JPH0552578B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention is applicable to, for example, video signals and audio signals.
The present invention relates to a method for recording and reproducing digital signals, which is suitable for use in cases where a PCM signal is converted into a PCM signal, recorded as one diagonal track on a recording medium by a rotating head in units of time, and then reproduced.

BACKGROUND TECHNOLOGY AND PROBLEMS There is a case in which video signals and audio signals are recorded on a magnetic tape by forming one diagonal track every unit time using a helical scan type rotary head device, and this is then played back. In addition, it is being considered to record and play back video and audio signals by converting them into PCM. This is because PCM allows high-quality recording and playback.

In this case, tracking control to ensure that the rotating head correctly scans the recording track during playback has conventionally been carried out by transmitting a control signal recorded at one end of the tape widthwise by a fixed magnetic head. This is normally achieved by reproducing with a fixed head so that the reproduction control signal and the rotational phase of the rotary head have a constant phase relationship.

However, this method requires the provision of a fixed magnetic head specifically for tracking control.

Providing such a fixed magnetic head is
When it is desired to downsize a recording/reproducing device, it causes inconvenience due to its installation location, etc.

Therefore, the applicant of the present invention previously proposed a method of performing tracking control of a rotary head for reproduction by using only the reproduction output of the rotary head without using the fixed head.

With this method, PCM signals can be easily compressed and expanded on the time axis, so unlike analog signals, there is no need to record and play back signals in a continuous manner. This was done with the focus on the fact that it is easy to record this PCM signal and separate signals by dividing the area.

In other words, when a PCM signal is compressed in the time axis and recorded by a plurality of rotating heads diagonally forming tracks on a recording medium without forming a guard band, the PCM signal is compressed in the longitudinal direction of each track. The recording area records multiple pilot signals for tracking independently, and during playback, the recording tracking is scanned by a rotating head whose scanning width is wider than the tracking width, and the rotating head scans the tracks on both sides of the track being scanned. The tracking of the rotary head is controlled by the reproduced output of the pilot signal from the rotary head.

The reference signal for recording and reproducing this tracking pilot signal is a 30Hz pulse signal (PG ) is used.

However, even during playback, if the PG signal is used as a detection position reference when reproducing the tracking pilot signal, the reference position of the PG signal may shift due to mechanical changes in the device over time, temperature changes, etc. It appears as a kind of steady-state tracking error (offset).

For this reason, it becomes difficult to reproduce the tracking pilot signal and control the rotary head at the same timing as during reproduction and recording, and there is a particular problem in that compatibility between devices becomes incompatible.

In addition, since the sampling pulse for obtaining the reproduction output of the tracking pilot signal is formed over the period of one revolution of the head using the PG signal as a reference, the error increases in the form of integration, resulting in the effect of so-called jitter. As a result, the position of the sampling pulse may shift.

Purpose of the Invention In view of the above, the present invention reliably reproduces a tracking pilot signal to correctly control a rotating head without being affected by mechanical changes over time, temperature changes, or jitters of the device, and allows equipment to communicate with each other. The purpose of the present invention is to provide a method for recording and reproducing digital signals that can achieve compatibility between the two.

Summary of the Invention This invention compresses the time axis of a digital signal, forms and records a diagonal track on a recording medium using a plurality of rotary heads without forming a guard band, and simultaneously determines the position of the pilot signal. In the method of recording a positioning signal of one frequency in the first scan and another frequency different from one frequency in the second scan for detection, and reproducing this, The above-mentioned digital signal is a recording area in which a plurality of independent tracking pilot signals are recorded, and when the recording track is scanned by a rotary head whose scanning width is wider than the width of the track during reproduction, the first scanning During the period, a pulse signal is formed based on the reproduced output of one of the positioning signals recorded on the track currently being scanned, and during the second scanning period, the pulse signal is generated based on the reproduction output of the positioning signal recorded on the track currently being scanned. A pulse signal is formed based on the reproduced output of the other positioning signal, and during the period of each of these pulse signals, the pilot signal is detected from the adjacent track that the rotary head is scanning, and this detection output is used to detect the pilot signal from the adjacent track that the rotary head is scanning. The device is configured to perform tracking control of the rotary head by reliably reproducing the tracking pilot signal and controlling the rotary head without being affected by mechanical changes over time, temperature changes, or jitters of the device. tracking control can be performed, and compatibility between devices can be achieved.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on FIGS. 1 to 5.

