JPS6015848A - Tracking controller - Google Patents

Abstract

PURPOSE:To decrease the lock-in time of a servo controller of the ATF system by skipping the order of circulation of a reference pilot signal at a skip control circuit with a detected output of a lock-in error detecting circuit. CONSTITUTION:Suppose that a pilot frequency of a regenerated pilot signal S2 is started with a shift of 1/2 circulating period to the circulation of a pilot frequency of the reference pilot signal S11, since a differential frequency component of an output S12 of a multiplier circuit 14 of an error signal forming circuit 3 is neither DELTAfA nor DELTAfB, an error signal S3 keeps 0 level. Since the regenerated pilot signal S2 generates the difference frequency components DELTAfA and DELTAB at an output S21 of the multiplier in a detection circuit 31 on the other hand, the level of an oscillating point error signal S24 takes a maximum level and then a level detection circuit 44 gives a skip signal S26 to a hold circuit 46. Switches 17C and 32D are thrown from a terminal a1 to an a2 position in this case, the order of circulation of the pilot frequency of the reference pilot signals S11 and S31 is phase shifted forcibly by a 1/2 circulating period.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a tracking control device, and particularly to a tracking control device that cyclically records pilot signals of different frequencies together with a video signal on recording tracks formed in sequence across the strike direction on a recording medium. , applied to an automatic track following method (hereinafter referred to as ATF method) tracking control device that detects the difference in frequency between signals reproduced from adjacent tracks during playback and tracks the playback head to a predetermined track. [Background Art and Problems Therein] A four-frequency type tracking control device has been proposed in which pilot signals of four frequencies are sequentially recorded on a recording track. The tracking state can be expressed by the relationship between the tracking position deviation amount and the tracking error signal as shown in Fig. 1.In other words, if we consider the case where the track pitch and head width are approximately equal, at the phase lock point TO, the error signal S
3 becomes 0, and at this time the reproducing head is controlled to a correct tracking state. On the other hand, if the reproducing head causes a tracking deviation in the positive direction, the amount of tracking deviation will be one track pitch, that is, the adjacent track T1.
It increases with the gradient of pressure until it becomes . The amount of increase takes the maximum value at track T1, and thereafter increases by the amount of tracking deviation or two track pitches (Tl
.about.T3), the error signal S3 decreases with a negative slope, reaches O at the position of track T2, and then becomes the value of the page. This phenomenon reaches a negative minimum value at the track T3 position, and when the tracking deviation amount passes this position T3, the error signal increases again with a positive slope for two track pitches, and soon reaches T4. The error signal becomes 0 at the position. Thus, the change in the error signal causes a change of 11 periods between the tracking deviations TO and 1.4 of the track pitch, and as the tracking deviation increases thereafter, this known 1 is repeated for every four track pitches. In response to such a change in the error signal, the tracking control system controls the playback head so that if the error F increases in the positive direction at the lock position TO, the tracking position deviation amount decreases, or if the error signal increases in the negative direction. If the amount of tracking deviation becomes smaller, the reproducing head is controlled to reduce the amount of tracking deviation. Therefore, the playback head has an error signal of 0.
On the other hand, error +3 becomes 0 at phase position T2, but the new signal increases slightly in the positive direction from phase point T2. If the amount of tracking deviation decreases in the negative direction, the playback head is controlled in a direction that increases the amount of tracking deviation, so it cannot become a stable point (this is called the oscillation point). In principle, the ATF type tracking control device shown in FIGS. 2 to 4 has been proposed. That is, this tracking control device controls the playback output of a rotating video head as a recording/playback head, as shown in FIG. A part of the signal S1 is received by a pilot signal detection circuit 1 having a low-pass filter configuration to generate a reproduced pilot signal S2 whose component is the reproduced output of the pilot signal recorded on a magnetic chip as a recording medium. S2 is given to the error signal forming circuit 3. The error signal forming circuit 3 sends out the tracking error portion 83' (FIG. 1) formed under the control of the reference signal generating circuit 4. As shown in the figure, there are four types of pilot signals f1, f2, f3 with different frequencies.
