| 摘要 |
PURPOSE:To demodulate an audio signal accurately with a TV receiver, by converting a broadcast frequency into a frequency of a TV audio signal and transmitting the signal mixed with an artificial video signal. CONSTITUTION:An FM broadcast signal received on an antenna 1e is amplified 16 via an input terminal 3e, given to a waveform conversion circuit 17 and converted into a square wave signal. The output of the circuit 17 is frequency- divided into e.g., 1/3 at a frequency division circuit 18 and an unnecessary frequency included in the square wave signal is rejected at a filter 19. This output signal is frequency-converted into an audio signal of a prescribed channel of TV band at a mixer 9e and mixed with a artificial video signal oscillated at a high frequency oscillating circuit 11e at a mixing circuit 12e, becomes a TV signal of the specified channel and applied to a TV receiver 5e from an output terminal 4e. |
