Brats club logo

Bredhurst Receiving and Transmitting Society

ILC title

Part 4


Learning outcomes of this part

  • Know the block diagrams of the crystal diode receiver, tuned radio frequency (TRF) or straight receiver and superhet receiver.

  • Know the functions of the RF amplifier, mixer, local oscillator, IF amplifier, demodulator (detector), and audio amplifier.

  • the intermediate frequency is the sum of or difference between the RF and local oscillator frequencies.

  • Know that tuned circuits in RF and IF amplifiers select the wanted signal.

  • 4i Detectors

  • Know how a diode detector will recover the audio from amplitude modulated signals.

  • Know that to generate the audio for CW signals a beat frequency oscillator (BFO) is used;

  • Know that for the recovery of single side band audio, a carrier insertion oscillator (CIO) is used;

  • Know that for the recovery of FM audio, a discriminator is used.

  • Know the waveforms produced in a diode AM detector.
  • Know that the automatic gain control (AGC) of a receiver operates by sensing the strength of the received signals to keep the audio output level fairly constant.


brats copyright logo