Reply analyser for signals of various frequencies - has amplified signal passed on to frequency changer detector and shaping circuit

摘要

The reply analyser for analysis of reply signals of various frequencies received from many sources comprises a sensing circuit, a receiver oscillator, for producing signals of periodically changing frequency, a frequency changer, for mixing signals received with signals of oscillator, and changing of the signal frequencies into a sensing intermediate frequency, amplifier for extraction of the fixed frequency and thus for separating the reply signals, a shaping circuit for shaping output and intermediate frequency amplifier into impulse form, a counter for counting the impulses arriving at the shaping circuit. The purpose is to produce a cheap analyser which pick up signals of many frequencies without any manual operation of the switching systems.