Pulse Amplitude Modulation (PAM)

Pulse Amplitude Modulation (PAM) is a type of modulation where the amplitude of a series of pulses is varied in accordance with the amplitude of the modulating signal.

In PAM, a continuous signal is sampled at regular intervals, and the amplitude of each sample is quantized into a discrete value. These discrete values are then used to modulate the amplitude of a series of pulses that are transmitted over the communication channel. The amplitude of each pulse corresponds to the amplitude of the discrete sample that was used to modulate it.

One of the major drawbacks of PAM is that it is susceptible to noise and interference. Since PAM uses the amplitude of a series of pulses to carry information, any noise or interference that is introduced into the communication channel can distort the amplitude of the pulses, which can result in errors in the transmitted signal. Additionally, PAM is not very efficient in terms of bandwidth usage, as it requires a large bandwidth to transmit high-frequency signals with high fidelity.

PAM and its drawbacks

 
Pulse Amplitude Modulation (PAM) is a digital modulation technique where the amplitude of a series of pulses is varied to represent the amplitude of a continuous-time signal. PAM is widely used in communication systems, data transmission, and digital signal processing.

One of the significant drawbacks of PAM is its susceptibility to noise and interference. Since PAM uses the amplitude of a series of pulses to transmit information, any noise or interference that is introduced into the communication channel can distort the amplitude of the pulses, which can result in errors in the transmitted signal. This noise and interference can be caused by various factors such as electromagnetic interference, atmospheric noise, and cross talk.

Another significant drawback of PAM is its inefficient use of bandwidth. PAM requires a large bandwidth to transmit high-frequency signals with high fidelity. The bandwidth required for PAM increases as the data rate increases. This is because the amplitude of the pulses needs to change rapidly to transmit high-frequency signals, which requires a high sampling rate and, in turn, a large bandwidth.

To overcome these drawbacks, several modulation techniques have been developed, such as Pulse Code Modulation (PCM), Delta Modulation (DM), and Adaptive Delta Modulation (ADM). PCM, for instance, quantize the analog signal to a digital signal, which can then be transmitted more robustly, while DM and ADM reduce the bandwidth requirements by transmitting only the difference between successive samples of the analog signal.