| 摘要 |
<p>The device (1) measures the amplitude of odd order intermodulation lines produced by a nonlinear amplitude high frequency circuit (2), when the circuit is fed by an input signal e(t) comprised of two equal tones of frequencies f, and f2. In practice the high frequency circuit is a high-frequency amplifier. The measuring device has a beat detection circuit (3) which is connected to the output of the high frequency circuit and detects low frequency beats of the signal s(t) obtained at this output.S A harmonic filter (4) connected to the output of the beat detection circuit removes the odd order harmonics of the fundamental beat frequency (f1-f2)/2, the amplitude of the harmonic of order m, m(f1-f2) (m odd) being proportional to the amplitude of intermodulation lines of order m produced by the nonlinear high frequency circuit. The bent detection circuit has an envelope detection circuit (5) and a circuit (5,9) for the detection of the inverse envelope. A beat reconstitution circuit (6,8,10,11,15,16) alternately accounts for the rhythm of passages through zero of the envelope and the inverse envelope.</p> |
