US 5,293,275 A · Data recovery system for information recording media

Abstract

A floppy disk recording data regeneration system having a voltage-controlled delay circuit, voltage-controlled data phase shifting circuit and a loop filter made up of a first-stage low-pass filter with a first cut-off frequency, and a second-stage low-pass filter with a second cut-off frequency lower than the first cut-off frequency. The output voltage of the second-stage low-pass filter drives the voltage-controlled data phase shifting circuit, and the output voltage of the first-stage low-pass filter drives the voltage-controlled delay circuit. The amount of delay of the oscillation output pulse is adjusted by the voltage-controlled delay circuit to suppress the occurrence of read errors in the event of peak shifts. In the event of a wow and flutter fluctuation, the amount of shift in the phase of the read data signal pulse is finely adjusted to suppress the occurrence of read errors in subsequent stages. In a data recovery system having this type of phase correction circuit, correction is also performed in the event of jitter due to the occurrence of power source fluctuations, and, therefore, countermeasures for suppressing power source fluctuations can be implemented relatively easily.

Claims8

Dependent claims

Data regeneration apparatus for use in data storage systems to suppress errors in data recovery where the data is digitally recorded on and retrieved from an information recording medium in the form of pulses which may be subjected to peak shifts and frequency fluctuations induced by storage system operation, comprising:

waveform shaping means for receiving and shaping data signals in the form of pulses from an information recording medium, and generating a shaped read data signal having a fundamental pulse period;
phase synchronizing means connected to an output of the waveform shaping means for generating a synchronizing signal synchronized with the data fundamental pulse period having a loop filter;
phase correction means connected to receive the synchronizing signal and an output of the loop filter, for adjusting the relative phase between said synchronization signal and the shaped read data signal in the presence of undesired frequency fluctuations, in response to an output voltage of the loop filter;
and
a data normalizer connected to receive at least one output from said phase correction means and receive said shaped read data signal and configured to generate a normalized read data signal and a window signal from the received read data signal in response to the phase correction means output.

2 more elements

Dependencies are inferred from the claim text.

Data recovery system for information recording media

Life of this patent

Data recovery system for information recording media

Life of this patent

Abstract

Claims8