JPS6275962A - Tracking control device - Google Patents

Abstract

PURPOSE:To control a normal tracking without being influenced by an external factor with a simple constitution by sampling the pilot signal of a track to scan at the time of reproduction and executing the gain control in accordance with a level. CONSTITUTION:At present, when the level of the pilot signal of the same azimuth in which as an initial condition, a switch SW3 is turned on, detected by a sampling pulse SP3 and obtained at the output side of a sample holding circuit 58 is larger than the first and second reference values VthH and VthL, the output of a comparing device 63 comes to be 'L', and the output of a comparing device 64 comes to be 'H'. Then, a microcomputer 57 turns off the switch SW3, turns on a switch SW2 and lowers the gain of an amplifier 50. Even in such a case when the level of the pilot signal is still high, the switch SW2 is turned off and the switch SW1 is turned on. Thus, the level of the pilot signal is between the reference values VthH and VthL, the values are adopted. Thus, without being influenced by the tape characteristic and the variance of the gain of the reproducing amplifier, the tracking control can be executed.

Description

[Detailed description of the invention]

The present invention will be explained in the following order. A. Field of industrial application B. Old view of the invention C. Conventional technology D. Problem to be solved by the invention 0 Problem 4 Solution 1-6th''''. Means 3 Figure 1 3
. F Effect G Embodiment 61 circuit configuration (Figures 1 and 2) 62 circuit operation (Figures 3 to 5) Circuit configuration and operation of G3 sampling generation circuit (39) (
(Figures 6 to 8) Operation of G4 gain control means (Figures 9 to 12) II
Effects of the Invention A: Industrial Field of Application This invention converts, for example, a video signal or an audio signal into a PCM signal, records it as one diagonal trunk on a recording medium by a rotating head for a medium time period, and reproduces it. (Relating to a racking control device suitable for use in a recording/reproducing device for digital signals, etc.) 116
In the digital signal recording and reproducing apparatus, the recording/reproducing apparatus for digital signals is configured to detect the crosstalk of the [-pyroso] signal of the adjacent track by a sample and hold means, and to perform tracking of the rotational axis i' using the detection output. A gain control means is provided before the sample and hold means, samples one rack of pilot signals being scanned during reproduction, and controls the gain of the gain control means in accordance with the rail. 1. By doing this, the loop gain of the tracking servo can be kept constant even if the strength of the tracking pilot signal fluctuates due to the internal circuit configuration.
This allows precise tracking control to be performed at all times. C. Prior Art Conventionally, the applicant of the present invention previously proposed a method of controlling the tracking of a rotary head for reproduction by using only the reproduction output of the rotary head without using a fixed head. In this method, the time axis of the P(', M signal can be easily compressed and expanded. Therefore, unlike analog signals, it is not necessary to record and reproduce the signal continuously in time. This method was developed by focusing on the fact that it is easy to record this PCM signal and separate signals by dividing the area into the trunk of the computer. rotation of
\ Form a guard hand with the track diagonally by Soto.
When forming and recording on a recording medium L- without a PCM signal, a plurality of tracking pilot signals are recorded in the longitudinal direction of each trunk as a recording area independently of the PCM signal. The recording trunk is scanned by a rotary head that is wider than the width of the recording trunk, and the tracking of the rotary head is controlled by outputting signals from tracks on both sides of the track that the rotary head is scanning. In a tracking control method like the one above, the loop gain of the tracking servo can change considerably due to variations in the recording sensitivity and playback behavior of the head, variations in tape characteristics, or variations in the 4L amplifier IU. , the servo may become unstable and may not work properly. Therefore, a W subtraction means that takes the difference between the tracking error signals of adjacent tracks, a transmission system that transmits the output of this subtraction means to the drive system, and a maximum value of the reproduced l ranking control signal are detected. The applicant previously proposed a method for stabilizing the tracking servo system by installing a comparison means for comparing the output with a reference signal and adjusting the amplification factor of the transmission system based on the output of this comparison means (Patent Application No. Showa 5
No. 9-187368). D. Problems to be Solved by the Invention However, in this method, signal processing is performed in an analog manner, so there is a drawback that the circuit configuration becomes complicated. This invention was made in view of this point, and the circuit configuration is simplified by performing signal processing digitally.
Furthermore, the present invention provides tracking control equipment that can keep the loop gain of the tracking servo constant even if the level of the pylon [signal for tracking changes]. E. Means for Solving Problems The tracking control device according to the present invention compresses the time axis of a digital signal, forms a diagonal trunk on a recording medium using a plurality of rotary heads, and records the signal in the longitudinal direction of each track. A plurality of tracking pilot signals are recorded independently as a recording area from the digital signal, and the crosstalk of the pilot signal of the adjacent track is detected by a sample bold means, and the tracking of the J-note rotation is performed using this detection output. In the digital signal recording/reproducing/i apparatus configured to perform this, a gain control means is provided before the sample and hold means described in -1-, and the pilot signal of the track being scanned during reproduction is sampled and The gain control means is configured to control the gain. F. Gain control means (50) to (64) are provided before the operation sampling and holding means (30), and sample the pilot signal of the trunk being scanned during reproduction, that is, the pilot signal of the same azimuth, and The gain of the gain control means is controlled so that it falls within a certain prescribed level. This makes it possible to reduce the amount of change in the loop gain, making it possible to always perform accurate tracking control. G Example 1 Below, an example of the present invention will be described in detail based on FIGS. 1 to 12. 01 Circuit configuration FIG. 1 shows the circuit configuration of this embodiment, and here,
Only the circuit configuration for recording and reproducing tracking pilot signals, positioning signals, and erasing signals that are directly related to this invention is shown.
