JPH10283736A - Signal recording device, signal reproducing device, and these methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record and reproduce a signal normally even if an external reference signal fails when recording and reproducing the signal by driving a storage medium in synchronization with the external reference signal being supplied externally. SOLUTION: When an external reference signal is normal a comparison circuit 104 sets an error signal to an inactive state, a counter circuit 112 counts a clock signal (CLOCK) in synchronization with a trailing edge signal being inputted from a trailing edge detection circuit 106 via a delay circuit 110, thus generating an internal reference signal. When the external reference signal is abnormal, the timing when an edge signal and a carry signal are activated does not match. The comparison circuit 104 activates the error signal and the counter circuit 112 ignores a trailing edge signal being inputted from the trailing edge detection circuit 106 via the delay circuit 110 and automatically travels, thus generating the internal reference signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal recording apparatus for driving a tape recording medium and recording or reproducing a signal on or from the tape recording medium in synchronism with a reference signal input from the outside, for example. Devices and methods.

[0002]

2. Description of the Related Art A recording / reproducing apparatus using a tape recording medium such as a video tape recorder (VTR) apparatus and a data recorder apparatus, or a recording apparatus using a disk recording medium such as a magneto-optical (MO) disk apparatus and a DVD apparatus.・
In some cases, a user wants to record / reproduce data or a signal by specifying a recording format for a reproducing apparatus. For example, when recording / reproducing a signal by specifying a format for a tape recording medium such as a VTR device and a recording / reproducing device using a rotating drum, a user needs to input an external reference signal from the outside according to the format. Is supplied to the recording / reproducing apparatus, and the recording / reproducing apparatus needs to run the recording medium in synchronization with the external reference signal and rotate the rotating drum to record / reproduce the signal.

As described above, in a recording / reproducing apparatus which performs recording / reproduction in synchronization with an external reference signal, usually, an internal reference signal synchronized with the external reference signal is generated, and recording is performed in synchronization with the internal reference signal. The medium and the rotating drum run and rotate, and recording / recording on the recording medium is synchronized with the internal reference signal.
Playback is performed.

However, an external reference signal supplied to such a recording / reproducing apparatus may have an error (error) such as noise and missing pulses. When these errors occur in the external reference signal, an error also occurs in the internal reference signal, and the signal cannot be recorded / reproduced in a prescribed format.

When an error occurs in the internal reference signal due to an error in the external reference signal, normal recording / reproduction on a recording medium becomes impossible, and a signal to be recorded is lost or the internal reference signal is lost. There is a possibility that a signal recorded during a period in which an error occurs in a signal cannot be normally reproduced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and has been made in consideration of the above-described problems, and has been made in consideration of the above circumstances. A signal recording device and a signal reproduction device that can record or reproduce a signal normally even when an error such as missing or noise occurs in an external reference signal when recording / reproducing a signal by running / rotating the device. It is an object to provide devices and their methods. Another object of the present invention is to provide a signal recording device, a signal reproducing device, and a method thereof that can record a signal to be recorded without loss even if an error occurs in an external reference signal, and can reproduce the signal properly. I do.

[0007]

In order to achieve the above-mentioned object, a signal recording apparatus according to the present invention provides a signal recording apparatus for an external reference signal which has no error when no error occurs in the external reference signal. An internal reference signal synchronized with the external reference signal is generated using a clock signal of an integer multiple frequency, and when an error occurs in the external reference signal, the internal reference signal is generated using only the clock signal. Reference signal generating means for generating a signal; recording medium driving means for driving a predetermined recording medium in synchronization with the generated internal reference signal; and recording a signal synchronized with the internal reference signal on the driven recording medium. Recording means.

Preferably, the clock signal has an even multiple (2N) times the frequency of the external reference signal, and the reference signal generation means detects a rising edge and a falling edge of the external reference signal. First edge detecting means for generating first edge signals indicating these edges, and dividing the clock signal by 1 / N in synchronism with the detected first edge signal. An error of the external reference signal is detected based on 1 / N frequency dividing means for generating a frequency-divided signal, a phase of the generated first edge signal, and a phase of the generated 1 / N frequency-divided signal. Error detecting means for generating the internal reference signal synchronized with the 1 / N frequency-divided signal when an error is detected in the external reference signal, and generating the internal reference signal in synchronism with the external reference signal when no error is detected. Said synchronized Having an internal reference signal generating means for generating a section reference signal.