．． A set of four video tracks TI, T2, T3, and T4, in which f4 is recorded together with the video signal, are formed closely diagonally so as to be repeated in a cyclical manner. Here, the effective 1-
For example, the width of the tracks T1 to T4 is selected to be approximately equal to the width of the tracks T1 to T4, and as a result, as shown in FIG. If tracking is performed correctly, the pilot frequency component included in the playback output will be 1 component by generating only the Byron No. 1 recorded on the relevant track, and on the other hand, as shown by the broken line, On the other hand, when the head 6 is shifted to the right or left, the pilot frequency V number component included in the playback output is also generated by generating the pilot signal recorded on the track adjacent to the right or left side of the playback track. is 2λ
In addition, each pilot frequency component σ) is made to have a magnitude corresponding to the opposing length of the reproduction RAD facing the corresponding track. However, the frequencies if□ to f of the four types of pilot signals are selected in the lower a band of the color component converted to the low frequency (600 to 700 Ck th track T1. Centering on T3, the frequency difference with the pilot signal of the right track is ΔfA, and the HtW number difference with the pilot signal of the left track is ΔfB, and even-numbered tracks T2. Right side σ with T4 as the center] Circumference F with the track pilot signal
1 difference is ΔfB, and the frequency difference with the pilot signal of the left track is ΔfA. Therefore, the head 6 is on odd-numbered track T1. When reproducing T3, if there is a signal component with a frequency difference of ΔfA as a frequency component of the pilot signal included in the reproduced signal, it can be seen that the head 6 is in the right-hand state, and if there is a signal component with a frequency difference of ΔfB. If this is the case, it can be seen that the head 6 is in a left-handed state, and if there is no signal component with a frequency difference of ΔfA and ΔfB, it can be seen that the head 6 is being correctly tracked. Same (Eternally, head 6 is on even-numbered track T2゜T4
'& When replaying, if there is a signal component with a frequency difference of ΔfB as a frequency component of the pilot signal included in the reproduced signal, it is known that the head 6 is in a stone-slip state, and a signal component with a frequency difference of ΔfB is found. If there is, it can be seen that the head 6 is shifted to the left. In this embodiment, the first. Second. Third. The frequencies erilf1. assigned to the fourth tracks TI, T2, T3, T4. f2. f3. f4 is 1 t = 1
02 (kHz). f2-116 [kllZ], f3=160 [kz],
f4=146 [kH2], so the difference frequency Δ
fA and Δrice are ΔfA-Ifl-f21 = 1f3
-f41 =14Ckllz:]・・・・・・・・・
(1) ΔfB== 1f2-f31 = 1f4-fll =
44 [kllz)...- (2). A reproduced signal S1 having such inherent characteristics obtained from the head 6 is given to a pilot signal detection circuit 1 having a low-pass filter configuration, and a reproduced pilot No. 48 S2 obtained by extracting the pilot signal included in the reproduced signal S1 is sent to a multiplication circuit 14. is given as the first multiplication input. Multiplication circuit 14
A reference pilot signal 811 of the reference signal generating circuit 40 is applied to the reference signal generating circuit 40 as a second field calculation input. The reference signal generation circuit 4 includes a pilot signal generation circuit 16 that generates four pilot frequency outputs of frequencies f□ to f4.
and a Herad switching pulse RF-8W (Fig. 4(A)) which changes the logic level every time the tape scanning head of the two video heads is switched in relation to the rotating drum (not shown). and a switch circuit 17 that receives the signal. In this embodiment, the switch circuit 17 has a head switching pulse R
Counts every time the level of F-8W changes 4
The gate signal corresponding to the first to fourth tracks T1 to T4 can be sequentially repeated from this counter circuit.
The gates are opened by the gate signals 1 to 4, respectively, and the outputs of the pilot frequencies f1 to f4 of the pilot signal generation circuit 16 are sequentially sent out as the reference pilot signal Sll, as shown in FIG. Note that the reference pilot signal Sll obtained at the output end of this switch circuit 17 is sent to the video head 6 as a recording pilot signal S4 via the signal line 18 during recording, and thus the video head 6 is connected to the first to fourth tracks T1.
~ While scanning T4, the corresponding period 7NIii, i1
-f4 pilot signals are given to the no-next video head 6 to record on each track T1-T4. In this way, when the head 6 scans the 31st to 4th trunks T1 to T4, respectively, the output of the pilot signal detection circuit 1 is detected, and the reproduced pilot signal S2 obtained at 1 is applied to the corresponding endogenous track. By multiplying the synchronously generated reference pilot signal S11, when there is a tracking error, a signal component having a frequency difference between the frequency component included in the reproduced pilot signal S2 and the frequency of the reference pilot signal S11 is eliminated. Multiplication output 812
(In fact, the multiplication output 812 also includes other signal components such as the frequency component of the sum). This multiplication output S12
are applied to the first and second difference frequency detection circuit sides and 2J, which are respectively configured with bandpass filters. First difference frequency detection (b) When the multiplication output 812 contains a signal component of the difference frequency ΔfA based on the above equation (1), the road side extracts this and sends it to the rectifier circuit. Sei's blood ω

The first error detection signal 813 at a DC level is obtained by converting it into a DC signal using a conversion circuit &. Similarly, the 20th difference frequency detection circuit 21 extracts the signal component of the difference frequency ΔfB based on the above-mentioned formula (2) in the multiplication output 812 and outputs it from the DC conversion circuit B to the second difference frequency detection circuit 21. 814 error detection signals are obtained. Here, head 6 is the first. Second. Third. 4th track T
l, T2. When attempting to track T3, T4 (therefore, the switch circuit 17 changes frequencies f□, f2. f3.
f40) If the reference pilot signal S11 is being sent out), if the reference pilot signal S11 is shifted to the right, the reproduced pilot signal S2 obtained based on the reproduced signal S1 of the head 6 will have a frequency vaf and f2 as shown in FIG. 4 (C1). 2 and f3 ” 3 and f4. The pilot signals of f4 and f□ are included, and the difference frequencies ΔfA (=f1 to f2) and ΔfB (=f
2 to 13), ΔfA (-f3 to f4), ΔfB (=f4
~t□) is generated sequentially. On the other hand, when the head 6 is shifted to the left, the reproduced pilot signal S2 becomes as shown in FIG. 4 (C2).
, f□ and f2. f2 and f3. It now includes the bi-fourth X8 of f3 and f4, and accordingly the multiplication output S1
2 is the difference frequency ΔfB (-f4) as shown in FIG. 4 (D2).
〜f1), ΔfA(=f□〜f2), ΔIB(-d2〜
f3). It comes to include ΔfA (-f3 to f4) to Ila order. Thus, as shown in Fig. 4 [F] and (2) (for example, showing a right-shifted state), the first and second error detection signals S13 and 2 whose DC level rises every time the track on which the head 6 travels changes. 814 can be obtained from the 111 flow circuit 22 and the like. The first and second error detection signals S13 and 814 are given as an addition input and a subtraction input, respectively, to the 7-circuit subtraction circuit, so that the first and second error detection signals 813 and 814 are input as shown in FIG. 4(G). S 14 or alternately. The output S 1.5, which changes AC depending on the amount obtained.
