JPS62270065A - Erroneous disk insertion detecting device - Google Patents

Abstract

PURPOSE:To detect the erroneous insertion of a disk without fail by generating a detecting signal of an erroneous insertion when the impropriety of the signal is decided with a deciding means after the disk is inserted and a prescribed time passed. CONSTITUTION:By the reproducing device insertion of a disk 1, a detecting switch 2 is turned on, the output comes to H, a servo circuit 4 is driven, a motor 3 is turned and the disk 1 is rotated. The recording signal of the disk 1 is picked up 5, demodulated 6 and converted to a sound signal. At the time of the erroneous insertion of the disk 1, a satisfactory signal is not generated, a signal to show a reproducing signal defect exists even after a constant time passes, then, the output of a gate circuit 11 comes to H, comes to the detecting signal of the erroneous insertion and the detecting signal displays the disk erroneous insertion as an erroneous insertion alarm signal. Thus, the erroneous insertion of the disk can be detected without fail.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention The present invention relates to an apparatus for detecting erroneous insertion of a disk.

Generally, in a video disc playback device, when a video disc is inserted, the monitor screen starts if the signals from the disc are picked up well, and with digital audio discs, the output is output to the speakers in the same way. At this time, there is no problem if the signal peak/qua knob is good, but if this happens (for example, when a single-sided disc is inserted in the opposite direction), the monitor screen may not be displayed for a long time. This results in people having to stare at the speaker or listen to the speaker, which is extremely unkind.

The present invention has focused on this point, and is designed to notify the user if a signal from the disc cannot be picked up satisfactorily within a certain period of time when the disc is inserted.

An example of the present invention will be described below. In Figure 1,
(1) is the disk, (2) is the detection switch that detects the insertion of the disk, (3) is the motor to rotate the disk (1), (4) is the motor servo circuit, and (5) is the signal from the disk. (6) is a demodulation circuit for the picked up signal; and (7) is a demodulation circuit for the picked up signal. (8) is a reference signal generation circuit; (9) is a first one-shot circuit; (1)
0) is the second round shot circuit, and <11) is the gate circuit.

Next, the operation will be explained with reference to FIG. Disc (1
) is inserted into the disc playback device, the detection switch (
2) is turned on, and its output (Fig. 2a) becomes high level. In response to the rise of this output, the motor servo circuit (4) is driven, the motor (3) starts rotating, and the disk (1) rotates. When the disk (1) starts rotating, the signal recorded on the disk (1) is picked up by the pickup means (5) and demodulated by the demodulation circuit (6).The demodulated output is a digital audio signal. In the case of a disc, the demodulated output is applied to a data processing circuit (not shown) to perform various digital processing and converted into an audio signal.On the other hand, the demodulated output is also applied to a synchronization detection circuit (7) to perform demodulation. :l! A synchronization signal can be detected from the flaw signal.The motor servo circuit (4) can compare the phases of this synchronization signal and the reference signal output from the reference signal generation circuit (8), and the two match. Servo control is performed so that

Now, in response to the rise of the detection output (a) of the detection switch (2), the first one-shot circuit (9) is triggered,
The output (2nd r!!Ab) remains at a high level for a certain period (T). This fixed period (T) is usually longer than the time required from when the disk (1) is fully inserted until the reproduction signal becomes stable (good).

After this predetermined period of time has elapsed, the second shot circuit (10) is triggered, and its output (FIG. 2C) remains at a high level for a predetermined period of time.

By the way, for example, if a disc with only one side recorded is inserted backwards, a signal indicating that a good signal cannot be generated forever or that the reproduced signal is defective (Fig. 2 d) will remain for a certain period of time ( If the gate circuit (11) still exists after T), the output of the gate circuit (11) becomes high level, and this detection signal (e) becomes the incorrect insertion detection signal (Fig. 2e).
) may be used as an erroneous insertion alarm signal to indicate that a disc has been erroneously inserted, or an ascending mechanism (not shown) may be driven to remove the disc from the playback device.

Various methods can be considered to detect whether the reproduced signal is good or not. A counter (12) counts whether or not an appropriate number of synchronization signals exist within a predetermined period, and when the number is less than the appropriate number,
Further, the judgment may be made based on the presence or absence of the playback signal (RF scratch signal), or in the case of a digital audio disc, the error rate of the data.

Incidentally, when a disk on which only 30 minutes of signals have been recorded is inserted, erroneous insertion is detected even when the pickup means (5) is at a position corresponding to 45 minutes (no signal).

According to the present invention described above, erroneous insertion of a disk can be reliably detected, and based on this detection, a warning of erroneous insertion can be issued.

[Brief explanation of the drawing]

FIG. 1 shows an apparatus for detecting erroneous disk insertion according to the present invention, and FIG. 2 is an operational waveform diagram thereof. (2) is a disk insertion detection switch, (9)<10) and (11) are one-shot circuits and gate circuits that constitute the detected store name generation means, and (12) is a counter (means for determining quality of reproduced signal).

Claims (1)

[Claims] (1) Determination means for determining the quality of the signal reproduced from the disc, and a signal for detecting incorrect insertion of the disc when the determination means determines the quality of the signal after a predetermined period has elapsed after the disc has been inserted. An apparatus for detecting erroneous insertion of a disk, comprising means for detecting erroneous insertion of a disk.