The circuit configuration for recording and reproducing CM signals is omitted. In the same figure, (l^) and (IB) are rotating heads, (2
) is a magnetic tape as a recording medium. Rotating head (
IA) and (IB) are arranged around the periphery of the drum (3) at equal angular intervals, i.e. 180 degrees apart, as shown in FIG. On the other hand, the magnetic tape +21 is wound around the tape inner drum (3) over an angular range of, for example, 90 degrees, which is narrower than its 180-degree angular range. Then, the rotating heads (IA) and (IB> are rotated at a rate of 30 revolutions per second in the direction of the arrow (4), and the tape (2) is run at a predetermined speed in the direction shown by the arrow (4T). Then, the rotating heads (IA) and (18) write on the magnetic tape (2)-H one by one diagonal magnetic track (5A) (511> as shown in FIG. 3, for example, in a so-called overwritten state. In other words, the width (scanning width) W of the headgear 7 is wider than the track width. In this case, the head (1^) and (
The width directions of the middle grooves of IB) 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. And 2 (lit rotating head (IA) (Ill
) is not in contact with the tape (2) (this is a period corresponding to a 90 degree angle range in this example), and this period is used to add redundant data during recording and to add redundant data during playback. The device can be simplified by performing correction processing or the like. Reference numeral (6) denotes an oscillator that generates a tracking pilot signal P. The pilot signal P has a frequency fo of, for example, about 200 kllz, and is recorded monthly at a relatively high frequency. It should be noted that the frequency of this pilot signal P is preferably a frequency with relatively little azimuth loss, as long as the linearity of the tracking phase shift versus the pilot reproduction output can be guaranteed. Also, (71, (8
Reference numeral 1 denotes an oscillator that generates positioning signals S and T, respectively, for detecting the position of the pilot signal, and these positioning signals S and T also serve as signals for erasing the pilot signal, and are previously recorded. When a new recording is later made on top of the previously recorded tape, erasing the previous recorded information,
It is also used when it is necessary to erase the previously recorded pilot signal because the recording track does not necessarily match the previous recording track. Examples of practical distances from the signal frequency fQ are 700kllz and 500kl, respectively.
It is considered to be before lz. In addition, the recorded novel also puts pilot signal P into practical use-1
,2,cuff 644,. Yo 5. ,,oh.
[Also, (9) is an oscillator that generates the erasing signal Eo, and when the erasing signal Eo is overwritten with the pilot signal P and positioning signals S and T, these signals P and S , T having a high erasure rate is desirable, and the frequency f3 used is, for example, about 2M1lz. (1ω, (11), (12> and (13) are recording waveform generation circuits, and the pulse PG expressed as 1!
The edge of the delayed signal associated with A predetermined time tp depending on the
(tp is the recording time of the pilot signal, etc.) and the generation circuit (Ill, (+2)
and (13) are the oscillators f71, (R1 and (9
) for a predetermined period of time depending on how many positioning signals qS, T and erasing signals Eo are inserted per track and in what arrangement, based on the positioning signals S, T and erasing signals F, o. A positioning signal and an erasing signal are generated at predetermined intervals. (14) is the generation circuit (10) to (13)
・. This is an OR circuit that logically processes each output. (15) is a switch circuit for switching the rotary head (18) and (IB).°ζ, timing signal generation times 1i! Switching signal St from 8 (16) (Fig. 4A)
Switched by. This timing signal generation circuit (
16), pulse completion 1: rotary head (], IA (I
A pulse PG of 3011z is supplied without showing the rotational phase of B). Further, in response to the pulse PG, a 3011z pulse from the timing signal generation circuit (16) is supplied to the phase servo circuit (19), and the rotational phase of the motor (18) is controlled by the servo output. The pylon signal from the switch circuit (15) switched by the switching signal S from the timing signal generation circuit (16) is amplified by the amplifier (19A) or (19B) and then output to the switch circuit (2OA) or It is supplied to the rotary head (18) or (IB) through the contact side of (20B) and recorded on the magnetic tape (2). The switch circuits (20A) and (20B) are connected to the contact R side during recording, and are switched to the R side during playback. Further, the output signal 32 (D in FIG. 4) from the timing signal generation circuit (16) is supplied to the delay circuit (21).
Here, the rotating head (1^) (1B) and pulse generator (17) are taken; after a delay corresponding to the interval of one position, etc., the pulse is supplied to the recording timing generation circuits (22) to (25). be done. In addition, the switching signal S1 from the timing signal generation circuit (16) is divided by one by the frequency divider (2]') to become the signal 34 (Fig. 4C), which is sent to the recording timing generation circuits (23) to (25). Supplied. Then, in the recording timing generation circuits (22) to (25), a timing signal as a recording reference such as a pilot signal is generated. Incidentally, the fall of the signal S3 (FIG. 4E) delayed by the delay circuit (21) is made to coincide with the time when the first head contacts the tape during one rotation period. The recording timing generation circuit (22) generates a signal S during one half-rotation period of the head, for example, during a half-rotation period of the head (IB).
3, and during the other half-rotation period of the head, the signal S3 is delayed by a time T0-tp (T is a time equivalent to the half-rotation period of the head) from the fall of the signal S3, and for a predetermined period T.
1 generates a signal S5 (FIG. 4F) of duration tp. The recording timing generation circuit (23) only generates data during one half-rotation period of the head, for example, only during a half-rotation period of the head (IB).
At a predetermined interval T1 delayed by the time -tp from the falling edge of the signal S3, however, for example, at an odd numbered head rotation period, the duration is -tp, and at an even numbered head rotation period, the duration is -t1. tp respectively generates a signal S6 (FIG. 4G). The recording timing generation circuit (24) is
During the other half-rotation period of the head, for example, only during the half-rotation period of the head (1^), the duration is delayed from the falling edge of the signal S3 by a predetermined interval T1, but for example, in the odd-numbered rotation period of the head, the duration is -tp, and the signal S? whose duration is -tp at the even numbered rotation period of the head? , (Fig. 4H). Also, a recording timing generation circuit (25)
is the duration of a pair of pulses at an interval of time '-tp, extending by a time tp from the falling edge of signal S3 during one half-rotation period of the head, at an odd number of head rotation periods. generate a signal tp at a predetermined interval T,
During the period of the other half rotation of the head, a signal with a duration of tp is emitted at a predetermined interval T] with a delay of time T+---t') from the falling edge of signal S3!-P l
,,On the other hand, at the even number of the rotation period of the head, the time from the fall of the signal S3 during one half rotation period of the head

[With a delay of ρ, one signal is generated at a predetermined interval T1 at an interval of time −tp, and a signal S3 is generated during the other half rotation period of the head.