A4# will be displayed. This subtracted output 815 is applied to the first input terminal a1 of the direct changeover switch circuit 5, and its polarity is inverted in the inverting circuit 26 and applied to the second human input 9a2. Changeover switch circuit 2!5 is head changeover pulse R
For example, when the head 6 is scanning the stitch-numbered tracks T1 and T3, the switch is switched to the first input terminal al side by the F''-SW, and on the other hand, the even-numbered tracks T2,
When scanning T4, switching to the second manual power 9a2 is performed,
Thus, as shown in FIG. 40, when the head 6 is in the rightward deviation state, a positive blood flow level output S16 of a magnitude corresponding to 4b to the rightward deviation amount is obtained (on the other hand, when the head 6 is in the leftward deviation state, the DC level is The output 816 has a magnitude corresponding to the leftward shift amount and has a negative polarity), and is sent out as a tracking null signal S3 via an output amplification circuit 27 consisting of a DC amplifier. By the way, if the head 6 is shifted one position to the right, the playback track will be the odd numbered TI. At T3, the signal component of the difference frequency ΔfA appears at the output terminal of the summation circuit 14, so that the output from the 1f) difference frequency detection circuit side is given to each subtraction circuit, and at this time, it is determined whether it is the changeover switch circuit or not. 1, the tracking error signal S3 at a positive DC level is sent out. On the other hand, if the raw track is even-numbered T2. At T4, the negative component of the difference frequency ΔfB is removed from the output terminal of the summation circuit 14, so that the output from the second difference frequency detection circuit 21 side is given to the subtraction circuit, and the output terminal of the summation circuit 14 is also At this time, since the changeover switch circuit 5 is switched to the second input terminal C2 side, the polarity of the negative output of each subtracting circuit is inverted by the inverting circuit and sent as a tracking error signal S3 of a positive DC level. Therefore, if this tracking error signal S3 is used as a correction signal in the phase servo circuit of the capstan servo loose and corrected so that the tape running speed is increased when it is positive and slowed down when it is negative, it is possible to make a correction between the video head and the playback track. The phase shift can be corrected and thus a correct ATF) racking servo can be realized. In the above principle configuration, the principle has been described assuming that no difference frequency component occurs at the output terminal of the calculation circuit 14σ when the head 6 correctly tracks each track, but in reality, in this tracking state... Also, pilot signals of adjacent tracks on the left and right sides are generated in the reproduced signal S1 of the head. In other words, in practice, there is no cart space between tracks during recording.
If it is not provided, in the recording mode, a newly recorded track missing 1- is sequentially recorded so as to partially overlap the @-contact track recorded i. Therefore, in this case, the width of the head 60 is larger than the width of each of the tracks 11 to 140, so that when tracking correctly, the head 6 protrudes into the adjacent tracks on the left and right sides. Therefore, since the head 6 reproduces the pilot signals of the L-racks adjacent to the left and right sides, the error detection signals s13 and 514 (Fig. and y) are generated by the DC conversion circuit η and okara. When a grooved card band is provided, the width of the head 60 is equal to the width of the track, but the pilot signal recorded in the adjacent tracks on the left and right side becomes a crosstalk signal and the playback amount of the head 6 is smaller than the width of the track. get mixed in. Therefore, the error detection signal 813 and S14 contain a signal component of a difference frequency comparable to the crosstalk signal. However, since the pilot signal mixed into the playback output S1 of the head 6 from the track that comes into instant contact in this way is simultaneously generated at the output terminal of the multiplication circuit 14 as signal components with difference frequencies Δi6 and ΔtB, the error detection signals 813 and 814 are output from the subtraction circuit 14. When they are subtracted from each other in Sae, they cancel each other out. Moreover, when the head 6 is tracking correctly, the head 6 is in a symmetrical position with respect to the adjacent tracks on the left and right sides, so the protrusion length of the head 6 is equal on the left and right sides, and the crosstalk is thick. The width of the left and right sides is also almost equal, and the content of the subtraction output S15 is equivalent to the above case in which the width of the head 60 is considered to be approximately equal to 1j4 of the track. Because of their large size or crosstalk, there is no adverse effect of difference frequency components arising simultaneously from adjacent tracks on both sides. Note that the error signal forming circuit 3 described above obtains signal components of the difference frequencies ΔfA and ΔfB between the pilot signals of the reproduced track and its adjacent tracks, and obtains the error detection signals S13, Sl, and 4' based on these signal components. Instead of this, the levels of the reproduced pilot signals of frequencies f□ to f4 are detected by respective reproduced pilot signal detection circuits each having a band-pass filter configuration, and the error detection signals S13 and 814 are obtained based on the detection outputs. It's so weird though. In the above configuration, for example, if we consider the timing at which the base f'u pilot signal 811 shown in FIG. T.O.(
When the state shown in Fig. M1 is reached, the content of the regenerated pilot signal S2 is the frequency f1, so the output S of the circuit F4 is
12 does not include either the difference frequencies ΔfA and ΔfB. From this state, the reproducing head causes a tracking deviation in the positive direction, and the endogenous head 6 comes to face tracks 1 and 2, so a component of frequency f2 is generated in the reproducing pilot signal S2, and this becomes the amount of tracking deviation. Correspondingly, as the opposite direction of the track T2 gradually becomes larger and eventually becomes smaller as it reaches too far, the frequency f2 component also gradually becomes larger and reaches a maximum of 1.
