Double frequency converter making possible shifting of the frequencies of first and second local oscillation signals by the same frequency

摘要

The bandwidth of the band pass filter is to be kept narrow to prevent C/N deterioration, and yet the video carrier and the audio carrier on the final output channel are to be maintained at the same level even if its center frequency deviates from the design value. A double frequency converter is provided with a first mixer for frequency conversion of input signals with first local oscillation signals into first intermediate frequency signals; a second mixer for frequency conversion of the first intermediate frequency signals into output signals with second local oscillation signals; and a band pass filter disposed between the first mixer and the second mixer, wherein the frequency of the first local oscillation signals and that of the second local oscillation signals can be shifted by the same frequency.