JPH03119571A - Signal recording method and signal reproducing device - Google Patents

Abstract

PURPOSE:To prevent data error by the phase deviation between reproduced waveforms in the inner periphery and the outer periphery of a disk by comparing the phase of the reproduced signal of a reference clock signal with the phase of a synchronizing clock signal and controlling the phase of the synchronizing clock signal by the comparison output. CONSTITUTION:A reproduced RF signal is inputted to diodes 11 and 12 from an input terminal 5 through an equalizer 6 and a capacitor 7. A low-frequency signal B included in a reproduced reference clock signal A is extracted by a resistance adding circuit consisting of an LPF consisting of resistances 13 and 15 or resistances 16 and 18 and a capacitor 14 or 17 and resistances 21 to 23, and a signal B is eliminated by a differential amplifier 24, and a signal C is inputted to a comparator 28. It is compared with prescribed threshold by the comparator 28, and outputted binary data D is gated in an AND gate 30 by a signal E from a comparator 29 and has the phase compared with the synchronizing clock by a phase comparator 31. The phase difference signal passes an integrating circuit 33 and an S/H circuit 34 and is averaged by an average value circuit 35. The average value binarizes the saw tooth wave from a saw tooth wave generating circuit 37 in a control circuit 36 and outputs it as the clock signal to a terminal 37.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a signal recording method for recording data on a recording medium, for example, a magneto-optical disk, and a signal reproducing device for reproducing a magneto-optical disk on which data is recorded. Regarding.

[Summary of the invention]

The signal recording method according to the present invention records a reference clock signal when recording data in accordance with a synchronized clock signal obtained from a recording medium.

A signal reproducing device according to the present invention is a signal reproducing device for reproducing data recorded as described above, and includes a phase comparing means for performing a phase comparison between a reproduced signal of a reference clock signal and the synchronized clock signal; and a phase control means for controlling the phase of the synchronized clock signal according to the output from the comparison means, and corrects the phase of the synchronized clock signal using the reproduced signal of the reference clock signal so that data can be reproduced correctly. ing.

Further, the clock forming means forms a plurality of external clock signals having mutually different phases, the data reproducing means regenerates a plurality of series of data using the plurality of clock signals from the clock forming means, and the data reproducing means generates a plurality of series of data from the data reproducing means. and optimal data determining means for determining optimal data using the reference clock signal, and a clock signal for data reproduction is selected from a plurality of external clock signals based on the determination output from the optimal data determining means, so that data can be reproduced correctly. That's what I do.

[Conventional technology]

As shown in FIG. 9, magneto-optical recording records data by magnetizing a portion of a disk that has reached its Curie temperature through laser irradiation in the direction of an externally applied magnetic field. In other words, for example, a laser diode is driven in pulses to emit light, an external magnetic field is modulated with recording data, and a point (portion magnetized by the external magnetic field) corresponding to the spot size of the laser beam is placed on the recording surface in a time-division manner. Data is recorded by forming an image. By the way, in order to increase the recording density, if the interval between the pulses that drive the laser light source is made smaller than the laser beam spot size, part of the laser beam spot overlaps with a part of the previously formed pit, causing magnetization to occur first. A portion of the area (pit) that has been created will be overwritten by a pit that will be formed later. In other words, pits are formed one by one in a time-division manner, and as the recording density is increased, overramp occurs, resulting in so-called edge recording in which information is stored at the point of change in the direction of magnetization (edge).

Furthermore, a magneto-optical recording medium, such as a magneto-optical disk, is rotated by a spindle morph at a constant linear velocity (CLV) or a constant angular velocity (CAV), so that the pits are formed in a spiral or concentric pit row. It has become.

By the way, in the case of constant angular velocity (CAV) driving, the distance (length) that the recording head advances per unit time is smaller on the inner circumference than on the outer circumference. Therefore, as shown in FIG. The amount of overlap becomes larger than the overramp speed at the outer periphery.

When data is reproduced from the pits recorded in this way, as shown in Figure 1I, the signals reproduced from the inner pits are temporally advanced (shifted) than the signals reproduced from the outer pits. It takes shape. Therefore, in the so-called external clock method, for example, if the pits on the inner periphery are reproduced using the same synchronized clock signal (external clock signal) obtained from the magneto-optical disk for reproducing the pits on the outer periphery. , it becomes impossible to accurately detect the change point (edge) or the position of the edge.