Since the difference frequency component ΔfA of the output 812 of the multiplier circuit 14 gradually increases as it passes from the phase position '■'0 to 'v1 and reaches the T2 position, it reaches the maximum value. It passes through and becomes smaller. Accordingly, the error (the value of No. 1 S3 increases in the positive direction, passes through the maximum value, and decreases as shown in FIG. When the frequency component 4 is generated in the reproduced pilot signal S2, the head passes from the T2 position to the T3 position and reaches the T4 position.
Since the magnitude of the frequency component element 4 gradually increases as the position increases and decreases through the maximum value, a frequency component of ΔfB is generated at the output 812 of the multiplier circuit 14, and thus the error signal S3 becomes the first As described above with respect to the figure, from point T2 through T3 to T4, the value decreases in the negative direction, reaches the minimum value, and increases. In this way, in the 4-track 1 ATF type tracking control device, there is one lock position for each of the 4 tracks. In other words, the lock-in time) is quite large. Incidentally, conventionally, a control signal (CTL signal) is recorded along the take feeding direction by a fixed head as a pulse signal whose polarity is inverted for each vertical synchronization signal of the television signal (therefore, for each track). Tracking system using this CTL signal
A so-called CTL) racking servo system was used. In this case, the change in the error signal relative to the tracking deviation amount is shown in FIG. 5 as shown in FIG. 5, corresponding to FIG. T2. 'f'3...
If a tracking deviation occurs as in ..., the lock points TO, T2, ... will occur alternately with the oscillation point T3, and this means that one lock point will be generated for every two tracks. This means that Therefore, C in Figure 5
Comparing the case of the TL method and the case of the ATF method shown in Figure 1, it is found that if the servo time saving custom orders are selected equally, the lock-in time of the probabilistic VCATF method is twice that of the ATF method. You will need a length of . [Object of the Invention] The present invention has been made in consideration of the above points, and is intended to shorten the lock-in time of an ATF type servo control device as much as possible. [Summary of the Invention] In order to achieve the above object, the present invention provides a lock-in error detection circuit when the difference frequency component occurring in the multiplication output of the reproduced pilot signal and the reference pi A lock-in error detection signal is generated from , and the detection output causes a skip control circuit to skip the circulation order of the reference pilot signal by a predetermined number of steps. [Example] Below, parts corresponding to those in FIG. An embodiment of the present invention will be described in detail with reference to FIG. 6, which is shown in FIG. 6. The tracking control device in FIG. The oscillation point detection circuit 31 also includes an oscillation point detection circuit 31 and an oscillation point detection switch circuit 32 for the oscillation point detection circuit 31.Similar to the error signal formation circuit 3, the oscillation point detection circuit 31 receives the regenerated pilot signal S2 of the pilot signal detection circuit 1. The multiplication output 821 received by the multiplication circuit 35 is given to the ΔfA detection circuit 36 and ΔfB detection circuit 37 having a band-pass filter configuration, and the detection outputs are converted to a DC level in the blood flow circuit and 39, respectively, and then sent to the subtraction circuit 40. The subtraction q-output S22 of the subtraction circuit 40 is directly connected to the contact a1 of the switch 41, and is also applied to the contact a2 via the inverter 42, and the oscillation point is sent to the level detection circuit 44 through the switch output sz3'e amplifier circuit 43. The output of threshold level voltage 45 is given as a reference signal to the level detection circuit 44, and the oscillation point error signal 824 given from the amplifier 43 is given as an error signal S24.
When the 0 level becomes higher than the threshold level box pressure 1RL45 (D output), the oscillation point detection signal 825 is given to the hold circuit 46, which is, for example, a flip-flop circuit. Thus, the oscillation point detection signal held in the hold circuit 46 is given as skip 1g 826 to the switch circuit 17 of the error signal forming circuit 3 and the oscillation point detection switch circuit 32. In this embodiment, the switch circuit 17 is a switch circuit that receives the pilot signals f1 to f4 of the pilot signal generating circuit 16. It has a main body i7A, receives a head switching signal 1ζF-8W as a switching condition signal, divides this head switching signal RF-8W in a frequency divider circuit 1.7B, and then outputs a switch 17C0) following contact a1. The control condition signal 5EL2 is applied to the switch circuit main body 17A. Here, the first control condition signal 5ELI changes in the same way every time the logic level of the head switching key 1''-8W changes (Fig. 7), whereas the second control condition signal 5ELI changes in the same way every time the logic level of the head switching key 1''-8W changes (Fig. 7).
The IJ control condition signal 5EL2 is the first control condition signal 5ELI.
Since the logic level changes at twice the period of , these two logic signals cause the switch circuit main body 17A to output frequency outputs f1 to f4 when the logic is "00" to "11" as shown in FIG. It is sent out as a reference pilot signal 811. On the other hand, the oscillation point detection switch circuit 32 has a switch circuit main body 17A of the switch circuit 17 and a switch circuit main body 32A having a configuration of 1 DJbl. It is inverted and received at 32B (Fig. 7). The output S29 of this inverter 32B is the 1 frequency divider circuit 32C.
is given to the head switching signal R as shown in FIG. 8 (ω).
In response to the rise of the signal S29 obtained by inverting F"-8W, the 7-minute pigeon output 8 rises to the logic rf (J level) and falls to the logic rLJ level in response to the next rise of the signal 829.
