Question

How do you demodulate PAM?

Answer 1

Explanation:

Demodulation of Pulse Amplitude Modulated (PAM):

1. A holding circuit is used for the demodulation of pulse amplitude modulated (PAM) signals. The PAM demodulator's block diagram is shown in $Figure1$.
2. As illustrated in $Figure1$, the received $PAM$ signals in this manner are allowed to pass via a holding circuit and a low pass filter $\left(LPF\right)$.

Now,$Figure2$ shows a remarkably basic holding circuit.

1. In this case, the switch $S$ is closed before the pulse begins and opened after the pulse has finished.
2. The capacitor$C$ is charged to the pulse amplitude value in this manner, and it maintains this value throughout the pause between the two pulses. $Figure3$ displays the sampled values in this case.
3. Following that, the Low Pass filter smooths the holding circuit output as shown in $Figure3$.

It is possible to see that the holding circuit introduces some sort of distortion. The circuit is shown in $Figure4$. is actually referred to as a zero-order holding circuit. To determine the difference between the two pulses, this zero-order holding circuit simply takes into account the preceding sample.