Question

In microwave relay communication, the repeater is usually an amplifier for the amplification of
1. Carrier signal 
2. Baseband signal
3. Amplitude modulated IF signal
4. Frequency modulated IF signal

Answer 1

Correct Answer - Option 4 : Frequency modulated IF signal

In a two-way microwave relay communication system, there are three basic equipment units:

1) Multiplexing apparatus

2) Terminal stations

3) Repeater stations

• At the terminal station of such a system, multiplex equipment (which may be of either the frequency division or time division type) is utilized to provide a multiplex signal. This multiplex signal is caused to frequency modulate a microwave transmitter.

• Also, the terminal station is provided with equipment to receive and demodulate for use, frequency-modulated intelligence having a center frequency somewhat different from that of the transmitted frequency.

• An automatic frequency control (AFC) arrangement is provided at each repeater station to control the frequency of a local heterodyne oscillator in order to maintain the proper intermediate frequency.