JPH0756715B2 - Tracking controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial field B Outline of invention C Conventional technology D Problems to be solved by the invention E Means for solving problems (Fig. 1) F Action G Example G ₁ Circuit configuration (Fig. 1) , utilization of the FIG. 2) G ₂ circuit operation (effect a industry Figure 3 - Figure 5) G ₃ circuit configuration and operation of the sampling pulse generator (39) (Figure 6-Figure 8) H invention BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal recording / reproducing apparatus for converting a video signal or an audio signal into a PCM signal, recording it as a single diagonal track on a recording medium by a rotary head for each unit of time, and reproducing it. The present invention relates to a tracking control device suitable for use in.

B Summary of the Invention According to the present invention, a digital signal is recorded by forming a diagonal track on a recording medium by a plurality of rotary heads, and is provided independently of the recording area of the digital signal in the longitudinal direction of each track. A tracking pilot signal is recorded in the recorded area, and the crosstalk between the tracking pilot signals of the adjacent tracks is detected by the sample and hold means at the time of signal reproduction, and the rotary head is tracked by the detected output. A tracking control device for reproducing a signal, comprising switch means for selectively switching between a detection output of the sample hold means and a signal of a predetermined level provided at the start of a reproducing operation to perform tracking of the rotary head. Equipped with the switch means for the sample hold By controlling based on the signal for controlling the stage, the operation of the sample-hold means and the switching operation of the switch means are controlled in association with each other, so that the rising characteristic of the tracking servo can be improved. It was made possible.

C. Related Art Conventionally, the present applicant has previously proposed a method of performing tracking control of a rotary head by using only the reproduction output of a reproducing circuit head without using a fixed head.

According to this method, the PCM signal can be easily compressed / expanded on the time axis. Therefore, unlike the analog signal, it is not always necessary to record and reproduce the signal continuously in time, and therefore, an area is formed on one track. This was done by paying attention to the fact that it is easy to record the PCM signal separately from the PCM signal separately.

That is, when a PCM signal is compressed on the time axis and a plurality of rotary heads form tracks diagonally on a recording medium without forming a guard band, the PCM signal is the recording area in the longitudinal direction of each track. Independently, a plurality of tracking pilot signals are recorded independently, and during reproduction, the recording track is scanned by a rotary head whose scanning width is wider than the width of the track, and the rotary head scans the pilot signals from both adjacent tracks. The tracking of the rotary head is controlled by the reproduction output.

By the way, in such a tracking control method, a capstan motor as a rotating body for running the tape is usually operated by a tracking control signal from the tracking servo system, a speed error signal from the speed servo system, and an addition signal of the bias signal. I'm trying to control.

D. The problem to be solved by the invention. However, in the case of this method, the positioning signal for detecting the position of the pilot signal is not detected when the rotary head scans the track of reverse azimuth at the rising edge of the tracking servo and sampling is performed. In some cases, there is a state in which no pulse is generated, and there is a drawback that the rising characteristics of the tracking servo are poor.

The present invention has been made in view of the above problems, and provides a tracking control device capable of improving the rising characteristics of a tracking servo with a simple circuit configuration.

E Means for Solving the Problems In the tracking control device according to the present invention, when a digital signal is recorded by forming a diagonal track on a recording medium by a plurality of rotary heads, the digital signal is recorded in the longitudinal direction of each track. The tracking pilot signal is recorded in a recording area provided independently of the recording area of the digital signal, and the sample-hold means (30), (32) is provided for crosstalk of the tracking pilot signal of the adjacent track during signal reproduction. ), And a tracking control device for digital signal reproduction in which the rotary heads (1A), (1B) are tracked by the detection output, the detection of the sample hold means (30), (32). The rotary head (1A) by selectively switching the signal of a predetermined level provided at the start of output and reproduction operation , (1B)
Switch means (55), (5
7), and by controlling the switch means (55), (57) based on a signal for controlling the sample hold means (30), (32), the sample hold means (30), ( 32) operation and the switch means (55),
The switching operation of (57) is controlled in relation to each other.

According to the present invention, the sample hold means (30), (3
The rotary head (1A), by selectively switching the detection output of 2) and the signal of a predetermined level provided at the start of the playback operation,
Switch means for tracking (1B) (5
5) and (57), by controlling the switch means (55) and (57) based on the signals for controlling the sample and hold means (30) and (32), the sample and hold means (30), The operation of (32) and the switching operation of the switch means (55) and (57) are controlled in relation to each other. As a result, the rising characteristics of the tracking servo can be improved, and accurate tracking control can always be performed.

G Embodiment One embodiment of the present invention will be described in detail below with reference to FIGS.

G ₁ Circuit Configuration FIG. 1 shows the circuit configuration of this embodiment.
Only the circuit configuration for recording and reproducing the tracking pilot signal, the positioning signal and the erasing signal, which are directly related to the present invention, is shown, and regarding the circuit configuration for recording and reproducing the recorded information, for example, a PCM signal. Omitted.

In the figure, (1A) and (1B) are rotary heads, and (2) is a magnetic tape as a recording medium. Rotating head (1A)
And (1B) are equiangular intervals, that is, as shown in FIG.
They are arranged around the drum (3) at intervals of 180 degrees. On the other hand, the magnetic tape (2) is wound around the tape guide drum (3) over, for example, a 90-degree angle range narrower than the 180-degree angle range. Then, the rotary heads (1A) and (1B) show an arrow (4H) at a rate of 30 revolutions per second.
The tape (2) is rotated at a predetermined speed in the direction indicated by the arrow (4T) while being rotated in the direction of, and is rotated by the rotary heads (1A) and (1B) onto the magnetic tape (2) to form a third tape.
One diagonal magnetic track as shown (5A)
(5B) is formed in a so-called overwritten state, for example. That is, 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 different from the direction orthogonal to the scanning direction. That is, the so-called azimuth angles are made different.

