Amplitude modulation
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The document discusses amplitude modulation (AM) in which a carrier signal's amplitude is varied in proportion to that of a modulating baseband signal. The modulated signal contains the original baseband information as well as the carrier frequency. In AM, the carrier signal amplitude is increased or decreased based on the amplitude of the baseband signal. The modulated signal can then be demodulated using a simple diode detector circuit to recover the original baseband signal by extracting the signal from the carrier amplitude variations.
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![Introduction
A frequency-translated signal from which the baseband
signal is easily recoverable is generated by adding, to the
product of baseband and carrier, the carrier signal itself.
Such a signal is shown in fig.(1)
Figure l(a) shows the carrier signal with amplitude Ac, in 1
(b) we see the baseband signal.
The translated signal l(c) is given by
v(t)=Ac[1+m(t)]cos ωct (1)
2](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Lab Overview
The objective of Lab 1 is to familiarize students with a variety of basic applications of
passive R, C devices, and also how to measure the performance of these circuits using
both Spice simulations and the Digilent Analog Discovery 2 on the circuits constructed.
Prelab
Before coming to lab, students need to complete the following items for each of the
circuits studied in this lab :
• Any hand calculations needed to determine the values of components used in the
circuits such as resistors and capacitors, or specifications such as pole frequencies.
• A Spice simulation of each circuit to get familiar with how it works, and determine
what to expect when the circuit is built and its performance is measured.
Making connections on a Breadboard
Breadboards are used to easily construct circuits without the need to solder parts on a
printed circuit board. As seen in Figure 0 they have columns of pins that are connected
together internally, so that all the wires inserted in a column are shorted together. Note
that the columns on top and bottom are not connected together. There are also rows of
pins at the top and bottom that are connected together. These rows are intended for use
as the power supplies, and are typically labeled + and – and color coded red and blue for
the positive and negative power supplies. These rows are not connected in the middle.
Figure 0.
EEE 117L Network Analysis Laboratory Lab 1
2
Circuits to be studied
When choosing resistor and capacitor values use standard values available to you,
and keep all resistor values between 100 W and 100 kW.
1. Voltage and Current Dividers
One of the most commonly used circuits is a voltage divider
like the one shown in Figure 1.a. For example, if a signal is
too large to be input to a voltmeter or oscilloscope it can be
attenuated (reduced in size) using voltage division. The DC
voltage that an AC signal like a sine wave varies around can
also be reduced using this circuit.
For example, if all of the resistors in this circuit are the same
value, and the VS input source provides a DC voltage of 4V,
then the voltages in this circuit will be VA = 4V, VB = 3V,
VC = 2V, and VD = 1V. That is, voltage division will cause the voltage at node B to be
¾ of VS , the voltage at node C to be ½ of VS , and the voltage at node D to be ¼ of VS.
If a sine wave with an amplitude of 1V is then added so that VS = 4 + sin(wt) Volts, then
voltage division will cause the new values of VA , VB , VC and VD to be :
VA = 1.00*VS = 1.00*(4 + sin(wt)) = 4 + 1.00*sin(wt) Volts
VB = 0.75*VS = 0.75*(4 + sin(wt)) = 3 + 0.75*sin(wt) Volts
VC = 0.50*VS = 0.50*(4 + sin(wt)) = 2 + 0.50*sin(wt) Volts
VD = 0.25*VS = 0.25*(4 + sin(wt)) = 1 + 0.25*sin(wt) Volts
In this example both the amplitude of the ...
balanced modulator.pptx breif introduction
The document summarizes the operation of an envelope detector used in AM radio receivers. An envelope detector uses a diode and RC filter to extract the envelope of a narrowband AM signal. During each positive half cycle of the AM wave, the diode conducts and charges the filter capacitor to the peak voltage. Between positive peaks, the capacitor discharges through the load resistance, reproducing the signal envelope. The time constants of the RC filter must be selected so the capacitor can quickly charge but slowly discharge, accurately recovering the modulating signal. Distortions can occur if the time constant is too long, causing diagonal clipping, or if overmodulation causes negative peak clipping at higher modulation indices.
