difference in
amplitude, the deeper the notches are).
SPECTRUM OF
A SINGLE
TRANSMITTER SPECTRUM OF TWO
TRANSMITTERS
WITH 10μs DELAY
(1/10μs = 100kHz)
SPECTRUM OF TWO
TRANSMITTERS
WITH 20μs DELAY
(1/20μs = 50kHz)
12. 12
«Analog» FM Isofrequency
To benefit from all the advantages previously described it is necessary
that the implementation meets all the necessary requirements.
The implementation can be done in «analog» mode (see the ABE
Elettronica patent filed in 1989) using microwave links that
transfer a FM modulated subcarrier, that is converted to the
emission frequency (87.5 - 108MHz) with an oscillator
synchronized by another signal transferred by the same
microwave links. In this case, the delay compensation takes place
with analog delay lines acting on the FM modulated subcarrier.
The main drawbacks of this system are the high bandwidth
occupation of the microwave links (over 10MHz) and the cost of
analog delay lines.
Another even more expensive "analog" implementation made by
RAI is based on the use of optical fiber for the transfer of the
modulated FM carrier.
13. 13
“Digital" FM Isofrequency made by WaveArt-ABE
Nowadays the use of "digital" techniques allows implementations of synchronized FM
emissions that are much more efficient than those made in the past with "analog" technologies.
The implementation developed by WaveArt with ABE Elettronica is based on the following technologies:
The generation of a digital MPX signal (mono or stereo + RDS) whose data flow (about 2Mbit/s) is
encapsulated in a Transport Stream MPEG with ASI interface or other.
The insertion in the Transport Stream of a «Time Stamp» for the synchronization of the emissions.
The insertion in the
Transport Stream of a
time offset data (Network
delay) to take into
account the latency with
which the digital MPX
data flow reaches all
transmitters in the
Isofrequency network.
14. 14
The transfer, through digital microwave links (terrestrial or satellite), of the MPX data stream
(Transport Stream) to the FM transmitters in the Isofrequency/Isomodulation network.
“Digital" FM Isofrequency made by WaveArt-ABE
15. 15
The use, in all transmitters, of an adjustable digital memory (FIFO) to synchronize the digital MPX
received with the «Time Stamp» contained in the Transport Stream, to compensate the Network
Delay and the delay with which the emissions reach the potentially interfered area.
The modulation (digitally carried out in all transmitters) of the carrier at the emission frequency
(87,5 – 108 MHz).
The synchronization of all the system (MPX data, Time Stamp, FM emission carriers) to the same
reference (UTC second received through GPS/GLONASS - using proprietary algorithms).
NOTE
ABE Elettronica has filed an
international patent application for the
Isofrequency/Isomodulation system
described in this presentation
“Digital" FM Isofrequency made by WaveArt-ABE
16. 16
The best implementation of the Isofrequency
In this implementation example, the
synchronized Gap Filler covering the
«City 2» at the edge of the coverage
area of the main Transmitter, has a
directive antenna radiating the signal
in the same direction as that coming
from the main Transmitter.
In this way, in the dual-serviced area
a sufficiently constant delay between
the two emissions is maintained,
allowing to benefit from the
advantages of the FM Synchronized
emissions (significantly lower
protection ratios).
17. 17
With reference to the previous slide, the
delay differences of the signals coming from
the main Transmitter and the Gap Filler
arriving in the «City 2» (in particular at its
edges, where the difference of delay is
greater), are between 0 and 1.9μs.
This means that, to have an «Impairment
Grade» equal to 4 (signal defined as “good”
with “perceptible but not disturbing
degradation”), it is not necessary to have
any level difference between the two
signals, based on test results of the new
WaveArt-ABE implementation.
This is the best possible implementation of
Isofrequency system.
The best implementation of the Isofrequency
18. 18
With reference to the previous slide, it is
advisable that the front/back ratio of the
Gap Filler’s directive antenna is high, in
order to reduce interference towards the
main transmitter.
A method to obtain this result is to use two
directive antennas, oriented in the same
direction and placed one below the other at
about 0.9 λ.
The upper antenna must be advanced λ/4
(about 75 cm) with respect to the other and
have the connection cable to the antenna
divider at -90° offset (-λ / 4) with respect to
the other cable.
In this way, the front/back ratio of the
system with two antennas improves of
about 20dB.
GAP-FILLER’S
DIRECTIVE
ANTENNA
2 ANTENNAS IN PHASE
2 ANTENNAS WITH
λ/4 PHASE DIFFERENCE
The best implementation of the Isofrequency
19. 19
A possible implementation of Isofrequency
In this example of implementation, the delays
with which the signals of the two synchronized
transmitters arrive in the area of potential
interference (in particular at the margins of the
same, where the difference of delay is greater
and that we have assumed to be 6km as in the
previous example), are between 0 and 10µs.
This means that, to have an «Impairment
Grade» equal to 4 (signal defined as “good”
with “perceptible but not disturbing
degradation”), it is necessary to have a level
difference between the two signals of only
1dB, based on test results of the new WaveArt-
ABE implementation.
This is only possible with well-calculated and
structured antennas.
20. 20
In this example of implementation, with transmitters in
opposite directions, the delays with which the signals of the
two synchronized transmitters arrive in the central
interference zone (in particular on the margins of the same,
where the difference of delay is greater and that we have
assumed to be always 6km as in the previous example), are
between 0 and 20µs.
This means that, to have an «Impairment Grade» equal to 4
(signal defined as “good” with “perceptible but not disturbing
degradation”), it is necessary to have a level difference
between the two signals of 3dB, based on test results of
the new WaveArt-ABE implementation.
