The ett101 is unrivalled in offering a wide range of over 42 modern communications topics that can be studied with one compact trainer. Follow the instructions of the lab incharges and lab supervisor. Pulse amplitude modulation is a scheme, which alters the amplitude of regularly spaced rectangular pulses in. The fraction of the period for which the signal is on is known as the duty cycle. In general, the larger the command signal, the wider the pulse.
Control the brightness of an led using a hardware pwm pulse width modulation module. The term pulsewidth modulation refers to the alteration modulation of the high time, t 1, while maintaining a constant period, t. Procedure 1 check all the components and signal probes 2 set up the circuit as per the diagram. Although pwm is also used in communications, its main purpose is actually to.
Pulse width modulation pulse width modulation pwm is a common technique for controlling an electricallyactuated device by turning the device on and off or pulsing it very quickly. Before doing this experiment, students should be able to analyze simple circuits consisting of combinations of resistors. Lab 8 motor control and frequency measurement introduction this laboratory is designed to introduce students to methods of measuring angular speed, as well as pulsewidth modulation for motor control. Pulse width modulation pwm is a technique of controlling the amount of power delivered to an electronic load using an onoff digital signal. To study of pulse amplitude modulation and time division multiplexing. Examples of applications with the pulse width modulator tl5001 2 2. Chapter 5 part 4 pulse width modulation pwm for led. In this experiment we look at the 555timer, a device that uses digital devices and other electronic switching elements to generate pulses. User manual for pulse width modulation and demodulation trainer. Pulse width modulation pwm cornerstone electronics. Ece 2c laboratory manual 4 infrared pwm transmitter overview in this lab you will construct a circuit to produce a 40khz analog pulsewidthmodulator pwm, to be used later in our oneway analog audio communication link.
A pulse width modulator circuit made up of 555 timer is shown in figure. In a pcm stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps. In the past lessons, our leds were either on or off, and they blinked on or off at a programmed rate. Analog communication lab manual, prepared by nakka. In ece 469, the voltages will usually be kept low to minimize hazards. There is a verticle position control, set it so the wave form is visible. To study sampling and reconstruction of pulse amplitude modulation. Download it once and read it on your kindle device, pc, phones or tablets. Terry sturtevant electronics pulse width modulation sensors. To study and perform amplitude modulation 2 to study and perform frequency modulation and demodulation. Pulsewidth modulation the output of a pwm amplifier is either zero or tied to the supply voltage, holding losses to a minimum. The modulation input dc supply now controls the width of the pulse since it is the modulation voltage. The objective of this activity is to explore pulse width modulation pwm.
A class d amplifier uses some form of pulsewidth modulation to control the output devices. Measuring pulse width modulation pwm electronics forum. Stepdown converters the circuit diagram of a stepdown converter is shown in figure 2. Ece 2c laboratory manual 4 infrared pwm transmitter overview in this lab you will construct a circuit to produce a 40khz analog pulse width modulator pwm, to be used later in our oneway analog audio communication link. The blue lines are pwm output from an mcu, and the red line is the average voltage.
Control the brightness of an led using a hardware pwm pulsewidth modulation module. To study sensitivity, selectivity, and fidelity characteristics of super heterodyne receiver 8. The length of time that a pulse is in a given state highlow is the width of a pulse wave. Laboratory manual for pulsewidth modulated dcdc power converters kindle edition by kazimierczuk, marian k. A class d amplifier uses some form of pulsewidth modulation to control the output. Use emios to generate pulse width modulation pwm signal to the motor 24 channels with many different operating modes see chapter 17 mpc5553rm emios operation modes. Laboratory manual for pulsewidth modulated dcdc power. To study and perform pulse width modulation and demodulation. Pulse width modulation and in position ppm, pulse position.
To study sampling and reconstruction of pulse amplitude modulation system 6. The duty cycle for each pwm cycle ranges from 0 0% to 255 100%. In fact, the type of modulation to choose depends of practical application. General information on pulse width modulation demodulation. The average value of voltage and current fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The speed at which the device is pulsed is called the frequency and is expressed in cycles per minute or hertz hz. Pulsewidthmodulation pwm and filter characteristics objective. Pwm is employed in a wide variety of applications, ranging from measurement and communications to power control and conversion. The purpose of this lab is to explore digital communications with a software radio to understand how each component works together. The output pulse width should not change by much since the external dc supply voltage of 3. Pdf a pulsewidth modulation controlled wiremesh heater.
Pulsewidth modulation pwm, or pulseduration modulation pdm, is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. Pulse width modulation pwm is a nifty current control technique that enables you to control the speed of motors, heat output of heaters, and much more in an energyefficient and usually quieter manner. An approac h to designing the pwm circuit is discussed in section 2. Cme3lab manual pulse modulation experiment2 german jordanian university department of communication engineering digital communication systems lab cme 3lab experiment 2 pulse modulation eng. Pin may be a constant, 0 15, or a variable that contains a number 0 15 e.