The falling edge of 1 is delayed by the time T'0--tp,
A signal of duration -tp is generated at predetermined intervals T1 (see FIG. 4, 1). 1 recording timing generation circuit (22), (23),
Signal S5 from (24) and (25) (Fig. 4F
), signal 86 (Fig. 4G), signal S? (Figure 4H)
and signal S8 (FIG. 4 I) are respectively output from the recording waveform generation circuit O1.
,(,11). (12) and (IB) as gate signals, and the pyroso 1 signal P1 positioning signals S, T and erasure signal Eo from the generators (61, +71, (81 and (9), respectively) form the recording waveform. Generation circuit 00), (11)
, via (12) and (13) or times FI8. (
14) as a composite signal Ss (FIG. 4, 1). (26^) (26B) is a switch circuit (2OA) during playback.
) (20B) is switched to the contact P side, the reproduction output from the corresponding rotary head (IA) (IB) is supplied, and these amplifiers (26A) (2
6R) is supplied to a switch circuit (27). The switch circuit (27) is connected to the timing signal generation circuit (1
The 30Hz switching signal St (Fig. 5A) from 6) causes a half-rotation period including the tape contact period of the head (IA) and a half-rotation period including the tape contact period of the head (IB), as in recording. It can be switched alternately with the period. (28) is a pylon bus filter from the reproduction output from the switch circuit (27) and a narrow band bus filter with a 1fffi overcenter frequency fo that does not extract only the signal P.
) is an envelope detection circuit for envelope detection of the output of the filter (28), and (30) is a sample hole for sampling the output of the envelope detection circuit (29) and performing ball 1 to ball 1. &, (
31) is a comparison circuit that compares the outputs of the envelope detection circuit IM (29) and the sample bold circuit (30), such as a differential amplifier, and (32) is for sampling and holding the comparison error signal from the differential amplifier (31). These sample bold circuits (30) and (32) are essentially (as shown in multiple series) circuits for the sample hole 1'' circuits (30, 32), which are connected to the track on both sides adjacent to the track currently being scanned during normal playback. The sample and hold circuit 118 serves to sample and halt the crosstalk of each pilot signal recorded at each end of the trunk.
The output of (32) is taken out as a tracking control signal to an output terminal (33). In addition, in order to form sampling pulses etc. for the sample bold circuits (30) and (32), positioning signals S and 1 are sent from the reproduction output to the output side of the switch circuit (27).
Passing center frequency f1 for extracting only . (2 narrowband bandpass filters (34) and (35) are installed)
Their output S+o (5th IE), 5s1
(FIG. 5F) is supplied to a comparator (37) as a waveform shaping circuit via a switch circuit (36). The switch circuit (36), like the switch circuit (27), is switched by the switching signal 81' of 3011z from the timing signal generating circuit (16). (3B) and (39) are sampling pulse generation circuits provided on the output side of the comparator (37), and the sampling pulse generation circuit (38) is provided on the output side of the comparator (37).
The sampling pulse generation circuit (39) generates the second sampling pulse SPs at a predetermined time t p Ilt after the first sampling pulse SP1 is generated. Generate pulse SP2. These sampling pulses SPI and SF3 are connected to sample and hold circuits (
30) and (32). (50) is an amplifier provided between the band pass filter (28) and the envelope detection circuit (29) via a resistor (51), and the input and output terminals of this amplifier (50) are connected in series. Connection switch SW1 and resistor (52
), switch SW 2 and resistor (53), switch S
W3 and the resistor (5/I), switch S W 4 and resistor (55), and switch S W 5 and resistor (56) are connected in parallel, respectively. Assuming that the resistance values of the resistors (52) to (56) are Rs, R2, R3, R4, and Rb, respectively, R5>T? 4 >Ri >R2>I? It is set so that there is a relationship of □. Further, the gain G of the amplifier (50) is G, the resistance value of the resistor (51) is R, and the gain G decreases as it goes toward the resistor (52) and increases as it goes toward the resistor (56). Switches SW1 to SW6 are connected to a microcomputer (5
7) can be selectively switched by the output. As will be described later, the microcomputer (57) switches the gain (I) of the amplifier (50) according to the level of the pilot signal of the same azimuth. ) is set to F, and when it is small, switch S is set to set the gain of the amplifier (50) to 1.
Switch Wi-3Wa. In order to detect the pilot signal of the same azimuth, an envelope I'J-B 4* wave circuit (2
A sample hole I' circuit (58) is provided on the output side of 9). Further, a delay circuit (59) for delaying the second sampling pulse SP2 by a predetermined time, for example, tp, is provided on the output side of the sampling pulse generation circuit (39), and its output is outputted via a monostable multivibrator (60). The switching signal S+' from the timing signal generation circuit (16) is supplied to one input terminal of the AND circuit (61), and the switching signal S+' from the timing signal generation circuit (16) is supplied to the other input terminal of the AND circuit (61). Third sampling signal sP3 (
The sample and hold circuit (58) is supplied as FIG. 5I). The output of the sample and hold circuit (58) is supplied via a low-pass filter (62) to an inverting input terminal of a comparator (63) and also to a non-inverting input terminal of a comparator (64). The first reference value VthH is supplied to the non-inverting input terminal of the comparator (63), and the second reference value VthL is supplied to the inverting input terminal of the comparator (64). Comparator (6
3), when the level of the input signal supplied to the inverting input terminal is greater than the first reference value VthH, a low level "■" signal is generated on the output side, and when it is smaller, a high level "■" signal is generated.
On the other hand, when the level of the input terminal supplied to the non-inverting input terminal is greater than the second reference value VthL, the comparator (64) generates a high level "H"signal; When it is small, a signal of low level "17'" is generated. The outputs of the comparators (63) and (64) are supplied to the microcomputer (57).
), the level of the pilot signal of the same azimuth supplied through the low-pass filter (62) is the first reference value V.
thH and the second reference (dkVthL), the amplifier (5
Adjust the gain of 0). In this way, (50) ~ (
64) forms a gain control means. 62 Circuit Operation 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, the pulse pQ from the pulse generator (I7) indicating the rotational phase of the rotating head (IA) (1B>
In response, a signal S2 as shown in the fourth diagram is generated from the timing signal generation circuit (16), and this signal S2
is delayed by a predetermined time in a delay circuit (21), and a signal S3 as shown in FIG. 4E is outputted to its output side. This signal S3 is supplied to the recording timing generation circuits (22) to (25) as described above, and the output side of the recording timing generation circuit (22) receives a signal S5 as shown in FIG. 4F.
is generated. Further, the switching signal S1 from the timing signal generating circuit (16) is supplied to the frequency divider (21'), and a signal S4 as shown in FIG. 4C is obtained at its output side. This signal S4 is generated by recording timing generation circuits (23) to (2).
