ANti side tone circuit in telephone is used to?

Answer 1

The anti-sidetone circuit in telephone is used to suppress side-tone.

The anti-sidetone circuit is an assemblage of Transformers, resistors, and capacitors

that perform a number of functions.The primary function is to reduce sidetone, which

is the distracting sound of the speaker's own voice coming through the receiver from

the transmitter. The anti-sidetone circuit accomplishes this reduction by interposing

a transformer between the transmitter circuit and the receiver circuit and by splitting

the transmitter signals along two paths. When the divided signals, having opposite

polarities, meet at the transformer, they almost entirely cancel each other in crossing

to the receiver circuit. The speech signal coming from the other end of the line, on

the other hand, arrives at the transformer along a single, undivided path and crosses

the transformer unimpeded.

The anti-sidetone circuit also matches the low electrical impedance of the telephone

instrument's circuits to the higher electrical impedance of the telephone line.

Impedance matching allows a more efficient transfer of energy between the

instrument and the line.