JPH0785640A - Method and apparatus for detecting P channel signal writing error - Google Patents

Abstract

(57) [Summary] [Purpose] During the audition inspection of the songs recorded on the CD,
It is an object of the present invention to provide a P-channel signal write error detection method and apparatus capable of simultaneously inspecting a deviation between a P-channel signal write position and a musical sound. [Structure] A pulse shaper 1, 3 and an oscillator 2 and a frequency comparison circuit 4 are used to select only P-channel signals from input signals. Based on the output signal of the comparison circuit 4, the monostable multi-circuit 5 outputs a pulse. A peak hold circuit 8 is provided which is reset by the pulse and holds the peak value of the tone signal input thereafter, and the output of the hold circuit 8 is compared with a reference value by a comparator 9 to output a signal. A determination circuit 10 is provided which is reset by the pulse of the multi-circuit 5 and outputs a determination when there is an output signal of the comparator 8 when the output signal of the comparison circuit 4 falls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a P for detecting whether or not a writing position of a P channel signal used for cueing a music recorded on a CD or the like is accurately written at a predetermined position. The present invention relates to a channel signal write error detection method and apparatus.

[0002]

2. Description of the Related Art Due to its structure, a CD (Compact Disc) is easy to access recorded music unlike a music tape. For example, if several songs are recorded on a CD and you select any of the songs, the pickup will move directly to the beginning of the song and the selected song will be played. It is supposed to be done. This is because there is about 3% of a place (subcode area) where signal information other than music is put in a CD, and there is a pulse code called P channel that indicates the position of the head of music on the disc, When a song is selected, the P-channel signal is detected while the pickup is fast-forwarded, and the cue is performed at the trailing edge of the signal.

This P channel signal is inserted as a control signal in a gap of 2 to 3 seconds between music pieces as a control signal at the time of recording a musical sound on a CD, and is normally written manually. It is done. For this reason, after recording the musical sound of the CD (master stage), first of all, it is sequentially auditioned whether there is an abnormality from the first song to the last song, and then whether the P channel signal is in a normal position. It is inspected while performing a cueing operation.

[0004]

For this reason, it takes a lot of inspection work, and due to an error in writing the P-channel signal, a signal is written at the position where the music has already started, and the sound pressure level of the music at that position is low. However, there is a risk that the inspector who has performed the cue inspection may overhear and manufacture a CD in a state where the P channel signal position is defective.

The present invention is a P-channel signal write error detection method capable of simultaneously checking whether or not the position of a P-channel signal has been accurately written at the time of a listening test of a song recorded on a CD. And to provide a device.

[0006]

A P-channel write error detection apparatus according to the present invention selects a P-channel signal only from input sub-code data and outputs it, and a pulse based on an output signal of the selection unit. , A peak hold circuit that is reset by the output pulse of the monostable multicircuit and holds the peak value of the tone signal that is input thereafter, and the output of the peak hold circuit as a reference value. In comparison with a comparator that outputs a signal when it is equal to or greater than a reference value, and is reset by the output pulse of the monostable multi-circuit, and the presence or absence of the output signal of the comparator when the output signal of the sorting means falls. There is a judgment circuit that judges whether or not there is an output signal of the comparator, and a judgment output by the judgment circuit. It is characterized by comprising an alarm means for generating an alarm.

Further, in the P-channel write error detection method according to the present invention, only the P-channel signal is selected and output from the input subcode signal by the selecting means, and the pulse is generated based on this output signal by the monostable multi-circuit. Then, the peak hold circuit is reset by the output pulse, and the peak value of the tone signal input to the peak hold circuit thereafter is held, and the output of the peak hold circuit is set to the reference value by the comparator. By comparison, if there is a reference value or more, a signal is output, and the presence or absence of the output signal of the comparator at the fall of the output signal of the selecting means is determined by the determination circuit that is reset by the output pulse of the monostable multi-circuit. If there is an output signal from the comparator, the judgment output is made, and the judgment by the judgment circuit is made. If there output, is characterized in that so as to generate an alarm by the warning means.

[0008]

With the above-described structure, the P-channel signal written for the beginning of the music is selected and output from the input subcode data by the selecting means. When the P-channel signal is selected and output by the selecting means, a pulse is generated by the monostable multi-circuit based on this signal, and this pulse becomes a signal for resetting a peak hold circuit and a determination circuit described later.