5), and the recording timing generator IM (23) ~
(25) is the signal S3. In response to S4, signals 36 to S8 as shown in FIG. 4G-1 are generated on the 111 side, respectively. Signal S5. S6. S? and S8 are respective recording waveform generation circuits 001. (11), (12) and (13), recording waveform generation circuit 0 (O is the pilot signal 1 from the oscillator (6) in synchronization with the supplied signal S5)
LP for a predetermined time at predetermined intervals as shown in FIG. 4F.
1), and the recording waveform generation circuit (11
) generates a recording waveform generating circuit (8) that emits the positioning signal S from the oscillator (7) in synchronization with the supplied signal S6 at predetermined intervals for a predetermined period of time as shown in FIG. 4G. ) generates an oscillator (8) in synchronization with the supplied signal S7.
) is passed for a predetermined time at predetermined intervals as shown in FIG. The erasing signal Eo from 9) is passed for a predetermined time at predetermined intervals as shown in FIG. The output signals from the recording waveform generation circuits (10 to (13)) are summed by OR[-!11#f (14), and a signal S9 as shown in FIG. 4 is taken out at the output side. Incidentally, at this time, if we consider, for example, that the head (Ill) is recording the trunk (5Bt) shown in FIG. 3 (during the tB period in the first half of FIG. 4), the signal S5 in FIG. The first and second pulses of pyroso [signal PAI
and P^2, and the first of the signal S6 in FIG. 4G
and the second pulse correspond to the positioning signals SAI and SA2, respectively, and the first and second pulses consisting of the pair of pulses of the signal S8 in FIG.
The signals PAl, EO correspond to the erasing signals Eo adjacent to both sides of A2, and correspond to the arrangement of these signals, namely PAl, EO.
. SAI, R[1 and PA2. EO, SA2. The combined signals of EO are taken out to the output side of the OR circuit (14) for each group. For example, if the head (IA) is recording track (5A2) in Figure 3 (tA in the first half of Figure 4),
period), the first and second pulses of signal S5 in FIG. 4F correspond to pilot signals PB3 and PH1, respectively, and the first and second pulses of signal S7 in FIG.
The pulses correspond to positioning signals T83 and Ta2, respectively,
The first and second pulses of the signal S8 in FIG. 41 correspond to the positioning signal T81 and the erasing signal Eθ adjacent to one side of Ta2, respectively, and are signals corresponding to the arrangement of these signals. 1゛B3, Eo, PBa and Ta41 Ea
The combined signals of tPH1 are taken out to the output side of the OR circuit (14) for each group. Also, for example, (IB) is the track (5B) in FIG.
2) (period tB in the second half of FIG. 4), the first and second pulses of the signal S5 in FIG. 4F correspond to the pilot signals PA3 and PA4, respectively, and the fourth The first and second pulses of signal S6 in FIG. One word, ie, PA3., corresponds to the erasing signal IRo adjacent to both sides of S^3 and S^, respectively, and corresponds to the arrangement of each of these signals. EO, SA3. E
O and PA4°Ro, SA4. The combined signals of Ro are taken out to the output side of the OR circuit (14) for each group. For example, if the head (IA) is recording track (5^) in FIG. 3 (during the second half of FIG. 4), then the signal S5 in FIG. The second pulses correspond to the pilot signals P[(5 and PH6, respectively; the first and second pulses of the signal S7 in FIG. 4H correspond to the positioning signals TB5 and Ta6, respectively; the fourth
The first and second pulses of the signal SL1 in FIG. A composite signal of Pes and "rF]G+Eo+PBG is taken out to the output side of the OR circuit (14) for each group. On the other hand, from the timing signal generation circuit (16), a pulse generator (17) A switching signal S1 as shown in FIG. 4A is generated in response to the pulse PG from
] is synchronized with the rotation of the rotating heads (IA) (IB), and as shown in FIGS. 4A and 4B, the head (
1A) comes into contact with the tape (2), and the head (IB) comes into contact with the tape (2) within a half rotation period tB during which the signal S1 is at a low level. Then, the switch circuit (15) is switched to the state shown in the figure during the period (^) and to the state opposite to the state shown in the figure during the period ts, respectively, by the switching signal S1, and head switching is performed. Therefore, the OR circuit ( 14) The signal S9 obtained on the output side of
When the switch circuit (15) is in a state opposite to that shown in the figure, the amplifier (19B) and switch circuit (20B)
) on the R side ii! 1 is fed 04 to the head (IB),
At the beginning and end of the contact period of the head (IB) to the tape (2) within the period to, the trunk (
5B) Recording areas ATI and A-2 for trussogging signals provided at both longitudinal end portions of the track (5B) equidistant 1111 from the center position in the longitudinal direction are recorded at odd numbers of the rotation period of the head, respectively. (t BI in the first half of Figure 4
JI), the data is recorded for the time tp+-1--tl), and in the even-numbered rotation period of the head (period 1B in the second half of FIG. 4), the data is recorded for the time tp+-1--tp. When the one-way switch circuit (15) is in the state shown in the figure,
The signal S9 is connected to the amplifier (19^) and the switch circuit (20).
The R side of the head (IA) is supplied to the tape (IA) at the beginning and end of the contact period of the head (IA) with the tape (2) within the period tA, as shown in the figure. , truck (5A
) The recording areas AT1 and Ar1 similar to those described above are provided at both end portions of the track (5A) in the longitudinal direction, which are equidistant MIl apart from the center position in the longitudinal direction of the track (5A). In the first half (tp period of B), time -tp+tp+tp and -1p
+ tp + tp, and is recorded during even-numbered head rotation periods (period tA in the latter half of FIG. 4). Also, at the time In when these pilot signals, positioning signals, and erasing signals are recorded, the audio PCM signal of one segment portion to be recorded as one track (not shown) is transmitted to the amplifier (19A) during the period tA. ) is supplied to the head (IA) through the amplifier (1
911) to the head (IB) and are recorded in the recording area AP1 other than the above-mentioned pilot signal recording area of each track (5A) (5B). Next, reproduction of the signal recorded as described above will be explained. During this playback, the motor (18) also receives the drum phase signal by the phase servo circuit (19) in the same way as during recording.