And the two rotary heads (1A) (1B) are tapes (2)
There is a period in which they do not touch each other (this is the period for the 90 degree angular range in this example), and redundant data is added during recording and correction processing is performed during playback using this period. By doing so, the device can be simplified.

(6) is an oscillator that generates a tracking pilot signal P, and the pilot signal P is, for example, its frequency.
f ₀ is, for example, about 200 kHz and is recorded at a relatively high level. The frequency of the pilot signal P is preferably a frequency with a relatively small azimuth loss as long as the linearity of the tracking phase shift and the pilot reproduction output can be guaranteed. Further, (7) and (8) are oscillators for respectively generating position finding signals S and T for detecting the position of the pilot signal, and these position finding signals S and T are pilot signal erasing signals. Combined with
When a new recording is made on the previously recorded tape after erasing the previously recorded information over the tape, the recording track does not always match the previous recording track. It was intended to be used when it is necessary to erase the pilot signal, the frequency f ₁ and
For example, f ₂ is set to 500 kHz or 700 kHz or less before being practically separated from the frequency f ₀ of the pilot signal. Also, the recording level of the pilot signal P can be practically erased.

Also, (9) is a generator for generating an erase signal E _0, the erase signal E ₀ is thereby pilot signal P
When the position finding signals S, T are overwritten, it is desirable that the erasing rate of these signals P, S, T is high, and its frequency f
_{As 3} is used about 2 MHz, for example.

Reference numerals (10), (11), (12) and (13) are recording waveform generating circuits, which respond to a trailing edge of a delayed signal associated with a pulse PG, which will be described later. Based on the pilot signal from the generator (6), it has a predetermined time t _P (t _P is a recording time of the pilot signal etc.) depending on how many pilot signals P are inserted in one track and in what arrangement. The pilot signal P is generated by the generation circuit (1
1), (12) and (13) are the number of positioning signals per track based on the positioning signals S, T and the erasing signal E ₀ from the oscillators (7), (8) and (9), respectively. Positioning signals and erasing signals having a predetermined time are generated at predetermined intervals depending on how the S, T and erasing signals E ₀ are inserted. (14) is an OR circuit that logically processes the outputs of the generation circuits (10) to (13).

(15) is a switch circuit for switching the rotary heads (1A) and (1B), and is switched by a switching signal S ₁ (FIG. 4A) from the timing signal generating circuit (16). The timing signal generating circuit (16) has a rotary head (1A) obtained in synchronization with the rotation of the rotary drive motor (18) for the rotary heads (1A) and (1B) from the pulse generator (17).
A 30 Hz pulse PG indicating the rotation phase of (1B) is supplied. Further, in response to the pulse PG, a 30 Hz pulse from the timing signal generation circuit (16) is supplied to the phase servo circuit (19), and the rotation phase of the motor (18) is controlled by the servo output.

The pilot signal or the like from the switch circuit (15) switched by the switching signal S ₁ from the timing signal generation circuit (16) is amplified by the amplifier (19A) or (19B) and then respectively switched to the switch circuit (20A) or ( 20B) is supplied to the rotary head (1A) or (1B) via the contact R side, and the magnetic tape (2)
Recorded above. The switch circuits (20A) and (20B) are connected to the contact R side during recording and switched to the P side during reproduction.

In addition, the output signal S ₂ from the timing signal generation circuit (16)
(Fig. 4D) is supplied to the delay circuit (21), and after a delay corresponding to the distance between the mounting positions of the rotary heads (1A) (1B) and the pulse generator (17), etc., is made, recording is performed. It is supplied to the timing generation circuits (22) to (25). The switching signal S ₁ from the timing signal generation circuit (16) is output by the frequency divider (21 ').
The signal is frequency-divided into 1/2 to become a signal S ₄ (FIG. 4C), which is supplied to the recording timing generation circuits (23) to (25). Then, in the recording timing generation circuits (22) to (25), a timing signal as a recording reference such as a pilot signal is formed. The trailing edge of the signal S ₃ (FIG. 4E) delayed by the delay circuit (21) coincides with the time when the first head contacts the tape during one rotation period.

Recording timing generation circuit (22), while the half rotation period of half rotation periods eg head (1B) of the head is synchronized with the falling edge of the signal S _3, the signal S ₃ on the other half rotation period of the head
Than the fall of (T is the time corresponding to the half rotation period of the head)
A signal S ₅ (FIG. 4F) of duration t _P is generated for a predetermined period T ₁ . The recording timing generation circuit (23) outputs the time from the falling edge of the signal S ₃ only in one half rotation period of the head, for example, in the half rotation period of the head (1B). Delayed by a predetermined interval T ₁ , but for example the duration of an odd number of head rotation periods The duration is the even number of head rotation periods Respectively generate the signal S ₆ (FIG. 4G). The recording timing generation circuit (24) delays by a time T from the trailing edge of the signal S ₃ at a predetermined interval T ₁ only during the other half rotation period of the head, for example, the half rotation period of the head (1A), for example The odd number of rotation period is the duration The duration is the even number of head rotation periods Respectively generate the signal S ₇ (FIG. 4H). Further, the recording timing generation circuit (25) delays the time t _P from the trailing edge of the signal S ₃ in one half rotation period of the head in the odd-numbered period of the head rotation period, The duration of a pair of pulses in the interval Is generated at a predetermined interval T ₁ and the time from the falling edge of the other half-rotation period signal S ₃ of the head With a delay of t _{P at} a predetermined interval T ₁ , while at an even number of head rotation periods, the time t _P from the falling edge of the signal S ₃ during one half rotation period of the head. Delayed, time The duration of a pair of pulses in the interval Is generated at a predetermined interval T ₁ and the time from the fall of the signal S ₃ during the other half rotation period of the head Only delayed, duration Signal is generated at a predetermined interval T ₁ (see FIG. 4I).

