Abstract: A recording and reproducing apparatus for recording and reproducing sound using a semiconductor memory as a recording medium, the apparatus including index recording means for storing an index having retrieval information for retrieving an arbitrary position of recorded sound and positional information for indicating a memory address to be retrieved by the retrieval information; and retrieving and reproducing means for retrieving the index containing a specified retrieval information to reproduce the sound from the memory address indicated by the positional information of the index.

Abstract: In a recording and reproducing apparatus, a plurality of data groups having arbitrary data capacities are recorded in and reproduced from a memory card formed of a plurality of batch erasable semiconductor memories having equal capacities. At least one of the plurality of semiconductor memories is set to be a spare memory which does not contain recorded data. To erase only one data group, those data groups (other than the data group to be erased) stored in the same semiconductor memory containing the data group to be erased are recorded in the spare memory. Individual index data and card index data including updated reproduction order data and rewrite number data are also recorded in the spare memory. Thereafter, the semiconductor memory containing the data group to be erased is batch-erased and becomes a new spare memory.

Abstract: An error correction apparatus for reproducing data that have been multi-encoded with error correcting codes and recorded on a recording medium, and for correcting errors contained in the reproduced data through decoding the same. The apparatus includes: a reproducing circuit for reproducing the data encoded and recorded on the recording medium; a memory for storing the reproduced data; an error correction circuit adapted to correct errors of the data with the error correcting codes from the lowest to the highest levels in due order, for detecting that correction is impossible at the highest level and at an intermediate level between the lowest and the highest levels and for outputting a first and a second correction incapability detecting signals, respectively; and a controller responsive to the first and second correction incapability detecting signals for controlling the reproduction circuit, the memory and the error correction circuit.

Abstract: A sound recording and reproducing apparatus includes a semiconductor memory, an acoustic signal writing unit for writing a digital acoustic signal to the semiconductor memory, and a read out unit for reading out digital acoustic signals addressed in the semiconductor memory during sound reproduction (replay). An address memory stores these addresses as the acoustic signals are read out. A silence detector detects recorded silent or nearly silent portions during sound reproduction. The address(es) of these silent portions is (are) sequentially stored. In response to a recall or replay instruction, a controller reads out from the semiconductor memory digital acoustic signals at memory addresses that follow those sequentially stored in the address memory. As a result, recorded sound information (as opposed to recorded silence) may be quickly accessed and replayed upon recall at the beginning of recorded acoustic signals.

Abstract: A magnetic recording/reproduction device is disclosed that records data while forming serially a plurality of recording tracks on a magnetic tape. Each of the plurality of recording tracks have a plurality of data blocks recorded of the same bit length. Each of these plurality of data blocks includes a track data indicating the number of the track to be recorded and a synchronizing data indicating a synchronizing signal. The magnetic recording/reproduction device includes circuits for extracting the synchronizing data and the track data from each of the data blocks reproduced immediately after recording, a circuit for counting the number of synchronizing data extracted from the read out data blocks, a circuit for detecting a time period interval of synchronizing data for each recording track, a circuit for extracting track data from the read out data blocks, and a circuit for comparing the extracted track data with an expected data for each recording track.

Abstract: In a DAT (digital audio tape) recorder in which data is recorded and reproduced in a helical scanning system by using a rotary head, a magnetic tape is firstly wound back for usual reproduction when performing reverse reproduction. Data thus reproduced is once memorized in a memory, and data is outputted in the reverse sequence of the reproduction sequence from the memory. In this kind of reverse reproduction movement, the total sum of the number of data in each recording area is obtained by detecting the number of data thereof when winding back the magnetic tape. Winding back is stopped when this total sum exceeds the memory capacity of the memory. After that, usual reproduction is carried out and data after the next recording area of the recording area in which the total sum exceeds the capacity of the memory is memorized one after another in the memory.

Abstract: A coefficient setting circuit sets, in registers, coefficients corresponding to a position of each magnetic heads on a rotary drum. A counter circuit counts the number of pulses of a first reference clock signal employed as a reference signal for rotational control of the rotary drum. Comparison circuits compare the coefficients, set in registers, with a count value of the counter circuit and outputs reset pulses r1 and r2 when a match is detected between the set coefficients and the count value. In response to these reset pulses r1 and r2, counter circuits are reset to start the counting operation of a second reference clock signal. Consequently, decoders output timing pulses for controlling the timing of recording or reproducing operations for each magnetic head. The coefficients set by coefficient setting circuit are altered in accordance with alterations in the position of each magnetic head or the shape of the rotary drum, resulting in appropriate timing pulses.