Preferably, a second edge signal which detects any one of a rising edge and a falling edge of the external reference signal and is activated at any of the rising edge and the falling edge of the external reference signal Further comprising a second edge detecting means for generating
The edge detecting means activates the first edge signal at the rising edge and the falling edge of the external reference signal, and the 1 / N frequency dividing means counts the clock signal by N cycles, The count value is cleared to 0 when the first edge signal is activated, and when the clock signal is counted for N cycles, the 1 / N frequency-divided signal is activated. Signal and said 1
An error signal to be activated is generated during a period from the time when the / N frequency-divided signals are not simultaneously activated to the time when the second edge signal is activated, and the internal reference signal generation means generates the clock signal. Counting is performed every 2N cycles, and when the error signal is not activated and the second edge signal is activated, the count value is cleared to 0 to generate the internal reference signal.

In the signal reproducing apparatus according to the present invention, when no error occurs in an externally input external reference signal, the clock signal having an integral multiple of the frequency of the external reference signal is used. An internal reference signal synchronized with an external reference signal is generated, and when an error occurs in the external reference signal, reference signal generating means for generating the internal reference signal using only the clock signal; A recording medium driving unit that drives a predetermined recording medium in synchronization with the internal reference signal; and a reproducing unit that reproduces a signal from the driven recording medium in synchronization with the internal reference signal.

In the signal recording apparatus and the signal reproducing apparatus according to the present invention, the reference signal generating means may include, for example, an external reference signal input for designating a format from the outside, which is caused by an abnormality caused by noise, missing pulses, or the like. If no (error) occurs, an internal reference signal synchronized with the external reference signal is generated, and if an error occurs, an internal reference signal synchronized with the external reference signal before the error is generated.

The first edge detecting means generates a first edge signal which is activated when a rising edge and a falling edge (change point) of the external reference signal are detected. In the reference signal generating means, the 1 / N frequency dividing means starts counting a clock signal having a frequency 2N times the frequency of the external reference signal from the time when the first edge signal is activated. A 1 / N frequency-divided signal activated at the time of counting, that is, at a change point of a normal external reference signal is generated.

The fact that the 1 / N frequency-divided signal and the first edge signal are activated simultaneously means that the external reference signal has changed at a predetermined position. Therefore, when these signals are activated simultaneously, the error detecting means determines that no error has occurred in the external reference signal,
If they are not activated at the same time, it is determined that an error has occurred in the external reference signal, and the error signal is activated.

In the internal reference signal generating means, the second edge detecting means generates, for example, a second edge signal which is activated when the external reference signal falls. When the error signal is not activated, the internal reference signal generation means clears the count value to 0 when the second edge signal is activated, that is, when the normally supplied external reference signal falls. As a result, the internal reference signal is generated by synchronizing the internal reference signal with the external reference signal. When the error signal is activated, the internal reference signal is free-running to generate the internal reference signal.

The recording medium driving means runs and rotates (drives) the tape recording medium and the rotary drum in synchronization with the internal reference signal generated by the reference signal generating means, or rotates (drives) the disk recording medium. ). The recording means records a signal supplied from the outside together with the external reference signal and synchronized with the external reference signal on a recording medium driven in synchronization with the internal reference signal. The reproducing means reads out a signal from a recording medium driven in synchronization with the internal reference signal in synchronization with the internal reference signal, and reproduces the signal.

Further, in the signal recording method according to the present invention, when no error occurs in an external reference signal input from the outside, the clock signal having an integral multiple of the frequency of the external reference signal is used. Generate an internal reference signal synchronized with an external reference signal, if an error has occurred in the external reference signal, generate the internal reference signal using only the clock signal, and generate the internal reference signal. A predetermined recording medium is driven in synchronization, and a signal synchronized with the internal reference signal is recorded on the driven recording medium.

Further, in the signal reproducing method according to the present invention, when no error occurs in the external reference signal input from the outside, the clock signal having an integral multiple frequency of the external reference signal is used. An internal reference signal synchronized with an external reference signal is generated, and when an error occurs in the external reference signal, the internal reference signal is generated using only the clock signal, and the generated internal reference signal is generated. A predetermined recording medium is driven in synchronization, and a signal is reproduced from the driven recording medium in synchronization with the internal reference signal.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
The recording / reproducing apparatus 1 will be described.

