Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Haruo Ohta

Masaaki Kobayashi

Etsuto Nakatsu

Hideaki Mukae

Haruo Isaka

Takeshi Otsuka

Masao Tomita

Jun Takeuchi

Yoshikazu Katoh

Akihiro Takeuchi

Hiroaki Shimazaki

Tokikazu Matsumoto

Yasuo Hamamoto

Hideaki Yamashita

Atsuo Ochi

Masayuki Yoneyama

Takeshi Ootsuka

Hiroshi Higashitani

Mutsuyuki Okayama

Akio Hashima

Takeshi Ohtsuka

Yoshikazu Kato

Kouhei Baba

Kouhei Suzuki

Tadaaki Matsuo

An information recording system includes a recording medium capable of limiting a function by password and an information recording device for controlling the recording medium. The recording medium stores an input password, counts updating event(s) of a password, stores the update count of the password, outputs information stored in the password related information storage according to a READ request issued from the information recording device, compares a input password with a password stored in the password register, limits a predetermined function of the recording medium according to the comparison result from the password comparator. The information recording device stores a password and a password identification ID which is associated with the update count of the password, selects a password with reference to the update count of the password and the password identification ID and outputs the selected password into the recording medium to compare the passwords.

Information recording device, recording medium, and information recording system

A semiconductor memory device according to the present invention comprises a housing including a card bus connector for connection to a host device and having a PC card shape having a thickness of 5.0 mm, four SD memory cards housed in the housing and a control circuit for controlling transmission/reception of a signal between the card bus connector and the respective SD memory cards. The semiconductor memory device is suitably used as a recording medium of a host device for which a higher data transfer rate and a larger memory capacity are demanded. Further, a semiconductor memory device, which is attachable and detachable relative to the host device and thereby portable, and relatively inexpensively obtainable, can be provided, and is directly insertable into a laptop personal computer to be used.

Semiconductor memory device

In a recording device having one or more semiconductor memories mounted thereon, the number of semiconductor memories operating in parallel is restricted according to an available supply current of an accessing apparatus to which the recording device is attached.

Recording apparatus receiving current supply from an accessing apparatus

A memory card is equipped in a host apparatus and used for data recording. The memory card has a built-in flash memory and an internal ROM, and there is prestored a predetermined writable block size corresponding to a certain integral multiple of a size of an erase block. A write block size of a write command is issued by the host apparatus. The data size is detected and compared to the writable block size, so as to decide whether the write block size is an integral multiple of the writable block size, thereby judging whether write is permitted. Only when the write is permitted, data is written from the host apparatus into the memory card. If the write is not permitted, a response to inform an error is returned to the host apparatus.

Memory card able to guarantee a recoding rate and memory card system using the memory card

A magnetic recording/reproducing apparatus is provided in which among diametrically oppositely disposed heads, a recording head and an erasing head of a same channel are disposed adjacently to each other. The recording head is disposed so as to precede by two tracks the erasing head with respect to a direction of cylinder rotation, when insert-editing, using a reproduced signal obtained by the recording head, erase and record timing setting and head tracking are performed and an erasing current is not applied during the reproduction by the recording head. The reproducing heads are disposed so as to be angularly apart by about 90 degrees from the recording and erasing heads, and a rotary transformer for reproduction is applied with a shield measure and then, formed as a core independently at an upper portion of the cylinder. In addition, more narrow tracks are compatibly reproduced by the recording head.

Magnetic recording/reproducing apparatus with the recording/reproducing heads preceding the erasing heads

A reproduction signal is processed in an AD converter and an equalizer to be a decoder input signal . The decoder input signal is used to calculate a phase error signal and a quality judgement signal . A phase-frequency error detection circuit retains a sign of the phase error signal obtained when the quality judgement signal is changed in quality from &ldquo;good&rdquo; to &ldquo;bad&rdquo;. The phase-frequency error detection circuit then outputs, as a phase-frequency error signal , the phase error signal when the signal quality is &ldquo;good&rdquo;, and a given value corresponding to the retained sign when the signal quality is &ldquo;bad&rdquo;. A voltage controlled oscillator generates a recovered clock signal whose frequency is based on the oscillation control signal generated by the phase-frequency error signal

Clock recovery apparatus

A data detecting method and its apparatus for equalizing an input signal reproduced from magnetic recording media by partial response by employing at least one of partial response class 4 (PR4) and extended partial response class 4 (EPR4), and decoding the input signal. The input signal is equalized by PR4, and a first equalized signal is obtained. First decoded data is obtained from the first equalized signal. The input signal is equalized by EPR4, and a second equalized signal is obtained. Second decoded data is obtained from the second equalized signal. From the first equalized signal and second equalized signal, the signal condition of the input signal is judged, and the optimum data detecting method is discriminated. Thus, either the first decoded data or second decoded data is selected as detected data.