On the other hand, a tone signal is inputted to the peak hold circuit, and when a reset signal from the monostable multi-circuit is inputted, the peak value of the tone signal inputted thereafter is held and outputted. The comparator to which this output is input compares this reference value with a predetermined reference value, and outputs a signal when the input value is larger. The determination circuit connected to the comparator is reset by the reset signal from the monostable multi-circuit, and determines the presence or absence of the output signal of the comparator when the P-channel signal output from the selection circuit falls, When there is an output signal from the comparator, it makes a judgment output. When there is a determination output, the alarm means issues an alarm to notify that the P channel signal is erroneously overlapped and written at the tone signal.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a circuit example of a P-channel signal write error detection device of the present invention. In the figure, 1 is a pulse shaper, which is a circuit for shaping a signal from a P (pause) channel signal extraction terminal of a CD player into a pulse having a sufficiently narrow width and outputting the pulse.

Reference numeral 2 denotes an oscillator, which is a circuit for oscillating a pulse signal of 2 Hz. The output pulse signal of the oscillator 2 is shaped into a pulse having a sufficiently narrow width by the next pulse shaper 3 and output. Reference numeral 4 denotes a frequency comparison circuit, which uses a parallel series register as a left and right shift register, compares the frequencies of the output pulse of the pulse shaper 1 and the output pulse of the pulse shaper 2 and Output pulse is 2Hz
When it is lower than that, "H" is output, and when it is higher, "L" is output. The pulse shapers 1 and 3, the oscillator 2, and the frequency comparison circuit 4 constitute the selecting means according to the present invention, and among the signals input to the pulse shaper 1, the P channel signal having a frequency lower than 2 Hz. Only the signal is selected and "H" is output by the width of the signal, and "L" is output in the case of a noise pulse having a high frequency.

Reference numeral 5 is a monostable multi-circuit, which generates a pulse when the frequency comparison circuit 4 outputs the "H" signal.
This pulse serves as a reset signal for the determination circuit and the peak hold circuit described later.

Reference numeral 6 denotes an amplifier circuit, which is a circuit for amplifying a signal from a tone signal extraction terminal of the CD player. The tone signal amplified by this amplifier circuit 6 is converted into a DC signal by the following AC / DC converter 7. . A peak hold circuit 8 holds the peak value of the DC signal input from the AC / DC converter 7 and outputs the peak value. When the reset signal from the monostable multi-circuit 5 is input, the peak value of the DC signal input from that point onward is held. Reference numeral 9 is a comparator, which is a circuit for comparing the DC signal output of the peak hold circuit with a predetermined reference value and outputting "H" if the DC signal output is greater than or equal to the reference value. That is, the circuit outputs "H" if there is a tone DC signal equal to or higher than the reference value (threshold value).

A determination circuit 10 is reset by a reset signal from the monostable multi-circuit 5 and the output signal of the comparator 9 is "H" or "H" when the P-channel signal output from the frequency comparison circuit 4 falls. When the output signal of the comparator 9 is "H", that is, when there is no musical tone signal, "L" is output, and when there is a musical tone signal, "H" is output. Reference numeral 11 is a display device including an LED, which is turned on when the output of the determination circuit is "H". This corresponds to the alarm means according to the present invention, and it is not limited to the LED and may be another display or a sound such as a buzzer. The display 11 is configured to be manually reset.

Since the P-channel signal write error detection device in this embodiment has the above-mentioned circuit configuration, the operation when a signal is actually input will be described below.
As shown in FIG. 2, the musical tone signal input to the amplifier circuit 6 is provided with a gap t _{1 of} 2 sec or more between the previous song and the following song. And P channel signal (pulse width 2 sec
) Is written in the portion corresponding to the void t ₁ .

When there is a P-channel signal, the frequency comparison circuit 4 outputs the same pulse as the P-channel signal, and the trigger of the rising edge of this pulse causes the monostable multi-circuit 5 to output a pulse for the reset signal. This reset signal resets the peak hold circuit 9, and if there is a tone signal after that, holds the peak value and outputs it to the comparator 9. Therefore, as shown in the figure, the output of the comparator 9 becomes "L" in the place where there is no musical tone signal following the reset signal, and if there is a musical tone signal after that, it continuously outputs "H" from that time. Will be done.