The Class-D Amplifier
The document summarizes the operation of a class-D amplifier. It describes how class-D amplifiers use transistors as switches that are either fully on or fully off to achieve high efficiency. A comparator compares an audio signal to a high frequency triangle wave to generate a pulse width modulated square wave. A passive filter converts this into an analog output. Class-D amplifiers can be operated in a bridged configuration to increase output power without increasing voltage. Negative feedback is also used to improve performance.
Bridge Rectifier with Capacitor filter
1. The document describes using a capacitor to filter the output of a bridge rectifier circuit in order to produce a smoother DC voltage.
2. It explains that a capacitor allows the AC components of the rectified signal to pass to ground, leaving a smoothed DC voltage, and discusses how the size of the smoothing capacitor affects the ripple voltage.
3. The procedure has the user construct the circuit in a simulator with different load resistors and capacitor values to observe the rectified and filtered waveforms and understand the concepts of ripple voltage and factor.
Electrical Engineering
Electrical Engineering is the Branch of Engineering. Electrical Engineering field requires an understanding of core areas including Thermal and Hydraulics Prime Movers, Analog Electronic Circuits, Network Analysis and Synthesis, DC Machines and Transformers, Digital Electronic Circuits, Fundamentals of Power Electronics, Control System Engineering, Engineering Electromagnetics, Microprocessor and Microcontroller. Ekeeda offers Online Mechanical Engineering Courses for all the Subjects as per the Syllabus Visit : https://ekeeda.com/streamdetails/stream/Electrical-Engineering
Principles of communication systems for reference
This document provides information about the Principles of Communication Systems course offered in the 4th semester by the Department of Electronics and Communication Engineering. It includes details about the course code, modules covered, learning objectives, textbooks, and an introduction to modulation techniques like amplitude modulation and double sideband suppressed carrier modulation. Key concepts discussed are generation of AM waves using a switching modulator, frequency spectrum of AM signals, envelope detection for demodulation, and power savings achieved by suppressing the carrier in DSB-SC systems.
International Refereed Journal of Engineering and Science (IRJES)
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Acmanual ww8
This document provides instructions for experiments on amplitude modulation (AM) and frequency modulation (FM). It describes the basic principles of AM, including how the amplitude of a carrier wave is varied by a modulating signal to produce an AM wave. It also covers AM demodulation using a diode detector. For FM, it explains how the frequency of a carrier wave is varied proportionally to the amplitude of a modulating signal. The document includes circuit diagrams for an AM modulator, AM demodulator, and FM modulator. It provides procedures for experiments to study modulation index for AM and FM, and to demonstrate FM demodulation using a slope detector. Tables are included to record experimental measurements and results.
unit.pptx
The document discusses amplitude modulation techniques. It describes the switching modulator, which uses a diode to generate an amplitude modulated wave by multiplying a carrier signal with the sum of the carrier and modulating signal. It then discusses the envelope detector, which uses a diode and low-pass filter to extract the modulating signal by detecting the envelope of the amplitude modulated wave. Finally, it explains double sideband suppressed carrier modulation, which suppresses the carrier wave to increase efficiency by distributing its power to the two sidebands.
Short notes on digital electronics for specialist officer it exam by das sir,...
For Study Material Or Coaching Of Any Government Job Exam Like Bank/Rail/SSC Etc Or Any Other Entrance Exam Call 08961556195/09874581055
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Unit ii
This document discusses various types of filters used in power electronics, including L, C, and LC filters. It also discusses capacitor filters and how they smooth the DC output voltage of a rectifier. Finally, it discusses firing circuits for thyristors, including resistance and RC firing circuits, and provides equations for calculating voltage and current in half-wave converter circuits with resistive and RL loads.
