| 摘要 |
PURPOSE: To remove any distortion in a receiver output by adding wobbling to a first local oscillator frequency. CONSTITUTION: This device is provided with a first local oscillator 28 which forms a first local oscillation signal to be supplied to first and second mixers 16 and 17, and a second local oscillator 30 which forms a second local oscillation signal to be supplied to third and fourth mixers 20 and 21 in an orthogonal relation. Then, this device is provided with an adding circuit 22 and a subtracting circuit 24 having inputs connected with the outputs of the third and fourth mixers 20 and 21, and a means which frequency-modulates the first local oscillation signal by a wobling frequency smaller than an offset frequency. That is, an error signal component Du can be separated from a desired signal component Dw except a moment when the amplitude of a wobling signal is turned into 0, and this is operated with the frequency precision (margin) of (2|fO-fW|). Thus, an output without any distortion can be obtained independently of the output of the subtracting circuit.
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