# US 6,519,715 B1 · Signal processing apparatus and a data recording and reproducing apparatus including local memory processor

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- Number: US 6,519,715 B1
- Document ID: US6519715B1
- Status: Granted
- Kind: B1
- Application number: 09/314,955
- Filed: 1999-05-20
- Granted: 2003-02-11
- Earliest claimed: 1998-05-22
- Assignees: Hitachi, Ltd.
- Inventors: Terumi Takashi; Seiichi Mita; Atsushi Saito
- Web page: https://patentgrep.com/patent/US6519715B1

## CPC

- G11B 20/10009: {Improvement or modification of read or write signals}
- G11B 20/00086: {Circuits for prevention of unauthorised reproduction or copying, e.g. piracy (indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00)}
- G11B 20/10055: {using partial response filtering when writing the signal to the medium or reading it therefrom}
- G11B 20/10074: {EPR4, i.e. extended partial response class 4, polynomial (1-D) *(1+D)2}
- G11B 20/10481: {optimisation methods}
- G11B 20/18: Error detection or correction; Testing {, e.g. of drop-outs}
- G11B 2020/10638: {First-in-first-out memories [FIFO] buffers}
- G11B 2020/183: {wherein at least one additional attempt is made to read or write the data when a first attempt is unsuccessful}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

In a data recovery processing, the conventional overhead, primarily, latency due to a rotational recording media is removed. Secondary, in a signal processing or in a recording and reproducing apparatus, reliability of data reproduction is improved by repeatedly processing data. These processing are achieved that input signal, i.e., raw analog signal read from the recording media is digitized to be stored in a secondary storage such as a memory or a FIFO memory. The apparatus includes a signal processing circuit to repeatedly process the stored digital signal in the secondary storage. When detecting data, operation of the circuit is efficiently controlled by a change over detector parameters, in which characteristics for the detecting performance. Resultantly, data recovery processing speed is increased and reliability of data reproduced is improved.

## Claims

### Claim 1

A data recording and reproducing apparatus, comprising:
a recording media;
a controller coupled to an external processing unit;
a recording and reproducing head controlled by the controller for recording information on the recording media and for reproducing information from the recording media;
a processor coupled to the controller;
a read/write amplifier for exchanging recording and reproducing information with the recording and reproducing head;
a recording circuit for outputting recording information to the read/write amplifier; and
a reproducing circuit, including a memory, for receiving as an input a signal from the read/write amplifier, detecting reproducing information in the signal from the read/write amplifier and supplying as an output a signal representing the detected reproducing information,
wherein the memory stores the signal from the read/write amplifier, and
wherein the reproducing circuit includes a function for outputting a signal to the processor in accordance with a predetermined condition, the signal changing a condition of signal processing in the reproducing circuit.

### Claim 2 (depends on 1)

A data recording and reproducing apparatus in accordance with claim 1, wherein the predetermined condition is a condition in which part of the reproducing circuit compares a signal with a predetermined threshold value.

### Claim 3

A data recording and reproducing apparatus, comprising:
a recording media;
a controller coupled to an external processing unit;
a recording and reproducing head controlled by the controller for recording information on the recording media and for reproducing information from the recording media;
a processor coupled to the controller;
a read/write amplifier for exchanging recording and reproducing information with the recording and reproducing head;
a recording circuit for outputting recording information to the read/write amplifier; and
a reproducing circuit, including a memory, for receiving as an input a signal from the read/write amplifier, detecting reproducing information in the signal from the read/write amplifier and supplying as an output a signal representing the detected reproducing information,
wherein the memory stores the signal from the read/write amplifier, and
wherein the reproducing circuit comprises:
a selector which selects a signal output from the memory or the signal output from reproducing circuit.

### Claim 4

A signal processing apparatus, comprising:
a reproducing means for receiving an analog signal;
analog-to-digital (A/D) conversion means for converting the analog signal into a digital signal;
storage means for storing the digital signal;
detecting means for detecting the digital signal; and
selection means for selecting an output from the storage means or an output from the A/D conversion means.