30 is applied as the control condition signal 5EL2 to the switch circuit main body 32A through the contact a1 of the switch 32D. Thus, as shown in FIG. 7, the switch circuit main body 32A receives the control condition signal "00" when the control condition signal 5ELI and 11, 2 for the switch circuit main body 17A is "11", and receives a pilot signal of frequency f4. It sends out a reference pilot signal S31 for oscillation point detection, and when the control condition signal for the switch circuit main body 17A is "01", it receives a control condition signal "11" and sends out a pilot signal of frequency f0 as a reference pilot signal 831, Further, when the control condition signal for the switch circuit main body 17A is "10", the control condition signal "01" is received and a pilot signal of frequency f2 is sent out as the reference pilot signal S31, and the control condition signal for the switch circuit main body 17A is "00". '', it receives the control condition signal ``10'' and sends out a pilot signal with the same wave number 13 as the reference pilot signal S31. However, the raw reference pilot signal 811 of the switch circuit main body 17AOh represents the frequency sequence of the pilot signal recorded on the tape, and its content is as shown by the solid line arrow in FIG.
→f4→f□... indicates that the pilot signals are recorded in the r=order. On the other hand, as is clear from Figure FG7, the reference pilot signal S31 for oscillation point detection is delayed by one cycle N Jtl,i with respect to the one cycle synchronization of the reference bit signal 811 for reproduction. The frequency is switched. This means that while it is possible to obtain the capstan phase error signal S3 as shown on the real axis in FIG. 10 by using the reproduction standard Bairotzu HD No. 811 having the frequency switching 1iI order in FIG. 7, The frequency switching order of the oscillation point detection circuit auxiliary pilot signal S3 in FIG. 7 is as shown by the broken line in FIG.
3, the phase of one track (corresponding to L circulation period 1-
This means that it is possible to obtain the oscillation point detection error signal S24 with a relationship such as 1-1, which is represented by 2 in an error hourglass shape. In other words, by doing this, the maximum value of the phase error signal S for oscillation point detection crystal form 2 (Figure 1O) will be determined by the phase position ( 1-that is, the oscillation point phase position) T2,
7])
Also, if this is used to select the value of the threshold level power supply 45 of the level detection circuit 44 to level 5i-i in FIG. is the oscillation point T2. When the error signal S24 enters the range of 10 across T6..., the error signal S24 exceeds the threshold/hold level SH'&, so the oscillation point is detected in the range of 2a (i. This is reproduced as shown by the dotted arrow in FIG.
→f2→f3→f4→f1, the oscillation point detection circuit 31 detects every other frequency, that is, f3. f
, , f□, f2. When the regenerated pilot signal S2 of f3 arrives, the oscillation point detection signal S25 is sent out. In this way, the skip signal 826 sent from the hold circuit 46 is given as a switching signal to the switch 17C of the regeneration switch circuit 17 and the switch 32D of the oscillation point detection switch circuit 32, which constitute the skip control path. A divide-by-1 circuit 17 is connected to the switching terminal a2 of the switch 17C.
The frequency divided output S27 of B is inverted and given by the inputter 17D, and when the skip signal 826 arrives, the switch 17C switches from terminal a1 to a2 and switches this inverted signal as the control condition signal 5EL2. It is applied to the circuit main body 17A. Similarly, oscillation point detection switch circuit 3
1 frequency divider circuit 32 is connected to the switching terminal a2 of the second switch 32D.
The frequency-divided output S30 of C is inverted and given by the inverter 32E, and when the skip signal 826 arrives, this inverted signal w' is the control condition signal 5E of the switch circuit main body 32A.
It is given as L2. In this way, the logic level of the control condition signal 5EL2 for the switch circuit units 17A and 32A is inverted by the skip signal 826, and as is clear from FIG. This means advancing or delaying the frequency switching order by a period of 7 minutes. For example, switch circuit bodies 14A and 32A
In a state where control condition signals of logic "11" and logic r00J are respectively given to , the frequencies of the pilot signals 811 and 831 are f
□ and f4. In this state, control condition signal 5E
If the logic level of L2 is reversed, the switch circuit main body 17
A and 32A have logic rl OJ and "ol" respectively.
Since the control condition signal 831 will be given, the frequencies of the pilot signals of the reference pilot signals S11 and 831 will be switched to f3 and f2. When the frequencies of the reference pilot signals 811 and 831 are switched in this way, the tracking control device is in a state where the trunking phase is skipped by seven cycle cycles (i.e., a state in which one head is tracked to the adjacent track). In the configuration shown in FIG. 6, when the tracking control device is in the four-in state, the signals of each part become as shown in FIG. 11. That is, the reproduction reference pilot signal 511 ( 2)) The circulation order of the pilot frequencies is synchronized with the circulation order of the pilot frequencies of the regenerated pilot signal 82 (FIG. 11(C)), and the reference pilot signal for oscillation point detection 531 (FIG. 11(C) ) is delayed by T minutes with respect to the pilot frequency circulation order of the reproduced pilot signal S2.Therefore, a difference frequency component of the pilot signal is generated in the multiplication output S12 of the error signal forming circuit 3. Therefore, the error signal 83 of the error signal forming circuit 3 ((0) in FIG. 11 becomes 0. In contrast, the multiplication output 521 of the oscillation point detection circuit 31 (■ in FIG. 11) When the pilot frequency of the reproduced pilot signal s2 is f, , f2.f3.f40, the pilot frequency of the reference Byron l[No. 831 is f4° fl
, f2. Since it becomes f3, the difference frequency component becomes ΔfB, Δ. ΔfB and ΔfA are obtained, and as a result, the level of the oscillation point detection signal S24 becomes the prefectural level as shown in FIG. 110. In this case, since the oscillation point error signal S24 of the level detection circuit 44 has not exceeded the threshold level SH, the hold circuit 46 does not perform a hold operation, and thus the skip signal 826 is not sent out. As a result, the tracking control device as a whole continues the tracking control operation. On the other hand, when the tracking control device starts operating, the first
As shown in Figure 2 ω) and υ 1-, the pilot frequency of the regenerated biloft signal $2 deviates by one circulation period with respect to the circulation of the pilot frequency of the reference pilot signal S11 sent from the regeneration switch circuit main body 17A. Thus, the capstan servo system adjusts to the oscillation point position of the tracking control device (phase position T in Fig. 10).
