Superheterodyne receiver for different bandwidth signals - has narrow band-pass filter and wobbulator for local oscillator output signal

摘要

In the superheterodyne receiver, has a conventional antenna (1) and tuner (2) and a narrow band-pass filter (5) is inserted between the mixing stage (3) and i.f. stage (6). Its bandwidth corresponds to the narrowest bandwidth signals to be received, and its centre frequency is equal to the nominal i.f. The oscillator stage (4) output signal frequency (f), is wobbled by an auxiliary oscillator (9), whose frequency (F) is at least twice the highest frequency in received signals. The wobble swing is adjusted to the received signal bandwidth.