| 摘要 |
PURPOSE:To obtain a frequency converter which prevents the interference with other channels without requiring channel filters for input and output for every channel signal, by using two frequency converting circuits. CONSTITUTION:A television channel signal of the UHF band is inputted to an input-side frequency converting circuit 14 through an input band filter circuit 12, through which all of the band of this signal can pass, and is converted to an intermediate frequency. The converted signal is amplified in an intermediate frequency circuit 18 and is converted to a prescribed VHF band signal by an output-side frequency converting circuit 20 and is outputted through an output band filter 24. Frequencies from local oscillating circuits 16 and 22 applied to frequency converting circuits 14 and 20 are set to be higher than the maximum frequency of the UHF channel signal. In the frequency converting circuit shown in figure, the interference with other channels and the mixture of an image signal are prevented without narrow-band input and output filters. |
