Sharp Kabushiki Kaisha Corporation

Hiroaki Nogami

Soichi Iwamura

Hironobu Katayama

Kenichi Shiraishi

Junichi Aoki

Kazuya Aoki

Koichi Kawaguchi

Saori Akimoto

A digitally recording and reproducing apparatus simultaneously records two kinds of digital signals of an identical video program, generated by high-efficiency coding, or a relatively high bit-rate signal and a relatively low bit-rate signal, onto the approximately the same positions on the tape. The apparatus is constructed so that the low bit-rate signal is commonly used for normal playback and search-playback. Further, the recording time can be lengthened by reducing the recording bit-rate.

Digital recording and reproducing apparatus which multiplexes and

A digital recording and reproducing apparatus records two kinds of digital signals of an identical video program, generated by high-efficiency coding, or a relatively high bit-rate signal and a relatively low bit-rate signal, onto approximately the same positions on the tape. When the low bit-rate signal is commonly used for normal playback and search-playback or when it is used only for the search-playback, the amount of the search-playback data is adjusted so that data on a number of frames to be a unit for edit work may be recorded onto an integer number of tracks.

Recording apparatus which adaptively records amounts of low resolution

A digital VTR which is able to record a band-compressed signal having a bit-rate of 17 to 60 Mbps of a program while creating a low-bit-rate signal (1.5 to 5 Mbps) having the same program content as well as utilizing the low-bit-rate signal as a signal for the special playback. Variable speed playback data for a certain speed, which is recorded in the limited recording areas for variable-speed playback mode, is adapted to be used for playback at another speed in the variable-speed playback mode. The data structure of variable-speed playback data is adapted to change depending on the image areas on the image frame. Either of these embodiments or the combination of them, improves the quality of a reproduced picture during variable-speed playback mode in which a less amount of data is available than that of data read out at the time of a normal playback mode.

Recording and playback system for variable speed playback wherein more

A magnetic reproduction apparatus which uses a magnetic recording medium on which frequency-modulated signals produced by frequency-modulating a carrier with video signals are recorded, and demodulates reproduced signals from the magnetic recording medium into the video signals. The apparatus includes a frequency convertor for causing the reproduced signals to shift to a higher frequency region and a pulse-count-type FM demodulator for demodulating the reproduced signals which have shifted to the higher frequency region into the video signals. This arrangement restrains the mixing of the reproduced signals in the video signals. Therefore the video signals are reproduced with lessened waveform distortion, achieving a high-quality image.

Magnetic reproduction apparatus for reproducing a video signal

A magnetic recording-reproduction apparatus records and reproduces a wide-band video signal without a color burst signal. For this purpose, a two-step phase resetting operation is conducted on the FM carrier at the front porch and the horizontal sync pulse of the video signal so as to permit those phases to coincide with reference phases. A synchronizing panel clock generator generates the first reference signal with the first FM frequency corresponding to a peak level of the horizontal sync pulse and the second reference signal with the second FM frequency corresponding to a front porch level. In this case, the reference signals are phase-synchronous with each other at the leading edge of the horizontal sync pulse, and each of the FM frequencies is set to be an integer multiple of the horizontal scanning frequency. In another arrangement, a secondary FM carrier whose frequency has been shifted to a low-band is formed by generating a frequency conversion signal synchronous with the horizontal sync pulse and combining the phase-reset FM carrier with the frequency conversion signal. Either of the above arrangements can eliminate unwanted higher harmonic wave components and transient distortions in the frequency-demodulated output, thereby improving the image quality.

Recording-reproduction apparatus applying double reset to the phase of

An FM carrier is FM-modulated with a video signal for recordal on a magnetic medium. The phase of the FM carrier corresponding to a tip portion of a horizontal synchronizing pulse in the video signal is reset to, and the phase is fixed at, a reference phase at a leading edge of the horizontal synchronizing pulse and is fixed during every period of the horizontal synchronizing pulse width. In reproducing the video signal, the FM carrier, with its frequency doubled, is demodulated by a pulse count type FM demodulator having a frequency-doubling function. The FM carrier is always maintained in phase with the horizontal synchronizing pulse in the video signal, so that beat stripes or moire do not appear on the reproduced picture, and interference due to the leakage appears as reproduced picture distortion in correlation with the video signal. A reference burst signal necessary to a time base correction is extracted from the reproduced FM carrier.

Magnetic reproducing apparatus for reproducing a video signal from a

An FM modulator includes a base clock generating circuit (7) receiving an incoming video signal for generating an AFC reference frequency signal having a frequency and phase corresponding to a horizontal synchronizing signal of the incoming video signal, a first carrier reset pulse having the same frequency as the horizontal synchronizing signal and a second carrier reset pulse whose frequency is an integer mutliple of that of the horizontal synchronizing signal. The second reset pulse is generated at a timing speed lagged behind the first reset pulse. The FM modulator further includes an adder (3) for adding the first reset pulse to the incoming video signal for lowering the DC level at the leading edge portion of the horizontal synchronizing signal, and an oscillator (9, 9a, 9b, 10, 10a, 10b) whose oscillation frequency is changed dependent on the DC level of the output signal from the adder to produce a carrier FM modulated by the video signal. The oscillator is reset by the second reset pulse.

Growing community of inventors

Matsudo, Japan

Hiroaki Nogami