A port is placed on it. The signals taken out from the tape (2) by the rotating heads (1^) and (IB) are sent to the contact R side of the switch circuit (2OA>), the amplifier (26A), and the switch circuit (20B), respectively.
) is supplied to the switch circuit (27) via the contact 5 P side and the amplifier (26B). This switch circuit (27)
is a half-rotation period t, which includes the tape contact period of the head (1^), in the same way as during recording, by a 30Hz switching signal 3.1 as shown in FIG. 5A from the timing signal generation circuit (16).
A and a half-rotation period tB including the tape contact period of the head (1B). Therefore, from this switch circuit (27), an intermittent PCM signal SR is obtained segment by segment as shown in FIG. The data is then supplied to a decoder, where the data is detected block by block using a block synchronization signal, subjected to processing such as image correction and de-interleaving, and then converted back to an analog audio signal by a D/A converter and sent to the output side. . Tracking control G is performed as follows. Now, for example, if the head (Ill> is −J(λ
Assuming that the range of scanning width W including the trunk (5B+) is scanned as shown by the chain line, the head (IB) scans the track (5^2) (
5^1), and as shown in Figure 3, in area A, the trunk (5B+) is
The signal P^, the pilot signal PB3 of the rank (5A2) on both sides and the pilot signal PRI of the truck (5^1) are reproduced, and in the area AT2, the pilot signal PA2 of the trunk (5th) and the pilot signal PA2 of the trunk (5th) are reproduced. The pilot signal PB4 of the adjacent truck (5A2) and the truck (
5^1) and the pilot signal PR2 are regenerated. At this time, the head (ll'l) from the switch circuit (27)
The reproduced output of In addition, the output SR of the switch circuit (27) is supplied to a narrow band band pass filter (with passing center frequencies of 11 and f2, respectively).
34) and (35), and positioning signals SIO and Ssl as shown in FIG. 5E and F are taken out at their output sides, respectively. These signals Sho and SIX
is supplied to the switch circuit (36), and when the switching signal S+' is at a low level, a signal 3+o is taken out, and when it is at a high level, a signal Ss1 is taken out and supplied to a comparator (37). In the comparator (37) the supplied signals S, IO and Sli
is compared with a reference value, the waveform is shaped, and the waveform is supplied to sampling pulse generation circuits (38), (39). The sampling pulse generation circuit (38) generates a waveform-formed signal Sh.
The first sampling pulse SPz as shown in 5' FXIG is generated in accordance with the first 1 yen of o, and this pulse '
The sampling pulse SP1 is generated by a sampling hold circuit (
30). At this time, sampling pulse S
As is clear from Figure 5, P+ is the arrow (4T)
The adjacent trunk (on the opposite side to the transport direction shown in Figure 3)
582) pylon] - The state is in which the crosstalk of the signals PR3 and PH4 is sampled, and this sampled signal leads to tracking of the leading phase (No. 4 is supplied to one input terminal of the differential amplifier (31)). In addition, after a time tp after the generation of the sampling pulse SP+, the crosstalk between the pilot signals PB1 and pBz of the adjacent trunk (5A□) on the tape transport direction side is caused by the envelope detection circuit (29)! ) is supplied as a tracking signal with a delayed phase to the other input terminal of the pilot signal PH.
The tracking signals corresponding to crosstalk between PH4 and PH2 are sequentially compared. Then, the comparison error signal from the differential amplifier (31) is supplied to the sampling hold circuit (32), so that the comparison error signal is generated from the sampling pulse generation circuit (39) after a time tp from the point in time when the sampling pulse SP1 is generated. It is sampled by sampling pulse SP2. Therefore, from this simple hold circuit (32), the difference between the two inputs to the differential amplifier (31) is obtained as a tracking control signal, and this is supplied from the output terminal (33) to the capstan motor (not shown) to tape the tape. As a result, the level difference between the two inputs to the differential amplifier (31) is zero, that is, the head (IB) is
) is controlled to span the two tracks (5^2) and (5^1) on both sides by the same amount. That is, the scanning is controlled so that the center position in the width direction of the gear 7F (IB) matches the center position of the track (5B1.). The same process is performed for other tracks. For example, when the head (IA) scans the trunk ('5A2), the tracks (5B2) and (5L) on both sides of the trunk ('5A2) are scanned by the head (IA).
) to the pilot signal P of 3+ Ph4 and Ph3゜P
Since the crosstalk of A2 is obtained, these are the sampling pulses 5 supplied from the sampling pulse generation circuit (38) to the sampling hold circuit (30) as described in F.
1) According to 1, the crosstalk of the pilot signal PA31P A4 is siped to obtain a tracking signal, and this is supplied to the next stage differential amplifier (31). Supply the output from the detection circuit (29) and
Then, the pilot signal PAI is compared with the tracking signals corresponding to the crosstalk of PAI, P^, and Ph2, respectively, and the comparison error signal is sampled and held in the Hall MI circuit.
4 (32) with the sampling pulse SP2 supplied to
By non-pulling, a tracking control signal for the head (18) can be obtained. Also, in the same way, move the truck (5R2) to navel 1' (IB).
) scans, the pilot signals PB5.
The PHG crosstalk is sampled with the sampling pulse SP1, and the differential amplifier (31) compares the tracking signals corresponding to the crosstalk of the pilot signals PB5 and PO2, and PH1 and PH1, respectively, and finally outputs the comparison error signal. By sampling with the sampling pulse SP2, a tracking control signal for the head (IB) can be obtained. Similarly, the track (5A3) is connected to the head (IA).
) scans, as shown in FIG. 3, the pilot signals P A6 , P Ali and Ph3 . P
Since the crosstalk of Δ is obtained, the pilot signal P
^6+PA6 crosstalk sampling pulse SP
1, and the differential amplifier (31) outputs the pilot signals PA5 and PA], P8. A tracking control signal for the head (1^) can be obtained by controlling the I/ranking signals corresponding to the crosstalk of and Ph4, respectively, and finally subjecting the comparison error signal to the sampling pulse SP2. . Circuit configuration and operation of G3 sampling pulse generation circuit (39) Figure 6 shows an example of a specific circuit configuration of sampling pulse generation plane II (39).