Figure 1 shows the circuit configuration of this embodiment.
Here, only the circuit configuration for recording and normally reproducing a tracking pilot signal, which is directly related to this invention, is shown, and the circuit configuration for recording and reproducing recorded information such as a PCM signal is omitted. has been done.

In the figure, 1A and 1B are rotary heads, and 2 is a magnetic tape as a recording medium. The rotating heads 1A and 1B are arranged around the periphery of the drum 3 at equal angular intervals, that is, 180 degrees apart, as shown in FIG. On the other hand, the magnetic tape 2 is wound around the circumferential surface of the tape guide drum 3 over an angular range of, for example, 90 degrees, which is narrower than each range of 180 degrees. Then, the rotating heads 1A and 1B rotate in one second.
The tape 2 is rotated at a rate of 30 rotations in the direction of arrow 4H, and is also run at a predetermined speed in the direction of arrow 4T, so that the rotating heads 1A and 1B create a pattern on the magnetic tape 2 as shown in FIG. The diagonal magnetic tracks 5A, 5B are formed in a so-called overlapping state, for example. In other words, the width of the head gap (scanning width) W
is made larger than the track width. In this case, the width directions of the gaps of the heads 1A and 1B are set in different directions with respect to the direction orthogonal to the scanning direction. In other words, the so-called azimuth angles are made different.

Then, a period (in this example, a period corresponding to an angular range of 90 degrees) occurs during which the two rotary heads 1A and 1B do not come into contact with the tape 2, and this period is utilized during recording. The apparatus can be simplified by adding redundant data and performing correction processing during reproduction.

Reference numeral 6 denotes an oscillator that generates a tracking pilot signal P. The frequency ₀ of the pilot signal P has a relatively small value of azimuth loss, for example, about several hundred kHz, and is recorded at a relatively high level. Further, 6A and 6B are oscillators that generate signals E ₁ and E ₂ for erasing pilot signals,
The erasing signals E ₁ and E ₂ are used to ensure that when new recording is made on a previously recorded tape while erasing the previously recorded information, the recorded track always matches the previous recorded track. This is used because it is necessary to erase the previously recorded pilot signal, and its frequency
₁ and ₂ are different from each other and are sufficiently far away from the pilot signal frequency ₀ for practical purposes,
Moreover, the value is such that the pilot signal P can be erased. Further, the recording level is also such that the pilot signal P can be practically erased. Further, in the present invention, these erasing signals E ₁ and E ₂ are used as positioning signals for detecting the position of the pilot signal.

7, 7A, 7B are recording waveform generation circuits,
In response to an output from an edge detection circuit 8 that detects the edge of a delayed signal related to a pulse PG, which will be described later, a generation circuit 7 determines how many pilot signals are generated per track based on a pilot signal from an oscillator 6. A predetermined time depending on whether to insert in a sequence
The generation circuits 7A and 7B generate the number of erasing signals per track in any manner based on the erasing signals from the oscillators 6A and 6B, respectively. An erasing signal having a predetermined time 3/2 tp is generated at predetermined intervals _T0 depending on whether the data is inserted in an array or not. 8A
is an OR circuit that logically processes the outputs of the generation circuits 7, 7A, and 7B. 9 is the rotary head 1A and 1
This is a switch circuit for switching the switching signal S ₁ (fourth
Figure A). This timing signal generation circuit 10 is supplied with a 30 Hz pulse PG indicating the rotational phase of the rotary heads 1A, 1B obtained in synchronization with the rotation of the rotation drive motor 12 of the rotary heads 1A, 1B from a pulse generator 11. has been done.
In addition, the timing signal generation circuit 10 is connected to the pulse PG.
The 30Hz pulse from the motor is supplied to the phase servo circuit 13, and the rotational phase of the motor 12 is controlled by the servo output.