Signals S ₅ (FIG. 4F), signals S ₆ (FIG. 4G), signals S ₇ (FIG. 4H) from the recording timing generation circuits (22), (23), (24) and (25). And signal S ₈ (I in FIG. 4) are recorded waveform generation circuits (10), (11), (12) and (13), respectively.
Substantially as a gate signal to the generator (6),
The pilot signals P from (7), (8) and (9),
Positioning signals S, T and erase signal E ₀ are recorded waveform generation circuit (1
OR circuit (1 through 0), (11), (12) and (13)
The combined signal S ₉ (FIG. 4J) is output to the output side of 4).

(26A) (26B) is a switch circuit (20A) (20B) at the time of reproduction
Is switched to the contact P side, the corresponding rotary head (1
A) The amplifiers to which the reproduction outputs from (1B) are supplied, and the outputs of these amplifiers (26A) (26B) are supplied to the switch circuit (27). The switch circuit (27) has a switching signal S ₁ ′ of 30 Hz from the timing signal generating circuit (16).
As in the case of recording, the half rotation period including the tape contact period of the head (1A) and the half rotation period including the tape contact period of the head (1B) are alternately switched by (FIG. 5A).

(28) is a narrow bandpass filter with a passing center frequency f ₀ for extracting only the pilot signal P from the reproduction output from the switch circuit (27), and (29) is for envelope detection of the output of the filter (28). Envelope detection circuit, (30) is a sample and hold circuit for sampling and holding the output of the envelope detection circuit (29), and (31) is each output of the envelope detection circuit (29) and the sample and hold circuit (30). A comparison circuit for comparison, for example, a differential amplifier, (32) is a sample and hold circuit for sampling and holding the comparison error signal from the differential amplifier (31), and these sample and hold circuits (30)
As will be described later, (32) substantially samples and holds the crosstalk of each pilot signal recorded on both ends of both adjacent tracks adjacent to the currently scanning track during normal reproduction. Work to do. The output of the sample hold circuit (32) is taken out to the contact b of the switch (55) as a tracking control signal.

Further, a pass center frequency f ₁ for extracting only the positioning signals S and T from the reproduction output at the output side of the switch circuit (27) in order to form sampling pulses for the sample hold circuits (30) (32) and the like. , f ₂ narrowband bandpass filters (34) and (35) are provided, and their output S
₁₀ (Fig. 5E) and S ₁₁ (Fig. 5F) are switch circuits (3
It is supplied to the comparator (37) as a waveform shaping circuit via 6). The switch circuit (36) is a switching signal of 30 Hz from the timing signal generating circuit (16) as in the switch circuit (27).
It is switched by S ₁ ′.

(38) and (39) are sampling pulse generation circuits provided on the output side of the comparator (37), and the sampling pulse generation circuit (38) is synchronized with the leading edge of the output of the comparator (37). To generate the first sampling pulse SP ₁ , and the sampling pulse generation circuit (39) generates the second sampling pulse SP ₂ after a predetermined time t _P from the generation of the first sampling pulse SP ₁ . These sampling pulses SP ₁ and SP ₂ are supplied to sample hold circuits (30) and (32), respectively.

Further, an adder (50) is provided on the output side of the sample and hold circuit (32), and the signal from the sample and hold circuit (32) and the DC power supply (5
A bias signal from 1) which is a reference for normal operation and a speed error signal from a speed servo system (not shown) are supplied and added, and the added signal is passed through a motor drive circuit (52) to a capstan motor ( 53).

Further, in this embodiment, a speed control means (54) is provided. That is, the speed control means (54) is provided with a switch (55) provided between the sample hold circuit (32) and the adder (50).
And a DC power supply (56) provided in parallel with the DC power supply (51) and having its potential set within the tracking servo pull-in range, a switch (57) for switching between the DC power supplies (56) and (57), and a switch. When the flip-flop circuit (58) for generating a signal for switching between (55) and (57) and the signal S _{2 are} reset and the second sampling pulse SP ₂ is detected by a predetermined amount during one rotation of the drum, for example, twice or four times. "1"
And a counter (59) for setting the flip-flop circuit (58). Switches (55) and (5
7) is on the contact a side at the time of the rise of the tracking servo, but at the time of the rise of the tracking servo, the second sampling pulse SP ₂ is supplied twice or 4 times during one rotation of the drum as described above.
When the flip-flop circuit (58) is set after being detected once, it is switched to the contact b side to start a normal tracking operation.

G ₂ Circuit Operation Next, the circuit operation of FIG. 1 will be described with reference to the signal waveforms of FIGS. 4 to 5.