This is possible, despite some difficulties, only with well-
calculated and structured antennas.
This implementation of Isofrequency is the most difficult to
achieve.
A more complex implementation
21. 21
Further benefits of WaveArt-ABE Isofrequency
Currently, most backhauling systems (signal transfer from radio studios to transmitting sites) use
analog MPX microwave links in the 900MHz or 2GHz band, with all the related problems (frequency
overcrowding, noise, degradation of the C/N ratio and stereo separation, etc.).
Even those who use the satellite for backhauling still find the degradation due to compression and
decompression of the audio channels, to overshoots (again due to compression/decompression,
which cause unwanted peaks of modulation often “out of mask"), etc.
The solution for backhauling developed by WaveArt-ABE, in addition to making possible the
implementation of Isofrequency, solves all the problems mentioned above, as it digitally transfers (at
high resolution – 16bit) the uncompressed MPX signal through digital terrestrial (or satellite) links that
require a C/N of only 6 or 7 dB (standard implementation) to have an error-free reception (perfect
quality, very high signal-to-noise ratio, no degradation in repetitions, etc.).
These links are available on different frequency bands and may have a channel bandwidth even
below 1MHz (the standard channel bandwidth required is 1.75MHz).
The consistent quality improvement with the digital transfer of the MPX signal
22. 22
The system developed by WaveArt-ABE provides for the insertion, in the data stream of the digitalized
MPX (Transport Stream), of a time stamp referred to the UTC second (by means of
reception/synchronization with GNSS - GPS/GLONASS carried out with proprietary algorithms) to
facilitate synchronization of the transmitters in the Isofrequency network and, in case of use of a
satellite connection for the backhauling, to make it possible. In addition, it is inserted a «time offset»
data to allow the flow of the MPX data to reach all the transmitters in the Isofrequency/Isomodulation
network and to be processed thus allowing the correct emission timing and therefore, the consistency
of synchronized emissions.
The use of the «Time Stamp» and the «Network Delay» data allow the adjustment of the latencies
necessary for the correct implementation of the Isofrequency only to the delays between the
transmitters and the potentially interfered area, automatically absorbing the latencies and any
instability due to the backhauling (signals transfer by means of links or other).
Systems that do not have a similar mechanism for synchronization make it quite difficult (nearly
impossible) the synchronization itself and to keep it constantly.
The insertion of the «Time Stamp» and the «Network Delay» data in the MPX
Further benefits of WaveArt-ABE Isofrequency
23. 23
The so-called "geostationary" communication satellites orbit over the Equator at about 36,000km from
the Earth's surface. Their angular speed is equal to the one of the terrestrial rotation, so they have the
effect of being "stationary" with respect to the earth's surface.
Actually, in spite of the term "geostationary", satellites are not really "stationary" but, because of the
"solar wind" and other, they move very slowly and are, from time to time, re-positioned by means of on-
board small rockets. Satellites typically move within an imaginary cube having about 50 kilometers of
side. This means that the overall path of the RF signal from Earth to Satellite and vice-versa can vary
even of 100Km (equivalent over time to more than 300μs), depending on where the satellite is located.
Therefore, satellite links can not be considered to have stable latency (as the connections with
terrestrial microwave links) and cannot be used, without constant corrections in an FM Isofrequency
system that requires precision and stability of a few tenths of a microsecond.
The system developed by WaveArt-ABE, by means of the "time stamp" inserted in the Transport Stream
and the GNSS synchronization (GPS + GLONASS) carried out with proprietary algorithms,
compensates the instability of the satellite making it possible to use it also in FM Isofrequency
networks.
The implementation of the Isofrequency with backhauling via satellite
Further benefits of WaveArt-ABE Isofrequency
24. 24
The UTC timing information available receiving GPS and GLONASS satellites
GNSS Locked Timing Reference
ABE GNSS Locked Timing Reference (1PPS + 10MHz) employ proprietary algorithms that have been
specifically developed to generate and maintain frequency and timing stability in any condition and to
prevent telecommunication networks de-synchronization that often happens using standard products, not
specifically developed for this purpose.
Main features include:
High sensitivity 32 channels GNSS (GPS + GLONASS)
receiver specific for the timing function
Fast satellites acquisition and single satellite operation capability
Fast cold start-up function
Long term «Zero cumulated error» function
Holdover error recovery function (the timing error accumulated during the holdover period is
slowly compensated, so re-synchronizing the modulators)
Hi stability 10MHz oven oscillator allowing long holdover time in case of lack of GNSS signals
For more detailed information, please see also the «GNS 1000» presentation available on www.abe.it
25. 25
The system developed by WaveArt in cooperation with ABE allows the integration of the satellite or
microwave link receiver in the FM transmitters, thus allowing a simplification in the installations, an
economic saving and the possibility to have the receiver controls integrated in the transmitter
telemetry.
For the reception, only the antenna (usually a dish) and a suitable LNB (Low Noise Block
downconverter) has to be installed.
Satellite and Microwave Link receiver on board WaveArt Transmitters
Further benefits of WaveArt-ABE Isofrequency
SAT/DTT
receiver board
LNB
26. 26
The modulator board inside the WaveArt transmitter can be used simultaneously to transmit the FM
Isofrequency signal and to generate the Transport Stream with the digital MPX data flow with Time
Stamp and Network Delay to be sent to one or more other transmitters in Isofrequency operation.
In this way an extremely simplified (and less expensive) configuration can be built for the implementation
of the Isofrequency, without going to affect the entire structure of an existing FM transmitter network, but
implementing the Isofrequency only between the transmitters where necessary.
The "light" implementation of the Isofrequency
Further benefits of WaveArt-ABE Isofrequency