Analog Circuits Cookbook

8 RF circuits and techniques

Direct conversion FM design

Although many people are familiar with homodyne (direct conversion)

reception of CW and SSB signals, it is not immediately obvious that FM

signals can be received by direct conversion. But with some crafty signal

processing, the original baseband modulation can indeed be recovered.

Homodyne

reception

of FM

signals

Homodyne or direct conversion reception has always attracted a good deal

of attention, especially in amateur circles (Hawker, 1978). It has the attraction

of simplicity, both in principle and in hardware terms. Figure 8.1 shows a

simple homodyne receiver which could in principl ...