First, at the time of recording, in response to the pulse PG from the pulse generator (17) indicating the rotational phase of the rotary heads (1A) (1B),
A signal S ₂ as shown in FIG. 4D is generated from the timing signal generating circuit (16), and this signal S ₂ is delayed by a delay circuit (21) for a predetermined time so that the output side thereof is shown in FIG. E
The signal S ₃ as shown in is output. This signal S ₃ is supplied to the recording timing generation circuits (22) to (25) as described above, and the signal S ₅ as shown in FIG. 4F is generated at the output side of the recording timing generation circuit (22). . Further, the switching signal S ₁ from the timing signal generating circuit (16) is supplied to the frequency divider (21 '), and the signal S ₄ as shown in FIG. 4C is obtained at the output side thereof. This signal S ₄ is the recording timing generation circuit (23)
~ (25) is supplied to the recording timing generation circuit (23) ~
(25) generates a signal S ₆ to S ₈ shown in FIG. 4 G~I in response to the signal S _3, S ₄ respectively its output side.

Signals S ₅ , S ₆ , S _7, and S ₈ are recorded waveform generation circuit (10),
The recording waveform generating circuit (10) is supplied to (11), (12) and (13), and the oscillator (6) is synchronized with the supplied signal S _5.
The pilot signal P from the circuit is passed through for a predetermined time t _{P at} predetermined intervals as shown in FIG. 4F, and the recording waveform generating circuit (11) synchronizes with the supplied signal S ₆ to generate an oscillator ( The positioning signal S from 7) is passed for a predetermined time at predetermined intervals as shown in FIG. 4G, and the recording waveform generating circuit (8) synchronizes with the supplied signal S ₇ to generate an oscillator (8 ), The positioning signal S ₈ from the) is passed for a predetermined time at a predetermined interval as shown in FIG. 4H. Further, the recording waveform generating circuit (13) synchronizes with the supplied signal S ₈ to generate an oscillator. The erasing signal E ₀ from (9) is passed for a predetermined time at predetermined intervals as shown in FIG.

The output signals from the recording waveform generating circuits (10) to (13) are added by the OR circuit (14), so that the output side thereof is shown in FIG.
The signal S ₉ as shown in is taken out.

Incidentally, at this time, for example, when the head (1B) is recording the track (5B ₁ ) in FIG. 3 (t in the first half of FIG. 4).
_B period), the first and second pulses of the signal S ₅ in FIG. _4F correspond to the pilot signals P _A1 and P _A2 , respectively, and the first and second pulses of the signal S ₆ in FIG. 4G are considered. Correspond to the positioning signals S _A1 and S _A2 , respectively, and the first and second pulses consisting of a pair of pulses of the signal S ₈ in FIG.
Signals corresponding to the erasing signal E ₀ adjacent to both sides of the positioning signals S _A1 and S _A2 , respectively, corresponding to the array of these signals, that is, P _A1 , E ₀ , S _A1 , E ₀ and P _A2 , E The combined signal of ₀ , S _A2 and E ₀ is taken out to the output side of the OR circuit (14) for each group.

Further, for example, when the head (1A) is recording the track (5A ₂ ) in FIG. 3 (t _A period in the first half of FIG. 4)
Considering the above, the first and second pulses of the signal S ₅ in FIG. _4F correspond to the pilot signals P _B3 and P _B4 , respectively, and the first and second pulses of the signal S ₇ in FIG. Corresponding to the output signals T _B3 and T _B4 , the first and second pulses of the signal S ₈ in FIG. _4I correspond to the erasing signal E ₀ adjacent to one side of the position output signals T _B3 and T _B4 , respectively. However, the signals corresponding to the arrangement of these signals, that is, the combined signals of T _B3 , E ₀ , P _B3 and T _B4 , E ₀ , P _B4 , are taken out to the output side of the OR circuit (14) for each group. become.

Also, for example, (1B) is the track (5B ₂ ) in FIG.
Considering the case of recording (t _B period in the latter half of FIG. 4), the first and second pulses of the signal S ₅ in FIG. _4F correspond to the pilot signals P _A3 and P _A4 , respectively, The first and second pulses of the signal S ₆ in FIG. 4G are the positioning signal S respectively.
Corresponding to _A3 and S _A4 , the first and second pulses consisting of a pair of pulses of the signal S ₈ in FIG.
_The signals corresponding to the erasing signals E ₀ adjacent to both sides of _A3 and S _A4 , respectively, corresponding to the array of these signals, namely P _A3 ,
A combined signal of E ₀ , S _A3 , E ₀ and P _A4 , E ₀ , S _A4 , E ₀ is taken out to the output side of the OR circuit (14) for each group.

Further, for example, when the head (1A) is recording the track (5A ₃ ) in FIG. ₃ (t _A period in the latter half of FIG. 4)
Considering that, the first and second pulses of signal S ₅ in FIG. _4F correspond to pilot signals P _B5 and P _B6 , respectively, and the first and second pulses of signal S ₇ in FIG. Corresponding to the output signals T _B5 and T _B6 , the first and second pulses of the signal S ₈ in FIG. _4I correspond to the erasing signal E ₀ adjacent to one side of the positioning signals T _B5 and T _B6 , respectively. , The signals corresponding to the array of these signals, that is, the combined signals of T _B5 , E ₀ , P _B5 and T _B6 , E ₀ , P _B6 are taken out to the output side of the OR circuit (14) for each group. Become.

