| 摘要 |
PURPOSE: To reduce the noise having a considerably bad influence upon the signal quality by providing an even numbered wave noise suppressing means which suppresses the noise component having two-fold frequency of a local oscillation signal. CONSTITUTION: A high frequency signal input circuit 10 which takes a high frequency signal as the input and adds the high frequency signal to a bias voltage or a bias current to output it, a local oscillation signal input circuit 20 which takes the local oscillation signal as the input and adds the local oscillation signal to the bias voltage or the bias current to output it, and a multiplication circuit 30 which takes the outputs of the high frequency signal input circuit 10 and the local oscillation signal input circuit 20 as the input and outputs the product of the high frequency signal and the local oscillation signal are provided, and the local oscillation signal input circuit 20 is provided with an even numbered wave noise suppressing means 21 which suppresses noise components having approximately even number-fold frequencies of the local oscillation signal. Thus, the frequency converter of less noise is constituted, and the current consumption of the high frequency amplification circuit is reduced.
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