[Problem to be solved by the invention] As a method to solve the above problem, a method of forming pits by performing correction in advance during recording based on radius information and surrounding environment (temperature, power of laser light source, etc.) has been considered. However, it is difficult to determine detailed recording conditions for making corrections. Furthermore, there may be differences in the characteristics of magneto-optical disks (individual differences) or differences between the signal reproducing devices and the signal reproducing devices, so correction during recording alone is not sufficient to solve the above-mentioned problems. Therefore, to achieve high density recording,
Waveform of the signal played back during data playback (playback signal waveform)
Based on this, it is necessary to correct, for example, the synchronization clock signal (external clock signal).

In addition, a clock signal is superimposed on a data signal recorded on a magneto-optical disk, and this recorded clock signal is extracted during playback, and this clock signal is used as a clock signal for playback. There is a clock method, but this method requires the use of a dedicated modulation method and also requires a lock pull-in area in order to allow sufficient clock extraction.

The present invention has been made to solve the above-mentioned problem, and when reproducing a magneto-optical disk, for example, which is driven at a constant angular velocity (CAM) using an external clock system, it is possible to The purpose of the present invention is to provide a signal recording method and a signal reproducing device that can prevent data errors caused by a phase shift between the reproduced waveforms between the inner and outer circumferences of the disk when reproducing a magnetic disk. An object of the present invention is to provide a signal recording method and a signal reproducing apparatus that allow a modulation method to be freely selected without being affected by differences (individual differences), recording environments, and differences in signal recording devices and signal reproducing devices.

[Failure to solve the problem]

As shown in FIG. 1, the signal recording method according to the present invention, when recording a take in response to a synchronized clock signal obtained from a recording medium, for example The above problem is solved by recording a reference clock signal at the beginning of the .

As shown in FIG. 2, the signal reproducing device according to the present invention is a signal reproducing device for reproducing data recorded by the signal recording method, in which a phase difference between a reproduced signal of the reference clock signal and the synchronized clock signal is provided. By having a phase comparator 31 serving as a phase comparison means for performing comparison, and a clock phase control circuit 36 serving as a phase control means controlling the phase of the synchronized clock signal based on the output from the phase comparator 31, Solve the above issues.

Further, the signal reproducing device according to the present invention includes: a clock forming means for forming a plurality of external clock signals having mutually different phases; and a data reproducing means for reproducing a plurality of series of data using the plurality of clock signals from the clock forming means. Problem -F is solved by having an optimal data determining means for determining optimal data from a plurality of series of data from the data reproducing means using the reference clock signal.

[For production]

In the signal recording method and signal reproducing device according to the present invention, when recording data, a reference clock signal is recorded together with the data,
The phase of the synchronized clock signal (external clock signal) obtained from the recording medium during take reproduction is corrected by the reproduction signal of the reference clock signal. Furthermore, multiple series of data are reproduced using a plurality of external clock signals, and optimal data is selected based on the reproduced reference clock signal.

〔Example〕

Embodiments of a signal recording method and a signal reproducing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram without showing a specific recording format of a signal recording method according to the present invention. This recording format is a type of external synchronization method (external clock method).
This is the recording formant for the two-way servo. This first
In the figure, one sector (or block) serving as an information recording unit is composed of a predetermined number of segments (or frames). One segment is composed of a storage area 1 and a data area 2 (in the first segment of the sector, a header area in which information such as Atto I7 is recorded). →
In the node area 1, a pair of so-called wobble pins I for obtaining a trunking error signal and a clock pin for synchronizing clocks are provided in advance. Data area 2 contains data (information) using the magneto-optic effect.
is recorded/played.

In order to solve the problem caused by the phase shift of the data reproduction signal between the inner and outer circumferences of the magneto-optical disk as described above, the reference clock signal is placed in the data area of the second segment, for example, on the order of several Hyde. recorded. That is, when reproducing a recording medium having the above-mentioned recording format, for example, a magneto-optical disk, the clock signal for data reproduction is performed by a synchronized clock signal (external clock signal) reproduced from the clock focus. In the present invention, the phase of the synchronized clock signal is corrected using the reference clock signal, as will be described later.

FIG. 2 is a block circuit diagram of the main parts of a signal reproducing device for reproducing a magneto-optical disk having the recording format shown in FIG. 1, and FIG. 3 and FIG. It is a figure which shows a waveform.