On the other hand, a switching signal S ₁ as shown in FIG. 4A is generated from the timing signal generation circuit (16) in response to the pulse PG from the pulse generator (17), and this signal S ₁ is rotated. head (1A) is synchronized with the rotation of (1B), as shown in Figure 4 a and B, in a half turn period t _a of the head signals S ₁ is at the high level heads (1A) is a tape ( 2) so that the head (1B) abuts the tape (2) within the half-rotation period t _B in which the signal S ₁ is at a low level. Then, the switch circuit (15) is switched by the switching signal S ₁ to the state shown in the figure in the period t _A and to the state opposite to the state shown in the figure in the period t _B , and the head is switched.

Therefore, the signal S ₉ obtained at the output side of the OR circuit (14) is
When the switch circuit (15) is in a state opposite to the state shown in the figure, it is supplied to the head (1B) through the amplifier (19B) and the R side of the switch circuit (20B) and is supplied to the head (1B) within the period t _B. 1B)
At the beginning and end of the contact period of the tape (2) with the tape (2), as shown in FIG. 3, both ends of the track (5B) in the longitudinal direction, which are separated by an equal distance 1 from the center position of the track (5B) in the longitudinal direction. In the recording areas A _T1 and A _T2 of the tracking signal provided in the portion, the time is set at an odd number of the head rotation period (t _B period in the first half of FIG. 4). During the head rotation period and the time at the even number of the head rotation period (t _B period in the latter half of FIG. 4). Recorded during.

On the other hand, when the switch circuit (15) is in the condition
S ₉ is supplied to the head (1A) through the amplifier (19A) and the R side of the switch circuit (20A) and is supplied to the head (1A) within the period t _A.
At the beginning and the end of the contact period of A) to the tape (2), as shown in the same figure, in the longitudinal direction of the track (5A) which is equidistant from the center position in the longitudinal direction of the track (5A). In the same recording areas A _T1 and A _T2 that are provided at both ends as described above, the time is changed in the odd-numbered head rotation period (t _P period in the first half of FIG. 4). During the period of the head rotation, the time is recorded at the even number of the head rotation period (t _A period in the latter half of FIG. 4). Recorded during.

Also, except for the time when these pilot signal, position finding signal and erasing signal are recorded, audio of one segment portion which should be recorded as one track, not shown, is shown.
The PCM signal is supplied to the head (1A) through the amplifier (19A) during the period t _A , and is supplied to the head (1B) through the amplifier (19B) during the period t _B so that each track (5A) (5B) is supplied.
Recording area A other than the above-mentioned pilot signal recording area
Recorded in _P1 .

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

Even during this reproduction, the drum phase servo is applied to the motor (18) by the phase servo circuit (19) in the same manner as during recording.

The signals taken out from the tape (2) by the rotary heads (1A) and (1B) are contact points P of the switch circuit (20A), respectively.
Is supplied to the switch circuit (27) via the amplifier side (26A) and the contact P side of the switch circuit (20B) and the amplifier (26B). This switch circuit (27) is a switching signal of 30 Hz from the timing signal generation circuit (16) as shown in FIG. 5A.
By S ₁ ′, the half rotation period t _A including the tape contact period of the head (1A) and the half rotation period t _B including the tape contact period of the head (1B) are alternately switched by S ₁ ′. Therefore, an intermittent PCM signal S _R for each segment as shown in FIG. 5C is obtained from the switch circuit (27), and this PCM signal is supplied to the reproduction processor (not shown).
It is demodulated into a signal and further supplied to the decoder to detect the data for each block by the block sync signal and to perform processing such as error correction and de-interleaving, and D / A
It is converted back into an analog audio signal by the converter and is output to the output side.

Tracking control is performed as follows.

Now, for example, if the head (1B) scans a range of the scanning width W including the track (5B ₁ ) shown by the dashed line in FIG. 3, the head (1B) will scan this track (5B 1).
Scanning across the tracks of the two neighboring of _{1) (5A 2) (5A} 1), a pilot signal P _A1 of the track (5B ₁₎ in the region A _T1 as shown in FIG. 3, track two neighboring ( 5A
₂₎ reproduces the pilot signal P _B1 pilot signal P _B3 and a track (5A ₁₎ of, in a region A _T2 and the pilot signal P _A2 of the track (5B _1), neighboring Ri track (5
The pilot signal P _B4 of A ₂ ) and the pilot signal P _B2 of the track (5A ₁ ) are reproduced. At this time, switch circuit (2
The reproduction output of the head (1B) from 7) is the pass center frequency f _0.
Is supplied to the narrow band band pass filter (28) of FIG. 5 and only the pilot signal is taken out as its output S _A as shown in FIG. 5D, which is the envelope detection circuit (29).
Is supplied to.

In addition, the output S _R of the switch circuit (27) is a narrow band pass filter (34) whose pass center frequencies are f ₁ and f ₂ , respectively,
Is supplied to (35) and its output side is shown in FIGS. 5E and 5F, respectively.
Positioning signals S ₁₀ and S ₁₁ as shown in FIG.
These signals S ₁₀ and S ₁₁ are supplied to the switch circuit (36). When the switching signal S ₁ ′ is low level, the signal S ₁₀ is extracted, and when it is high level, the signal S ₁₁ is extracted and compared. Supplied to the vessel (37).