2), the output 512 of the multiplication circuit 14 of the error signal forming circuit 3 (Fig. 12 ■)
Since the difference frequency component of is neither ΔfA nor ΔfB, the error signal 83 (FIG. 12 U)) maintains the 0 level. In contrast, the multiplication output 5 of the oscillation point detection circuit 31
21 (Fig. 12 ω)), the difference Ji! is reached at the timing when the regenerated pilot signal S2 becomes the pilot frequency f□, f2° f3/f4. d drum count component number component. Since ΔfB, ΔfA, and ΔfB are generated, the level of the oscillation point error signal S24 takes the maximum value (FIG. 12, 0). Therefore, since the oscillation point error signal 824 has exceeded the threshold level SH, the level detection circuit 46
A hold operation is performed to send out a skip signal S26. At this time, the switches 17C and 321J of the switch circuits 17 and 32 are controlled to switch from the terminal a1 to the a2 side.
Pilot period t of reference pilot signals Sll and S31
Since the cyclic order of the BL number is forcibly made to phase during the medical imitation period (Fig. 13) and (C)), the cyclic order of the pilot frequency of the reproduction reference pilot signal 811 or the reproduction pilot signal s2 is different. Since it will be synchronized (first
3), the multiplication output 512 (Fig. 13 [F]) no longer produces a difference frequency component, and the error signal S3 (Fig. 13-
) maintains O level. On the other hand, when the pilot frequency of the reproduced pilot signal S2 is f, f2.f3.f4, the same difference occurs. Since the frequency components ΔfB, ΔfA, ΔfB, ΔfA are generated, the level of the excavation point error signal 524 (FIG. 13 0) becomes a negative level. This condition is the same as the threshold tracking condition described above for FIG. In this way, the tracking control device performs tracking control correctly.In this embodiment, since the hold circuit li6 is provided in the oscillation point detection @path 31, the oscillation point detection signal 825 is Even if it is no longer obtained, the hold circuit 46 continues to send out the skip signal S26 to maintain a normal tracking state, and the hold circuit 460 maintains the hold state when the playback mode ends and the record mode is switched to the recording mode. It is configured to be reset when the recording mode signal REC arrives.The above operation has been described for the case where the tape is at the oscillation point of the tracking 11J11 value 1 device when the VTR starts playing, but it is not limited to this case. If it is within the detection range 2a in Fig. 10, then in Figs. Therefore, with the configuration shown in Figure 6, the lock-in time when the VTR starts playing can be significantly reduced (in terms of probability, the lock-in time can be halved). ).Incident FC
Without the skip component shown in FIG. 6, if the position of the tape at the start of playback is at the oscillation point T22 shown in FIG. Instead, first manually accelerate or decelerate the capstan servo system, and this will cause the error signal curve to rise in the positive direction and track to point TO or T4, where it crosses the 0 point, and enter a stable state. On the other hand, with the configuration shown in Fig. 6, pilot standards (M S Ll and S31
By electrically performing a skip operation, the tracking control device can be immediately locked into the capstan servo. FIG. 14 shows another embodiment of the present invention, in which the configurations of the oscillation point detection circuit 31 and the oscillation point detection switch circuit 32 in FIG. The purpose of this is to simplify the configuration of the tracking control device by using the following. In this case, the switch circuit body 17A of the switch circuit 17
has the same configuration as the switch circuit main body 17A of FIG. 6, except that it is controlled by control condition signals 5ELI and SEL, 2 generated by a switch control circuit 51 having a logic circuit configuration. As shown in FIG. 15, the switch control circuit 51 time-divides the one-cycle period M into an oscillation point detection period m□ and a reproduction error signal generation period m2, and the oscillation point detection period m is described above in FIG. As described above, the control condition signal SE given to the switch circuit main body 32A
L, 1 and SEL, 2 at each pilot frequency f4゜fl
The logic level assigned to "2" 3 [0 is given to the switch circuit 17A every period section M. On the other hand, the control condition signal SEL given to the switch circuit main body 17A in FIG.
] and 5EL2 at the pilot frequency f1°f2. f
3. The logic levels [1] IJ, rolJ, rlOJ, and rooJ assigned to f4 are sequentially given every seven circular sections M. In this way, the reference voltage (Ilot 4
No. g S42 is generated in the switch circuit main body 17A in a time-sharing manner (Q3 in Figure 15)). In order to generate such a time division control condition signal, a head switching signal F-8W is applied to a switch control circuit 51 serving as a skip control circuit, and the head switching signal F-8W is further divided in a dividing circuit 52 to be divided into two signals. and the head switching signal RF-
8W is applied to the time division signal generation circuit 5'3, which is made up of, for example, a monochrome ibrator, and the generation circuit 53 is tripped every time the head switching signal RF-8W changes its exposure level (i.e., rises and falls). oscillation point detection section nl□
A time-division signal 841 having a time width corresponding to , is applied to the switch control circuit 51 . In addition, the switch control circuit 51 receives the skip signal 826 generated in the oscillation point detection signal forming circuit 54 in the same manner as described above with reference to FIG. control condition signals 5ELI and 5EL2 are generated. Thus, the oscillation point detection/regeneration pilot signal 84 as shown in the 15th output from the switch circuit main body 17A
2 is applied to the multiplication circuit 14 of the error signal forming circuit 3. In this embodiment, the oscillation point detection signal forming circuit Tatsumi includes an amplifier 43,
It has a level detection circuit 44 and a hold circuit 46, but the other configurations are the same as those of the error signal forming circuit 3. That is, the multiplication output 812 of the multiplication circuit 14 is the reference pattern signal 8420 launch point detection section m
□ Reproducing the pilot reference signal part for excavation point detection arriving at (15th appearance))
Difference frequency signal part X1 obtained by multiplying by Figure 5 (Cl)
and a difference signal portion X2 obtained by combining the pilot signal portion of the reproduced error signal generation section m2 with the reproduced pilot signal S2 (Fig. 150).
