Switchable input circuit for radio receiver e.g. car radio has circuit for varying inductance forming selection device

摘要

The circuit includes a selector which uses a means of varying the inductance. A coil can be connected to ground at different points via a switch (S1,S2). The circuit may include an input circuit (10), a preamplifier (11) and an intermediate circuit (12), the input circuit and the intermediate circuit being switchable. The circuit may include a switchable oscillator (14) and/or a mixer (13) with image frequency suppression.