Switching signal S ₁ from timing signal generation circuit 10
The pilot signal from the switch circuit 9 switched by
is supplied to the rotary head 1A or 1B via the side,
Recorded on magnetic tape 2. switch circuit 15
A and 15B are connected to the R side during recording, and are switched to the P side during playback.

Further, the output signal S ₂ (FIG. 4C) from the timing signal generation circuit 10 is supplied to the delay circuit 16,
Here, the rotating heads 1A, 1B and the pulse generator 11
After a delay corresponding to the distance between the mounting positions, etc., the signal is supplied to one input side of the edge detection circuit 8, and edge detection is performed as a recording reference for the pilot signal. Note that the signal delayed by the delay circuit 16
The falling edge of S ₃ (FIG. 4D) is made to coincide with the time when the first head contacts the tape during one revolution.

Further, the signal from the delay circuit 16 has a delay time T corresponding to a half-rotation period of the head and a track (1
The pilot signal is supplied to a delay circuit 17 having a delay time +3/2 tp corresponding to the distance from the end of the rear track (of the two tracks formed during the rotation period) until the pilot signal is first recorded. So, T
+3/2 tp and is applied to the other input of the edge detection circuit 8, thereby setting the reference for starting the recording of the pilot signal by head 1A relative to one rotary head relative to the other head, i.e. in this case head 1B. Edge detection is performed to determine. Further, 17A and 17B are delay circuits having delay times T and tp, respectively, and by supplying the outputs of these circuits to the edge detection circuit 8, the reference for starting recording of the erasing signal in the periods _tA and _tB is determined. Edge detection is performed.

18A and 18B are switch circuits 15 during playback.
These amplifiers 18A, 1 are supplied with reproduction outputs from the corresponding rotary heads 1A, 1B when A, 15B are switched to the contact P side.
Each output of 8B is supplied to a switch circuit 19.
The switch circuit 19 includes the timing signal generation circuit 1
0 to 30 Hz switching signal _S1 ' (Fig. 5A), a half-rotation period including the tape contact period of head 1A and a half-rotation period including the tape contact period of head 1B, as in the case of recording. Can be switched alternately.

20 is a narrowband band pass filter with a passing frequency of ₀ for extracting only the pilot signal P from the reproduction output from the switch circuit 19; 21 is for holding the peak value of the output of the filter 20 in order to improve response characteristics; peak hold circuit,
22 is a sampling and holding circuit for sampling and holding the held peak value; 23 is a comparison circuit for comparing the outputs of the peak holding circuit 21 and the sampling and holding circuit 22; for example, a differential amplifier; 24 is a differential amplifier 23 These sampling and holding circuits 22 and 24 are sampling and holding circuits for sampling and holding a comparison error signal from a track that is currently being scanned during normal playback, as will be described later. It functions to sample and hold the crossstrokes of each pilot signal recorded at both end portions and the center portion of both adjacent tracks, respectively. The output of the sampling and holding circuit 24 is outputted to an output terminal 25 as a tracking control signal.

In addition, in order to form sampling pulses etc. for the sampling and hold circuits 22 and 24, an erasing signal is sent from the reproduction output to the output side of the switch circuit 19.
Narrow band bandpass filters 26 and 27 with passing center frequencies ₁ and ₂ , _respectively , are provided to extract only E 1 and E ₂ , and these outputs S _E1 and S _E2 (5th
The waveforms in FIGS. K and L) are shaped by waveform shaping circuits 28 and 29, respectively.

30 and 31 are waveform shaping circuits 28 and 29, respectively.
The outputs S _{14 and 31} of the detection circuits 30 and 31 are rise detection circuits for detecting the rise of the signal from the detection circuits 30 and 31, and as described later, the rise of the erasing signal is detected every half rotation period of the head. S ₁₅ (5th
Figures M and N) are supplied to a plurality of gate circuits 33 ₁ , 33 ₂ , 33 ₃ , 33 ₄ , 33 ₅ and 33 ₆ via an OR circuit 32, and the gate signals are, for example, window signals using a counter. Window signals S _W1 -S _W6 (FIGS. 5C-H) from the generation circuit 34 are used. The window signal generation circuit 34 counts the clocks from the clock terminal ₃₈ in response to the output signal S2 from the timing signal generation circuit 10,
Wind signals (S _{W1 to S}
S _W6 ) occurs.

