Abstract: A video recorder for recording a video signal having one frame period and having a high resolution such as a high definition television signal. The video signal in a frame period is divided into two groups for corresponding to a respective field period of the video signal. The two groups are encoded efficiently and independently of each other. After encoding the respective data as respective variable length data signals, pseudo data is added to either one of the variable length data signals having a smaller amount of variable length data than the other variable length data signal so that the amount of variable length data in the divided signals is substantially equal for a designated period. The encoded data is then recorded on an optical disk by a recording mechanism using two respective channels. When reproducing a video signal having lower resolution, such as is used for a standard television system, the video signal is reproduced by decoding the encoded data for one channel.

Abstract: An optical disk apparatus having rewritable optical disk with a spiral groove which is used as an information recording track. The track has two hard address mark areas formed once every rotation of the track around the center of the disk. The hard address mark areas are arranged in a single virtual straight line passing through the center of the disk to avoid crosstalk between recorded data and the hard address mark area. The track also has a periodic radial wobble groove containing frequency information at a specified period. A servo control circuit controls rotation of the disk at a constant linear velocity (CLV) in response to frequency information from the wobble groove. The hard address mark area and the wobble groove are pre-formed when pressing the disk. Sectors of equal length, where picture and sound information is recorded, are formed by recording a soft address mark signal produced in response to the hard address mark.

Abstract: A method for encoding image data according to the present invention includes the steps of: specifying a type of a picture in a picture sequence including an I-picture, a P-picture and a B-picture; determining a position of at least one slice header in the picture in accordance with the type of the picture; and inserting the at least one slice header at the position determined in the determining step, wherein the position of the slice header is determined so that at least one of the relationships N.sub.i >N.sub.b and N.sub.p >N.sub.b is satisfied, where N.sub.i denotes the number of slices in the I-picture, N.sub.p denotes the number of slices in the P-picture and N.sub.b denotes the number of slices in the B-picture.

Abstract: A coding and decoding apparatus is used to code and decode video signals. Input video signals are enhanced by an emphasis circuit having a nonlinear characteristic increasing an enhancement degree as amplitude of the input video signal decreases. The enhanced video signal, outputted from the emphasis circuit, is compression coded in an encoder and a code stream, representing a compression coded video signal, is outputted from the encoder. The code stream is transmitted to a decoder and the decoder decodes the code stream, outputting a decoded video signal. The decoded video signal is fed to a de-emphasis circuit having a nonlinear characteristic increasing a suppression degree as amplitude of the input signal decreases. As a result, low noise high quality video signals is reproduced from the de-emphasis circuit.

Abstract: A disk apparatus composed of a disk recording system includes a disk recording medium divided into a plurality of regions in a track direction; a data compressor for compressing the data in terms of time, a recording data delaying apparatus for rearranging the compressed data in time series, a data compounding apparatus for compounding the respective channels into one data a data recording apparatus for recording on the disk recording medium the compounded data; and a data reproducing system including a data reproducing apparatus for reproducing compressed data recorded on the disk recording medium; a data separating apparatus for separating for each channel the reproduced data; a reproducing data delaying apparatus for adjusting the timing of the data of each channel; a data expander for expanding the compressed data of a plurality of channels; an apparatus for compressing in terms of time the data of each channel of signals of a plurality of channels; and separating, recording in a track direction the data

Abstract: In a recording and/or reproducing apparatus, digital video data to be recorded is temporarily stored in a buffer, and when the amount of data being stored in the buffer exceeds a predetermined value, the data is recorded on a recording medium for a constant period of time, and when the amount of data is less than the predetermined value, the data is intermittently recorded onto the next track of the recording medium. When being reproduced, the reproduced data is stored in the buffer temporarily so as to be decoded gradually, and when the amount of data being stored in the buffer is smaller than a predetermined value, the information is reproduced from the recording medium for a constant period of time, and when it exceeds the predetermined value, the information is intermittently are produced from the next track.

Abstract: In an image coding method, a picture is divided into blocks composed of adjacent plural pixels, and a reference picture is used to predict the picture to be coded. A block including an image region not existing in the reference picture, i.e. newly appearing in the picture to be coded by the movement of an object included in the picture, is detected as an independent block, and the independent block is coded independently, without prediction from the reference picture.

