| 摘要 |
<p>1275813 Keying oscillators PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 30 Oct 1969 [31 Oct 1968] 53201/69 Heading H3R In a modulation system for television signals the carrier signal oscillator 6 is keyed by the synchronizing pulses to interrupt the oscillation during each synchronizing pulse. The video and synchronizing pulses are applied at 12. The synchronizing pulses being separated and applied via amplifier 13 to key a Gunn oscillator 6. The video signal is fed via a further amplifier 14 to a further Gunn device 10 which is biased below its oscillation threshold, and which acts as a variable impedance modulator across the output of a directional coupler 8 is the oscillator 6 output circuit. The Gunn device 10 is mounted in a waveguide, Fig. 2 (not shown).</p> |