Therefore, the edges of the signals S E1 and S _E2 , that is, the signals S ₁₄ and S _E2 that have entered during the periods of these window signals _SW1 to S _W6 , are output to the respective output sides of the gate circuits ₃₃ 1 to _{33 6} .
Only _S15 is led out to the output side of the OR circuit 35 as an output signal _S16 (FIG. 5D), and is essentially used as a start pulse during period _tB via a delay circuit 36 using a counter and a switch circuit 37. period
During _tA , the signal is supplied to the input side of the pulse generation circuit 39 via only the switch circuit 37.

The delay circuit 36 sets a delay time ta (equivalent to 1/2 tp) from the time of generation of the signal _S16 until the sampling of the pilot signal substantially starts within the first half-rotation period of the head, for example, the period _tB .

That is, the delay circuit 36, which is a counter, receives the signal
Counts the clock from the clock terminal 38 for the set time using _S16 as a start pulse,
At the end of the count, a narrow signal S ₁₇ is present at its output.
(Fig. 5P) is generated. Also, during the second half rotation period t _A of the head, the signal S ₁₆ is not delayed and this signal S ₁₆
The point in time at which the pilot signal is actually sampled is the point in time at which the pilot signal is actually sampled. In addition, switch circuit 3
7 is controlled in its switching by a switching signal S ₁ '.

As the pulse generation circuit 39, for example, a counter is used, which counts the clocks from the clock terminal 38 using the signal from the switch circuit 37 as a trigger pulse, and generates a pair of pulses Pi (Fig. 5) having a predetermined connection time at a predetermined interval to. Q) is generated in response to each pilot signal to be detected. This pulse Pi is supplied to a peak hold circuit 21 and also to a sampling pulse generation circuit 40 using, for example, a D-type flip-flop circuit.

In response to the pair of pulses Pi, the sampling pulse generation circuit 40 generates a pair of sampling pulses SP ₁ and SP ₂ (R and S in FIG. 5) having approximately the same phase difference as these to the sampling and hold circuits 22 and 2.
Occurs for 4.

Next, the operation of the circuit shown in FIG. 1 will be explained with reference to the signal waveforms shown in FIGS. 4 and 5.

First, during recording, a pulse PG from the pulse generator 11 indicating the rotational phase of the rotary heads 1A and 1B is generated.
In response, _the timing signal generating circuit 10 generates a signal _S2 as shown in _FIG .
However, on the output side there is a signal as shown in Figure 4D.
S ₃ is output. This signal _S3 is the edge detection circuit 8
The edge (falling edge) is detected here, and in synchronization with this edge, a fourth signal is applied to the output side.
A narrow signal _S4 as shown in FIG. E is generated and supplied to the recording waveform generation circuit 7. Signal S ₄ at this time
The detection time point is made to approximately coincide with the time when the head 1B actually contacts the tape 2 for the first time, and this determines the standard for starting recording of the pilot signal by the head 1B.

The recording waveform generating circuit 7 generates the pilot signal P from the oscillator ₆ at predetermined intervals _T0 for a predetermined time tp in synchronization with the signal _S4 supplied under the control of the switching signal S1.
Thus, the signal _S6 , which is an intermittent pilot signal as shown in FIG. 4G, is taken out at the output side.

Further, the signal _S3 from the delay circuit 16 is transmitted to the delay circuit 1
7. This delay circuit 17 generates a signal _S5 as shown in FIG. 4F having a connection time T+ ₃ /2tp in synchronization with the fall of the signal S3. This signal _S5 is supplied to the edge detection circuit 8, where its edge (falling edge) is detected as described above, and in synchronization with this edge, a narrow signal is applied to its output side as shown in the right part of FIG. 4E. A width signal S ₄ is generated and supplied to the recording waveform generation circuit 7. The signal _S4 at this time determines the reference for starting recording of the pilot signal by the head 1A.

