Answer to Question #87659 in Electric Circuits for Shivam Nishad

Question

Describe the various multiplexing techniques used for switching in telephony.

Answer 1

Among these techniques are:

Wavelength division multiplexing or WDM allows transmitting-receiving different signals in one common optical fiber by means of different frequencies (wavelengths) of laser light.

Time division multiplexing or TDM means receiving and transmitting independent signals in one common signal path. Different signals pass through the path synchronized by time so that when signal 1 passes, there is no signal 2 and as soon as signal 1 finished, the signal 2 passes through the pass.

Frequency division multiplexing or FDM implies having some width of a spectrum, for instance, 8 MHz. If you are given a frequency of 600 MHz, the next successive subscriber or channel will have frequency of 600+8=608 MHz, the next one 616 MHz, so there is room for many channels or subscribers.