Abstract: An optical apparatus digitizes a first signal, reproduce or records and reproduce the digital information compressed in a band up to a specified bit rate A1 at a specified rotating speed K or specified linear velocity V, digitizes a second signal, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A2 at a rotating speed of about K.times.A2/A1, or a linear velocity of about V.times.A2/A1, and thereby reproduce or records and reproduces information of plural signals, or reproduces or records and reproduces information of plural compression rates by using only one apparatus. It also digitizes a first signal, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A1 in n optical channels, digitizes a second piece of information, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A2 in about n.times.

Abstract: In signal processing method, bandwidth compression codes an image signal by blocks of plural proximal pixels, and outputs the decoded signal after decoding by the same block units. When a level difference occurs during decoding at the border between adjacent blocks, the level of the pixels near the block border is corrected so that the level difference is reduced before outputting the decoded signal. In addition, if the level difference between two pixels within the same block and at the border thereof is less than a predetermined level during decoding, and the difference between the level of two border pixels in adjacent blocks is greater than the level difference of the two pixels within the same block, the decoded signal is output after pixel level correction is applied near the block border to reduce the level difference of the two pixels in the adjacent blocks. Thus, the level difference between blocks is smoothed, and visual image deterioration resulting from block distortion can be greatly improved.

Abstract: A recording and reproducing system for digitizing the image signal and compression coding the signal by in-field and inter-field, or in-frame and inter-frame coding, wherein the inter-field or inter-frame coding is used as the primary coding method, in field or in-frame coding is applied at a regular interval, and when scene changes are detected, in-field or in-frame coding is mandatorily applied to the field or frame immediately after the scene change. Furthermore, a new in-field or in-frame coding cycle is started at the field or frame immediately after the scene change to absorb the increased information resulting from in-field or in-frame coding by increasing the compression ratio of the inter-field or inter-frame coding means within the period to the next in-field or in-frame coded field or frame.

Abstract: An optical apparatus digitizes a first signal, reproduce or records and reproduce the digital information compressed a band up to a specified bit rate A1 at a specified rotating speed K or specified linear velocity V, digitizes a second signal, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A2 at a rotating speed of about K.times.A2/A1, or a linear velocity of about V.times.A2/A1, and thereby reproduces or records and reproduces information of plural signals, or reproduce or records and reproduces information of plural compression rates using only one apparatus. It also digitizes a first signal, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A1 in n optical channels, digitizes a second piece of information, reproduces or records and reproduces the digital information compressed in a band up to a specified bit rate A2 in about n.times.

Abstract: The coded signal is output with a frame sequence that differs from the frame sequence of the input video signal by outputting the frame information coded by in-frame or inter-frame coding before the frame information coded bay interpolation coding based on the successively preceding frames. Frames immediately preceding a scene change are coded by a method other than field interpolation coding, frames immediately after a scene change are coded by in-frame coding, and the coded information for the frame immediately after the scene change is output after the coded information for the frame immediately before the scene change.

Abstract: A signal reproducing apparatus reproduces a video signal from a recording medium in which a first modulation signal has a video signal frequency-modulated at carrier frequency fc and a second modulation wave has a second signal modulated in a lower frequency region than the frequency fc. A frequency demodulation circuit for frequency-demodulates a first modulation wave and subtracts the cross modulation interference generated in the demodulation signal depending on the output from a detecting circuit. A first filter separates the second modulation wave from the reproduced signal. A detecting circuit detects the cross modulation interference component remaining in the demodulation signal in a specified period from the output signal of the first filter and the output of the demodulation circuit.

Abstract: A video tape recorder wherein when a video signal is frequency-modulated, the phase of a frequency-modulated wave is in a predetermined phase relationship with respect to the video signal. The frequency modulator is driven so that the video signal is time-base compressed to form a space of time. Then, a non-video signal is inserted into the space of time, and the frequency-modulated wave is brought into a predetermined phase having a synchronous relationship with the video signal. Furthermore, in another arrangement, during the reproducing operation, a regenerative demodulated signal is time-base expanded in order to avoid outputting noise due to the discontinuity in phase of the frequency-modulated wave which has arisen within the non-video signal contained space of the regenerated demodulated signal.