In this case as well, the recording waveform generating circuit 7 passes the pilot signal P from the oscillator 6 at predetermined intervals _T0 for a predetermined time tp in synchronization with the supplied signal _S4 , and the 4. An intermittent pilot signal _S6 as shown in FIG. 4G is output.

Further, the signal _S3 from the delay circuit 16 is sent to the delay circuit 1.
7A and 17B. Delay circuit 17A, 1
7B generates signals S ₇ and S ₉ as shown in FIGS. 4H and J, having durations tp and T, respectively, in synchronization with the falling edge of signal S ₃ . These signals S ₇ and S ₉
is supplied to the edge detection circuit 8, where its edges (falling edges) are detected in the same manner as described above, and in synchronization with these edges, a narrow width is applied to the output side as shown in FIG. 4 I and K, respectively. Signals S ₈ and S ₁₀ are generated and supplied to recording waveform generation circuits 7A and 7B. The signals S ₈ and S ₁₀ at this time determine the reference for starting recording of the erasing signals E ₁ and E ₂ by the heads 1B and 1A, respectively.

In this case as well, recording generation circuits 7A and 7B
is the supplied signal under the control of the switching signal S ₁
In synchronization with S ₈ and S ₁₀ , the erasing signals E ₁ and E ₂ from the oscillators 6A and 6B, respectively, are passed for a predetermined time 3/2tp at every predetermined interval _T0 , and the output side of each is shown in FIG. Intermittent erasing signals as shown in L and M
S ₁₁ and S ₁₂ are output.

The respective signals S ₆ , S ₁₁ and S ₁₂ from the recording waveform generation circuits 7, 7A and 7B are supplied to the OR circuit 8A and are substantially added, so that the output side of the signal S ₆ in the period _tB is Rise in synchronization with the rise, signal
Falling in synchronization with the rising edge of S ₁₁ , while period t _A
Then, a signal _S13 as shown in FIG. 4N is obtained, which rises in synchronization with the rise of signal _S12 and falls in synchronization with the fall of signal _S6 . And this signal
_S13 is supplied to the switch circuit 9.

The timing signal generating circuit 10 generates a switching signal _S1 as shown in FIG. _4A in response to the pulse PG from the pulse generator 11. As shown in Fig. 4A and B, the head 1A contacts the tape 2 during the head half-rotation period _tA when the signal _S1 is at a high level, and the signal _S1 is at a low level. The head 1B is in contact with the tape 2 within a certain half-rotation period _tB . and,
The switch circuit 9 is switched to the state shown in the figure during the period _tA and to the state opposite to the state shown in the figure during the period _tB by the switching signal _S1 , thereby performing head switching.

Therefore, the signal _S13 at the predetermined interval _T0 obtained at the output side of the OR circuit 8A will connect the R side of the amplifier 14B and the switch circuit 15B when the switch circuit 9 is in a state opposite to that shown in the figure. tape 2 of head 1B within period _tB .
At the beginning, middle and end of the contact period, as shown in _FIG .
Tracking signal recording areas A _T3 and A _T2 provided at both longitudinal ends of track 5B, and a similar recording area provided at the center of track 5B.
At _AT3 , the pilot signal P is recorded for a time tp, and the erasing signal _E1 is recorded for a time 3/2tp.

On the other hand, when the switch circuit 9 is in the state shown in the figure,
Signal S ₁₃ is amplifier 14A and switch circuit 15A
The tape is supplied to the head 1A through the R side of the tape 2, and at the beginning, middle and end of the contact period of the head 1A with the tape 2 within the period _tA , as shown in the figure, the tape 5A is Equidistant l from the center direction position
The same recording areas A _T1 and A _T2 as described above are provided at both ends of the track 5A in the longitudinal direction, which are separated by a distance (equivalent to T ₀ ), and the same recording area A _T3 is provided at the center of the track 5A. The erasing signal _E2 is recorded during the time 3/2 tp, and the pilot signal P is recorded during the time tp.

