Questions:
1-Define PAM in brief?
2- Why flat top sampling is better than natural sampling?
3- What do you understand by sample and hold circuit?
4- What is the importance of doing sample and hold of signals?
5-Write the advantages of sample and hold circuit.
Answers
1. 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. 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.
2.In flat top sampling the top of samples are constant and are equal to instantaneous value of the signal while a more practical method of sampling is natural sampling in which the width of pulse is finite
3.In electronics, a sample and hold (also known as sample and follow) circuit is an analog device that samples (captures, takes) the voltage of a continuously varying analog signal and holds (locks, freezes) its value at a constant level for a specified minimum period of time.
4.Sample and hold circuits and related peak detectors are the elementary analog memory devices. They are typically used in analog-to-digital converters to eliminate variations in input signal that can corrupt the conversion process.
5.With the help of sample and hold circuit we can take samples of the analogue signal, followed by a capacitor. It holds these sample for a particular period. As a consequence of this, a constant signal is generated this can be converted into the digital signal with the help of analogue to digital converters.
Answer:
Pulse-amplitude modulation (PAM), . 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