The diagram 1 of a recording and reproducing apparatus 1 is a diagram showing a recording and reproducing apparatus 1 configured according to the present invention. As shown in FIG. 1, the recording / reproducing apparatus 1 includes a reference signal generating circuit 10, a driving circuit 20, a motor 22, a drum 24, a recording unit 26, and a reproducing unit 28.

FIG. 2 shows the reference signal generating circuit 1 shown in FIG.
FIG. 3 is a diagram showing a configuration of a zero. As shown in FIG. 2, the reference signal generation circuit 10 includes an edge detection circuit 100, a counter circuit (N) 102, a comparison circuit 104, a falling edge detection circuit 106, a delay circuit 110, and a counter circuit (2
N) 112.

The recording / reproducing apparatus 1 is, for example, a data recorder apparatus. With these components, the drum 24 is rotated in synchronism with an external reference signal supplied from outside by a user to instruct a format. Then, a tape recording medium (not shown) is run, a recording signal synchronized with the external reference signal is recorded on the recording medium, and the recorded signal is reproduced.

Components of Recording / Reproducing Apparatus 1 Each component of the recording / reproducing apparatus 1 will be described below. FIG.
FIGS. 3A and 3B are diagrams illustrating an external reference signal and a clock signal supplied from the outside to the recording / reproducing apparatus 1.

Reference Signal Generating Circuit 10 The reference signal generating circuit 10 (FIG. 1) is free from abnormalities (errors) due to noise and missing pulses in the external reference signal shown in FIG. When the external reference signal is normal, as shown in FIG. 3B, the clock signal (C) is synchronized with the external reference signal and has a frequency 2N times that of the external reference signal.
LOCK) to generate an internal reference signal synchronized with the external reference signal to generate the driving circuit 20, the recording unit 26, and the reproducing unit 28.
Output to In addition, the reference signal generation circuit 10 generates an error due to noise and missing pulses in the external reference signal, and when the external reference signal is abnormal, the external signal is synchronized with a normal external reference signal before the occurrence of the abnormality. The generated internal reference signal is generated by a free-running operation based on a clock signal (CLOCK) and is output to each of the above components.

Edge detection circuit 100 FIGS. 4A to 4F are timing charts illustrating signal waveforms of respective parts of the recording / reproducing apparatus 1. FIG. In addition,
In FIGS. 4A to 4F, for the sake of simplicity of illustration and description, a time delay of a signal generated in each component of the recording / reproducing apparatus 1 is ignored. Edge detection circuit 1
00 (FIG. 2) detects a rising edge and a falling edge of the external reference signal shown in FIGS. 3A and 4A, generates an edge signal shown in FIG. It outputs to 102 and the comparison circuit 104.

Counter circuit 102 The counter circuit 102 is cleared to 0 when the edge signal shown in FIG. 4B is activated (logical value 1), and the clock signal (CLOCK) shown in FIG. ) Are counted for N cycles, and a carry signal having a frequency of 1 / N of the clock signal (CLOCK) is output to the comparison circuit 104. That is, when the external reference signal is normally supplied, the count value of the counter circuit 102 changes between 0 and N-1 shown in FIG. At the time of N-1, the carry signal shown in FIG. 4D is activated and output to the comparison circuit 104.

As can be seen with reference to FIGS. 4B and 4D, during the period in which the external reference signal is normally supplied before time A and after time E (error-free period), The timing at which the edge signal output from the edge detection circuit 100 is activated coincides with the timing at which the carry signal output from the counter circuit 102 is activated. Conversely, for example, an error (time B) caused by missing a part of the pulse of the external reference signal, an error caused by superimposing noise on the external reference signal (time C), and noise are superimposed on the external reference signal. During a period (error period) in which an error (time points B to C, C to D) occurs when the period of the logical value 1 of the external reference signal is divided into two, the counter circuit 10
The activation timing of the edge signal output from the comparator 2 does not coincide with the activation timing of the carry signal output from the comparison circuit 104.