Also, other than the time when these pilot signal P and erasing signals E ₁ and E ₂ are recorded, the audio PCM signal of one segment portion to be recorded as one track is not shown in the period _tA. It is supplied to the head 1A through the amplifier 14A, and the period t _B
Then, the signals are supplied to the head 1B through the amplifier 14B and recorded in recording areas A _P1 and _AP2 other than the above-mentioned pilot signal recording area of each track 5A and 5B, respectively.

Next, reproduction of the recorded signal as described above will be explained.

Also during this reproduction, drum phase servo is applied to the motor 12 by the phase servo circuit 13 in the same manner as during recording.

First, the tape 2 is
The signals taken out from the respective switch circuits 15
Contact P side of A, amplifier 18A and switch circuit 1
The signal is supplied to the switch circuit 19 via the contact P side of 5B and the amplifier 18B. This switch circuit 19 is activated by a 30 Hz switching signal S1 _' as shown in FIG.
It is alternately switched between _tA and a half-rotation period _tB that includes the tape contact period of the head 1B. Therefore,
From this switch circuit 19, 1 as shown in FIG.
An intermittent PCM signal S _R is obtained segment by segment,
This signal is supplied to a reproduction processor (not shown), where it is demodulated into the original PCM signal, and further supplied to a decoder, where data for each block is detected using a block synchronization signal, and processes such as error correction and deinterleaving are performed. , the signal is returned to an analog audio signal by a D/A converter, and then output to the output side.

Tracking control is performed as follows.

Now, for example _, if the head 1B scans a range of scanning width W including the track _5B2 as shown by the _dashed line in _FIG .
area as shown in Figure 3.
A In _T1 , the pilot signal of track 5B ₂
P _A2 and erasure signal E ₁ , and adjacent tracks 5A ₂ on both sides
The pilot signal P _B2 of the track 5A 1 and the pilot signal PB ₁ of the track 5A ₁ are reproduced, and in the area A _T3 , the pilot signal P _A4 of the track 5B ₂ and the signal for erasing are reproduced.
Pilot signal of E ₁ and adjacent trucks 5A ₂
PB ₄ and the pilot signal P _B3 of the track 5A ₁ , and in the area A _T2 , the pilot signal P _A6 of the track 5B ₂ and the erasing signal E ₁ , and the pilot signal P _B6 of the adjacent track 5A ₂ and the track 5A 1 are reproduced. 5
Regenerate the pilot signal P _B5 of _A1 . At this time, the playback output of the head 1B from the switch circuit 19 is supplied to a narrowband bandpass filter 20 with a passing center frequency _{of 0} , and only the pilot signal is taken out as its output _SF , as shown in FIG. 5J. ,
This is supplied to the peak hold circuit 21.

Further, the output S _R of the switch circuit 19 is supplied to band pass filters 26 and 27, from which erasing signals S _E1 and S _E2 of frequencies ₁ and ₂ as shown in FIG. 5 K and L are taken out, respectively. . These signals are supplied to rise detection circuits 30 and 31 via waveform shaping circuits 28 and 29, respectively, where the rise and fall of the signals are detected, respectively, and the signals M and N shown in FIG. Signals S ₁₄ and S ₁₅ as shown in are obtained. These signals S ₁₄ and S ₁₅ are supplied to gate circuits 33 ₁ to 33 ₆ via an OR circuit 32.

Further, the window signal generation circuit 34 generates window signals S W1 to _W6 as shown in FIGS. 5C to 5H in response to the signal S ₂ shown in FIG. _5B from the timing signal generation circuit 10. They are sequentially generated and supplied to the gate circuits 33 ₁ to 33 ₆ as gate signals, and therefore, on the output side of these gate circuits,
Signals that entered during each period of window signals S _W1 to _{S W6}
Only S ₁₄ or S ₁₅ is substantially taken out, and as a result, at the output side of the OR circuit 35 at the output side of the gate circuits 33 ₁ to 33 ₆ , as shown in _FIG . coincides with the beginning of S ₁₄ , that is, the erasing signal S _E1 , and during the period t _A , the signal S ₁₅ , that is, the erasing signal
A narrow signal S ₁₆ is obtained that coincides with the beginning of S _E2 .