Abstract: A frequency demodulation circuit superposes pulses on an input frequency-modulated (FM) signal at substantially the peaks of the FM signal before demodulating the FM signal so that zero cross points of the FM signal can be correctly restored. A peak detection circuit detects peaks of the FM signal or peaks of the fundamental wave of the FM signal, which substantially correspond to the peaks of the FM signal. A pulse generating circuit generates, from the peak detection result, pulses respectively occurring at the same timings as those of the detected peak occurrance timings. The generated pulses are added to the FM signal to obtain the pulse-superposed FM signal.

Abstract: Disclosed is a video tape recorder capable of recording and reproducing signals with largely different frequency bands such as narrow band signals including NTSC signal and wide band signals represented by high definition television signal. In a time axis expansion circuit, wide band signals are expanded of their time axis and divided into plural channels, and the band frequencies of these channels are lowered, and at the same time, the widths of plural heads are set narrower than the head width used when recording and reproducing the existing narrow band signals, thereby realizing the recording and reproduction of narrow band signals and wide band signals at identical rotating speed of the cylinder and at identical rotating speed of the capstan.

Abstract: A frequency demodulation circuit disclosed superposes pulses on an input frequency-modulated (FM) signal at substantially peaks of the FM signal before demodulating the FM signal so that zero cross points of the FM signal can be correctly restored. A peak detection circuit detects peaks of the FM signal or peaks of the fundamental wave of the FM signal, which substantially correspond to the peaks of the FM signal. A pulse generating circuit generates, from the peak detection result, a train of pulses respectively occurring at the same timings as those of the detected peak occurrance timings. The generated train of pulses and the FM signal are respectively fed to differential inputs of a differential input type limiter. An output signal of the limiter is fed to a pulse count circuit to obtain a frequency demodulated signal.

Abstract: A waveform improving apparatus improves the contour of a waveform of a first signal which has a reduced frequency band by using a control signal generated from a second signal which has a correlation to the first signal. A waveform adjusting circuit increases the level of the first signal waveform at the rising slope portion thereof and decreases the level of the first signal waveform at the falling slope portion thereof to obtain a waveform-adjusted first signal. A control pulse generating circuit differentiates the second signal twice to obtain a control pulse having a predetermined duration and terminating at the center of a slope portion of the first signal waveform. A sample/hold circuit is responsive to the control pulse for sampling a level of the waveform-adjusted first signal and holding the sampled level during the duration of the control pulse thereby obtaining a waveform improved first signal.

Abstract: An FM signal obtained by modulating a carrier f.sub.c with a signal f.sub.s is demodulated by a frequency demodulator to obtain a demodulated signal which contains a lower sideband component as an undesired moire component. A moire component generator generates an mf.sub.c -nf.sub.s component (m and n: natural numbers) from the demodulated signal or generates an nf.sub.1 -(n-m)f.sub.c component (f.sub.1 : first lower sideband component of the FM signal) from the FM signal. A subtractor subtracts an output of the moire component generator from the demodulated signal so as to thereby eliminate the undesired moire component. Furthermore, to eliminate a cross-modulation moire due to crosstalk of a low-frequency signal f.sub.L, the moire component generator generates a 2f.sub.L component from the FM signal.

Abstract: Disclosed is an encoder circuit for converting a color difference signa into a carrier chrominance signal for use in a component VTR, camera, etc. The color difference signal is clamped by an automatic clamper, and then, this signal is used for balanced-modulating a color subcarrier whereby a first balanced-modulated output is obtained. Then, within a conversion circuit receiving the color subcarrier and the first balanced-modulated output as inputs thereto, a carrier leak existing in a predetermined period of the first balanced-modulated output is converted to D.C. levels changing at predetermined intervals. Here, the changes of the D.C. levels are such that their polarities aare inverted at the predetermined intervals with respect to a D.C. level appearing when no carrier leak exists. A difference between the D.C. levels changing at the predetermined intervals is detected, and a feedback loop is formed for controlling the D.C. level in the automatic clamper using the detected difference.