Abstract: In a video signal processing circuit for removing an energy diffusion signal from a broadcasting satellite signal superposed with the energy diffusion signal, a video clamp circuit including a switching circuit for pedestal clamp for the purpose of maintaining a pedestal level as the basis of the black level of a video signal and a noise detection circuit for detecting the noise contained in the video signal, whereby the output from the noise detection circuit is applied to the switching circuit for pedestal clamp so that the clamp performance of the switching circuit for pedestal clamp is reduced by means of the output of the noise detection circuit when an S/N ratio applied to the noise detection circuit is not good, thereby improving the quality of the reception picture.

Abstract: A Colpitts type quartz crystal oscillator comprises a resonant circuit consisting of two capacitors connected in series across a quartz crystal, the latter serving as an inductive element. The resonant circuit is connected between the base and collector of a transistor, with the junction of the capacitors being connected to the emitter of the transistor to provide feedback. Means are provided to increase the gain of the transistor and thereby the driving excitation of the crystal above a normal value for a brief length of time after the oscillator is initially energized.

Abstract: A Colpitts type quartz crystal oscillator comprises a resonant circuit consisting of two capacitors connected in series across a quartz crystal, the latter serving as an inductive element. The resonant circuit is connected between the base and collector of a transistor, with the junction of the capacitors being connected to the emitter of the transistor to provide feedback. Means are provided to increase the gain of the transistor and thereby the driving excitation of the crystal above a normal value for a brief length of time after the oscillator is initially energized.

Abstract: Two pilot signals each transmitted with a predetermined but different frequency are demodulated in the receiving station and sent to a control circuit controlling a saw-tooth wave form voltage generator which is continually varying the frequency of an automatic tuner. The control circuit acts to stop the voltage generator when the demodulated pilot signals have a frequency equal to the predetermined frequency. The received signal can thus be automatically tuned to the transmitted signal.

Abstract: Two pilot signals transmitted at the beginning of transmission from a transmitting station are demodulated in the receiving station and one of the demodulated pilot signals is phase compared with a reference signal generated by the transceiver. A phase comparator generates a control signal having a voltage corresponding to the difference between the compared signals. The control signal is input to a local oscillator of the transceiver which generates a signal to automatically tune the transceiver to the incoming signal frequency.

Abstract: A transmitter unit comprises two resonant circuits which are caused to oscillate during transmission to produce two pilot signals of predetermined frequencies. The pilot signals are mixed with an audio signal and used to modulate a transmission carrier signal in a balanced modulator which forms two sideband signals. The transmission carrier signal and one of the sideband signals are suppressed to form a single sideband signal which is used to modulate a channel signal for transmission. A receiver unit comprises a voltage controlled local oscillator which produces a local oscillator signal which is hetrodyned with the modulated channel signal to recover the single sideband signal. A reception carrier signal is hetrodyned with the single sideband signal in a balanced demodulator to recover the pilot signals and audio signal, the latter of which is fed to a speaker.

Abstract: The video local oscillator signal is mixed with a signal from a fixed frequency oscillator to produce a difference frequency signal, which is frequency divided and gated to a counter during a predetermined time period in such a manner that the final count of the counter contains the channel number, which is digitally displayed.