Abstract: A first rotational head of a first azimuth angle and a second rotational head of a second azimuth angle are arranged on a rotational drum rotated at a constant rotational speed. Also, input digital signals are processed in a signal recording system to form blocks of digital recording signals, a magnetic tape is moved by a tape driving unit according to an information signal generated in a control unit, and the blocks of digital recording signals and the information signal are recorded on the magnetic tape in a recording operation through the first and second heads alternately tracing the magnetic tape. In a reproducing operation, the signals are read through the first and second heads and are reproduced in a signal reproducing system. When the input digital signals are transmitted at a standard data rate, the magnetic tape is rotated at a first traveling speed in the recording and reproducing operations.

Abstract: Digital signals are recorded in sequential tracks on a tape-form recording medium. In the case where the digital signals are recorded in accordance with a first recording format, at least first digital signals for normal reproduction are recorded in a single area of the first format on each track. In the case where the digital signals are recorded in accordance with at least a second recording format, at least the first digital signals are recorded in a specific area among divided areas of the second format, the divided areas being rewritable independently on each track, the specific area being common for both the first and second formats. And, second digital signals for special reproduction are recorded in previously determined areas among recording areas on each track, the recording areas being common for both the first and second formats.

Abstract: A method of recording video data and the accompanied sound data capable of editing the video data and sound data track by track without editing gaps is disclosed. The track format includes a first block of tracks for video data and a second block of tracks for sound data for a predetermined number of frames. Another method of selectively recording one of a plurality of kinds of video data having different amounts of data per frame or field and the accompanied sound data (NTSC and PAL for example) is provided. In this method, the video data and sound data are recorded with a recording and editing unit which is a determined by a common multiple of the selected one of kinds of video data among the amounts of data of the different kinds of video data.

Abstract: A packet recording/reproducing system is provided which records or reproduces packets on or from tracks formed in time sequence on a magnetic tape. In a recording operation, the packet recording/reproducing system adds to input packets time stamps whose values are synchronous with packet arrival time control clocks produced by the system. The timing with which the packets are recorded on the magnetic tape is controlled by the arrival time control clocks so that a given number of the packets inputted at high data rate are recorded within a one-track area, a two-track area, or a one-track over area defined across at least two of the tracks, thereby minimizing the loss of capacity of the magnetic tape.

Abstract: A device for recording an information signal on a magnetic tape by using a helical scan include a rotary drum, a plurality of types of magnetic heads including at least one magnetic head of each of said types provided on the rotary drum for recording a corresponding type of the information signal, and switching units which switch said at least one magnetic head between a recording of the information signal and an erasing of the information signal. During rotation of the rotary drum, one type of said at least one magnetic head erases the information signal prerecorded on the magnetic tape before another type of said at least one magnetic head records a corresponding type of the information signal on the magnetic tape.

Abstract: In a recording and reproducing apparatus, time stamps are generated which represent moments of arrival of sequentially-inputted packets of data respectively. The generated time stamps are added to the sequentially-inputted packets respectively, and thereby the sequentially-inputted packets are converted into second packets respectively. The second packets are recorded on a recording medium. The second packets are sequentially reproduced from the recording medium. The time stamps in the respective reproduced second packets are detected. A detection is made as to whether each of the detected time stamps is correct or wrong. When a wrong time stamp is detected, a reproduced second packet is discarded which relates to the detected wrong time stamp.

Abstract: A recording/reproducing method which is capable of responding to the recording of various applications by flexibly changing the format of recording regions on a track of a recording medium. A track 20 is divided into a plurality of recording regions 22-32, and the data format of each recording region is selected in accordance with applications to be recorded. The preamble (or IBG) E.sub.PI is provided at the head portion of a track and the recording region to be independently rewritten or reloaded as occasion demands. A format information D.sub.PI indicating the presence of preamble or IBG is recorded in the data region E.sub.D. By designating required number of recording regions using the preamble (or IBG) E.sub.PI, it becomes possible to flexibly respond to the recording of various applications.

Abstract: A digital signal is recorded along tracks on a recording medium. Each of the tracks has plural areas. A portion of the digital signal which is recorded on a first area out of the plural areas includes information for reproduction of the digital signal. The information is recorded also on at least one of second areas out of the plural areas. The second areas are greater in size than the first area. The information includes, for example, subcode header information.

Abstract: Audio packets are separated from an input stream of packets including audio packets and video packets. The audio packets relate to audio information. The video packets relate to video information. The video packets are separated from the input stream of packets. The separated audio packets are recorded on first tracks among an array of tracks on a recording medium. The first tracks are spaced by equal intervals corresponding to a given number of tracks. The separated video packets are recorded on second tracks among the array of tracks on the recording medium. The second tracks differ from the first tracks. The first tracks are scanned, and the audio packets are reproduced from the first tracks during high-speed playback. An output stream of packets is generated in response to the reproduced audio packets during the high-speed playback.

Abstract: Identification (ID) error detection codes are formed which are synchronized at least with ID data and digital data of fixed length. The ID data are firstly separated into four-bit units of data. A first data is added to each separated four-bit unit of data. The data to which the first data is added is delayed by a period corresponding to each four-bit data. Further, a second data is added to the delayed data. The data to which the second data is added is delayed by the period corresponding to each four-bit unit of data. The delayed data to which the second data is added is multiplied by a coefficient .alpha..sup.4 related to a Galois Field (2.sup.4) to generate the second data. Further, the delayed data to which the second data is added is multiplied by a coefficient .alpha. related to the Galois Field (2.sup.4) to generate the first data. Four-bit Reed-Solomon codes defined on the Galois Field (2.sup.4) is thus formed. The Reed-Solomon codes become the ID data error detection codes.

