The amplitude modulation receiver will be wider when compared. There are many methods of generating am, and this experiment explores only one of them. Pulse modulation may be subdivided broadly into two categories, analog and digital. In amplitude modulation am, we utilize the amplitude of the audio signal to modulate the amplitude of carrier signal, which means that the amplitude of carrier signal will be varied with the amplitude of the audio signal. Study on performance analysis of pulse code modulation pcm. Sinusoidal amplitude modulation amplitude demodulation. Cr1 is the input diode which allows capacitor c1 to charge to the peak value of the pam input pulse. Pulse amplitude modulated pam fluorometry is a useful technique for identifying the amount of energy that is not used in photosynthesis but is reemitted as fluorescence or dissipated as heat in.
T1 time division multiplexing lab university of pittsburgh. Amplitude modulation am is defined as a process in which the amplitude of the. Pam, pwm, and ppm modulations belong to analog modulation and the pcm modulation belongs to the digital modulation. At least 10 experiments are to performed by students in the semester. Another method, which introduces more variables into the model, is explored in the experiment entitled. Dhanalakshmi college of engineering is committed to provide highly disciplined, conscientious and. Indian institute of technology kanpur ee 381 electrical. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal.
Tdm pulse amplitude modulationdemodulation trainer st2102. For amplitude modulation, we use simple and low cost circuit. Reddy college of engineering eluru534007 department. Yet, am continues to be used today in many communication applications. Analog communication pulse modulation tutorialspoint. Sinusoidal amplitude modulation amplitude demodulation synchronous and asynchronous double and singlesideband am modulation pulseamplitude modulation pulse code modulation frequencydivision multiplexing timedivision multiplexing narrowband frequency modulation. It is a modulation system in which the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the signal at the instant of sampling. Pulse amplitude modulation has some applications, but it is not used by itself in data communication. Pulse amplitude modulation pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. To study and perform frequency modulation and demodulation. Laboratory manual principles of communication system lab ee226f ivth semester prepared by. To study and perform pulse width modulation and demodulation. Sampling theorem and pulse amplitude modulation pam.
In this experiment, a carrier signal and an audio modulating signal are applied to the modulator ic mc 1496 and the produced modulated waveform is observed. The wave form of am modulation is shown in figure 3. Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. To study and perform pulse position modulation and demodulation. Pulse amplitude modulation pulse code modulation sampling. The particular form of pulse amplitude modulation is referred to as natural pam, because the tops of the pulses follow the. Amplitude modulation and demodulation objective amplitude modulation am is one of the simplest methods for modulating a sinusoidal carrier wave. Before we study in detail about pam lets know the concepts of modulation.
No information is lost, but the energy is redistributed in the frequency domain. In the positive half cycle of pam signal, diode conducts and current flows through r, whereas in negative half cycle, the diode is reversed biased and. Fig 3 flat top sampling as shown in fig 3, the output obtained after sampling an analog signal is a pulse amplitude modulated signal. Pulse amplitude modulation pam theory of and its applications. The pulse amplitude modulated signal, will follow the amplitude of the original signal, as the signal traces out the path of the whole wave.
By varying the amplitude of the pulses the carrier signal in proportion to the instantaneous values of the analog signal the message signal. Before going to discuss the difference between pam, pwm, and ppm, let us discuss individually each. In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. While the bit streams we wish to transmit are inherently discretetime, all physical media are continuoustime in nature. An informationbearing signal must conform to the limitations of its channel. It is an analog pulse modulation scheme in which the amplitudes of a train of carrier pulses are varied according to the sample value of the message signal. To study sampling and reconstruction of pulse amplitude modulation system 6. Oct 03, 2011 this is a ppt for pulse modulation for final year ej diploma slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising.
Pulse amplitude modulation is the basic form of pulse modulation. To study amplitude demodulation by linear diode detector 3. Figure 321 includes a simplified circuit view a for this demodulator and its waveforms views b and c. Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. In pam, the amplitude of the message or modulating signal is mapped. The output is a series of pulses, the amplitudes of which vary in proportion to the modulating signal. Because of amplitude modulation wavelength, am signals can propagate longer distances. Amplitude modulated signal can be represented by the following equation. The particular form of pulse amplitude modulation is referred to as natural pam, because the tops of the pulses follow the shape of the modulating signal. Application note of pampulse amplitude modulation signal.
In pulseamplitude modulation pam the amplitude of the pulses are varied in accordancewith the modulating signal. This process is known as pulse amplitude modulation pam. In pam, the amplitude of the message or modulating signal is mapped to a series of pulses, with two possible variant detailed below. In the former, the indication of sample amplitude may be infinitely variable, while in the latter a code which indicates the sample amplitude to the nearest predetermined level is sent. To study frequency modulation and determine its modulation factor 4. The original waveform amplitude is quantized with a resulting loss of information. In the case of psk, ask or qam, where the carrier frequency of the modulated signal is constant, the modulation alphabet is often conveniently represented on a constellation diagram, showing the amplitude of the i signal at the xaxis, and the amplitude of the q signal at the yaxis, for each symbol. This weeks laboratory investigates pulse amplitude modulation pam.
It is deserved to pay attention that pcm modulation is a real digital signal that can be processed. If you continue browsing the site, you agree to the use of cookies on this website. Ritchie1 and sakshin bunthawin biotechnology of electromechanics research unit, faculty of technology and environment, prince of songkla university, phuket, 83120 thailand. Pulse amplitude modulation pam is an analog modulating scheme in which the amplitude of the pulse carrier varies proportional to the instantaneous amplitude of the message signal. The pulse may take any real voltage value that is proportional to the value of the original waveform. Amplitude modulation a1 49 you will see in this experiment, and in others to follow, that there is no problem in generating an am signal with a depth of modulation exceeding 100%, and without. To study and perform pulse amplitude modulation and demodulation. We use modulation technique to alter signals in time and frequency to accomplish desired objectives. Denoting the modulating signal as mt, pulse amplitude modulation is achieved by multiplying the carrier with the mt. However, it is the first step in another very popular conversion method called pulse code modulation. To study and perform amplitude modulation and demodulation. Pulse amplitude modulation pam is the simplest of all pulse modulation techniques. We will be using the 4066 chip to sample small pulses of a sine wave.