. Thus, the output 81 of the switch 5 of the error signal forming circuit 3
6, an oscillation point detection output portion is obtained in the oscillation point detection section m□, and this is sampled and held in the sampling and holding circuit 55. On the other hand, the output signal 5lfi
The signal portion of the reproduced error signal generation section m2 is sampled and held in the sampling and holding circuit 56 of the error signal forming circuit 3. In this way, the output of the sampling and holding circuit 55 is used as the oscillation point error signal 824 via the amplifier circuit 43 of the excavation point detection signal forming circuit 54, and the output of the sampling and holding circuit 56 is passed through the amplifier circuit 27 and used as a reproduction error signal. Sent as S3. In addition, in this way, the No. 48 part of the oscillation point detection interval m□ is sampled and held by the sampling and holding circuit 5.
5 and to hold the signal portion of the reproduction error signal generation section m2 in the sampling hold circuit 56, the time division signal 841 of the time division signal generation circuit 53 is inverted by the inverter 57 and a sampling pulse is sent to the sampling hold circuit 55. At the same time, a signal 841 is provided as sampling No. 48 to the interview sampling and hold circuit 56. According to the configuration shown in FIG. 14, by processing the oscillation point detection operation and the reproduction error signal generation operation in a time-sharing manner, the error signal forming circuit 3 is shared as the configuration of the main part for obtaining the oscillation point detection signal. At the same time, switch circuit main body 1
7A can be shared in the same way. Therefore, according to the configuration shown in FIG. 14, paddy rice can be harvested with a much simpler configuration than the configuration shown in FIG. FIG. 16 shows still another embodiment of the present invention, in which the oscillation point detection switch circuit 32 of FIG. 6 can be omitted. In this case, the excavation point detection circuit 3 in Fig. 6
In place of the difference frequency detection circuits 36 and 37 of 1, the difference I¥number of drums Δf. and Δf, which is composed of a bandpass filter that passes through ΔfD. The configuration differs from that of FIG. 6 in that a detection circuit 61 and a ΔfD detection circuit 62 are used. Here, Δfo and ΔfD are selected as shown in FIG. In FIG. 17, the pilot frequency f. The difference frequency ΔfA of ~f2 is selected as the required reference frequency reference, and the difference frequency Δf of the pilot frequencies f2~f4
D is selected to be 2fH, and the pilot frequency f4~
The difference frequency Δf of f3 is selected as ifH. Therefore, the difference frequency ΔfB between pilot frequencies f1 to f4 and f2 to f3 becomes 3fH, and the pilot frequency f
The difference frequency Δfo of f3 becomes 4fH. Thus, the multiplication output S12 is given by
f3 difference II! tI wave component hum component, this is ΔfA
It is detected through the detection circuit 2tJ, and the frequency Eif1~
If there is a difference frequency component between f4 and f2-f3, this is Δ
It is detected by following the fB detection circuit 21, and furthermore, the frequency f0
If there is a difference frequency component of ~f3, this is Δf. It is detected through the detection circuit 61, and if there is a difference frequency component between frequencies jfif2 to f4, this is detected through the ΔfDt projection circuit b2. In the configuration shown in FIG. 16, when the tracking control device is performing normal tracking operation, the circulation order of the pilot frequency of the regenerated pilot signal S2 (FIG. 18 (C)) is the same as that of the reference pilot signal, as shown in FIG. 18. S11
(Synchronized with the circulation order in FIG. 18 (Bl), therefore, no difference frequency component occurs in the multiplication output 512 (0 in FIG. 18) of the multiplication circuit 14. Therefore, on the detection circuit side,
61 and 62, the error signal 83 (FIG. 18 (G)) of the error signal forming circuit 3 is 0.
The oscillation point error signal 524 (18th drawing) of the oscillation point detection circuit 31 also maintains the 0 level. On the other hand, if the playback head is located at the oscillation point of the tracking control device when the VTR starts playback operation, the circulation order of the pilot frequencies of the playback pilot signal 82 (FIG. 19(C)) Since the phase is delayed by l circulation period (that is, 2 tracks) with respect to the circulation order of the 1' pilot frequency of the reference pilot signal 511 (Fig. 19 @), the phase calculation output 512 (Fig. 19a) is Pilot frequencies f, , f2 . of the reference pilot signal S11. f3. When f40 occurs, difference frequency signals of Δf□+Δ et al., Δfo, and ΔtD are generated, and these are detected by the detection circuits 61 and 6.
As a result, the oscillation point error signal 524 (FIG. 19) of the oscillation point detection circuit 31 exceeds the threshold 7 hold level SH of the level detection circuit 44 and becomes the maximum value. Therefore, a skip signal 826 is sent from the hold circuit 46, and the switch 1rcy contact a2 of the switch circuit 17 is
The reference pilot No. 16 811 sent out from the switch circuit main body 17A by switching to ill is shown in Fig. 19 ■
As shown in Figure 1), the pilot of the regenerated pilot signal S2 is skipped to a state synchronized with the circulation order of the wave number, and this causes the same normal operation as described above in Figure 18. This results in lock-in to the tracking state. In this way, the structure shown in FIG. 16 also provides the same effect as described above with respect to FIG. Therefore, the overall configuration can be further simplified. In the above, when detecting the oscillation point, the judgment is made based on whether the error signal exceeds the zero point by adding the error signal g, but instead of this, the error signal crosses the zero point with a negative slope. The determination may be made based on whether or not cut'>'k. In addition, in the above example, the number of tracks when skipping is set to 2.