Abstract: A method for recording and reproducing digital signals in and from a recording medium is provided. The digital signals are to be recorded in any given k-th mode of N-kind digital signal transmission modes of mutually different packet sizes. Digital signals of p.sub.k packets with additional data are recorded on tracks of the recording medium in unit of d.sub.k data blocks. Data blocks of a multiple of the least common multiple R of the data block recording units of the respective digital signals of the N-kind digital signal transmission modes are recorded in each track. The data blocks recorded in the recording medium are reproduced. Here, N is a two or more natural number, k is 1 to N, and p.sub.k and d.sub.k are a natural number. There is a case where the digital signals are to be recorded in first and second digital signal transmission modes of two different packet sizes.

Abstract: A magnetic recording and reproducing apparatus has a rotary magnetic head mechanism having at least a first rotary magnetic head with a magnetic gap set to a azimuth angle less than 90 degrees in a clockwise direction with respect to a width direction of recorded traces and a second rotary magnetic head with a magnetic gap set to a azimuth angle less than 90 degrees in a counterclockwise direction with respect to the width direction. The traces are formed on a magnetic tape moving in a forward direction at a speed in accordance with a rotational locus of the heads moving and obliquely crossing a travel direction of the tape. The first output signals obtained by the first head are selected in the case where a rotational locus surface of the heads changes in a reproduction operation within an angular range less than 180 degrees in a clockwise direction with respect to the traces formed on the tape.

Abstract: A digital TV broadcasting signal is demodulated to obtain a bit stream containing at least a first packet of a first program specific information concerning all TV programs conveyed by the digital TV broadcasting signal and first packets of the TV programs themselves. Selection data is entered for selecting at least one of the TV programs. In response to the selection data, only second packets are selected from among the first packets. The second packets contain only data of the selected TV program. The second packets are decoded. Further, the first packet and the second packets are output without decoding and accepted. The first program specific information is modified into a second program specific information concerning the selected at least one of the TV programs. The modification is executed after the first packet and the second packets are output. Or, the modification is executed before the first packet and the second packets are accepted.

Abstract: Information is divided into first blocks each having m bits, and n bit or bits in each of S different states are added to a head of each of the first blocks to change the first block into S second blocks each having m+n bits, where m and n denote predetermined natural numbers and S denotes a predetermined natural number equal to or smaller than 2.sup.n. Each of the S second blocks is pre-coded into S pre-coded information blocks respectively. One of the S pre-coded information blocks is selected as a modulation-resultant information signal in response to error signals related to the S pre-coded information blocks respectively. The modulation-resultant information signal has q different notch frequencies. The S pre-coded information blocks are converted into S amplitude signals representing amplitude values respectively. A set of q first waveform signals and a set of q second waveform signals are generated. The q first waveform signals represent waveforms related to the q notch frequencies respectively.

Abstract: A device for recording an information signal on a magnetic tape by using a helical scan include a rotary drum, a plurality of types of magnetic heads including at least one magnetic head of each of the types provided on the rotary drum for recording a corresponding type of the information signal, and switching units which switch the at least one magnetic head between a recording of the information signal and an erasing of the information signal. During rotation of the rotary drum, one type of the at least one magnetic head erases the information signal prerecorded on the magnetic tape before another type of the at least one magnetic head records a corresponding type of the information signal on the magnetic tape.

Abstract: In a digital information modulating apparatus, first information signal is separated every m bit or bits, and n bit or bits are added to the head of every m bit or bits to change every m bit or bits of the first information signal into every m+n bits of a second information signal, where "m" and "n" denote predetermined natural numbers. The second information is pre-coded into plural pre-coded information signals in accordance with combinations of the added n bit or bits. A determination is made as to whether or not predetermined sync information is present in the pre-coded information signals. A sync detection signal is generated which represents the result of the determination. One of the pre-coded information signals is selected as a modulation-resultant output signal in response to the sync detection signal.

Abstract: A method of generating codes for error checking from a first and second types of data trains, first type of data trains having m symbols, second type of data trains having n symbols, m and n being natural numbers and m<n, comprising the steps of: generating n-m dummy data: and attaching the n-m dummy data to the first types of data train is disclosed.

Abstract: A method for transmitting pieces of synchronized picture data having the same data length of which each include a synchronizing signal, an identifying code, pieces of compressed picture data having different data lengths and an error correcting code in that order is disclosed. To correctly decode each of the compressed picture data, it is required to start a decoding operation from a head address of each of the compressed picture signal. Therefore, in cases where a head address of a piece of compressed picture data exists in a piece of synchronized picture data, an existence information flag for informing the existence of the head address, an address pointer for indicating an address of the head address, and a block number for indicating a position of the compressed picture data having the head address are added just after the identifying code to correctly decode the compressed picture data and other pieces of following compressed picture data in the synchronized picture data.

Abstract: A standard definition (SD) corresponding image is derived from a high definition (HD) image by performing a vertical line sub-sampling for every field with a ratio of an N:1, where N is an odd number greater than 1. One of the simple sub-sampling methods, the pyramidal coding method and the sub-band coding method may be used. For first fields, every third line is derived. For the remaining fields, every third line positioned at the center of the lines derived from the first field is derived by taking positional relation thereof on a reproduced image screen into consideration. As a result, it is possible to obtain an SD corresponding image having an unbroken interlace structure.