Matsushita Electric Industrial Co., Ltd.

Ryoichi Wada

Mitsuharu Tsuchiya

Takanori Senoo

Kanji Odagi

Mitsuaki Oshima

Takeji Kimura

Atsushi Iga

Masahiko Tsunoo

Masaya Nakajima

Takanori Seno

Katsumi Fujisaki

Seno Takanori

Yutaka Neichi

A digital signal processor for recording an analog signal in the form of a PCM signal and/or for reproducing the PCM signal in the form of an analog signal. It has functions of generating a first and a second check code each by performing a modulo 2 operation and of adding a third check code to each of the first and the second check codes for detecting errors. The original signals can thereby be restored completely, even when up to two data sets have been subjected to errors.

Digital signal processor for use in recording and/or reproducing

A magnetic recording and reproducing system having a magnetic switching device of the thin film type which is disposed in a magnetic head and composed of a layer which is made of a magnetic material having a low coercive force and a layer which is made of a magnetic material having a high coercive force both layers are premagnetized by a magnetizing means; the magnetic switching is effected in the magnetic switching device in response to a magnetic recorded signal located on a facing magnetic recording media so that the magnetic switching is detected as a pulse voltage by means of a detecting coil which is wound around the magnetic switching device, so as to thereby generate a reproduced output corresponding to the recorded signal.

Magnetic recording and reproducing system

A synchronizing signal detecting circuit for synchronizing digital data receiving equipment is disclosed. Digital signals consisting of data and synchronizing signals obtained by repeating a predetermined pulse pattern many times are fed to a shift register in succession in synchronism with clock pulses. A gate circuit connected to the shift register detects the synchronization pulse pattern. A detector circuit detects a duration period of a coincidence signal which is the output of the gate circuit, and outputs a synchronous detection signal when the duration period of the coincidence signal exceeds the predetermined value. This synchronizing signal detecting circuit can detect synchronizing signals even when data errors are produced to some extent.

Synchronizing signal detecting apparatus

An error correcting device which is useful for digital data transmission, e.g.--in PCM (pulse coded modulation) type tape recorders. The positions of erroneous data are ascertained by an error detecting method such as the CRCC (cyclic redundancy check code) method. The error correction is performed using two kinds of check codes, P and Q. Check code P is obtained by a modulo 2 operation on each bit of a plurality of data. Check code Q is obtained by a modulo 2 operation on each bit of data which is successively shifted by adding extra bits having a predetermined polarity to the individual data units. By means of above-rated error detection method and the two check codes, the present invention provides an error correcting device which is capable of correcting up to two erroneous data units. The error correcting circuit is constructed simply, and error correcting performance is increased.

Error correcting device

A digital audio signal recorder for obtaining coded signals having a first check code generator for generating the sum of module 2 for each bit of pieces of predetermined sampled data; and further has a circuit operatively coupled to said generator for arranging the sampled data, a first check code and a second check code at positions spaced on a time axis from each other. This invention also provides a method of generating such a digital audio signal. This invention is advantageous because it makes possible a low rate of redundancy and a simple decode circuit.

Digital audio signal recorder

An apparatus for detecting the recording and reproducing state of a video tape recorder used in conjunction with a pulse code modulation adapter and including a signal processor for comparing for a predetermined period data from signals transmitted from the pulse code modulation adapter apparatus to the video tape recorder with data from the signals received from the pulse code modulation adapter apparatus from the video tape recorder and detecting whether the video tape recorder is in the recording or reproducing state in dependence upon the result of the data comparison.

Apparatus for detecting recording and reproducing state

An electronic musical instrument has a plurality of tone selectors which select musical tones; a waveshape calculator which calculates a waveshape represented by amplitudes at two or more than two sampled points of one period of the selected tone and which is operative whenever the tone selectors are actuated; a plurality of waveshape memories which temporarily memorize the calculated waveshapes; clock signal generator which generates clock signals with high frequencies corresponding to pitches of depressed keyswitches of the musical instrument and which is operative whenever the keyswitches are depressed; a reading circuit which repetitively and successively reads out the memorized waveshape amplitudes by the clock signal generated by the clock signal generator; and a converter which converts the waveshape amplitudes read out by the reading circuit to a musical tone, wherein a musical tone is generated by repetitively reading out the temporarily memorized musical waveshape.

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Habikino, Japan

Ryoichi Wada