JPS59127270A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To control a reproduced synchronizing clock and the number of revolution of a disk by counting minimum and maximum edge lengths Nmin and Nmax by the reproduced synchronizing clock, and detecting an edge interval longer than an Nmax clock when a following edge comes before an Nmin clock. CONSTITUTION:When the number of revolution increases (decreases), a VCO6 outputs a clock synchronizing with a pulse train from an edge detector 3 within the locking range of a phase-locked loop 14. This clock leads (lags) the clock of a reference clock oscillator 9 in phase and decreases (increases) the number of revolution through a phase-voltage converter 10. When the loop 14 enters a step- out state to increase (decrease) the number of revolution, a minimum (maximum) pulse length detector 7(8) increases the oscillation frequency of the VCO6 so that the minimum (maximum) pulse interval of the pulse train from the detector 3 is larger than the Nmin clock (Nmax clock) by the clock of the VCO6. This frequency becomes larger (smaller) of the clock of an oscillator 9 and the number of revolution is increased (decreased) by converters 10 and 11 and a driving circuit 12 to a number of revolution that the loop 14 synchronizes with.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to disc reproduction and is to control the disc rotation speed and linear velocity to be constant.

Generally, Digital Fist Audio Disc (hereinafter referred to as DAD)
), the disk rotational speed χ linear velocity is constant (CL
V: constant 1inear velo
When trying to control the pressure so that the disc playback position (distance from the center of disc rotation) is to be detected by a position sensor, it is conceivable to control the disc rotational speed χ based on this information. Another possibility is to control based on the reproduction signal χ from the disc.

The signal recorded on the disc is NRZ-1 (information is 1
The regenerated synchronization clock can be regenerated using the edge when the signal is inverted.

Here, the edge interval is 8m of the reproduction synchronization clock.
It is in the range from 1n clock to %r'imax lock.

The present invention relates to disc rotation speed control and playback synchronization clock generation in a digital Audica fist disc player, and relates to the minimum and maximum edge lengths Nm1.
n*Nmax 'l, is counted using the reproduction synchronization clock, and detects when the next etch comes earlier than the Nm1n clock, and when the edge interval is longer than the N1naX clock, and thereby the reproduction synchronization clock is detected. In addition, the disk rotation speed control 7 is performed.

An embodiment of the present invention will be described below with reference to FIG.

In the figure, l is the disc to be played, 2 is the pickup that reads signals from the disc, and 3 is the pickup 2.
An etch detector that extracts the etch portion of the signal read out. 4.5.6 are a phase comparator, a charge pump and a low-pass filter, and a voltage controlled oscillator (VCO), respectively.
These constitute a phase locked loop 14 (PLL). 7.8 are a minimum pulse length detector and a maximum pulse length detector, respectively, and the edge interval from the etch detector 3 is compared with the clock of the voltage controlled oscillator 6.

It is detected whether it is shorter than Nm1n or longer than f'JmaH, and an error signal for the charge pump 5 is generated.

10 and 11 are converters that perform phase-to-voltage conversion (compared with reference clock oscillator 9) and speed-to-voltage conversion for the regenerated synchronized clocks generated by 1 to 8 above. Reference numeral 12 indicates a motor drive circuit. %13 indicates a motor.

When this system is in a synchronous state, the pulse train from the etch detector 3 has an interval of Nmi. above and below NmaX, the above detection fM7. The phase-locked loop 14 outputs the error signal from 8, and generates a clock synchronized with the pulse train. In this state, the regenerated synchronization clock is also synchronized with the reference clock of the reference clock oscillator 9, and the system is balanced.

Here, when the rotation of the disk l changes and the rotation speed becomes faster (slower), within the synchronization range of the phase locked loop 14, the output of the voltage controlled oscillator 6 is a clock signal synchronized with the pulse train from the etch detector 3. oscillate. The clock of the voltage controlled oscillator 6 leads (lags) the reference clock of the reference clock oscillator 90 in phase, and the clock of the voltage controlled oscillator 6 leads (lags) the reference clock of the reference clock oscillator 90.
The motor speed is slowed (advanced) by 130 rpm.

Also, due to the rotational change of the disk l, one phase locked loop 1
4 is out of synchronization and the number of revolutions becomes faster (slower) by one, the minimum pulse length detector 7 (maximum 2 < pulse length detector 8
) is a voltage controlled oscillator so that the minimum pulse interval (maximum pulse interval) of the Norse train from the etch detector 3 is equal to or more than Nrnln clocks (less than Nmax clock) with the clock of the voltage controlled oscillator 6. Raise (lower) the lift frequency by 60. Then, the oscillation frequency of the controlled oscillator 6 is based on M
It becomes thicker (less than) than the clock of the clock oscillator 9, and the rotation speed Y of the motor 13 is lowered (increased) by the converter io, II and the motor drive circuit 12, and the phase locked loop 14
Rotate the disc at a rotation speed that is synchronized with the discs.

With the above configuration, the disk can be rotated at a constant linear speed without detecting the reproduction position by any other means. Furthermore, the locking range of the phase-locked loop 14 can be greatly expanded.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. ■...Disk, 3...Etch detector, 7°...Minimum pulse length detector, 8...Maximum pulse length detector, 9
°°° Reference clock oscillator, 10... Phase-voltage converter, ]1... Frequency-voltage converter, 13... Motor, 14... Phase locked loop.

Claims (1)

[Claims] In a disc reproduction device in which the minimum and maximum etching intervals of information reproduced from a disc on which spiral or concentric circular information is recorded are predetermined, the reproduction synchronization clock is determined from the edge of the trace signal read from the disc.・Means for detecting edges shorter than a predetermined minimum etch interval of the input signal by comparing the etch interval of the input signal read from the disk with a reproduction synchronization clock; The oscillation frequency of the voltage-controlled oscillator in the phase-locked loop that generates the regenerative synchronized clock is raised or lowered by the means for detecting the interval, thereby making the etch interval of the input signal greater than or equal to the minimum edge interval and less than or equal to the maximum etch interval. means for making the oscillation frequency of the voltage controlled oscillator (
1. A single-disc playback device characterized in that it is configured to control the rotational speed χ of the disc by comparing the frequency and phase Y of the reference frequency with the reference frequency.