The comparison circuit 104 includes an edge detection circuit 100
The timing at which the edge signal input from is activated,
The timing when the carry signal input from the counter circuit 102 is activated is compared with the timing when the external reference signal is activated in the active state as shown in FIG. Generates an error signal indicating that the external reference signal is normally supplied. The comparison circuit 104 changes the timing of activation of the edge signal and the timing of the carry signal from the state where the timing of the activation of the edge signal does not coincide with the timing of the activation of the carry signal as in the period after the time E shown in FIG. In the case of transition to the state (time E), the state of the error signal is maintained in the activated state until the time when the activation timings of the edge signal and the carry signal match (time F), and the backward protection operation is performed. .

The comparison circuit 104 changes the state in which the activation of the edge signal coincides with the timing of the carry signal.
When the activation timing of the edge signal and the carry signal shifts to a state in which they do not match (time A), the state of the error signal is immediately set to the activated state.

The falling edge detection circuit 106 detects the falling edge of the external reference signal, and activates at the falling point of the external reference signal, as shown in FIG. Generate a falling edge signal.

The delay circuit 110 outputs the falling edge signal generated by the falling edge detection circuit 106 to the counter circuit 102.
The delay is given by the delay time given by the comparison circuit 104 to the error signal, and the error signal and the falling edge signal are output to the counter circuit 112 at the same timing.

Counter circuit 112 The counter circuit 102 operates only when the error signal input from the comparison circuit 104 is inactive and the falling edge signal shown in FIG. 4F is activated. 0 is cleared and the clock signal (CLOC) shown in FIG.
K) is counted by 2N cycles, and 1 of the clock signal (CLOCK) is counted.
/ 2N, generates an internal reference signal having a frequency of
0, output to the recording unit 26 and the reproducing unit 28 (FIG. 1).

The drive circuit 20 drive circuit 20 (FIG. 1) drives the motor 22 by the servo control based on the FG signal and the PG signal indicating a rotational phase of the motor 22, the reference signal generating circuit 10 rotation of the motor 22 And the rotation of the drum 24 and the rotation of the recording medium (not shown) are synchronized with the internal reference signal.

The recording unit 26 processes the recording data supplied from the outside and synchronized with the external reference signal and the clock signal (CLOCK) in synchronization with the internal reference signal input from the reference signal generation circuit 10. A recording signal is generated on the recording medium running under the control of the drive circuit 20 via a recording head (not shown) on the drum 24.

The playback unit 28 playback unit 28 (not shown) reproducing heads on the drum 24
Is processed in synchronization with the internal reference signal input from the reference signal generation circuit 10 to reproduce data recorded on the recording medium, and converts the reproduced data into a clock signal (CLOCK). Synchronized and output to outside as reproduction data.

The operation of the recording / reproducing apparatus 1 will now be described with reference to the case where the waveform of the external reference signal supplied from the outside to the recording / reproducing apparatus 1 is as shown in FIG. Will be described.

The period before the time A shown in FIG .
None period) In the period before time A, the external reference signal [FIG.
(A)], no error has occurred and the edge detection circuit 1
The activation timing of the edge signal [FIG. 4 (B)] output from 00 and the activation timing of the carry signal [FIG. 4 (D)] output from the counter circuit 102 match.

Accordingly, the error signal [FIG. 4E] output from the comparison circuit 104 becomes inactive, and the counter circuit 112 outputs the falling edge inputted from the falling edge detection circuit 106 via the delay circuit 110. The clock signal (CLOCK) is counted in synchronization with the signal, and an internal reference signal is generated. The recording unit 26 and the reproducing unit 28 record and reproduce data in synchronization with an internal reference signal output from the counter circuit 112 and a clock signal (CLOCK) input from the outside.

The period between times AE shown in FIG .
-Period) In the period between time A and time D, the external reference signal at time A (FIG. 4A) is partially lost, and noise superimposed on the external reference signal at time C causes the external reference signal to be lost. When an error occurs in the signal and the edge signal (FIG. 4B) output from the edge detection circuit 100 is activated, and the carry signal (FIG. 4D) output from the counter circuit 102 is activated. Does not match.

