Sony Corporation

Chihoko Takizawa

Takahito Seki

Hajime Inoue

Masaki Kawano

A synchronizing signal extracting apparatus comprising synchronizing signal detecting circuit for detecting a synchronizing signal of predetermined bits from entered digital data, synchronizing signal generating circuit adapted to be reset by an output of the synchronizing signal detecting circuit, the synchronizing signal generating circuit generating an output in a timing of said synchronizing signal, and synchronizing signal extracting circuit for outputting, as a synchronizing signal, a result of an OR operation performed on the output of said synchronizing signal detecting circuit and the output of said synchronizing signal generating circuit, the synchronizing signal extracting circuit changing a state thereof according to match/mismatch in timing between the output of said synchronizing signal detecting circuit and the output of said synchronizing signal generating circuit. The novel setup outputs correct synchronizing signals and data enable signal even if the detection of synchronizing signals is missed or erroneously made, reduces chances of the missed detection of synchronizing signals even when the signal-to-noise ratio of reproduced signal is poor at digital VTR variable-speed reproduction or high-speed search, and implements synchronizing signal extraction of high precision.

Synchronizing signal detecting and error-correcting apparatus

The characteristic of a regenerative signal from a magnetic head 11 is compensated by a filter 14 serving as an equalizer. The regenerative signal thus compensated is then decoded at a decoder 15. An adaptive control unit 17 adjusts (modifies) the characteristic of the filter 14 on the basis of a decode error (residual) at the decoder 15 and an input to the filter 14. A servo control unit 18 sends a servo lock signal to the adaptive control unit 17 when a servo control operation at the time of reproduction is stabilized to start an automatic adjustment operation of the filter characteristic. Thus, it is possible to prevent in advance bad influence or effect on a compensating operation of the equalizer resulting from the fact that an adaptive adjustment operation of the filter characteristic might be carried out at the time when the servo control operation is unstable like at the time of building up of a reproducing operation.

Adaptive equalizer for magnetic reproducing apparatus

Respective regenerative signals from magnetic heads 1A, 1B are combined into one system through a changeover switch 9. After the reproducing characteristic is compensated by using a filter 4 serving as an equalizer, that combined signal is decoded at a decoder 5. An adaptive control unit 7 adjusts (modifies) the characteristic of the filter 4 so that it becomes optimum on the basis of a decode error (residual) at the decoder 5 and an input to the filter 4. The adaptive control unit 7 carries out an adaptive processing in a time divisional manner for every regenerative signal of respective magnetic heads 1A, 1B to send filter coefficients for the respective magnetic heads 1A, 1B to the filter 4. Thus, since the adaptive processing is carried out in a time divisional manner by the filter 4 and the adaptive control unit 7, the circuit scale can be reduced, resulting in low cost.

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Saitama, Japan

Chihoko Takizawa