Data detecting apparatus and method thereof

In order to construct a PLL circuit corresponding to the plurality of reproduction channel rates by using only a digital loop filter, the generation of a clock in accordance with the reproduction signal, of which the reproduction channel rate varies, is implemented with only one voltage control oscillator in the case when the channel rate of the reproduction signal reproduced from the reproducer varies at n/m of the basic channel rate at the time of recording by allowing the divider to convert the output of the voltage control oscillator , which oscillates at the basic channel rate, into a reproduction clock through the n/m division. The control signal for controlling the voltage control oscillator is generated through the phase error detector and the digital loop filter , and by constructing this digital loop filter with a digital filter which processes using the reproduction clock gained through the n/m division, a PLL circuit with an equal loop delay and loop sensitivity for any data rate can be implemented where, even in the case that the reproduction channel rate varies at a ratio of n/m, the frequency characteristics vary in a similar manner accordingly.

Multi-rate clock generator and multi-rate digital data reproducing device

A reproduced signal is adaptively equalized in an adaptive equalizer after going through an AD converter. The AD converter, the adaptive equalizer, a phase error detector, a phase shifter, a DA converter, a loop filter, and a variable frequency oscillation circuit, all of which structure a PLL circuit, and a clock signal phase-locked to reproduced data is fed back to the AD converter. The phase shifter slightly shifts, as appropriate, a phase error detected in the phase detector according to the change in a barycenter of tap coefficients detected in a tap barycenter detection circuit. With such structure, signals can be processed in an accurate manner without causing competition in operation between the PLL and adaptive equalization.

Signal processing apparatus

A reproduction signal is processed in an AD converter and an equalizer to be a decoder input signal The decoder input signal is used to calculate a phase error signal and a quality judgement signal A phase-frequency error detection circuit retains a sign of the phase error signal obtained when the quality judgement signal is changed in quality from &ldquo;good&rdquo; to &ldquo;bad&rdquo;. The phase-frequency error detection circuit then outputs, as a phase-frequency error signal the phase error signal when the signal quality is &ldquo;good&rdquo;, and a given value corresponding to the retained sign when the signal quality is &ldquo;bad&rdquo;. A voltage controlled oscillator generates a recovered clock signal whose frequency is based on the oscillation control signal generated by the phase-frequency error signal

In a recording and reproducing apparatus having a simultaneous reproducing function, an adaptive filter outputs a pseudo crosstalk signal which approximates to frequency characteristics of crosstalk components leaking from recording data into a reproduced signal, and a subtractor subtracts the pseudo crosstalk signal from the reproduced signal, thereby canceling the crosstalk components

Recording and reproducing apparatus

Magnetic recording/reproducing apparatus with the recording/reproducing

A magnetic a tape recording/reproducing apparatus comprises a tape running unit, a recording and reproducing unit, a data memory, and a controller. The controller controls the tape running unit, the data memory and the recording and reproducing unit such that, in a recording mode, the input data are continuously written into the data memory at a first a data rate and the written data are intermittently read out from the data memory at a second data rate which is higher than the first data rate and intermittently recorded onto a magnetic tape, and that, in a reproduction mode, the recorded data are intermittently reproduced from the magnetic tape and intermittently written into the data memory at the second data rate and the written data are continuously read out from the data memory at the first data rate. The controller is responsive to indication information indicating that the tape is not in a recordable or reproducible position for stopping reading operation in the recording mode and writing operation in reproduction mode of the data memory and operation of the recording and reproducing unit and for controlling the tape running unit to transfer the tape to a recordable or reproducible position.

Magnetic tape recording/reproducing apparatus

A digital modulating/demodulating apparatus includes a demodulator for demodulating a modulated signal into a demodulated positional signal in response to a receipt of the modulated signal, a decoder for decoding the demodulated positional signal into a digital signal of N bits. A previous signal point on the constellation plane is defined by a previous demodulated positional signal and a current signal point on the constellation plane is defined by a current demodulated positional signal. The decoder outputs a digital signal of N bits, based on en amplitude and a phase of the previous signal point and the amplitude and the phase of the current signal point.

Digital modulating/demodulating apparatus and a digital demodulating

A digital signal magnetic recording/reproducing apparatus subjects a digital signal to a digital amplitude phase shift keying and records and reproduces the modulated signal thus obtained on a magnetic recording medium. Use of the digital amplitude phase shift keying technique makes it possible to remove the direct-current component in the recording signals, and to improve the utilization efficiency of the recording frequency band, thus making high density recording possible. In addition, since a plurality of modulated signals are frequency-multiplexed and recorded, almost the entire frequency band recordable on a magnetic recording medium can be utilized, resulting in an increase in recording density. Further in addition, a pilot signal produced by frequency-converting a carrier is frequency-multiplexed with a modulated signal and recorded and reproduced and the carrier is reproduced from the reproduced pilot signal, so that a redundant part for reproducing the carrier is not necessary.

Growing community of inventors

Kyoto, Japan

Haruo Ohta