| 摘要 |
PURPOSE:To suppress generation of an unnecessary angle modulation component, by inserting limiters of two stages or more between an AM-FM signal generator and a BPF, and also using a multiplication type amplitude modulator. CONSTITUTION:A signal wave of a sine waveform supplied to an input terminal IN is supplied to an AM-FM signal generator 15 and a waveform shaping circuit 16. In this case, when a degree of amplitude modulation by the generator 15 is large, an unnecessary angle modulation component is outputted by a limiter 9-1 and 9-2 of two-stage connection. On the other hand, a triangle waveform-like signal which is in phase with an input signal to the generatr 15, and whose head part becomes dull, namely, an output containing many 3rd higher harmonics is generated from a waveform correcting circuit 16. In this case, the circuit 16, a biased phase modulator 18 and a multiplication type amplitude modulator 11-1 operate jointly, and the unnecessary angle modulation component generated from the limiter 9-1 and 9-2 is reduced remarkably. |
