Nec Corporation

Tokyo Broadcasting System, Inc.

Hideo Makita

Akihiro Takahashi

Kazuo Kashigi

Takaya Morita

Takashi Tachibana

When the margin between a write frequency-divided clock signal and a read frequency-divided clock signal becomes remarkably decreased, a clock phase difference detecting circuit outputs a reset execution command. While a reset execution command is being output in a blanking interval, a reset signal generating circuit supplies a reset signal to an input side counter corresponding to a reset execution command so as to reset the phase of the write frequency-divided clock signal to an initial state.

Clock phase synchronizing circuit

Transmitting and receiving apparatus, for transmitting an input video signal having 525 lines/field progressive scanning by converting the input video signal into a signal compatible with the NTSC system, and for reproducing from that NTSC-compatible signal a video signal having 525 lines/field progressive scanning. The transmitting apparatus has a first separating system for separating vertical high frequency components in a three-dimensional horizontal-vertical-temporal domain from the input video signal; a modulating system for modulating the separated components from the first separating system by .mu.-modulation; a system for filtering a modulation output from the modulating system to remove a lower sideband component from the modulation output, the filtering system having a Nyquist characteristic; and a system for multiplexing a filtered output from the filtering system to form the NTSC-compatible signal. The receiving apparatus has a second separating system for separating the multiplexed filtered output from the NTSC-compatible signal; and a system for reproducing a video signal having 525 lines/field progressive scanning in response to the filtered output from the second separating system. More particularly, the vertical high-frequency components have a vertical spatial frequency of 515/4 cph, and the filtered output from the filtering system has a frequency band of 2.2 MHz to 4.2 MHz.

Growing community of inventors

Tokyo, Japan

Hideo Makita