In Figure 2, the angular velocity is constant (
An RF (high frequency) signal reproduced from a magneto-optical disk rotationally driven by a CAV is supplied to an equalization layer 6 via an input terminal 5. The signal waveform-shaped by the equalization layer 6 has its DC component removed by the capacitor 7, and then is transferred to the diode 1.
Sent on 1.12. The waveform of signal A, which is the output of capacitor 7, is shown in FIG. The signal A shown in FIG. 3 is a signal obtained by reproducing the reference clock signal recorded in the data area 2 of the second segment described above.

This signal A includes a low frequency component signal B,
LPF consisting of resistor 13.15 and capacitor 14,
In a resistance adder circuit composed of an LPF composed of resistors 16, 18 and capacitor 17 and resistors 21, 22, and 23, the low frequency component signal B is extracted and this signal B is sent to the differential amplifier 24. . This differential amplifier 24 is supplied with the signal A from the capacitor 7, and in this differential amplifier 24, the low frequency component of the signal B is removed, and a signal C is obtained. This signal C is sent to a comparator 28, where it is compared with a predetermined darkness value, and binarized reproduction data D is obtained. Also, the above two LPs
The outputs of F are sent to the differential amplifier 27 via buffer amplifiers 25 and 26 to calculate the difference, and the signal of this difference is sent to the comparator 29, where it is compared with a predetermined dark value and binarized. A signal E is obtained.

That is, when the RF multiplied signal level (amplitude) reproduced from the magneto-optical disk becomes below a predetermined level (darkness value) due to a defect in the recording surface of the magneto-optical disk, for example,
The value of the signal E is, for example, "0", and the signal E is used to detect that the RF multiplied signal reproduced from the magneto-optical disk is not a correct reproduction signal (so-called dropout, etc.).

2. The reproduced data D from the comparator 28 and the signal E from the comparator 29 are sent to an AND gate 30, and the reproduced data D is gated by the signal. That is, when the signal E is 1°'', the reproduced data D is output as is,
When the signal E is 0, the output is 0.

The reproduced data D from the AND game) 30 is sent to the phase comparator 31.
sent to. Further, this phase comparator 31 is supplied with a synchronized clock signal (external clock signal) from a synchronized clock recovery circuit 32 . That is, the synchronized clock reproducing circuit 32 is composed of, for example, a PLL (phase-locked loop), and reproduces the synchronized clock by a signal reproduced from the clock focus recorded in the servo area 1 of the magneto-optical disk. Signal Ref CK
(external clock signal) is reproduced and sent to the phase comparator 31. In this phase comparator 31, as shown in FIG. 3, phase comparison is performed between the reproduced data D and the synchronized clock signal (external clock signal) Ref CK&, and a phase difference signal F is obtained.

When the falling edge of the reproduced data D is delayed with respect to the falling edge of the synchronized clock signal RefCK, the phase difference signal F has a pulse width that corresponds to the amount of delay, as shown in FIG. 4, for example. When the fall of the reproduced data D is ahead of the fall of the synchronized clock signal Ref CK, it becomes a negative signal with a pulse width corresponding to the amount of advance. This phase difference signal F is supplied to an integrating circuit 33 and integrated into a signal G as shown in FIG. This integrated signal G is S/H (sample/
Bold) In the circuit 34, the synchronized clock signal Ref
It is sampled/bolded at CK and becomes a signal H. An average value AV is determined from this sampled/bold signal H in an average value circuit 35, and this average value AV is sent to a clock phase control circuit 36. This clock phase control circuit 36 includes a sawtooth wave generation circuit 3 as shown in FIG.
A sawtooth wave synchronized with the synchronized clock signal Ref CK from 7 is supplied, and the sawtooth wave is binarized using the average value AV as a threshold (slice level). This 2
The 3 4-valued signal is taken out from the terminal 38 and used as a clock signal for deck reproduction. In other words, the equalized clock signal Ref CK corresponds to the average value AV.
The rising phase of is controlled. In other words, the synchronized clock signal Ref CM (external clock signal) is
Phase control (correction) based on reproduced data D obtained by reproducing the reference clock signal recorded on the magneto-optical disk mentioned above.
Then, K is used for this corrected synchronization clock signal Ref to reproduce the data recorded on the magneto-optical disk. As a result, an overlap occurs between the focal points formed by high-density recording of data on the magneto-optical disk, and a phase shift occurs in the reproduced waveform between the inner and outer circumferences of the magneto-optical disk, as shown in Figure 11. Even in the case where the synchronized clock signal is f CM based on the reproduction signal of the reference clock signal actually recorded on the magneto-optical disk.
By correcting this, it is possible to obtain the optimal synchronization clock signal R (!fOK) corresponding to the radial position of the optical pink amplifier, and it is possible to reproduce a positive 6'ω deck. If the reference clock signal recorded in 5 cannot be reproduced due to a defect, etc., the synchronized clock signal Ref CK
It can be used as is to reproduce data. Also,
The sawtooth wave may be a sine wave.