Abstract: A data recording/reproducing apparatus can record/reproduce digital data because a parity check code is added to the data at the time of recording. The original data can be reproduced through error correction even though part of the data is lost at the time of reproducing. In the present recording and reproducing apparatus, data immediately after being recorded is read and the number of errors is detected by a parity check code. When the number of errors in the data is equal to or greater than a predetermined reference value, the data is re-recorded in another unit recording area. By setting the reference value at a value less than the maximum number of errors which can be corrected by parity check codes, data can be re-recorded without apprehension that the errors cannot be corrected because the increased number of errors has been caused by deterioration of the recording state of the unit recording area due to repetition of reproducing operations.

Abstract: An azimuth recording system has been adopted in order to heighten the recording intensity in a DAT (digital audio tape) recorder of rotary head type. For this reason, the width of a track is made more narrow than that of the magnetic head, and tracking control is conducted on the basis of the reproduction signals from the tracks at both sides during reproducing. In such a DAT recorder, in the case of rewriting data, the magnetic head is changed over to the recording mode at a point of time when reproduction operation is terminated for a corresponding track so that rewriting begins at a track which is disposed at least one thereafter the track to be rewritten, and new data is recorded, thereby causing a desired track which must be maintained to be prevented from being recorded over by a new track. In addition, a distinguisher information is recorded in each of tracks.

Abstract: Two magnetic heads having different azimuth angles are mounted on a cylindrical rotary drum. The data is recorded on the magnetic tape by means of the magnetic heads mounted on the rotary drum. When recording, a frame is composed of one track formed by one magnetic head, and another track formed by the other magnetic head. The data is recorded in the unit of one frame. When reproducing, one track is read by one magnetic head, and the other track is read by the other magnetic head. Plural sets of data to compose one frame are stored in the memory, when reproducing in the normal direction, as the addresses are specified for each set of data. The data stored in the memory is read out from the memory as the addresses are specified so as to be output in a predetermined sequence.

Abstract: A digital phase-locked loop system having an oscillator which generates a clock signal of a stationary frequency, a frequency divider which frequency-divides the clock signal to produce a phase-locked loop clock signal, a phase difference detector which detects a phase difference between an input signal and the phase-locked loop clock signal and outputs a phase difference detection signal, and a frequency dividing rate setting device to set a frequency dividing rate corresponding to the phase difference in response to the phase difference detection signal and apply the rate to the frequency divider. The phase difference detector includes a first counter to detect a phase difference at a leading edge of the clock signal from the oscillator and a second counter to detect it at a trailing edge of the clock signal.

Abstract: The preferred embodiment of the present inventioin hereby offers a unique and extremely useful multi-track magnetic recording and reproducing apparatus including: a data feed-out device comprised of one or two units of data-reproducing head(s) dealing with some of a plurality of data-recording heads; a control circuit controlling the tracking operations of the data-reproducing heads in response to the output of these reproducing heads; and an azimuth control circuit controlling the deviation time of synchronizing signals in response to the outputs of these reproducing heads.

Abstract: A multitrack magnetic recording and reproducing device of the type, which converts analog signals into digital signals and records and reproduces such converted data by splitting onto a plurality of tracks, comprises heads for both high and low recording densities such that track pitches corresponding to them are at an integral ratio. It includes a reproducing circuit having detecting-decision making means such as multiplexers which, when information recorded by a head for lower recording density is reproduced by corresponding heads for higher recording density, is adapted to determine whether any of the outputs from these heads is incorrect.

Abstract: The preferred embodiment of the present invention hereby offers a unique and extremely useful multi-track magnetic recording and reproducing apparatus including: a data feed-out device comprised of one or two units of data-reproducing head(s) dealing with some of a plurality of data-recording heads; a control circuit controlling the tracking operations of the data-reproducing heads in response to the output of these reproducing heads; and an azimuth control circuit controlling the deviation time of synchronizing signals in response to the outputs of these reproducing heads.

Abstract: A magnetic recording and reproducing device for recording information on the tape comprises an oscillation circuit for generating a reference clock, a position information generation circuit for generating position information, a recording head means, a reproducing head means, a means for controllably moving the magnetic tape and a central control circuit so that the device can record not only a primary information such as an audio signal but also a position information on the primary information. Such recording can be effected from any position on the tape such as immediately after an earlier recorded information (after-recording) by operating a simple input means such as a keyboard.

Abstract: A PCM type record-playback system converts an analog primary signal into a digital signal by sampling and quantizing it and concurrently records it on a magnetic tape with a secondary signal for showing the tape position. The primary and secondary signals are recorded on the same track in a time-divided manner so that recording can be effected with a small number of magnetic heads and the tracks on the magnetic tape can be effectively utilized.