The decision circuit 10 determines whether the same pulse as the P channel signal from the frequency comparison circuit 4 falls,
A determination trigger signal is generated internally, and at the time of generation of this trigger signal, it is determined whether the output of the comparator 9 is "L" or "H". In the case of the figure, since the output of the comparator 9 is "L", the judgment output becomes "L", the display 11 does not light up, and the P channel signal is the gap between the previous song and the following song. t ₁
You can see that it was written correctly.

Next, the operation of this device will be described in the case where the P channel signal is not written correctly.
As shown in FIG. 3, the musical tone signal input to the amplifier circuit 6 is provided with a gap t _{1 of} 2 sec or more between the previous song and the following song. Then, the P channel signal has the gap t ₁
It is written on the head part of the back song, offset from the corresponding part. When the intensity of the sound at the beginning of the succeeding song is low, it is mistaken that the song has not yet started, and such a thing occurs. In this case, as in the previous case, the frequency comparison circuit 4 outputs the same pulse as the P-channel signal, and the trigger of the rising edge of this pulse causes the monostable multi-circuit 5 to output the pulse for the reset signal. This reset signal resets the peak hold circuit 9, and if there is a tone signal after that, holds the peak value and outputs it to the comparator 9. Therefore, as shown in the figure, the output of the comparator 9 becomes "L" in the portion where there is no musical tone signal following the reset signal, and if there is a musical tone signal thereafter, it continuously outputs "H" from that time. Will be done.

Next, the decision circuit 10 includes the frequency comparison circuit 4
At the falling edge of the same pulse as the P channel signal from, a determination trigger signal is internally generated, and at the time of generation of this trigger signal, it is determined whether the output of the comparator 9 is "L" or "H". In the case of the figure, the output of the comparator 9 is "H".
Therefore, the judgment output becomes "H", the display 11 is turned on, and it is found that the writing of the P channel signal is abnormal.

In this way, when the CD is inspected by using the apparatus according to the present embodiment, the P from the first music to the last music is sequentially auditioned whether or not there is an abnormality.
Since it can be inspected whether or not the channel signal is in the normal position, the number of inspection steps can be reduced.

[0021]

As described above, according to the present invention,
Since the inspection of the recorded music and the written P channel signal can be inspected at the same time, it is possible to reduce the number of inspection steps and to alert the abnormal writing of the P channel signal by the alarm means. Therefore, the signal is written at the position where the song has already started, and the sound pressure level of the song at that position is low, so the inspector who performed the cue inspection would be unable to hear, and the P channel signal position may be defective. It is possible to prevent a situation where a CD is manufactured.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention.

FIG. 2 is a timing chart when the P-channel signal is normally written.

FIG. 3 is a timing chart in the case of abnormal writing of a P channel signal.

FIG. 4 is a schematic diagram showing a position of a P channel signal in a CD.

[Explanation of symbols]

 1,3 Pulse shaper 2 Oscillator 4 Frequency comparison circuit 5 Monostable multi-circuit 7 AC / DC converter 8 Peak hold circuit 9 Comparator 10 Judgment circuit 11 Indicator

Claims (2)

[Claims] 1. A selecting means for selecting and outputting only a P-channel signal from an input subcode signal, a monostable multi-circuit for outputting a pulse based on an output signal of the selecting means, and an output of the monostable multi-circuit. Reset by a pulse,
A peak hold circuit for holding a peak value of a tone signal to be inputted thereafter, a comparator for comparing the output of the peak hold circuit with a reference value and outputting a signal when the output value is equal to or more than the reference value, A determination circuit that is reset by the output pulse of the monostable multi-circuit, and determines the presence or absence of the output signal of the comparator when the output signal of the selection means falls, and outputs a determination output when there is the output signal of the comparator. A P-channel signal writing error detection device, comprising: an alarm means for generating an alarm when there is a determination output by the determination circuit. 2. A P-channel signal is selected and output by a selecting means from the input sub-code signal, a pulse is generated based on this output signal by a monostable multi-circuit, and the peak hold circuit is reset by the output pulse. Then, the peak value of the tone signal input to the peak hold circuit is held thereafter, and the output of the peak hold circuit is compared with the reference value by the comparator. A judgment circuit that outputs a signal and is reset by the output pulse of the monostable multi-circuit determines the presence or absence of the output signal of the comparator when the output signal of the sorting means falls, and the output signal of the comparator is present. If there is a judgment output from the judgment circuit, an alarm is issued by the alarm means. P-channel signal write error detection method, characterized in that the.