Next, a second embodiment of the signal reproducing device according to the present invention will be described. FIG. 5 is a diagram showing circuit portions in which the second embodiment differs from the first embodiment, and FIG. 6 is a diagram showing waveforms of main signals. In FIG. 5, the average value AV from the average value circuit 35 shown in FIG. 2 is sent to the A/D converter 41. Further, the synchronized clock signal Ref CK from the synchronized clock recovery circuit 32 shown in FIG. 2 is sent to a delay circuit 42 and a selector 43 in which a plurality of delay elements (for example, seven) are connected in series. As shown in FIG. 6, clock signals delayed by each delay element of the delay circuit 42 are supplied to the selector 43, respectively. And A/D converter 41
In step 7, the average value AV is converted into a digital value, and a clock signal corresponding to the digitalized average G value AV is selected in the selector 43. This selected clock signal is taken out from a terminal 45 via a buffer 44 and used as a signal for data reproduction.

In this way, a plurality of external clock signals (synchronized clock signal amount rcKl) having different phases from each other are converted into quasi-f-bo1, and the reproduced signal of the reference clock No. 13 actually recorded on the magneto-optical disk i12 is combined with the external clock signal. [1] Based on the difference in the number of external I:Jtsuku signals, by selecting the most suitable IIJtsuku Buddhist name for data reproduction,
Correct data playback becomes possible. Also in this embodiment, when the reference 1 cock signal recorded on the magneto-optical disk cannot be reproduced due to a defect or the like, the 1-1 knob-out state is set as described above, and the select state of the selector 43 is maintained. Then, the deck is played back using the previously selected clock signal as is.

Next, a third embodiment of the signal reproducing device according to the present invention will be described. FIG. 7 shows the main circuit configuration for selecting a clock signal having the optimum phase for data reproduction in the third embodiment, and the other parts are the same as in the first embodiment described above. Therefore, it is not shown in the drawings and the explanation will be omitted. FIG. 8 is a diagram showing waveforms of main signals for explaining the operation of the circuit configuration of FIG. 7. However, in the first embodiment, a phase comparator is used to compare the phases of the reproduced data D and the synchronized clock signal Ref CK in order to obtain the phase correction amount (phase correction information). In this third embodiment, by reproducing the reproduction deck D of a plurality of reference clock signals having different phases using a plurality of clock signals having different phases, and calculating the exclusive OR of the reproduced data 1] whose phases are adjacent to each other, , to obtain phase information.

In FIG. 7, reproduced data D from the AND gate 30 shown in FIG. 2 is sent to a plurality (for example, nine) of D type FFs (flip-flops) 61-69. Furthermore, the synchronized clock signal Ref CK (external clock signal) from the synchronized clock regeneration circuit 32 (not shown in FIG. 2) is transmitted to the delay element 7.
1 to 78 are sent to a plurality of delay circuits 70 and FF 61 which are connected in series (e.g. 8 (hard)). As shown in FIG. , ~DL, are supplied to the FFs 62 to 69, respectively.Then, in each FF 61 to 69, the reproduced data D of the reference clock signal recorded on the magneto-optical disk is transmitted to the FFs 61 to 69, as shown in FIG. clock signals DL, -DL.

Latch each. Next, the exclusive OR circuit (EX
-OR) In 81 to 88, the exclusive OR between adjacent FFs is determined from each output of FFs 61 to 69. That is, for example, as shown in FIG.
Between the rising edge of the clock signal DL5 and the rising edge of the clock signal DL5, a change point (edge) of the reproduced data D of the reference clock signal
, these clock signals DL, , DL
The respective outputs of FF65 and FF66 corresponding to 5 are as follows:
The logic is opposite (l! (excluding the time from the rise of the clock signal DL to the rise of the clock signal DL)), and the output of the other FF is the same as that of the adjacent FF.
(To be exact, the time from the rising edge of one clock signal in the previous stage to the rising edge of the clock signal in the next stage is divided (.)).

