Abstract: Input digital data are formatted into a data block composed of a predetermined amount of data, subjected to error correction encoding process, and recorded on a predetermined number of continuous tracks of a recording medium. In the error correction encoding process, the data block is subjected to an inter-track error correction encoding, an outer error correction encoding and an inner error correction encoding. In the inter-track error correction encoding, each information element to be coded is produced by symbols collected from the data which are to be recorded on different tracks of the continuous tracks. The error correction encoded data in the data block are distributed to a first predetermined recording area of each track of the continuous tracks, and parity code words produced by the inter-track error correction encoding are distributed to a second predetermined recording area of each track of the continuous tracks.

Abstract: A recording apparatus for recording digital data comprised of a plurality of recording blocks on a recording medium includes a grouping circuit which makes a group of the digital data according to a predetermined time-based interval, A sequence number generator divides the group into "N" sequences. "N" is an integer. A data block generator divides the input data in each sequence into a plurality of data blocks. A sequence number generator generates a sequence number for each data blocks associated with each recording blocks, An ID block generator generates an ID information of each data block based on the sequence number. A recording block generator generates the recording block based on the ID information and the data block.

Abstract: An apparatus serving as a digital videocassette recorder (VCR) for recording analog video and audio signals as digital signals. The apparatus serves also as a digital data storage drive. The digital VCR and the storage drive share common circuitry and a common magnetic recording medium. This reduces the cost and enhances the efficiency at which tracks are used. The apparatus has a large storage capacity. The apparatus divides input digital data into two parts and performs error correction encoding for each of these two data parts to form sync blocks. These sync blocks are recorded in an audio signal recording area and a video signal recording area, respectively, on the recording medium. Error correction codes used during reading of digital data are the same as those used during recording of video and audio signals. The same track structure and the same sync block structure are used for these two modes of operation.

Abstract: An apparatus for recording and reproducing a video signal has a recording portion and a reproducing portion. The recording portion has an analog-to-digital converter for converting analog video signal to digital video signal, a wave form data extraction circuit for extracting digital wave form data expressed in 8-bit detail and carried in a vertical blanking period of the video signal, and a converter for converting the digital wave form data to a quantized wave form data expressed in 2-bit detail. The video signal is recorded on a tape together with the quantized wave form data. The reproducing portion has a wave form data selector for selecting the quantized wave form data, a counter converter for converting the 2-bit quantized wave form data to the original digital wave form data of 8-bit detail, and an adder for adding the digital wave form data in a vertical blanking period of the video signal.

Abstract: A pilot signal is superposed and recorded on data at the beginning of each track. The beginning portion of the track is constituted only of codewords having a disparity of each 10 bits which is +2, 0 or -2. Also, the cumulative value of the disparities of every 10 bits may fluctuate in a period coinciding with the period of the pilot signal to be superposed. Therefore, the frequency spectrum in the beginning part of the track has a peak at the frequency of pilot signal, and using this peak as the pilot signal, tracking is controlled during reproduction.

Abstract: In order to reproduce highly important information easily and at high speed, such information is composed into data of fixed length and is assigned from the beginning of a block. Without increasing the recording rate, in order to record a signal so that the highly important information may be reproduced securely, a dummy sync block is inserted immediately before a data sync block which contains the highly important information for defining or explaining the content of the signal to be recorded. To maintain the error correction capability in a normal play mode, moreover, the sync block composition which is the same as in the signal to be recorded is used for the highly important information. In particular, as for such information, by assigning the information in plural sync blocks, reproduction is securely realized also in the case of a trick play mode.

Abstract: Two, HD and SD, signals are arranged so as to be identical to each other in the recorded form on a recording medium. Reciver circuits, encoder circuits, and a recording circuit for SD signals are provided. Also, a receiver circuit, an encoder circuit, and a recording circuit for HD signals are provided. In addition, a circuit is provided for identifying whether the input signal is an SD or HD signal. Accordingly, both the HD and SD signals can be recorded using one single digital VCR while no further hardware is involved. Simultaneous recording of a plurality of SD signals and high-speed dubbing of SD signals may be executed using an HD signal processing circuit.

Abstract: A data word of 8 bits is code-transformed into a code word of 12 bits, for an 8/12 code which is suitable for high density recording such as d=2 and k=10, two kinds of synchronous pattern which never appear in data can be respectively provided for the video and audio uses while keeping the limitation with respect to d and k. Accordingly, decision error between the video data and audio data resulting from reproducing error can be significantly decreased, leading to an improvement in error probability and yet it is realizable with an extremely practical circuit structure. In addition, a pilot signal can be generated digitally with an extremely simple circuit, being suitable for home-use digital VCRs or the like which requires a stable pilot signal. As a result, the error rate of a super high density recording apparatus such as, for example, a digital VCR can be significantly decreased, and thus, its practical effects are very large.

Abstract: A specific section provided in a track is set in a DC free state, and during reproducing, accurate tracking is conducted on the basis of the crosstalk from the pilot tone superposed in the adjacent tracks in this DC free section. Alternatively, a pilot tone is generated only in a specific section provided in the track, and when reproducing, accurate tracking is effected on the basis of the crosstalk of the pilot tone in the tracks adjacent to this section. As a result, the redundancy required for tracking is notably reduced.

Abstract: In a method of recording digital signals, in which all audio signals of N channels (N=integer) are recorded on M tracks (M=integer>N) where video signals of I fields (I=integer) are recorded, the improvement including: the M tracks being divided into N track groups each having S tracks (S=integer=M/N) arranged successively such that the audio signals of a j-th channel (j=integer) in the N channels are recorded on the tracks of an i-th track group (i=integer) in the N track groups.

