JPS6257173A - Digital signal reproducing control device - Google Patents

Abstract

PURPOSE:To reproduce a normal clock by moving automatically leading-in of a phase locked loop PLL, by supplying an error signal of a rotation control system to the PLL circuit control system of a self-clock circuit. CONSTITUTION:A rotary system controlling circuit 5 and a PLL circuit 2 are connected through a signal correcting circuit 8. In this state, a torque variation which appears in a rotary system such as a motor, etc. under the condition that a large jitter is generated is detected as an error signal by a detecting circuit 7, and this error signal is corrected to a correct state by the circuit 8, and thereafter, applied to the circuit 2. In this way, a leading-in range of the PLL can be moved automatically, and a normal clock reproduction can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a digital signal reproduction control device used in digital audio equipment and the like.

BACKGROUND OF THE INVENTION In recent years, digitalization of audio equipment has progressed rapidly, and in particular, compact discs (AN) have become widespread.

On the other hand, digital recording and reproducing devices using magnetic tape are also being put into practical use, and there are signs that they will penetrate deeply into the field of analog audio equipment in the future, along with CD players.

Furthermore, as various technological developments have progressed to make devices smaller and lighter, portable types of the above-mentioned devices have also begun to appear.

Generally, playback control devices for digital equipment use a so-called self-clock technology, which extracts a clock for reading data from data and uses it to extract bits.A typical self-clock circuit For this purpose, phase locked loop (PLL) is used. This allows the reproduction signal detection pickup means (
Fluctuations in the time axis of the reproduced signal caused by fluctuations in the relative speed between the data recording medium (including the magnetic head) and the data recording medium have almost no effect on demodulation.

Problems to be Solved by the Invention However, as mentioned above, as devices become more portable, the disturbances that devices receive become more complex, and for example, vibrations can cause skipping, distortion, noise, etc. in the reproduced sound. Ta. This is because a disturbance exceeding the control range of the PLL is added, and normal or lock playback is not possible, resulting in an error, which is a fatal problem for portable devices.

In view of the above problems, the present invention changes the control characteristics of the PLL circuit that constitutes the self-clock circuit in the digital signal reproduction system when a speed fluctuation occurs in a rotation system such as a motor due to disturbance such as vibration. The present invention provides a digital signal reproduction control device that changes the tracking characteristics for disturbances.

Means for Solving the Problems In order to solve the above problems, the digital signal reproduction control device of the present invention includes a PLL circuit control system of a self-clock circuit for clock reproduction of digital signals, for driving a digital signal recording medium. It is equipped with a configuration that can mix error signals of the rotation control system.

According to the above-described configuration, the error signal (error signal) obtained in the rotation control system that receives disturbance acts to expand the pull-in range of the PLL control system, so that the time axis fluctuation ( Even if the jitter increases more than usual, lock playback can be performed normally.

Embodiment Hereinafter, a digital signal reproduction control device according to an embodiment of the present invention will be described with reference to the drawings.

The figure shows a block diagram of the main parts of a digital signal reproduction control device according to an embodiment of the present invention.

In the figure, 1 is a self-clock circuit, and a phase locked loop (PLI, circuit) 2 and a waveform shaping circuit 3 are representatively shown. 4 is a reproduction signal input terminal to which a digitally modulated signal such as PCM before demodulation is applied. ◇ 6 is a rotation system control circuit, which is used to drive a recording medium such as a disk or magnetic tape or to trace a signal track. Necessary mechanical drive system control circuit, of which 6 is the motor and 7 is the control circuit of the mechanical drive system.
is the main error signal detection circuit of the motor control system.

8 is a signal correction circuit, which buffers between the error signal detection circuit 7 of the rotation system control circuit 5 and the feedback circuit 9 of the PLL circuit 2;
This circuit corrects signals to a state suitable for mixing.

In the digital signal reproduction control device of this embodiment configured as described above, normally, after the signal applied to the reproduction signal input terminal 4 is waveform-shaped by the waveform shaping circuit 3, the signal is subjected to self-clocking by the PLL circuit 2. The clock signal is extracted, the bits are extracted using the clock, and the data is transferred to a demodulation circuit (not shown).

Normally, the control pull-in range of PI and L is at least several percent with respect to the center frequency, so it is possible to sufficiently follow even slight changes in the input signal. However, when the jitter becomes large, it deviates from the control range of the PLL, so in the present invention, in order to prevent such a situation from occurring, the rotation system control circuit 5 and the PLL circuit 2 are connected via the signal correction circuit 8. It is configured to do this. That is, large.

Under conditions that cause jitter, the influence of vibrations appears as torque fluctuations in the rotating system such as a motor, and this can be detected as an error signal by the error signal detection circuit 7 of the rotating system control circuit 6. . After this error signal is corrected to an appropriate state by the signal correction circuit 8, it is applied to the PLI circuit 2, thereby making it possible to move the control range of the PLL.

Effects of the Invention As described above, the present invention is configured so that the error signal of the rotation control system is supplied to the PLL control system of the self-clock circuit of the digital signal reproducing device. As a result, when used in portable audio equipment, it is possible to automatically move the PLL pull-in range even when the PLL is affected by vibrations, etc.. The effects are very large, such as making it possible to significantly reduce the amount of water.

[Brief explanation of the drawing]

The figure is a block diagram of main parts showing an embodiment of the present invention. 1... Self-clock circuit, 2... Song P L
L circuit, 3... Waveform shaping circuit, 6... Surface rotation system control circuit, 8... Signal correction circuit.

Claims (1)

[Claims] The phase-locked loop circuit control system of the self-clock circuit for clock reproducing digital signals is configured to mix the error signal of the rotation control system for driving the digital signal recording medium via the signal correction circuit, and is designed to prevent disturbances. A digital signal reproduction control device, characterized in that the pull-in range of the phase-locked loop circuit is automatically moved accordingly.