| 摘要 |
<p>The carrier wave frequency circuit consists of two modulators (11, 12) in parallel lines and each in series with a low pass filter (21, 22) and a further modulator (51, 52). The latter modulators are responsive to the same local oscillator voltage as the former. The output signals of the further modulators (51, 52) are collected by an adder stage (6), the output from which passes to another low pass filter (7), and from thence to a rectifier (8) and a final low pass filter. The filtering stages have the effect of removing the harmonics. The local oscillator signal to one of the parallel lines passes through a 90 deg. phase shift unit (1).</p> |