The comparator (37) compares the supplied signals S ₁₀ and S ₁₁ with a reference value to perform waveform shaping, and a sampling pulse generation circuit (3
Supply to 8) and (39). The sampling pulse generation circuit (38) generates a first sampling pulse SP ₁ as shown in FIG. 5G at the rising edge of the waveform-formed signal S ₁₀ , and this sampling pulse SP ₁ is supplied to the sampling hold circuit (38). 30). At this time, the sampling pulse SP ₁ is shown by the arrow (4
T) (Fig. 3) The crosstalk of the pilot signals P _B3 and P _B4 of the adjacent track (5A ₂ ) on the opposite side to the transfer direction is sampled, and this sampled signal is the lead phase tracking signal. Is supplied to one input terminal of the differential amplifier (31).

Further, after the time t _P from the generation of the sampling pulse SP _1, the crosstalk between the pilot signals P _B1 and P _B2 of the adjacent track (5A ₁ ) on the tape transfer direction side is detected by the envelope detection circuit (29) by the differential amplifier (31). Is supplied to the other input end as a tracking signal with a delay phase. Therefore, the differential amplifier (31) sequentially compares the tracking signals corresponding to the crosstalk of the pilot signals P _B3 and P _B1 and P _B4 and P _B2 , respectively.

Then, the comparison error signal from the differential amplifier (31) is supplied to the sample and hold circuit (32), and is generated from the sampling pulse generation circuit (39) after time t _P from the time when the sampling pulse SP ₁ was generated. Sampling is performed by the sampling pulse SP ₂ . Therefore, the difference between both inputs to the differential amplifier (31) is obtained from this sample hold circuit (32) as a tracking control signal, which is supplied to the capstan motor (53) described later to control the tape transfer amount. Then, the level difference between both inputs to the differential amplifier (31) is zero, that is, the head (1B) moves to the track (5B
When scanning a _1), it is controlled so as to extend over only each the same amount on both sides of the two tracks (5A ₂₎ and (5A _1). That is, the center position of the gap of the head (1B) in the width direction is controlled so as to match the center position of the track (5B ₁ ) for scanning.

The same applies to other tracks, for example, when the head (1A) scans the track (5A ₂ ),
Since the crosstalk of the pilot signals P _A3 , P _A4 and P _A1 , P _A2 of the tracks (5B ₂ ) and (5B ₁ ) on both sides thereof is obtained, these are sampled and held from the sampling pulse generation circuit (38) as described above. The sampling pulse SP ₁ supplied to the circuit (30) samples the crosstalk of the pilot signals P _A3 and P _A4 to obtain a tracking signal, which is supplied to the differential amplifier (31) in the next stage and the pilot signal.
The output from the envelope detection circuit (29) corresponding to the cross talk of P _A1 and P _A2 is supplied, and the pilot signal
The tracking signals corresponding to the crosstalk between P _A3 and P _A1 and P _A4 and P _A2 are compared, and the comparison error signal is supplied to the sampling and holding circuit (32) Sampling pulse SP ₂
By sampling at, the tracking control signal for the head (1A) can be obtained.

Similarly, when the head (1B) scans the track (5B ₂ ), as shown in FIG. 3, the pilot signals P _B5 and P _B6 of the tracks (5A ₃ ) and (5A ₂ ) on both sides of the head (1B) are scanned. And P _B3 , P _B4 cross talk is obtained, the cross talk of pilot signals P _B5 , P _B6 is sampled by sampling pulse SP ₁ and the pilot signal is output by the differential amplifier (31).
By comparing the tracking signals corresponding to the crosstalk of P _B5 and P _B3 , P _B6 and P _B4 respectively, and finally sampling the comparison error signal with the sampling pulse SP ₂ ,
A tracking control signal for the head (1B) can be obtained.

Similarly, when the head (1A) scans the track (5A ₃ ), as shown in FIG. 3, the pilot signals P _A5 and P _A6 of the tracks (5B ₃ ) and (5B ₂ ) on both sides of the track (5A ₃ ). And the crosstalk between P _A3 and P _A4 is obtained, the crosstalk between the pilot signals P _A5 and P _A6 is sampled with the sampling pulse SP ₁ , and the differential amplifier (31)
By controlling the tracking signals corresponding to the crosstalk of P _A5 and P _A3 , P _A6 and P _A4 respectively, and finally sampling the comparison error signal with the sampling pulse SP ₂ ,
A tracking control signal for the head (1A) can be obtained.

The tracking control signal obtained in this way is supplied to the adder (50) via the switch (55), and here the speed error signal and the bias signal as the reference signal from the DC power supply (51) in normal operation are supplied. Is added to the capstan motor (53) via the drive circuit (52).

Further, in the tracking servo, the positioning signal may not be detected and the sampling pulse may not be generated when the rotary head is scanning the reverse azimuth track at the time of rising. So when starting operation capstan motor (53)
The position detection signal is detected by applying an offset to the rotation speed of
Make the sampling pulse occur earlier. Therefore, at the start of the operation, the switches (55) and (57) are connected to the contact a side, the signal from the sample hold circuit (32) is cut off, and the bias offset from the DC power supply (56) to the potential within the tracking servo pull-in range. The voltage is supplied to the adder (50) for speed servo. As a result, the positioning signal is detected and the sampling pulse can be quickly generated.

For example, the rotary head (1B) on the track (5A ₁ ) in Fig. 3
Came and became reverse azimuth. Sampling pulse is not detected positioning signal T _B1, T _B2 when the rotary head (1B) drift zero clogging on-track to the track (5A ₁₎ is not generated at all. Therefore, the DC power supply (5
If a bias signal from 6) is substantially offset by, for example, + 10% with respect to the bias signal of the DC power supply (51), the track of the same azimuth will always come in the track (5B ₅ ), so it is recorded in it. Positioning signals S _A9 and S _A10 are detected, and a sampling pulse is generated based on this.

