what is AC Coupling in receiver......?

AC coupling means DC is blocked by a capacitor.So, DC level is not wanted to prevent-for instance OP of a circuit-

It is very difficult to build an amplifier with 120 dB of gain and maintain the correct DC level through out. If the DC level changes at the input, it will also shift at the output by the gain of the receiver. To overcome this the DC between amplifier stages are blocked by a capacitor often in conjunction with a filter to reduce the bandwidth of a receiver. In real life most signals do not need their true DC levels to be received, and that can often be reconstructed at the output of a receiver, by say clamping to a known voltage
Frank

Chuckey
Thanks for your reply.what is dis advantage if we don't block the D.C?

Thanks in advance

- - - Updated - - -

chuckey

In one of paper i had read,he mentioned that "Due to the small coupling capacitance's only the high frequency transitions of the transmitted NRZ data are detected at the receiver"

could explain me reason behind it?

Hi walkman i have the same question as you. Can you please upload the paper you said that you read?
Also checki this out: http://en.wikipedia.org/wiki/Capacitive_coupling

Apparently the question doesn't refer to RF revceivers, as expectable in the RF, Microwave, Antennas and Optics forum.