Although the case where the number of stages is selected to be 39 (that is, the adjacent track with one track) has been described, this number of stages can be selected to any value as necessary. Furthermore, in the embodiment shown in FIG. 14, the time division signal S11 and the skip signal 826 are given to the switch control circuit 51, and the control condition signal 5ELI to the switch circuit main body 17A is
The oscillation point detection/reproduction reference signal S41 is formed from the switch circuit main body 17A by time-division control of No. 48 S11 and No. 826.
is applied to the switch circuit main body 17A, and the oscillation point is detected by the gate circuit provided in the switch circuit main body 17A.
The regeneration reference signal 842 may be generated. [Effects of the Invention] As described above, according to the present invention, when the reproducing head is located at a position outside the lock-in range of the tracking control device (for example, at the oscillation point position), the pilot frequency (71 -By skipping the monkey sequence by the number of steps, the tracking control device can be adjusted to VT.
It is possible to lock in the R phase servo yarn in a relatively short time. Therefore, for example, when the tracking control device is operated for lock-in at the start of playback of a VTR, the lock-in time can be statistically shortened by half.

[Brief explanation of drawings]

Figure m1 is a characteristic curve diagram showing the characteristics of the ATF type tracking control device, Figure 2 is a block diagram showing the principle configuration of the ATF type tracking control device, and Figure 3 is a dark line diagram showing the tape pattern. Fig. 4 is a route map of each part of the signal shown in Fig. 2, Fig. 5 is a characteristic curve diagram showing the characteristics of a CTL type tracking control device, and Fig. 6 is an embodiment of a tracking control device according to the present invention. A block diagram showing
Figure 7 is a diagram showing the configuration of the switch circuit, Figure 8 is a route map showing the signals of each part of the switch circuit in Figure 6, and Figure 9 is a diagram showing the configuration of the switch circuit.
The figure is a route map showing the shield order of pilot frequencies, No. 10.
The figure is a characteristic curve diagram showing the characteristics of the oscillation point detection circuit shown in Figure 6.
11 to 13 are route diagrams showing the signals of each part to explain the operation of FIG. 6, FIG. 14 shows another embodiment of the present invention, and FIG. 16 is a block diagram showing still another embodiment of the present invention, and FIG. 17 is a route diagram showing the relationship between the differential wave numbers of the differential drum count detection circuit. Figures 1 to 21) are j-continuation diagrams showing the signals at each t;i for explaining the operation of FIG. 16. DESCRIPTION OF SYMBOLS 1... Pilot signal detection circuit, 3... Error signal formation circuit, M, 35... 41-i arithmetic circuit, 16.
... Pilot signal generation circuit, 17... Switch circuit, 17A... Switch circuit main body, 17C... Skip control switch, addition. 21...ΔfA, ΔfB detection Ig circuit, 31...-oscillation point detection circuit, 32... oscillation point detection switch circuit,
32A...Switch circuit main body, 32D...Skip control switch, 44...Level detection circuit, 46...
- Hold circuit, 51... Switch control circuit, 53.
. . . Time division signal generation lrJ path, 54 . . . Oscillation point detection signal forming circuit, 55. Shame...sampling hold circuit, 61, 62...Δfo, ΔfD detection circuit. Printer's agent 1) Megumi Ben 6th reason? Figure II,! :24 Figure 72 (H) θ 13th r2i δ24 10Sll +ol +01 +C) I Display of the case 1982 Patent Application No. 122136 2, Name of the invention Tracking control device 3, Person making the amendment Relationship to the case Patent applicant address 6-7-35, Kitashinyo, Tokyo Parts Ward Name (21
8) Soni Co., Ltd. Representative: Norio Oga 4, Agent: 150 (Telephone: 03-4706591) Address: 3-22-10 Jingumae, Shibuya-ku, Tokyo "
Contents of amendment in Column 6 of “Scope of Claims” (1) The scope of claims of the present application will be corrected as shown in the attached sheet. A reference pilot whose frequency sequentially and cyclically changes with respect to a reproduced pilot signal obtained by recording a recording pilot signal whose frequency sequentially and cyclically changes on a recording track, and reproducing the recording pilot signal when the recording track is reproduced. In a tracking control device that multiplies signals, detects a difference frequency component generated in the multiplied output, and controls the tracking position of the multiplied head, a detection output is generated when the frequency difference component is not within a predetermined lock-in range. 1. A tracking control device comprising: a lock-in error detection circuit that generates a lock-in error detection circuit; and a detection output of the lock-in error detection circuit forcibly changes the phase of the 1-racking error signal by 180' to 4-hi.

Claims (1)

[Claims] A reference pilot whose frequency sequentially and cyclically changes with respect to a reproduced pilot signal obtained by recording a recorded pilot signal whose frequency sequentially and cyclically changes on a recording track, and which is obtained by reproducing the recorded pilot signal when the recording trunk is reproduced. In a tracking control device configured to control the tracking position of the playback head by multiplying signals and detecting a difference frequency component generated in the multiplied output, detecting when the frequency difference component is not within a predetermined lock-in range. a lock-in error detection circuit that generates an output;
A tracking control device comprising: a skip control circuit that skips the circulation order of the reference pilot signal by a predetermined number of steps based on the detection output of the lock-in error detection circuit.