Level limitation in high frequency receiver for frequency modulation or frequency shift keying modulation has amplifier limiter log amplifier and forwards gain control circuit

摘要

The limiting stage in a high-frequency receiver for frequency or FSK modulation comprises a high-frequency amplifier (2), signal limiter (3), a logarithmic amplifier (4) and a simple forward gain control (5) for additional damping. The circuit prevents an excess level being fed to subsequent stages, e.g. a filter or A/D converter, after frequency conversion.