Mumbai University > Electronics Engineering > Sem4 > Fundamentals of Communication Engineering

Marks: 5M

Year: Dec 2015

1. PCM is a type of pulse modulation like PAM, PWM or PPM.
2. PCM is a digital pulse modulation system
3. The PCM output is in the coded digital form. It is in the form of digital pulses of constant amplitude, width and position
4. A PCM system consist of a PCM encoder and a PCM decoder
5. The essential operations are sampling, quantizing and encoding and are usually preferred in the same circuit called as analog-digital converter

Applications of PCM

1. In telephony
2. In the space communications space crafts transmits signals to earth. Hwere the transmitted power is very low and the distances are huge. Still due to the high noise immunity only PCM systems can be used in such applications

Disadvantages

1. The encoding. Decoding and quantizing circuitry of PCM is complex
2. PCM requires a large bandwidth as compared to the other systems

Advantages

1. Very high noise immunity
2. It is possible to store the PCM signal due to its digital nature
3. It is possible to use various coding techniques so that only the desired person can decode the received signal. This makes the communication secure
4. The increased channel bandwidth requirement for PCM is balanced by the improved SNR.
5. There is a uniform format used for the transmission of different types of basic band signals. Hence is easy to integrate all the signals together and send them on the common network.