We have finally arrived at the part of the lesson where we can put all of this clock theory to good use and make pretty lighting displays in the real world. Recreate part 4 of lab 1 using assembly instead of c. Ece 4670 communication systems laboratory experiments. Power electronics laboratory manual introductory material v safety the power electronics laboratory deals with power levels much higher than those in most electronics settings. Existing applications for pwm include, but are not limited to. The lab will cover, analog to digital conversion, modulation, pulse shaping, and noise analysis 1. Pulsecode modulation pcm is a method used to digitally represent sampled analog signals. Pulse width modulation and demodulation objectives. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications.
Use features like bookmarks, note taking and highlighting while reading laboratory manual for pulsewidth modulated dcdc power converters. Free download books pulse code modulation lab manual ece printable 2019 you know that reading pulse code modulation lab manual ece printable 2019 is helpful, because we can get information from the resources. Pulse amplitude modulation is the basic form of pulse modulation. Sine pwm inverter electrical and computer engineering. Pulse width modulation pwm is a powerful technique for controlling analog circuits with a processors digital outputs. Students will use a multirotor quadcoptertype propeller and motor to investigate how to use an electronic speed controller esc, and to perform a speedthrust calibration experiment. The oc function used for the timer is also used to control the rate at which the duty cycle.
The longer the switch is on compared to the off periods. The original waveform amplitude is quantized with a resulting loss of information. Pulse amplitude modulation is a scheme, which alters the amplitude of regularly spaced. To study the pwm modulation and demodulation 64 khz carrier. Later we will combine this modulator with the microphone circuit from am earlier lab to form a complete ir audio transmitter.
The pwm is also known as pulse duration modulation. To study pulse width modulation and pulse position modulation 9. Pulse width modulation sensors raspberry pi python pwm control shaft encoders ultrasonic sensors v to f and f to v converters pulse width modulation sensors analog information can be communicated over digital signals. Pwm pin,duty,cycle outputs a pulse width modulated pulse train on pin.
To generate the pulse amplitude modulated and demodulated signals. Ece 4670 communication systems laboratory experiments manual spring 2010 mark a. Pulsewidth modulation pwm is a modulation process or technique used in most communication systems for encoding the amplitude of a signal right into a pulse width or duration of another signal, usually a carrier signal, for transmission. Be careful when working with spinning motors, and parts that can become hot. Pulse width modulation pwm is a form of pulse modulation where the width of the pulses in a carrier pulse train is made proportional to the instantaneous amplitude of the modulating signal.
Before we study in detail about pam lets know the concepts of modulation. Recognize pulse amplitude and pulse width modulated signals, and do simple experiments. Most pwm systems do not allow for 0% or 100% modulation because the output would be dc and may damage other components in the signal path. Pulse width modulation and introduction to simple virtual worlds pwm 2. To study pulse width modulation and pulse position modulation. No information is lost, but the energy is redistributed in the frequency domain. Peng sun 7790 varying vector pulse width modulation for three phase inverter pdf raju j, kowsalya m 91100 optimal determination of size and site of dgs in mesh system using pso pdf. The pulse may take any real voltage value that is proportional to the value of the original waveform. Y our lab oratory tasks are describ ed in section 4.
To construct and study the pulse width modulation technique. General information on pulse width modulationdemodulation. Schematic diagram of a stepdown converter the actual voltage converter is made up of a switch in this case, the transistor q, the inductor l, the diode d, and the capacitor c. The pulse width modulator takes a relatively lower frequency analog input signal and converts it to a much higher square wave signal where the dutycycle pulse width of the square wave varies in proportion to the analog input signal. In this case, the pulse width and corresponding duty cycle change so that the average voltage looks more like an analog output that is not in a steady. Pdf pulse width modulated pwm power supplies download. This exercise shows v t v oo, which is equal to the average of the switchingfrequency input voltage vt a, provided the lc resonance frequency of the lowpass filter is significantly lower than the switchingfrequency f s. The purpose of this lab is to learn how to generate a pulse width modulated signal and generate a timer to keep track of real time using 2 output compare functions. To study and perform pulse amplitude modulation and demodulation. Download pulse width modulated pwm power supplies ebook free in pdf and epub format. Pulse width modulation preparation reading lab manual chapter 4 the silicon labs c8051f020 and the evb sections on the c8051 timer functions, interrupts, and the programmable counter array chapter 5 circuitry basics and components the buffer chapter 6 motor control dc motors objectives in lab. Change the value of resistance and capacitance, repeat the process and check pulse width. In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal.
973 430 1219 176 1533 1149 1528 1160 158 559 282 352 621 1451 664 839 603 718 1408 201 933 1466 248 462 1060 192 421 1281 241 641 557 1053 104 197 287 1213 183 1016 665 577 1448 920 1057