(40) is a force counter that counts the wave number (pulse) of the positioning signal supplied from the comparator (37); (41)
) is the signal S4. the content of the positioning signal in response to Sl';
In other words, in this embodiment, the data set (42) is the count value of the counter (40) and the data A coincidence detection circuit for detecting a coincidence of data of a selector (41), the coincidence 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 SP1, and
40) is enabled by the output of the delay circuit (44) and cleared by the output of the delay circuit (45). (47) is a D-type flip-flop circuit, and this flip-flop circuit I/8 (47)
The output of the coincidence detection circuit (42) is supplied to the input terminal of , and the delay amount 1i'8 ('4
6), the sampling pulse SP1 is substantially applied via the reset terminal R of i! ! The output of the extension circuit (45) is supplied. (48) is a gate circuit, for example, an AND circuit, and one input terminal of this AND circuit (48) is a delay circuit (43).
) is supplied, and the output of the output terminal Q of the flip-flop circuit (47) is supplied to the other input terminal, and the sampling pulse SP2 is output from that output terminal. Next, the operation of the circuit shown in FIG. 6 will be explained with reference to the signal waveforms shown in FIG. Now, when a signal 313 as a positioning signal as shown in Figure 7 is supplied from the comparator (37) to the sampling pulse generation circuit (38), the sampling pulse generation circuit (38) receives the first signal 313 from the signal 313. A sampling pulse SPz as shown in FIG. 7H is generated in synchronization with the rising edge of the pulse.
occurs. This sampling pulse SPz is supplied to the above-mentioned sample and hold circuit (30) (FIG. 1) and also to delay circuits (43) to (46). The delay circuit (44) synchronizes with the sampling pulse SP and has a seventh pulse having a duration approximately equal to -tp on its output side.
A signal SL2 as shown in Figure C is generated, and this signal S12
is supplied to the kernonter (40) as an enable signal. The counter (40) calculates the pulse of the signal SI3 from the comparator (37) during the high level of the signal S12 by one. On the other hand, the data selector (41) selects data related to the positioning signal in response to the signals SP and S4 shown in FIGS. 7A and 7B. Then, if the selected data and the contents of the counter (40) match, the match detection circuit (
42) has a signal S1 on its output side as shown in FIG.
This signal 514 is supplied as data to the flip-flop circuit (47). The delay circuit (46) synchronizes with the 9-combination pulse SP+ and a predetermined time Δt1 thereafter, as shown in FIG. A signal SI5 as shown in FIG. 1 is generated, and this signal S16 is supplied to the clock 1 Mizuki CK of the flip-flop 1 circuit (47), and the signal SI4 supplied to the input terminal is latched. Note that the tp delay time Δt1 in the delay amount V8 (46) is tp>Δ1. ＞----It is considered to be one. Furthermore, the delay circuit (45) generates a signal S16 as shown in FIG. It is supplied to clear its contents and is supplied to the flip-flop circuit (40) to reset it. As a result, the li signal S□7 as shown in FIG. 7I is generated on the output side of the flip-flop circuit (47). Note that the delay time Δt2 in the delay circuit (47) is
It is assumed that Δt2>tp. Further, the delay circuit (43) synchronizes with the sampling pulse SP1 and after a predetermined time tp, generates a signal sia as shown in FIG. supplied to Since the other input terminal of the AND circuit (48) is supplied with a signal Sa1 formed like a double series, this signal S1? is essentially used as a gate signal in the AND circuit (
48) opens the gate, and in response to signal 31e,
A sampling pulse SP2 as shown in FIG. This sampling pulse SP2 is then supplied to a sampling hold circuit (32). In this way, sampling pulse SP2 can be generated. Note that this sampling pulse SP2 can also be generated by processing by a microcomputer (not shown). This 11 will be explained with reference to the diagram IJ-chart t4 in FIG. When the playback mode is entered in step (a), the positioning signals S and T are output at the stage 11 (opening), and if no detection is detected, the operation is repeated. When detected, the positioning signal S is output in step (c). A first sampling pulse SPs is generated based on the positioning signal S in step (d). The wave number (pulse) Ni is measured only during the detection period of the T signal. step (e), the detected positioning signal S,
When T enters the playback mode, it is determined whether or not the first occurrence occurs, and if it is the first, it determines the step I interval, and if any of the conditions are satisfied, then the second If the interval between sampling pulses or the -tp interval is not satisfied, it is not a positioning signal and the process returns to step (b). In step (e), if the positioning signal has been generated for the second time or later after entering the reproduction mode, the process advances to step (h), and it is determined whether the polarity of the signal S4 has changed. If the polarity of signal S4 has changed, step
If the previous detection interval is -tp, then if it is the current position in step (N), it is a true positioning signal, so in step (G), the second sampling pulse SP2 is
is generated, and if it is not --tp, return to step (b). In step (S), if the previous detection interval is 11P, go to step (R), and the current position output (7 signals is a true positioning signal, so in step (G), the second A sampling pulse SP2 is generated, and if it is not -tp, the process returns to step (B). Steps (ch) to (l) will be explained in detail with reference to FIG. 5B, E and F. ), for example, when it is determined that the polarity of the signal S4 has changed in the central part of Figure 5 ■3, step (in January, Figure 5 F
Since the signal SII Te4 is not shown in 1-tp, proceed to step (N). And here, signal S1 not shown in Fig. 5R
It is determined whether SA3 of o is -tp or not, and since it is -1P, the second sampling pulse SP2 is generated in step (g). At step (nu), signal SA3 is -
If not tp, return to step (b). Also, if -tp in step (S), the signal So
It is determined that it is the signal TB6, not Te3 (therefore, the time point at which the polarity of the signal S4 changed was not at the center part of FIG. 5B but at the right end part), and in step It is determined whether 5A5 (not shown) of the signal S+o shown in FIG. 5E is -tp, and since it should be -tp, the second sampling pulse SP is
Generates 2. In step (ru), signal SA5 is 1-1p
Otherwise, return to step (b). Now, in step (H), if the polarity of the C signal S4 has not changed, proceed to step (W), and judge whether or not the detection interval is the same as the previous positioning signal, and if it is the same. Then, go to step (g) and generate the second sampling pulse S.