Phase Shift, Collpitt's and Crystal oscillators.pptx
1) The document discusses different types of oscillators including phase shift oscillators, Colpitts oscillators, and Hartley oscillators.
2) Phase shift oscillators use RC networks to generate a 180 degree phase shift, while Colpitts oscillators use a tapped inductor and two capacitors in a tank circuit to produce feedback.
3) Key advantages of these oscillator circuits include good frequency stability, the ability to generate very low frequencies, and not requiring large inductors.
Phase Shift, Collpitt's and Crystal oscillators.pptx
1) The document discusses different types of oscillators including phase shift, Colpitts, Hartley, and crystal oscillators.
2) Phase shift oscillators use RC networks to generate a 180 degree phase shift instead of inductive coupling. Colpitts oscillators use a tapped inductor and two capacitors in a tank circuit.
3) Hartley oscillators use inductive coupling between two coils to provide feedback. Crystal oscillators use a piezoelectric crystal that resonates at a precise frequency in a feedback loop to generate stable oscillations.
A study of 220V AC-5V DC Converter
AC-DC converters are widely used in industrial and domestic applications. Input AC voltage is rectified and
filtered using filtering circuit which consists of large electrolytic capacitors. These capacitors draw a large
amount of current and the efficiency of the converter system decreases drastically. large ripple factor have made the converter system inefficient .This paper
analyses about different converter topology and proposes a different design which is based on converting Ac signal to specified Dc signal of about 5V by which ripple factor can be reduced to make the system enough efficient. The implification of this project is for charging or operating semiconductor devices .The results of respective topologies are shown through P-simulation program with integrated circuit emphasis (PSPICE) simulation and their
parameters are calculated. Three parameters are considered for the comparison of these topologies
Kirchhoff's rules and rc circuits
1. An RC circuit consists of a resistor and capacitor connected in series or parallel. When a voltage is applied across the circuit, the capacitor will charge up over time through the resistor according to the time constant of the circuit, which is equal to RC.
2. Kirchhoff's laws can be applied to the RC circuit to derive differential equations describing how the current and charge on the capacitor change over time during the charging and discharging processes. The solutions to these equations show that the current and charge decay exponentially with the time constant RC.
3. An oscilloscope can be used to observe the input voltage waveform and voltage across the capacitor to understand the capacitor's charging and discharging behavior in response to
Bipolar junction transistor characterstics biassing and amplification, lab 9
This document summarizes an experiment on characterizing the input and output properties of a bipolar junction transistor (BJT) and demonstrating its signal amplification capabilities. The experiment involved establishing the transistor's DC operating point, then evaluating its small-signal AC operation. Key results included measuring the transistor's DC current gain and small-signal voltage gain, which compared reasonably well to theoretical predictions. The document also discussed the different regions of BJT operation and their implications for circuit applications.
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International Refereed Journal of Engineering and Science (IRJES)
International Refereed Journal of Engineering and Science (IRJES)
Short notes on digital electronics for specialist officer it exam by das sir,...
Short notes on digital electronics for specialist officer it exam by das sir,...
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...
Phase Shift, Collpitt's and Crystal oscillators.pptx
Phase Shift, Collpitt's and Crystal oscillators.pptx
Phase Shift, Collpitt's and Crystal oscillators.pptx
Phase Shift, Collpitt's and Crystal oscillators.pptx
Bipolar junction transistor characterstics biassing and amplification, lab 9
Bipolar junction transistor characterstics biassing and amplification, lab 9
More from MOHAMMAD AKRAM
Coordinate system
An orthogonal system is one in which the coordinates arc mutually perpendicular
Examples of orthogonal coordinate systems include the Cartesian (or rectangular), the circular cylindrical, the spherical, the elliptic cylindrical, the parabolic cylindrical, the conical, the prolate spheroidal, the oblate spheroidal, and the ellipsoidal.1
A considerable amount of work and time may be saved by choosing a coordinate system that best fits a given problem
A hard problem in one coordi nate system may turn out to be easy in another system.