Then, the output of EX-OR85 becomes 2°1°', and the output of other EX-OR81~84.86~88 becomes °°0''.
(To be precise, excluding the delay time of the clock signal between adjacent FFs). Therefore, E
X-OR circuit (EX-OR5 in the specific example shown in Figure 8)
By determining this, it is possible to obtain the phase difference (phase information) between the reference clock signal reproduced from the magneto-optical disk and the synchronized clock signal Ref CK. Based on this phase information, the synchronized clock Ref CK (external clock signal) and each delay element 71 to 7 of the delay circuit 70 are
Correct data reproduction can be performed by selecting the clock signal with the optimum phase for data reproduction from among the clock signals DL, -DL delayed at 8.

Specifically, in order to align the phases of the outputs of EX-ORs 81 to 8, the outputs of EX-ORs 81 to 84 are
94, are latched at the falling edge of the synchronized clock signal Ref CK, and are sent to the FF
The outputs of 91 to 94 and the outputs of EX-OR85 to 88 are F.
They are sent to Fl0I-108, respectively, and latched at the rising edge of the synchronized clock signal Ref CK. FFl0
The output signals ED, ~ED8 of I-108 are AND gate 1
11 to 118, respectively. A signal Ref Area indicating that the reference clock signal is currently being reproduced and manually input as reproduced data D is input to these AND gates 111 to 118. For example, when the reference clock signal is currently being reproduced, 1” is input.

That is, when the reference clock signal is being reproduced, the change point (edge) of the reproduced data D of the reference clock signal is E.
It is detected by any of the X-ORs 81 to 88, and the output of the corresponding AND gate becomes "1".

For example, in the specific example shown in Part 8, the output of the AND gate 115 is 1''.

The outputs of AND gates 111 to 118 are AND gate 1
21 to 128 are gated with respective inverted (inverter) signals of the carrier signals CY and CY8 from counters 131 to 138, and the counters 131 to 138
Controls the counting operation (controls the start/stop of counting)
The signals are sent to the respective enable (EN) terminals. These counters 131 to 138 are n-ary counters (with loading) whose initial value of callan 1- can be set externally, and a signal Ref S representing the beginning of the reference clock signal is used.
The initial value m is loaded (read) by t.

That is, the initial value m is loaded and the AND gate 121
When the output of ~128 becomes 1'', counting starts, and when the count up ((nm) count), the carrier signals CY and ~CY8 become 1''.These carrier signals CY~cy are connected to the inverter. Gates 141-148
Since the AND gates 121 to 128 are manually inputted through the
'', the carrier signals CY to CY8 continue to be ``1'' until the signal Ref St representing the beginning of the next reference clock signal arrives. Based on the phase information between these carrier signals CY1 to CYll, that is, the synchronization clock 12 CK (No. 7i fief CK) and the reference clock, the selector' circuit The same jIJl conversion signal Ref
Each of the delay elements 71 to 8- of the CK and delay circuit 70 (respectively selects a clock signal with an optimal phase for deck reproduction from the delayed clock signals DL, to DLn) The example is not shown in Figure 8, but a specific example is Karan's IJ) 5.
1”, and other counters 131~134.136~
138 carrier signals CY, ~CY4, CY, ~CY8
becomes "o". By the way,” - (as stated)・
EX-
Accurate phase information can be obtained by setting carrier signals CY1 to CY8 to "1" when the number of change points (en) of the reference clock signal detected by OR81 to OR88 is equal to or greater than a predetermined number (nm). I can do it.

Next, let us explain the fourth embodiment. In the three embodiments described above, optimal data reproduction is performed by controlling the clock signal for data reproduction. Of course, the clock signal with the optimum phase for data reproduction is selected by correcting the position + [] of the synchronized clock (external clock signal) or from a plurality of clock signals with different phases. It is also possible to use this clock signal to reproduce data.

On the other hand, in this fourth embodiment, a plurality of external clock signals having mutually different phases are provided, and a plurality of series of reproduced data are provided by the plurality of external clock signals having different phases. , one optimum reproduction data is directly selected from the plurality of reproduction takes by uncovering the phase information of the external clock signal (the same 1υ1 clock signal) and the reference clock signal.