Then, this sampling pulse (the second sampling pulse SP _{2 in this case} ) is counted by the counter (39),
When a predetermined amount is detected during one rotation of the drum, for example, twice or four times, the flip-flop circuit (58) is set, and the outputs thereof are used to switch the switches (55) and (57) to the contact b side to switch to the normal speed.

G ₃ Sampling Pulse Generation Circuit (39) Circuit Configuration and Operation FIG. 6 shows an example of a concrete circuit configuration of the sampling pulse generation circuit (39). In FIG. 6, (40) is a comparator (37). ) counter for counting the wave number (pulses) of the supplied come positioning signals from, (41) the signal S _4, S
_In response to ₁ ', the data selector for selecting the contents of the position finding signal, that is, four kinds of data (setting values) classified by each frequency and recording length of the position finding signals S and T in this embodiment,
Reference numeral (42) is a match detection circuit for detecting the match between the count value of the counter (40) and the data of the data selector (41). As the match detection circuit (42), for example, a digital comparator is used.

(43) to (46) are delay circuits that generate a predetermined delay signal from the sampling pulse SP ₁ , and the counter (40) is enabled (energized) by the output of the delay circuit (44).
It is designed to be cleared by the output of the delay circuit (45). (47) is a D-type flip-flop circuit,
The output of the coincidence detection circuit (42) is supplied to the input terminal D of this flip-flop circuit (47), and its clock terminal CK
The sampling pulse SP ₁ is substantially applied to the reset terminal R via the delay circuit (46), and the output of the delay circuit (45) is supplied to the reset terminal R thereof.

Reference numeral (48) is a gate circuit such as an AND circuit. The output of the delay circuit (43) is supplied to one input terminal of the AND circuit (48) and the flip-flop circuit (47) is supplied to the other input terminal. The output of the output terminal Q is supplied, and the sampling pulse SP ₂ is output from the output terminal thereof.

Next, the circuit operation of FIG. 6 will be described with reference to the signal waveforms of FIG.

Now, the signal S ₁₃ as shown in FIG. 7D, which is a positioning signal from the comparator (37), is output to the sampling pulse generating circuit (3
8), the sampling pulse generating circuit (38) generates the sampling pulse SP ₁ as shown in FIG. 7H in synchronization with the rising of the first pulse of the signal S ₁₃ . The sampling pulse SP ₁ is supplied to the above-mentioned sample hold circuit (30) (FIG. 1) and also to the delay circuits (43) to (46).

The delay circuit (44) is connected to the output side of the delay circuit in synchronization with the sampling pulse SP _1. The signal S ₁₂ as shown in FIG. 7C having a considerable duration.
And the signal S ₁₂ is supplied to the counter (40) as an enable signal.

Counter (40) is the signal S ₁₂ a high level period comparator (3
Count the pulses of signal S ₁₃ from 7). On the other hand, the data selector (41) outputs signals S _P and S ₄ shown in FIGS. 7A and 7B.
In response to selecting the data associated with the locate signal.
When the selected data matches the contents of the counter (40), the match detection circuit (42) outputs a signal to its output side.
7th which continues for a predetermined time from the trailing edge of the last pulse of S ₁₃
A signal S ₁₄ as shown in FIG. E is generated, and this signal S ₁₄ is supplied as data to the flip-flop circuit (47).

The delay circuit (46) synchronizes with the sampling pulse SP ₁ and, after a predetermined time Δt ₁ thereafter, outputs a signal S as shown in FIG. 7F.
₁₅ is generated, and this signal S ₁₅ is generated by the flip-flop circuit (4
The signal S ₁₄ supplied to the clock terminal CK of 7) and supplied to the input terminal D is latched. The delay circuit (46)
The delay time Δt ₁ at It is said that

Further, the delay circuit (45) generates a signal S ₁₅ as shown in FIG. 7G after a predetermined time Δt ₂ from this in synchronization with the sampling pulse SP ₁ , and this signal S ₁₅ is supplied to the counter (40). The contents are cleared and supplied to the flip-flop circuit (40) to be reset. As a result, the signal S ₁₇ as shown in FIG. _7I is generated at the output side of the flip-flop circuit (47). The delay time Δt ₂ in the delay circuit (47) is Δt ₂ > t _P.

In addition, the delay circuit (43) synchronizes with the sampling pulse SP ₁ and, after a predetermined time t _P from this, outputs a signal as shown in FIG. 7J.
S ₁₈ is generated, and this signal S ₁₈ is supplied to one input terminal of the AND circuit (48).

Since the signal S ₁₇ formed as described above is supplied to the other input terminal of the AND circuit (48), this signal S _17
The AND circuit (48) opens the gate by substantially using ₁₇ as a gate signal, and the sampling pulse SP ₂ as shown in FIG. 7K is generated in response to the signal S ₁₈ . The sampling pulse SP ₂ is applied to the sampling hold circuit (32).
Is supplied to.

In this way, the sampling pulse SP ₂ can be generated.

It should be noted that this sampling pulse SP ₂ can also be generated by a process of a microcomputer, not shown.

This will be described with reference to the flowchart of FIG.