In this text, we shall restrict ourselves to the three best-known coordinate systems: the Cartesian, the circular cylindrical, and the spherical.
Vector
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Using Chebyshev filter design, there are two sub groups,
Type-I Chebyshev Filter
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The major difference between butterworth and chebyshev filter is that the poles of butterworth filter lie on the circle while the poles of chebyshev filter lie on ellipse.
Butterworth filter
Salient Features:
The magnitude response is nearly constant(equal to 1) at lower frequencies
There are no ripples in passband and stop band
The maximum gain occurs at Ω=0 and it is H(Ω)=1
The magnitude response is monotonically decreasing
As the order of the filter ‘N’ increases, the response of the filter is more close to the ideal response
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Amplitude modulation
- 2. Introduction A frequency-translated signal from which the baseband signal is easily recoverable is generated by adding, to the product of baseband and carrier, the carrier signal itself. Such a signal is shown in fig.(1) Figure l(a) shows the carrier signal with amplitude Ac, in 1 (b) we see the baseband signal. The translated signal l(c) is given by v(t)=Ac[1+m(t)]cos ωct (1) 2
- 4. Contd… We observe, from Eq. (1) as well as from Fig. l(c), that the resultant waveform is one in which the carrier Ac cos ωct is modulated in amplitude. The process qf generating such a waveform is called amplitude modulation. A communication system which employs such a method of frequency translation is called an amplitude-modulation system, or AM for short. 4
- 5. Contd… The designation “carrier” for the auxiliary signal Ac cos ωct seems especially appropriate in the present connection since this signal now “ carries ” the baseband signal as its envelope. The term “ carrier ” probably originated, however, in the early days of radio when this rela-tively high-frequency signal was viewed as the messenger which actually “ carried ” the baseband signal from one antenna to another 5
- 6. Contd… The very great merit of the amplitude-modulated carrier signal is the ease with which the baseband signal can be recovered. The recovery of the baseband signal, a process which is referred to as demodulation or detection, is accomplished with the simple circuit of Fig. 2(a), which consists of a diode D and the resistor- capacitor RC combination We now discuss the operation of this circuit briefly and qualitatively. For simplicity, we assume that the amplitude-modulated carrier which is applied at the input terminals is supplied by a voltage source of zero internal impedance. 6
- 7. Contd… 7 Fig.2(a)A demodulator for an AM signal Fig.2(b)Input waveform and output voltage across capacitor
- 8. Contd… We assume further that the diode is ideal, i.e., of zero or infinite resistance, depending on whether the diode current is positive or the diode voltage negative. Let us initially assume that the input is of fixed amplitude and that the resistor R is not present In this case, the capacitor charges to the peak positive voltage of the carrier. The capacitor holds this peak voltage, and the diode would not again conduct. Suppose now that the input-carrier amplitude is increased. 8
- 9. Contd… The diode again conducts, and the capacitor charges to the new higher carrier peak. In order to allow the capacitor voltage to follow the carrier peaks when the carrier amplitude is decreasing, it is necessary to include the resistor R, so that the capacitor may discharge. In this case the capacitor voltage vc has the form shown in Fig. 2(b) The capacitor charges to the peak of each carrier cycle and decays slightly between cycles The time constant RC is selected so that the change in vc between cycles is at least equal to the decrease in carrier amplitude between cycles. 9
- 10. Contd… It is seen that the voltage vc follows the carrier envelope except that vc also has superimposed on it a sawtooth waveform of the carrier frequency. In Fig.2(b) the discrepancy between vc and the envelope is greatly exaggerated. In practice, the normal situation is one in which the time interval between carrier cycles is extremely small in comparison with the time required for the envelope to make a sizeable change Hence vc follows the envelope much more closely than is suggested in the figure. 10
- 11. Contd… Further, again because the carrier frequency is ordinarily much higher than the highest frequency of the modulating signal, the sawtooth distortion of the envelope waveform is very easily removed by a filter. 11
- 12. Thank You 12