| 摘要 |
<p>An FM intermediate-frequency circuit into which there is integrated at least a limiter-amplifier (1A), a level detector included in the amplifier, and a phase-locked loop (2, 3, 4) which contains a VCO (4). A large dynamic range of the level detector is obtained without having to use excessive limiter-amplifier amplification, which would cause oscillation problems. In parallel with the said limiter-amplifier (1A) is at least a second limiter-amplifier (1B), in connection with which there is also a level detector. By means of a dividing circuit (R1, R2) the level of the input signal of the second limiter-amplifier (1B) is dropped. The signals (1A, 1B) obtained from the level detectors are combined to form one level detection signal (ITOT). If the signals are in the form of current, the combining can be carried out directly by summating the signals.</p> |