This signal _S16 is supplied to the delay circuit 36 and also to the contact a side of the switch circuit 37.

The delay circuit 36 delays the supplied signal _S16 by a time ta and supplies it to the contact b side of the switch circuit 37. Therefore, this switch circuit 37 receives the switching signal.
By controlling the switching to the contact b side during the t _B period and to the contact a side during the t _A period by S ₁ ', a signal as shown in FIG. 5P is generated on the output side of the switch circuit 37.
S ₁₇ is obtained.

This signal _S17 is supplied to the pulse generation circuit 39,
Now, based on the signal _S17 , as shown in FIG. 5Q,
A pair of pulses Pi corresponding to each pilot signal to be detected is formed and supplied to the sampling pulse generation circuit 40 and the peak hold circuit 21. Then, the sampling pulse generation circuit 40
Based on the pair of pulses Pi, the sampling pulses SP 1 and ₁ as shown in FIG.
SP ₂ is generated and supplied to sample and hold circuits 22 and 24, respectively.

Therefore, while the head 1B is scanning the track _5B2 , as is clear from FIG. ₂ pilot signal P _B2 ,
A state is reached in which the crosstalk of P _B4 and P _B6 is held at its peak in the peak hold circuit 21, and the output of the peak hold circuit 21 at this time is supplied to the sampling hold circuit 22, where it is sampled by the pulse SP ₁ and is advanced in phase. is supplied to one input terminal of the differential amplifier 23 as a tracking signal.

Further, the second pulse Pi is the pilot signal P _B1 , P _B3 and the adjacent track _5A1 on the tape transport direction side.
P _B5 cross stroke peak hold circuit 21
The output of the peak hold circuit 21 at this time is supplied to the other input terminal of the differential amplifier 23 as a tracking signal with a delayed phase. Therefore, differential amplifier 2
3 is the pilot signal P _B2 and P _B1 , P _B4 and P _B3 , P _B6 and
The tracking signals corresponding to the crosstalk of P _B5 are sequentially compared, and the comparison error signal from the differential amplifier 23 is supplied to the sampling hold circuit 24, where the second sampling pulse SP ₂
sampled by Therefore, from this sampling hold circuit 24, the differential amplifier 2
The difference between the two inputs to the differential amplifier 23 is obtained as a tracking control signal, which is supplied from the output terminal 25 to a capstan motor (not shown) to control the amount of tape transport, and the level of both inputs to the differential amplifier 23. When the difference is zero, that is, when the head 1B scans the track _5B2 , it is controlled so that it straddles the two tracks _5A2 and _5A1 on both sides by the same amount. That is, scanning is controlled so that the center position of the gap in the head 1B in the width direction coincides with the center position of the track _5B2 .

The same process is performed for the other tracks. For example, when the head 1A scans the track _5A2 , the pilots of the tracks _5B3 and _5B2 on both sides are scanned, as shown on the right side of FIG. Since the crosstalk of the signals P _A7 , P _A9 , P _A11 and P _A2 , P _A4 , P _A6 is obtained, these signals are sequentially peak held in the peak hold circuit 21 as described above, and are transferred from the sampling pulse generation circuit 40 to the sampling hold circuit 22 . Sampling pulse SP ₁ supplied to
The crosstalk of the pilot signals P _A7 , P _A9 , P _A11 is sampled to obtain the tracking signal.
This is supplied to the next-stage differential amplifier 23, and the output from the peak hold circuit ₂₁ corresponding to the crosstalk of the pilot signals P _A2 , P _A4 , P _A6 is supplied. _A2 , P _A9 and
By comparing the tracking signals corresponding to the crosstalk of P _A4 , P _A11 , and P _A6, respectively, and sampling the comparison error signal with the sampling pulse SP ₂ supplied to the sampling hold circuit 24,
A tracking control signal for head 1A can be obtained.

