JPS5819563A - Detecting circuit for speed - Google Patents

Abstract

PURPOSE:To obtain a speed signal without providing any special detecting mechanism, by obtaining the speed signal required for rotation or regeneration of a digital audiodisc from a regeneration signal of the disc. CONSTITUTION:A pulse-coded signal (a) from a disc is given to a waveform conversion circuit 3 and thereby a pulse corresponding to a part having inverted polarity is obtained. A counter circuit 4 counts a reference pulse C from a reference signal generating circuit 1 and is reset by an output (b) of the waveform conversion circuit 3, while an up-down counter circuit 5 is loaded with data therefrom. At this time, the part of the input data wherein the interval of inversion of polarity is long is constantly presented as the data of the up-down counter circuit 5 by a comparator 6. Moreover, subtraction is made constantly and gradually in the up-down counter circuit 5 by a signal (f) obtained through frequency division 2 of the reference pulse C, and therefore a load pulse (e) is always generated even with increased revolving speed of the disc. The data of said part is subjected to D/A conversion 8 and thereby a speed signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A digital audio disc (hereinafter referred to as DJ) of the present invention writes a 0-pulse coded digital signal related to Ogi@Ko-ta O control to the disc using a party head etc. and plays it back. A recording control method has been proposed in which the relative speed is always controlled at a constant wcw in the radial direction of the disk in order to increase the writing speed in O disk playback devices such as D, D, and video disks. Is it possible to record data using an ilt recorder and play it back on a nine-disk? ! It is necessary to change the rotation speed depending on the raw position. The position of the optical head for reproduction must be detected for the purpose of recording, and the nine rotation speed signals corresponding to the radius of the disc must be detected to obtain the required linear velocity.
-0 Based on such a detection signal, predetermined data is reproduced, a synchronization signal is extracted from the data, and phase napping is applied. this#! According to a control method, raw information is transmitted from the head position, and correspondingly, the ninth K1 requires a high speed signal.
If 1 m1 becomes complicated, it is also necessary to adjust the head position in order to make one correct rotation. Furthermore, if the predetermined rotational speed at the time of recording is different from the rotational speed at the time of reproduction, an intermediate layer is left due to compatibility.

The present invention was made in order to eliminate the above-mentioned disadvantages, and its purpose is to use the playback signals for discs such as D, D, etc., and also for the a* line. ! This is a signal that is designed to generate a speed signal, and is generally converted into a pulse signal.
The maximum reversal interval or the minimum reversal interval is determined by the modulation method.In the present invention, only the above-mentioned maximum or minimum reversal interval is taken out to determine the speed. The signals are set at predetermined intervals.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a waveform explanatory diagram of the present invention, and FIG. 2 is a system diagram of the present invention. In FIG. 2, an input signal a from a disk or the like is applied to the input terminal TIK.

As shown in Fig. 1a, the input signal a is mixed with various pulse intervals i. In this case, it is an MFM; , a pulse as shown in the gi diagram is obtained corresponding to the polarity inversion portion.

The waveform conversion circuit 3 mentioned above can be constructed from a differentiating circuit.

The output of the waveform conversion circuit 3 is applied to a counter circuit 4. Since the counter circuit 4 is supplied with a reference pulse as shown in FIG. When the next pulse b arrives, the counter circuit 4 loads the above counter data to the up/down counter circuit 5 and resets the counter circuit 4.
Furthermore, the pulse b is applied to one input of the AND circuit 70, the output pulse d shown in FIG. It is gated by a p-do pulse as shown in FIG.

The comparator 6 inputs the output of the counter circuit 4 and the output of the counter circuit s.
Since the output pulse d is output only when the data of the up/down counter circuit 5 is greater than the data of the up/down counter circuit 5, the output pulse 4
is added to the AND circuit 7 and the data of the running time counter circuit 4 is transferred to the up-down circuit 5.

Therefore, the data of the up/down counter circuit 5 always shows only the data of the part where the polarity inversion interval of the input data is long. Next, the frequency of the click C of the reference signal generation circuit 1 is divided by the frequency dividing circuit 2, and the period is set to be the number of pulses BO.
The signal shown in FIG. 10 is used as the subtraction input of the up/down counter circuit 5.

Now, for example, even if the number of revolutions of the disk increases and the pulse interval gradually decreases overall, the up/down counter circuit sH is always subtracting little by little, so no quad pulses will occur. do not have.

Normally, when the input signal is at a constant speed, the data of the output of the winding Kti changes by a minimum of 1 bit, so if the pulse interval suddenly narrows due to sudden acceleration, the countdown will be performed at a constant slope, and the value will gradually become correct. A specific pulse interval is always detected, such as pulses having various intervals such as 〇〇, which is determined by the time constant frequency f at this time. For example, in the MFM, data corresponding to 101 and the interval between Yoshitsugu's pulses is obtained.0 This data is converted to analog data by the digital-to-analyzer conversion circuit 8, and sent to the output terminal 8 as a control output for Tanabata etc. Output.

In the above embodiment, the maximum interval of data is output, and the comparator 6 is reversely colored so that the output pulse d is output when the data of the circuit 4 is smaller than the data of the up/down counter circuit 5. If the signal is the up (addition) signal of the up/down counter circuit 5, the minimum interval can be obtained. Although the input signal was explained using MFM, other coding methods such as 3PM and DARGUARD method can be used. Since the present invention is configured in the above-mentioned manner, the motor is controlled by the detected force and the predetermined rotation is achieved. If you do this, you can read the data correctly, and by adding phase rotation etc., you can create a complete servo loose. Furthermore, it has the feature that a speed control signal can be obtained from the data content without providing a special detection mechanism.

[Brief Description of the Drawings] Figure 311 shows the O waveform I! of the speed detection circuit of the present invention. Mingzu, 2nd
The figure shows one embodiment of the speed detection circuit of the present invention. In the figure, 1 is a reference signal generation circuit, 2 is a division j1 circuit, 3 is a waveform conversion circuit, 4 is a counter circuit, black is an up/down counter circuit, 6 is a pumbareta decoy circuit, 7 is an AND circuit, and 8
It is a battleground for digital-to-analog conversion. Patent Originator Japan: xO Mbia Co., Ltd. Agent Patent Attorney Kazumi Yamaguchi Figure 1 is the second figure

Claims (1)

[Claims] A means for recording data that has been strictly converted into /CC mode, and outputting a signal corresponding to the maximum reversal interval or minimum reversal interval of the data; A speed detection circuit consisting of a means for controlling the reproduction speed signal of the kikama intelligence body◇