Abstract: In a digital video signal recording/reproducing apparatus for recording digital VCR video and audio signals by using a rotary cylinder, for a video signal with a frame frequency fN of 30 Hz or 29.97 Hz, the rotating frequency of the cylinder is set to 2.5 times fN. On the other hand, for a signal with a frame frequency fP of 25 Hz, the rotating frequency of the cylinder is set to 3.0 times fP. As a result, as long as the cylinder diameters are identical, the relative speed of the tape and the head is the same for video signals of either frame frequency fN or fP.

Abstract: A train of data blocks, each carrying digital data and ID data are produced from a reading head as a tape passes the cylinder. A memory having a plurality of sections is provided, and a plurality of counters are provided correspondingly to the sections. The digital data are stored in a memory section identified by the ID data. Each time the digital data for one block is stored in a section in the memory, a counter corresponding to that section is incremented, and each time the digital data for one block is read out from a section in the memory, a counter corresponding to that section is decremented. Thus, as long as counter repeats "0" and "1", the data block is properly stored and properly read. However, if any one of the counters shows a number other than "0" and "1", it is understood that the writing or reading has been carried out twice in a row for the same section in the memory. Thus, an error in the ID data can be detected.

Abstract: A video signal recording/reproducing apparatus which records pictures by compressing the video signal in multiple field units and reproduces an signal by the expansion process, and which continuously and repeatedly outputs each field of the reproduced television signal on the screen by use of a field detecting unit which operates to ensure that a reciprocal of a multiplication index of a desired reproducing speed is selected as a number of continuous reproductions of one field and also by use of a change-over unit for changing over the reproduced signal in field units.

Abstract: A plurality of assumed detection value series correspond to combinations of a plurality of Viterbi detection series and a plurality of assumed detection values. The Viterbi detection series correspond to possible survived paths. The assumed detection values correspond to a current input value. A data series corresponds to intersymbol interference. Assumed input amplitude values are determined in accordance with the assumed detection value series and the data series. Differences between the assumed input amplitude values and the current input value are calculated. Likelihoods corresponding to degrees of sureness of survived path branches are calculated on the basis of the calculated differences. One of the possible survived paths is selected in accordance with the calculated likelihoods. A detection value is generated in accordance with the selected survived path.

Abstract: Each of data words has m bits. The m-bit data words are converted into corresponding n-bit code words. The n-bit code words are concatenated to form a bit sequence where the number of successive bits having a same binary value is limited to a range of a smaller value d to a larger value k. A code work W1 and also a following code word W2 are controlled to satisfy the limitation defined by the values d and k. The number of different code words forming an RLL code system is relatively large. For example, in respect of a first available RLL code word system, 8-bit data words are directly converted into 12-bit code words (Tw=0.667T) and the limitation defined by the values d and k equal to 2 and 10 respectively are satisfied. In respect of a second available RLL code word system, 6-bit data words are directly converted into 9-bit code words (Tw=0.667T) and the limitation defined by the values d and k equal to 2 and 23 respectively are satisfied.

Abstract: An apparatus converting three bits of binary data (B.sub.1, B.sub.2, B.sub.3) into two ternary symbols (T.sub.1, T.sub.2), in which even numbered pars of the ternary symbols (T.sub.1, T.sub.2), where (T1=T2), are replaced by a pair of ternary symbols (T'.sub.1, T'.sub.2) which do not correspond to any of the three bits of binary data (B.sub.1, B.sub.2, B.sub.3). The replacement occurs when the respective symbols in a respective pair of ternary symbols (T.sub.1, T.sub.2) are in the same ternary level; hence, a run-length of the same symbol can be restricted to four or less. Furthermore, the digital sum variation (DSV) is controlled in every synchronous block which is composed by the above-mentioned replaced output, thereby allowing a 3B-2T code which does not contain a DC component to be obtained. Moreover, inversion or noninversion of the synchronous pattern can be easily determined by distinguishing whether control of the DSV is applied or not to the synchronous block.

Abstract: A systematic method and apparatus for constructing a run length limited code in which the minimum number of continuous bits of the same binary value is constrained to d and the maximum number thereof is constrained to k.In converting m-bit data words to n-bit code words (n>m) to construct the run length limited code, selection means for n-bit code words usable to meet the d, k-constraint and a concatenation rule of the code words selected by the selection means are introduced.The selection means divides each of 2.sup.n n-bit bit sequences into a leading block L having l continuous bits of the same binary value, an end block R having .gamma. continuous bits of the same binary value and an intermediate block B having b(=n-l-.gamma.) bits between the blocks L and R.Only those n-bit bit sequences in which the blocks B thereof completely meet the d, k-constraint and the blocks L and R thereof meet conditions uniquely defined for given d and k are used as the code words.

Abstract: A block encoder comprises first block generating means for constituting a three-dimensional large-size block, and a plurality of second block generating means for dividing the large size block into small size blocks. The small size blocks of two dimensions and three dimensions are changed over adaptively in dependence on image information.

Abstract: Disclosed is a digital recording and reproducing apparatus for television signal, which is designed to record and reproduce by sampling a television signal at a frequency lower than the Nyquist frequency, by dividing the sampled signal into blocks each of which is composed of adjacent plural sampling points, by orthogonally transforming in each block, and by subjecting the orthogonally transformed signal to weighted quantizing. The apparatus has achieved the reduction of recording bit and decrease of error propagation rate simultaneously so as to be applicable to recording and reproduction even in a home use VTR.