| 摘要 |
PURPOSE:To transmit two analog picture signals through conventional one radio channel by transmitting a carrier after frequency-modulating the carrier with the 1st analog picture signal and further amplitue-modulating it with the 2nd analog picture signal. CONSTITUTION:The 1st analog picture signal supplied to a terminal 1 frequency- modulates a carrier by a frequency modulator FM. The output of the frequency modulator FM is further amplitude-modulated for about 50% with the 2nd analog picture signal supplied from another terminal 2 at an amplitude modulator AM. Then this modulated wave is mixed with the output wave of a transmitting local oscillator T-LOC at a frequency converter CON and radiated outside through an antenna ANT-1. At the receiving side, the mixed waves become the frequency-modulated component only by means of an amplitude limiter LIM and the 1st analog picture signal is regenerated by a frequency discriminator DISC which demodulates the frequency modulated component and, at the same time, only the 2nd analog signal is detected and outputted by means of an amplitude detector DET. |