Specifically, a plurality of delay elements (for example, delay elements 71 to 78 shown in FIG. 7 in the third embodiment) are connected in series, and a plurality of external clock signals having mutually different phases obtained from these delay elements are connected in series. (For example, the clock signals m, DL1 to DL, lI in the third embodiment) are set to multiple 0FF(
For example, in the third embodiment, the reproduction take D is latched as the clock signal of 4 G) 61 to 69).One reproduction data is extracted from the plurality of series of reproduction data D obtained in this way. The A/D converter 4 converts the phase information into phase information, for example, in the second embodiment.
The selection is made based on the phase information, etc., which is the output of 1.

As is clear from the following explanation, in the signal recording method and signal reproducing apparatus according to the present invention, a reference clock signal for detecting phase information is recorded at the beginning of recorded data, and during take reproduction, By reproducing this reference clock signal and correcting the phase of the synchronized clock signal (external clock signal) based on the reference clock signal, or selecting one optimal reproduction data from multiple reproduction takes. As a result, data can be recorded at high density on a magneto-optical disk that is rotationally driven at a constant angular velocity (CAV), and even if the formed bits overlap, the data can be reproduced accurately. Also, based on the reproduced waveform of the reference clock signal actually recorded on the magneto-optical disk, the same
By correcting the phase of the 4Jl clock signal, it becomes possible to reproduce data without being affected by environmental conditions during recording, differences in characteristics between the recording device and the reproduction device, individual differences between disks, etc.

Furthermore, since an external clock method can be used,
The modulation method can be freely selected.

〔Effect of the invention〕

According to the signal recording method and signal reproducing device according to the present invention,
By recording a reference clock signal for detecting phase information at the beginning of the recorded data, and reproducing this reference clock signal during take playback, the phase of the synchronized clock signal (external clock signal) is corrected. Or, by selecting one optimal reproduction data from multiple series of reproduction data, data is recorded at high density on a magneto-optical disk that is rotated at a constant angular velocity (CAV), and overlap occurs in the formed pits. Even in the case of a computer, data playback can be performed normally. Also, based on the reproduced waveform of the reference clock signal actually recorded on the magneto-optical disk, the same
By performing the phase correction of the clock signal for use 6, it becomes possible to reproduce data without being affected by environmental conditions during recording, differences in characteristics between the recording device and the reproduction device, individual differences between discs, etc. Furthermore, since an external clock method can be used, the modulation method can be freely selected.

[Brief explanation of drawings]

FIG. 1 shows a sample servo recording format ta which is an embodiment of the signal recording method according to the present invention, and FIG. 2 shows a block circuit of the main part of the first embodiment of the signal reproducing device according to the present invention. 3 and 4 are waveform diagrams of main signals of the signal reproducing device, and FIG. 5 is a waveform diagram of the main signals of the signal reproducing device.
6 is a block circuit diagram of the main parts of the signal reproducing device according to the third embodiment, FIG. 6 is a waveform diagram of the main signals of the circuit shown in FIG. 5, and FIG. FIG. 8 is a waveform diagram of the main signals of the circuit shown in FIG. 7, and FIG. 9 is a diagram for explaining the recording principle of a magneto-optical recording medium. 10 is a diagram showing pits formed on a magneto-optical disk using a constant angular velocity (CAV) drive method, and FIG. 11 is a diagram expressing the pits shown in FIG. 10 on a time axis. . 6...Equalization layer 24.27...Differential amplifier 28.28...Comparator 31...Phase comparator 32...Synchronization clock regeneration circuit 33...Integrator circuit 34... S/H circuit 35...Average value circuit 36...Clock phase control circuit 37...Sawtooth wave generation circuit 7 Sairi V Fig.9

Claims (3)

[Claims] (1) A signal recording method characterized by recording a reference clock signal when recording data in accordance with a synchronized clock signal obtained from a recording medium. (2) In a signal reproducing device for reproducing data recorded by the signal recording method, a phase comparison means for performing a phase comparison between the reproduced signal of the reference clock signal and the synchronized clock signal, and A signal reproducing device comprising: phase control means for controlling the phase of the synchronized clock signal by output. (3) a clock forming means for forming a plurality of external clock signals having mutually different phases, and determining the optimum data from the plurality of clock signals from the clock forming means and the plurality of series of data from the data reproducing means using the reference clock signal. A signal reproducing device characterized in that it has an optimum data determining means.