Generates P2. Referring to FIG. 5E, for example, the first SA1 and the second S of the positioning signal S1°
Since A2 is the same -tp, the second sampling pulse SP2 is generated in step (g). If the detected sections are not the same in step (w), it is regarded as an erroneous detection, and the process returns to step (b) while maintaining the initial computation state. In this way, the second sampling pulse SP2 can also be generated through processing by a microcomputer. G. Operation of gain control means 1 Returning to Figure 1, the operation of the gain control means is shown in Figure 9.
This will be explained with reference to FIGS. Now, in the initial state, switch SW3 is turned on and the third
Assume that the level of the pilot signal of the same azimuth detected by the sampling pulse SP3 and obtained on the output side of the zumbling hold circuit (58) is at the position (■) in FIG. At that time, as can be seen from FIG. 9, the level of the pilot signal of the same azimuth from the sample hold circuit (58) is the first reference value VthH and the second reference value Vt.
Since it is larger than hL, the output of the comparator (63) becomes "L", and the output of the comparator (64) becomes ")(". Therefore,
The microcomputer (57) turns off the switch SW3 and turns on the switch SW2 to lower the gain of the amplifier (50). At that time, the level of the pilot signal of the same azimuth from the sample and hold circuit (58) is higher than the position of ■.
The position of Since the first reference value (Vt1.H to 1 and the second reference value vtht) of the lechen eye 31 at the position of ■ is still larger than the output of the comparator (63), the output of the comparator (63) is "■,"
, the output of the comparator (64) remains at "11".Therefore, the microcomputer (57) turns off the switch SW2 and turns on the switch SW1 to lower the gain of the amplifier (50) to zero. At that time, the level of the pilot signal of the same azimuth from the sampling ball 1'' circuit (58) will be at the position ■ from the position ■. 1 noher at this position ■ is smaller than the first reference value Vtt+H and the second reference value Since the value is larger than the value Vtl, the output of the comparator (63) changes to "I", and the output of the comparator (64) remains "H". Therefore, the microcomputer (57) switches SW1
Connect the on. In other words, the gain of the amplifier (50) is kept constant in a lowered state, and the level of the pilot signal of the same azimuth from the sampling and hold circuit (58) is between the first reference value VtbH and the second reference value VthL. is set to Further, as an initial state, the switch SW3 is turned on,
Assume that the level of the pilot signal of the same azimuth detected by the third sampling pulse SP3 and obtained on the output side of the sample hold circuit (5th day) is at the position (■) in FIG. At that time, the level of the pylon I signal of the same azimuth from the sample hole 1' circuit (58) is smaller than the first reference value VthH and the second reference value VthL, as can be seen from FIG. 63) output is “H”
Therefore, the output of the comparator (64) becomes "L". Therefore, the microcomputer (57) switches SW 3
is turned off and switch SW4 is turned on to increase the gain of the amplifier (5o). At that time, the sample hold circuit (58)
The level of the pilot signal of the same azimuth from the position ■ is higher than that at the position ■. The level at this ■ position is the first level.
Since it is still smaller than the reference value VthH and the second reference value VthL, the output of the comparator (63) remains "H" and the output of the comparator (64) remains "L". Therefore,
The microcomputer (57) turns off the switch SW4 and turns on the switch SWa to further increase the gain of the amplifier (50). At that time, sample bold times 1m (5
The level of the pi 0 soto signal of the same azimuth from 8) is at the position ■ rather than the position ■. 1 noher at this position ■ is smaller than the first reference value VthH and the second reference value Vt
Since it is larger than l+L, the output of the comparator (63) is “11
Until then, the output of the comparator (64) changes to "11". Therefore, the microcomputer (57) uses the switch SW.
Keep 6 on. That is, in this case the amplifier (50)
The level of the pilot signal of the same azimuth from the sample and hold circuit 11 (5B) is set between the first reference value Vtbo and the second reference value VthL. . Further, the case of controlling the gain of the amplifier (50) will be explained with reference to FIG. H) and FIG. 11. First, Fig. 10 shows a case where the gain of the amplifier (50) is lowered because the level of the pylon Ml of the same azimuth is high, and now the switch SW3 is turned on, and the head is turned off during the first half-rotation period LA in Fig. 10. (I^) scans the track (5A2) in Figure 3, and the sample hold circuit (
58), the third sampling pulse SP3 produces a pilot signal P83.58 of the same azimuth. If PB4 is detected and its level is higher than the first reference value VthH and the second reference value VthL, the output of the comparator (63) becomes "L" and the output of the comparator (64) becomes "H". Therefore, the microcomputer (57) turns off the switch SW3 and turns on the switch SW2 to lower the gain of the amplifier (50).Then, in the next half-rotation period tΔ, the head (IA) switches to the third The track (5A3) in the figure is scanned, and the third sampling pulse SP is applied in the sample hold circuit (58).
3, the pilot signal of the same azimuth P H5 + P
B6 is detected and its level is the first reference value Vth1
4 and the second reference value VthL, the output of the comparator (63) remains "L" and the output of the comparator (64) remains "H". Therefore, the microcomputer (57) turns off the switch SW2 and turns on the switch SW1 to further lower the gain of the amplifier (50). Then, during the next 0 half-rotation period', the 1-rack (5A4) in FIG. Pilot signal PR for the same azimuth? +
P R& is detected and its level is the first reference value V
If it is smaller than thH and larger than the second reference value Vtl+L, the output of the comparator (63) becomes "H" (
To be precise, after a predetermined period of time has elapsed since the pilot signal PR7 was detected, the output of the comparator (64) remains at H''. Therefore, the microcomputer (57) keeps the switch SWs on. .That is, the amplifier (50)
is held constant with the gain lowered, and the level of the ``BI1'' signal of the same azimuth from the sample pull hold circuit (58) is equal to the first reference value VthH and the second reference value Vt.
ht. set between Next, in Figure 11, the level of the pilot signal at the same azimuth is low, so it is amplified! In the case of increasing the gain of (50), the switch SW3 is now turned on, and during the first half-rotation period t^ in FIG. 11, the navel l" (IA) scans the track (5A2) in FIG. 3, Sample hold circuit (58
), when the pilot signal P R3+ P R4 of the same azimuth is detected by the third sampling pulse SP3 and its level is smaller than the first reference value V tb I+ and the second reference value V tb L, the comparator The output of (63) becomes ['H'', and the comparator (64
) output becomes "L". So, I turned off the microphone controller 1 viewer (57) + switch SW 3.
