JPH0318370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device that detects whether the rotational phase of a rotating body is rotating in phase synchronization with a predetermined reference signal.

For example, a rotationally driven recording disk
In a device that records or plays back video signals or PCM signals, the rotation of the disk must be phase-synchronized with a predetermined reference signal during recording or playback.

If the rotational phase is out of phase, in the case of a video signal, there will be a shift in hue or no color, and furthermore, there will be a loss of vertical and horizontal synchronization. In the case of PCM signals, the data cannot be read and sufficient reproduction cannot be performed.

Therefore, when recording, start recording after confirming that the rotation of the disk is synchronized with the reference signal.
During playback, it is necessary to mute the video, audio, etc. until the rotation of the disks is synchronized.

The present invention provides a device for detecting whether or not one of these rotating bodies is in a synchronous relationship with a predetermined reference signal.

First, an example of a conventional synchronization detection device for a rotating body will be described with reference to the drawings.

FIG. 1 shows an example of a control system for synchronizing the rotation of a rotating body with a reference signal. A signal corresponding to the rotational phase of the turntable 1 is detected by a magnet 3 and a detection head 3 attached to a part of the turntable 1 (rotating body), and a rotation detection circuit 5 is detected from this detection signal (for example, 60Hz). to create a sampling pulse (Fig. 2b), and on the other hand, to create a reference signal, the output of the crystal oscillation circuit 9 is passed through the frequency divider circuit 8 to create a 60Hz signal, and from this signal, the trapezoidal wave generator circuit 7 generates a trapezoidal wave ( 2a) is generated and inputted to the sampling circuit 6. Then, by sampling the trapezoidal wave (Fig. 2a) created from the reference signal with the sampling pulse ((Fig. 2b) created by the rotation detection circuit 5), a rotational phase error signal is obtained. Applying the signal to the drive circuit 11 via the filter 10,
Drive control of motor 2.

Figures 2a and b show a trapezoidal wave and a sampling pulse, respectively, and a phase error signal is obtained by the position of sampling pulse b on the diagonal line of trapezoidal wave a. Indicates a state where synchronization is disrupted.

In such a rotation synchronization system, as a means for detecting whether or not the turntable 1 is in phase synchronization with the reference signal, it is sufficient to detect whether or not the output of the filter 10 is within a certain predetermined level range. However, this method has a limit in accuracy due to the integral effect of the filter 10, and also lacks reliability due to variations in temperature characteristics and parts.

The present invention aims to solve the above problems.

The feature of the present invention is that, as shown in the outline of one embodiment in FIG. 3, the detection signal obtained from the rotation detection circuit 5 (for example, 60 Hz during normal rotation) is used as the clock signal (FIG. 4b), and the reference signal is A signal obtained by frequency-dividing the output of the source 9 by the frequency dividing circuit 8 (FIG. 4a) is applied to the shift register 12 as a serial input, respectively.
The display means 13 displays the output when signals are input to all stages of the shift register 12 to indicate that a predetermined synchronization relationship has been entered.

FIG. 5 shows an embodiment of the main part of the shift register 12, in which the reference signal a with a constant period is applied to the serial input terminal S _I of the shift register 12 consisting of eight stages, and the clock signal b is applied to the clock signal input terminal C _K. The output terminals Q _A to Q _H of the shift register 12 are connected to the 8-input NAND gate 14.
The output of the NAND gate 14 is transferred to the inverter 15
If connected to , only when a high level signal H is obtained at all of the output terminals Q _A to Q _H , that is,
An output is obtained only when the phases are synchronized eight times in a row like both signals a and b in FIG. 4.

Therefore, by displaying this output, it can be detected that the rotating body is being rotated in phase synchronization with the reference signal.

In FIG. 6, two 8-stage shift registers 12A and _12B are used to further improve accuracy.As shown in FIG. The NAND gate 1 is connected to the serial input terminal S _I of the shift register 12B of No. 2, and is connected to the output terminals Q _A to Q _B of the shift registers 12A and 12B, respectively.
Lead the output of 4A and 14B to the NOR gate 16,
By displaying the output, it is possible to display the case of 16 consecutive phase synchronizations.

Further, accuracy can be improved by narrowing the pulse width of the serial input signal (FIG. 4a). Furthermore, since the present invention detects the temporal positional relationship between the reference signal and the sampling pulse, it is easy to obtain the same result by selecting appropriate pulse widths for the serial input signal and the clock signal, respectively, and vice versa. Analogous.

Reversing the serial input signal and clock signal is
In the above-mentioned method, the synchronization detection signal is temporarily generated even when the rotational speed is an integer fraction of the reference, which also has the meaning of preventing this operation.

FIG. 7 shows another embodiment of the present invention. The reference signal is input to the D terminal of the D-type flip-flop 23 (considered as a one-stage shift register), and the sampling pulse is input to the C _K terminal. Input "H" or "L" of the output of each sample to the clear terminal C _L of the counter 25, and
The output terminals Q _A to Q _D of are passed through the NAND gate 26,
The output is gated by the gate circuit 24 and inputted to the clock terminal _CK of the counter 25. In the circuit shown in FIG. 7, by increasing the number of bits of the counter 25, the accuracy of rotation detection can be freely and simply configured at a stable and low cost, similar to the circuit described above. Depending on the application, it can be freely set for parts that require precision, parts that require lower cost, etc.

As described above, according to the present invention, the synchronous relationship between the rotational phase of the rotating body and the reference signal can be detected with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a phase synchronization control system for a rotating body, Fig. 2 is an explanatory diagram of the same operation, Fig. 3 is a block diagram showing an overview of the present invention, Fig. 4 is an explanatory diagram of the same operation, FIGS. 5, 6 and 7 are block diagrams showing essential parts of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Rotating body, 5... Rotation detection circuit, 8... Frequency dividing circuit, 9... Reference signal source, 12... Shift register, 13... Display means, 14... NAND gate circuit, 15... Inverter .

Claims (1)

[Claims] 1 One of the detection signal that detected the rotational phase of the rotating body and the reference signal is used as a clock signal, and the other is input as a serial input signal to a shift register having multiple stages, and the outputs of all stages of the shift register match. 1. A rotational synchronization detection device, characterized in that a gate is provided for detecting this, and the output of the gate is used to detect that the rotating body is rotating in phase synchronization with the reference signal.