Similarly, move track 5B ₃ to head 1B.
When scanning, crosstalk is obtained between the pilot signals P _B7 , P _B9 , P _B11 and P _B2 , P _B4 , P _B6 of the tracks 5 A ₃ and 5 A ₂ on both sides as shown in FIG. , pilot signals P _B7 , P _B9 ,
The crosstalk of P _B11 is sampled with the sampling pulse SP ₁ , and the tracking signals corresponding to the crosstalk of the pilot signals P _B7 and P _B2 , P _B9 and P _B4 , and P _B11 and P _B6 are compared using the differential amplifier 23. death,
The comparison error signal is finally converted into a sampling pulse
By sampling with SP ₂ , head 1B
A tracking control signal can be obtained for the

In this way, in this embodiment, the signal for erasing the pulse signal has a different frequency for each head, and is also used as the positioning signal for the pulse signal, so that the circuit configuration for extracting the so-called self-clock is simplified. It can be simplified and its performance can also be improved.

Furthermore, in this embodiment, during playback, a pilot signal is detected and a sampling pulse is self-generated substantially based on the starting edge of the playback output of an erasing signal recorded on a track. Since it is made to occur substantially from the track pattern, there is no adverse effect when using the pulse PG as a reference, such as an offset.

In addition, the tracking position is detected by generating a sampling pulse as described above during each scanning period of each head. In other words, each head generates a self-clock as a sampling pulse on the track pattern each time, and each track is tracked. Since the position is detected, the effects of jitter are also eliminated.

The above-mentioned embodiment is a special rotary head device that records and reproduces data by winding the tape over an angular range narrower than the head angular interval.
Of course, the present invention can also be applied to the case where a rotary head device is used which wraps the tape in the same angular range as the head angular interval as usual.

Effects of the Invention As described above, according to the present invention, when a recording track is scanned by a rotating head, a pulse is generated to detect a pilot signal recorded on the track based on the reproduced output of a signal for erasing the pilot signal. Since a tracking control signal based on the detection output is used to control the tracking of the rotary head, even if the device is subject to mechanical changes over time, temperature changes, or jitter, these effects will not be affected. Tracking control during normal playback can be performed with high accuracy even if the device used during playback is different from that used during recording, and compatibility between devices can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the rotary head device used in FIG. 1, and FIG. 3 is an overview of the recording track pattern of the invention. 4 is a signal waveform diagram for explaining the recording operation in FIG.
FIG. 5 is a signal waveform diagram for explaining the reproduction operation in FIG. 1. 1A and 1B are rotating magnetic heads, 2 is a magnetic tape, 6 is a pilot signal oscillator, 6A and 6B are erase signal generators, 7, 7A and 7B are recording waveform generation circuits, 8 is an edge detection circuit, 8A and 32 is an OR circuit, 16, 17, 17A, 17B, 36 are delay circuits, 20, 26, 27 are bandpass filters,
21 is a peak hold circuit, 22 and 24 are sampling and hold circuits, 23 is a differential amplifier, 28,
29 is a waveform shaping circuit, 30 and 31 are rise detection circuits, 33 ₁ to 33 ₆ are gate circuits, 34 is a window signal generation circuit, 37 is a switch circuit, 39 is a pulse generation circuit, and 40 is a sampling pulse generation circuit.

Claims (1)

[Claims] 1. In a method for compressing the time axis of a digital signal, forming and recording diagonal tracks on a recording medium using a plurality of rotary heads without forming a guard band, and reproducing this, the longitudinal direction of each track is A plurality of tracking pilot signals of a predetermined frequency are recorded in the recording area independently from the digital signal in the direction, and in order to detect the position of the pilot signal, one frequency is set in the first scan, and one frequency is set in the second scan. A positioning signal different from the frequency of the pilot signal is recorded at another frequency different from one frequency, and when the recording track is scanned by a rotary head whose scanning width is wider than the width of the track during reproduction, During the first scanning period, a pulse signal is formed based on the reproduced output of one of the positioning signals recorded on the track currently being scanned, and during the second scanning period, a pulse signal is generated on the track currently being scanned. A pulse signal is formed using the reproduced output of the other recorded positioning signal as a reference, and during the period of each of these pulse signals, the pilot signal is detected from the adjacent track being scanned by the rotary head. A method for recording and reproducing digital signals, characterized in that tracking control of the rotary head is performed based on the detection output.