Switch SW 4 is turned on to increase the gain of the amplifier (50). Part 1. Then, the head (IA) moves to the third position in the next half-rotation period.
The track (5A3) shown in the figure is scanned, and the sample bold circuit (58) uses the third sampling pulse SP3 as the upstream pilot signal PH6,p with the same azimuth.
Assuming that s6 is detected and its level is still smaller than the first reference value VthH and the second reference value VthL,
The output of the comparator (63) remains at "H" and the output of the comparator (64) remains at "r7". Therefore, the microcomputer (57) turns off the switch SW4 and turns on the switch SW5 to further increase the gain of the amplifier (50). Then, in the next half-rotation period tA, the navel F (IA) scans the track (5A4) in FIG. 3, and in the sample-hold circuit (58), the pilot signal PR? of the same azimuth is generated by the third sampling pulse SP3. 1PF
18 is detected and its level is smaller than the first reference value VthH and larger than the second reference value VthL, the output of the comparator (63) remains "H" and the output of the comparator (64 ) becomes "H" (more precisely, after a predetermined period of time has elapsed since the pilot signal PB7 was detected). Therefore,
The microcomputer (57) keeps the switch SW6 on. In other words, the gain (l) of the amplifier (56) is held constant while being raised, and the sample and hold circuit (56) is held constant.
The level of the biloft signal of the same azimuth from 8) is the first
is set between the reference value VthH and the second reference value vtht. Next, the operation of the microcomputer (57) will be explained with reference to FIG. First, in step (a), set switch SW3 as the initial setting.
Turn on the switch and turn off the other switches. Next, in step (B), it is checked whether the output of the comparator (63) is 11'', and if it is not "H", the process proceeds to step (c).
and check whether the switch that is on is S W r. If not S W s, S W in step (d)
3 is turned off and SW 2 is turned on. Then, in step (e), after a predetermined time Δ has elapsed, the process returns to step (b), and it is checked whether the output of the comparator (63) is "1". If it is not "H", go to step (c) and check whether the switch that is on is SW1. If it is not SWl, step (d) is SW2.
Turn off and turn on SW1. Then, after the predetermined time Δ has elapsed in step (E), return to step (B) again,
Check whether the output of the comparator (63) is "H" or not. If it is not "H", proceed to step (c).
Check whether switch SW1 is on or not,
Since it is SWt, the operation is stopped. On the other hand, in step (B), if the output of the comparator (63) is "H", the process advances to step (63), and the output of the comparator (63) is "H".
4) Check whether the output is "H" or not. “1
If it is not 1, go to step (1.) and check whether the switch that is on is SWs. SW
If it is not 5, turn off SW3 in step (ch), and
Turn on 4. Then, in step (E), after the predetermined time Δ has elapsed, the process returns to step (B) again, and the comparator (63)
Check whether the output is "H" or not. and"
If it is 11", go to step (go) and comparator (64").
) is "H". “11
If not, go to step (g) and check whether the switch that is on is SWs. If it is not SWs, turn off SW4 and turn on SWs in step (h). Then, step After the predetermined time Δ seconds has elapsed in (e), return to step (b) again, go through step (g) as described above, and proceed to step (g) to check whether the switch that is on is SW 6 or not. Since it is SWs, the operation is stopped. Also, if the output of the comparator (64) is "H" in step (to), the level of the pilot signal of the same azimuth is within the first and second reference values. , so switch SW
The operation ends without switching 3. In this way, in this embodiment, since the variation in the pilot signal of the same azimuth is detected and AGC is substantially applied, stable tracking servo can be realized. (Effects of the Invention As described above, according to the present invention, the pilot signal of the track being scanned during playback, that is, the pilot signal of the same azimuth, is detected, and the loop gain of the tracking servo is controlled according to the detection level to keep it constant. Therefore, with a simple circuit configuration, it is possible to always obtain accurate information without being affected by other factors such as variations in the recording sensitivity and playback sensitivity of the head, variations in tape characteristics, and variations in the gain of the playback amplifier. You can go through tracking control.

[Brief explanation 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 the rotary head device used in FIG. 1,
3 is a diagram showing an outline of the 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 reproduction operation in FIG. 1. FIG. 6 is a circuit configuration diagram showing an example of the main part of this invention. FIG. 7 is a signal waveform diagram for explaining the operation in FIG. 6. FIG. 8 is a signal waveform diagram for the second sampling. Flowchart for explaining the operation of generating pulses, FIGS. 9 to 11 are diagrams for explaining the operation of the main part of the invention, and FIG. 12 is for explaining the operation of the main part of the invention. This is a flowchart for (■^) (IB) is a rotating magnetic head, (2) is a magnetic tape, (6) is a pilot signal oscillator, (7) is a positioning signal oscillator, (9) is an erasing signal oscillator, 0
IIO. (11), (+2), (13) are recording waveform generation circuits, (21) are delay circuits, (22), (2
3), (24). (25) is a recording timing generation circuit, (2B),
(34). (35) is a band pass filter, (29) is an enherobe detection circuit, (30), (32), (5
B) is a sample bold circuit, (31) is a differential amplifier,
(36) is a switch circuit, (37), (63)
, (64) is a comparator, (3B), (39) is a sampling pulse generation circuit, (50) is an amplifier, (5
7) is a microcomputer, and SW1 to SW6 are switches. B

Claims (1)

[Claims] A digital signal is compressed in the time axis and recorded by forming diagonal tracks on a recording medium using a plurality of rotary heads, and each track is recorded in a recording area independent of the digital signal in the longitudinal direction. In the digital signal recording and reproducing apparatus, the digital signal recording and reproducing apparatus records a plurality of tracking pilot signals, detects crosstalk of the pilot signals of adjacent tracks by sample and hold means, and tracks the rotary head using the detection output. Tracking control characterized in that a gain control means is provided before the sample and hold means, samples a pilot signal of a track being scanned during reproduction, and controls the gain of the gain control means according to the level of the pilot signal. Device.