Therefore, the error signal [FIG. 4E] output from the comparison circuit 104 becomes active after time A,
The counter circuit 112 includes the falling edge detection circuit 10
6 ignoring the falling edge signal input from the delay circuit 110 via the delay circuit 110, and runs on its own to generate an internal reference signal.
During this period, similarly, the recording unit 26 and the reproducing unit 2
8 are an internal reference signal output from the counter circuit 112 and a clock signal (CLOC
Recording and playback of data in synchronization with K).

The period between times E and F shown in FIG .
At the time E, the external reference signal [FIG. 4A] returns to normal, and the edge signal output from the edge detection circuit 100 [FIG.
(B)] and the counter circuit 10
The activation timing of the carry signal [FIG.

However, due to the backward protection function of the comparison circuit 104 described above, the error signal is again activated at the time F at the timing when the edge signal [FIG. 4B] is activated and when the carry signal [FIG. The error signal remains activated until the activation timing matches. Therefore, during the period between times E and F, the counter circuit 112 outputs the falling edge signal input from the falling edge detection circuit 106 via the delay circuit 110 while no error occurs in the external reference signal. It runs on its own ignoring the signal and generates an internal reference signal. Similarly, during this period, the recording unit 26 and the reproducing unit 28 record and reproduce data in synchronization with the internal reference signal output from the counter circuit 112 and the clock signal (CLOCK) input from the outside, respectively. .

The period after time F shown in FIG .
4) The external reference signal [FIG.
(A)] is supplied normally, the timing at which the edge signal [FIG. 4 (B)] output from the edge detection circuit 100 is activated, and the carry signal [FIG. 4 (D)] output from the counter circuit 102 are activated. At the same time.

When the timing at which the edge signal [FIG. 4B] is activated again coincides with the timing at which the carry signal [FIG. 4D] is activated at time F, the error signal becomes inactive. Return to the state. Therefore, in the period after time F, the counter circuit 112 operates similarly to the period before time A, so that the falling edge detection circuit 106
The clock signal (CLOCK) is counted in synchronism with the falling edge signal input through the delay circuit 110 to generate an internal reference signal. Similarly, during this period, the recording unit 26 and the reproducing unit 28
2 records and reproduces data in synchronization with an internal reference signal output by the second and a clock signal (CLOCK) input from the outside.

As described above, the recording / recording according to the present invention
According to the reproducing apparatus 1, even during a period in which an error occurs in the external reference signal, the signal can be recorded in the format specified by the user, and loss of a valuable signal can be prevented. Further, in the conventional apparatus, if an error occurs in the external reference signal, the motor may rotate abnormally, possibly damaging the recording / reproducing apparatus itself or the recording medium. According to the playback device 1, such a problem can be avoided.

FIGS. 3A and 3B and FIG.
The signal waveforms shown in (A) to (F) are examples, and even if the signal waveforms are different, the recording / reproducing apparatus 1 is not
It can be applied as it is or by making appropriate changes as needed. Further, in the above-described embodiment, the case where the digital signal is recorded has been described. However, the analog signal can be converted into the recording / reproducing apparatus 1 as it is or by making appropriate changes as necessary. It can be applied to a recording device.

In the embodiment described above,
The case where the digital signal is recorded on the tape recording medium has been described. However, the recording / reproducing apparatus 1 can be applied to an apparatus that performs recording on another recording medium such as a disk recording medium by making appropriate changes. . Further, for example, by monitoring the error signal output from the comparison circuit 104 with a control device using a CPU, a warning of occurrence of an abnormality can be issued to a user. Also,
The reproducing unit 28 of the recording / reproducing apparatus 1 may be omitted and used as a recording-only apparatus, or the recording unit 26 may be omitted and used as a reproducing-only apparatus.

[0047]

As described above, according to the signal recording apparatus, the signal reproducing apparatus and the method according to the present invention,
When recording / reproducing a signal by running / rotating a recording medium and a rotating drum in synchronization with a reference signal (external reference signal) supplied from outside, errors such as missing and noise are generated in the external reference signal. However, the signal can be normally recorded or reproduced. Further, according to the signal recording device, the signal reproducing device, and the methods of the present invention, even if an error occurs in the external reference signal, a signal to be recorded can be recorded without loss and can be normally reproduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a reference signal generation circuit illustrated in FIG. 1;

FIGS. 3A and 3B are diagrams showing an external reference signal and a clock signal which are externally supplied to a recording / reproducing apparatus.