When the reproduction mode is entered in step (a), the step (b) is skipped, and the position finding signals S and T are detected here, and if not detected, the operation is repeated. When detected, the first sampling pulse SP ₁ is generated based on the position output signals S and T in step (c), and the wave number (pulse) is detected only in the detection section of the position output signal S and T in step (d). ) Ni
To measure.

Go to step (e), and detect position detection signals S, T
Is in the playback mode and determines whether the first one is generated, and if it is the first one, go to step (f), When the section (1) is judged and either of them is satisfied, the second sampling pulse SP ₂ is generated in step (g). In step (f) If the interval is not satisfied, the signal is not a position-locating signal, and the process returns to step (b).

In step (e), if the position finding signal is generated after the second time in the reproduction mode, the process proceeds to step (h), and it is determined whether the polarity of the signal S ₄ has changed. If the polarity of signal S ₄ has changed, the previous detection section will be Determine which of the If so, the current position detection signal is If so, it is a true positioning signal, so step (g)
Generate a _second sampling pulse SP ₂ at If not, return to step (b).

In step (re), the last detected section If so, go to step (l) and the current position detection signal is If so, it is a true positioning signal, so step (g)
Generate a _second sampling pulse SP ₂ at If not, return to step (b).

The explanation of this step (h)-(l) is shown in Fig. 5B, E and F.
Will be described in detail. When it is determined in step (h) that the polarity of the signal S ₄ has changed, for example, in the central portion of FIG. 5B, the signal S shown in FIG.
₁₁ T _B4 Is determined, Therefore, go to step (nu). And here at 5th
S _{A3 of the} signal S ₁₀ shown in Fig. E is Whether or not Therefore, the second sampling pulse SP ₂ is generated in step (g). At step (nu), signal S _A3 If not, return to step (b).

Also, in step (ri) If so, it is determined that it is the signal T _B6 instead of the signal T _B4 of the signal S ₁₁ (therefore, the time when the polarity of the signal S ₄ changes is shown in FIG. 5B.
It means that it was the right end, not the center. ), S _A5 (not shown) of the signal S ₁₀ shown in FIG.
But Whether or not Therefore, the second sampling pulse SP ₂ is generated in step (g). Signal S at step (Le)
_A5 If not, return to step (b).

Now, if the polarity of the signal S ₄ has not changed in step (h), then go to step (wo) to determine whether the detection section is the same as the previous positioning signal. The second sampling pulse SP ₂ is generated. Referring to FIG. 5E, for example, the first S _A1 and the second S _A2 of the positioning signal S ₁₀ are the same. Therefore, the second sampling pulse SP ₂ is generated in step (g). Then, if the detection sections are not the same in step (wo), it is regarded as an erroneous detection, the first sampling state is held, and the process returns to step (b).

In this way, the second sampling pulse SP ₂ can be generated even by the processing by the microcomputer.

H Effect of the Invention As described above, according to the present invention, the switch means is provided for selectively switching the detection output of the sample and hold means and the signal of a predetermined level provided at the start of the reproducing operation to perform tracking of the rotary head. By controlling the switch means based on the signal for controlling the sample and hold means, the operation of the sample and hold means and the switching operation of the switch means are controlled in relation to each other, so that even when the tracking servo rises. It can detect the positioning signal and generate a sampling pulse earlier,
Therefore, the rising characteristic of the tracking servo can be improved, and the accurate tracking control can be performed over substantially the entire range of the tracking servo, which has the effect of favorably reproducing the digital signal.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a rotary head device used in FIG. 1,
FIG. 3 is a diagram showing an outline of a recording track pattern of the present invention, FIG. 4 is a signal waveform diagram for explaining the recording operation in FIG. 1, and FIG. 5 is for explaining the reproducing operation in FIG. 6 is a circuit diagram showing an example of a main part of the present invention, FIG. 7 is a signal waveform diagram for explaining the operation in FIG. 6, and FIG. 8 is a second sampling diagram. 6 is a flowchart for providing an invention of an operation of generating a pulse. (1A) and (1B) are rotary magnetic heads, (2) is magnetic tape,
(6) is a pilot signal oscillator, (7) is a positioning signal oscillator, (9) is an erasing signal oscillator, (10),
(11), (12) and (13) are recording waveform generating circuits, (21) is a delay circuit, (22), (23), (24) and (25) are recording timing generating circuits, and (28) and (28). 34) and (35) are bandpass filters, (29) is an envelope detection circuit, (30),
(32) ruhold circuit, (31) differential amplifier, (36) switch circuit, (37) comparator, (38), (39) sampling pulse generating circuit, (50) adder, (51) ),
(56) is a DC power supply, (52) is a motor drive circuit, (53) is a capstan motor, (54) is speed control means, (55),
(57) is a switch, (58) is a flip-flop circuit,
(59) is a counter.

Claims (1)

[Claims] 1. A digital signal is recorded by forming a diagonal track on a recording medium by a plurality of rotary heads, and recording is provided independently of the recording area of the digital signal in the longitudinal direction of each track. The tracking pilot signal is recorded in the area, and the crosstalk of the tracking pilot signal of the adjacent track is detected by the sample hold means at the time of signal reproduction, and the rotary head is tracked by the detection output. A tracking control device for controlling the rotary head by selectively switching between the detection output of the sample and hold means and the signal of a predetermined level provided at the start of the reproducing operation, The switch means controls the sample and hold means. By controlling based on a signal for tracking control apparatus characterized by switching operation of the operation and the switch means of the sample-and-hold means are associated to control each other.