FIGS. 4A to 4F are timing charts illustrating signal waveforms of respective parts of the recording / reproducing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording / playback apparatus, 10 ... Reference signal generation circuit, 100
... edge detection circuit, 102 ... counter circuit, 104 ... comparison circuit, 106 ... falling edge detection circuit, 110 ...
Delay circuit, 112 ... Counter circuit.

Claims (12)

[Claims] An internal reference signal synchronized with the external reference signal by using a clock signal having a frequency that is an integral multiple of the external reference signal when no error occurs in the external reference signal input from the outside. A reference signal generating means for generating the internal reference signal using only the clock signal when an error has occurred in the external reference signal; and a predetermined signal synchronized with the generated internal reference signal. A signal recording apparatus comprising: a recording medium driving unit that drives the recording medium; and a recording unit that records a signal synchronized with the external reference signal on the driven recording medium. 2. The clock signal has an even multiple (2N) times the frequency of the external reference signal, and the reference signal generation means detects a rising edge and a falling edge of the external reference signal. A first edge detecting means for generating a first edge signal indicating an edge of the clock signal; dividing the clock signal into 1 / N in synchronization with the detected first edge signal; Generate 1 /
N frequency dividing means; error detecting means for detecting an error of the external reference signal based on a phase of the generated first edge signal and a phase of the generated 1 / N frequency dividing signal; If an error is detected in the external reference signal, the internal reference signal synchronized with the 1 / N frequency-divided signal is generated. If no error is detected, the internal reference signal synchronized with the external reference signal is generated. 2. The signal recording apparatus according to claim 1, further comprising: an internal reference signal generating unit that generates the signal. 3. A method for detecting a rising edge or a falling edge of the external reference signal, and generating a second edge signal activated at any of the rising edge and the falling edge of the external reference signal. And a second edge detection unit that performs the first edge detection on the rising edge and the falling edge of the external reference signal.
The 1 / N frequency dividing means counts the clock signal by N cycles, clears the count value to 0 when the first edge signal is activated, and resets the clock signal. Activating the 1 / N frequency-divided signal when counting has been performed for N cycles, and the error detecting means starts the second edge from the time when the edge signal and the 1 / N frequency-divided signal are not simultaneously activated. An error signal to be activated is generated until the signal is activated, and the internal reference signal generating means converts the clock signal to 2N.
3. The signal according to claim 2, wherein the internal reference signal is generated by clearing a count value to 0 when the error signal is not activated and the second edge signal is activated, counting by a period. Recording device. 4. An internal reference signal synchronized with the external reference signal using a clock signal having a frequency that is an integral multiple of the external reference signal when no error occurs in the external reference signal input from the outside. A reference signal generating means for generating the internal reference signal using only the clock signal when an error has occurred in the external reference signal; and a predetermined signal synchronized with the generated internal reference signal. A signal reproducing apparatus comprising: a recording medium driving unit that drives the recording medium; and a reproducing unit that reproduces a signal from the driven recording medium in synchronization with the internal reference signal. 5. The clock signal has an even multiple (2N) times the frequency of the external reference signal, and the reference signal generation means detects a rising edge and a falling edge of the external reference signal. A first edge detecting means for generating a first edge signal indicating an edge of the clock signal; dividing the clock signal into 1 / N in synchronization with the detected first edge signal; Generate 1 /
N frequency dividing means; error detecting means for detecting an error of the external reference signal based on a phase of the generated first edge signal and a phase of the generated 1 / N frequency dividing signal; If an error is detected in the external reference signal, the internal reference signal synchronized with the 1 / N frequency-divided signal is generated. If no error is detected, the internal reference signal synchronized with the external reference signal is generated. 5. The signal reproducing device according to claim 4, further comprising: an internal reference signal generating unit that generates the internal reference signal. 6. A method for detecting a rising edge or a falling edge of the external reference signal and generating a second edge signal activated at any of the rising edge and the falling edge of the external reference signal. And a second edge detection unit that performs the first edge detection on the rising edge and the falling edge of the external reference signal.
The 1 / N frequency dividing means counts the clock signal by N cycles, clears the count value to 0 when the first edge signal is activated, and resets the clock signal. Activating the 1 / N frequency-divided signal when counting has been performed for N cycles, and the error detecting means starts the second edge from the time when the edge signal and the 1 / N frequency-divided signal are not simultaneously activated. An error signal to be activated is generated until the signal is activated, and the internal reference signal generating means converts the clock signal to 2N.
6. The signal according to claim 5, wherein the internal reference signal is generated by counting each cycle and clearing the count value to 0 when the error signal is not activated and the second edge signal is activated. Playback device. 7. An internal reference signal synchronized with the external reference signal using a clock signal having an integer multiple of the frequency of the external reference signal when no error occurs in the external reference signal input from the outside. And when an error occurs in the external reference signal, generates the internal reference signal using only the clock signal, and drives a predetermined recording medium in synchronization with the generated internal reference signal. And a signal recording method for recording a signal synchronized with the external reference signal on the driven recording medium. 8. The clock signal has an even multiple (2N) times the frequency of the external reference signal, and detects a rising edge and a falling edge of the external reference signal and a first signal indicating these edges. An edge signal is generated, the clock signal is frequency-divided by 1 / N in synchronization with the detected first edge signal, a 1 / N frequency-divided signal is generated, and a phase of the generated first edge signal is generated. And an error of the external reference signal is detected based on the phase of the generated 1 / N frequency-divided signal. If an error is detected in the external reference signal, the error is detected by the 1 / N frequency-divided signal. 8. The signal recording method according to claim 7, wherein the synchronized internal reference signal is generated, and when no error is detected, the internal reference signal synchronized with the external reference signal is generated. 9. A second edge signal which detects any one of a rising edge and a falling edge of the external reference signal and activates at any one of the rising edge and the falling edge of the external reference signal. Generating, activating the first edge signal at a rising edge and a falling edge of the external reference signal, counting the clock signal for N cycles, and activating the first edge signal. When the count value is cleared to 0 and the clock signal is counted for N cycles, the 1 / N frequency-divided signal is activated. From the time when the edge signal and the 1 / N frequency-divided signal are not simultaneously activated, An error signal to be activated is generated during a period until the second edge signal is activated, and the clock signal is counted for 2N cycles, and the error signal is counted. 9. The signal recording method according to claim 8, wherein when the signal is not activated and the second edge signal is activated, the count value is cleared to 0 to generate the internal reference signal. 10. An internal reference signal synchronized with the external reference signal using a clock signal having a frequency that is an integral multiple of the external reference signal when no error occurs in the external reference signal input from the outside. And when an error occurs in the external reference signal, generates the internal reference signal using only the clock signal, and drives a predetermined recording medium in synchronization with the generated internal reference signal. A signal reproducing method for reproducing a signal from the driven recording medium in synchronization with the internal reference signal. 11. The clock signal has an even multiple (2N) times the frequency of the external reference signal, and detects a rising edge and a falling edge of the external reference signal and a first signal indicating these edges. An edge signal is generated, the clock signal is frequency-divided by 1 / N in synchronization with the detected first edge signal, a 1 / N frequency-divided signal is generated, and a phase of the generated first edge signal is generated. And an error of the external reference signal is detected based on the phase of the generated 1 / N frequency-divided signal. If an error is detected in the external reference signal, the error is detected by the 1 / N frequency-divided signal. The signal reproducing method according to claim 10, wherein the synchronized internal reference signal is generated, and the internal reference signal synchronized with the external reference signal is generated when no error is detected. 12. A second edge signal which detects any one of a rising edge and a falling edge of the external reference signal and activates at any one of the rising edge and the falling edge of the external reference signal. Generating, activating the first edge signal at a rising edge and a falling edge of the external reference signal, counting the clock signal for N cycles, and activating the first edge signal. When the count value is cleared to 0 and the clock signal is counted for N cycles, the 1 / N frequency-divided signal is activated. From the time when the edge signal and the 1 / N frequency-divided signal are not simultaneously activated, An error signal to be activated is generated until the time when the second edge signal is activated, and the clock signal is counted for every 2N cycles, and the error is counted. 12. The signal reproducing method according to claim 11, wherein the count value is cleared to 0 and the internal reference signal is generated when the signal is not activated and the second edge signal is activated.