JP2597968B2 - Rotating head type video signal reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type video signal reproducing apparatus, and more particularly, to a method of displacing a recording track formed at a predetermined track pitch on a recording medium transferred by a transfer unit. The present invention relates to a device for reproducing a video signal by tracing with a rotating head displaced in a direction intersecting with the rotating surface of the recording device. The present invention relates to the control of the transfer means when the recording medium is transferred and reproduced.

<Background technology> In a rotary head type playback device such as a VTR, high speed playback,
When performing playback at a recording medium transport speed different from the recording speed (so-called special playback) such as low-speed playback (including still playback) and reverse playback, the generation of noise bars is prevented, and a stable clear image is obtained. To enable reproduction, it is necessary that the reproducing head accurately traces one recording track in each scanning field.

As one means for realizing such a function,
A pattern signal generator for generating a pattern signal corresponding to the distance from the scanning trajectory of the reproducing head to the recording track on the tape at an arbitrary tape running speed is provided, and reproduction is performed by a pattern signal obtained from the pattern signal generator. Means for controlling a conversion means such as an electro-mechanical conversion element (for example, a bimorph element) for displacing the head in a direction orthogonal to the plane of rotation is known.

By the way, when the tape speed at the time of recording is set to v and the tape speed at the time of reproduction is set to Nv (N indicates a positive direction speed and negative indicates a negative direction speed, respectively), the reproducing head is driven for one field period. The required head displacement during TP is (N-
1) The amount is proportional to the factor. This means that the inclination of the fixed pattern signal to be obtained is proportional to (1-N) in order to correct the inclination.

Therefore, as will be described later in detail with reference to the drawings, the conventional pattern signal generating method forms a signal having a slope corresponding to the tape traveling speed, and further forms a symbol of the slope of 1 / N to form these signals. To obtain a signal of the difference between the two.
However, according to this method, two gradient waveform forming circuits are required, and the timings of the two gradient waveforms must be matched. Therefore, the circuit configuration tends to be complicated.

<Purpose> The present invention has been made in view of the above circumstances, and a recording track formed at a predetermined track pitch on a recording medium transferred by a transfer unit is rotated by a displacement unit with a rotation surface thereof. It is an object of the present invention to provide a rotary head type video signal reproducing device having a simplified circuit configuration as a rotary head type reproducing device for reproducing a video signal by tracing with a rotary head shifted in an intersecting direction. is there.

<Explanation by Example> Hereinafter, means taken in the present invention to achieve the above object will be described by way of an example shown in the accompanying drawings.

Prior to the description of the embodiments of the present invention, a conventional VTR will be described.

First, referring to FIG. 1, 1 is a magnetic tape as a recording medium, 2A and 2B are magnetic heads for reproduction,
They are provided so as to face each other with the same azimuth angle of 180 degrees, and are respectively attached to free ends of electro-mechanical conversion elements 3A and 3B such as bimorph elements as displacement means. The conversion elements 3A and 3B are attached to the rotation member 4 at their tail ends, and the rotation member 4 is rotated by the head rotation motor 5 as shown by the arrow in the figure. Although not shown in the drawing, as is well known, the heads 2A and 2B are rotated while projecting from a slit between a pair of tape guiding drums. It is wound obliquely over a range of 180 degrees or more.

Reference numeral 6 denotes a rotation phase detector for detecting the rotation phases of the heads 2A and 2B. A signal from the detector 6 is used as a head switching signal (hereinafter, HSW signal) and is supplied to a head motor control circuit 7. The control circuit 7 controls the head motor 5 through the head motor drive circuit 8 so as to rotate the heads 2A and 2B at a predetermined phase and a predetermined number of revolutions based on the output of the detector 6. Reference numeral 9 denotes a control signal reproducing fixed head (hereinafter, CTL head) for reproducing a control signal (hereinafter, CTL signal) recorded at one frame interval in a longitudinal direction at a lower portion of the tape, and 10 denotes a pinch roller (not shown). A capstan 11 which cooperates to form a transfer means for transferring the tape 1 in the longitudinal direction; 11 a capstan motor for rotating the capstan 10;
12 is a frequency signal generator for generating a frequency signal corresponding to the rotation of the capstan 10 (hereinafter, capstan FG signal), 13 is a CTL signal from the CTL head 9 and a frequency signal generator
Capstan FG signal from 12 and based on capstan
A capstan motor control circuit that controls the capstan motor 11 through a capstan motor drive circuit 14 so that the capstan motor 11 is rotated at a predetermined phase and a predetermined rotation speed. Fifteen
Is the HSW signal from the rotation phase detector 6 and the CTL head 9
At the time of reproduction at an arbitrary speed (including stationary and reverse rotations) based on the CTL signal and the capstan FG signal from the frequency signal generator 12, the heads 2A and 2B are driven one by one on the tape 1 in each scanning field. A pattern signal generation circuit for generating a pattern signal for the electro-mechanical conversion elements 3A and 3B for tracing the recording track; and 16 a conversion element based on the pattern signal from the pattern signal generation circuit 15.
This is a conversion element drive circuit that drives 3A and 3B.

FIG. 2 shows a configuration example of the pattern signal generation circuit 15. In the figure, the capstan FG signal from the frequency signal generator 12, the CTL signal from the CTL head 9, and the HSW signal from the rotational phase detector 6 are input to input terminals 17, 18, and 19, respectively. . 20 is the capstan FG input to terminal 17
A binary counter which counts a signal and is reset by a CTL signal input to a terminal 18. The HSW signal based on the HSW signal input to a terminal 19
A timing signal generating circuit for generating a timing signal synchronized with the signal; a timing signal generating circuit for presetting an output of the counter according to a timing signal from the timing signal generating circuit;
A presettable binary counter for counting the capstan FG signal which is preset as data PD and input to the terminal 17; 23, a D / A converter for D / A converting the output of the presettable counter 22; Is a stale pattern generator that generates a fixed pattern signal for stale reproduction based on the timing signal from the timing signal generation circuit 21, and 25 is the output of the D / A converter 23 and the output of the stale pattern generator 24. Is an output terminal for outputting the conversion element control pattern signal which is the output of the adder 25.

Next, regarding the operation of the VTR with the above configuration during special playback,
In particular, the operation of the pattern signal generating circuit shown in FIG. 2 will be mainly described with reference to FIGS. In FIG. 3, (d) to (g) show the CTL signal at the time of 1.5 × speed reproduction, the output of the second illustrated counter 20, and the presettable counter.
4A and 4B show the output of the D / A converter 22 and the output of the adder 25, respectively. FIGS. It shows the relationship between the center trajectory of the heads 2A and 2B for the center trajectory of the upper recording track.

First, with the rotation of the heads 2A and 2B by the head motor 5, the rotation phase shift detector 6 outputs a signal as shown in FIG.
The HSW signal is output, and the timing signal generation circuit 21 of the pattern signal generation circuit 15 shown in FIG. 2 responds to the rising and falling edges of the HSW signal as shown in FIG. A synchronized timing signal is output. Based on this timing signal, the stale pattern generator 24 moves the heads 2A and 2B from 0 to -1 track pitch (hereinafter, referred to as TP) within one field scan as shown in FIG. 3 (c). A stale pattern signal for continuous conversion to minutes is output.

Here, a so-called field-stealing reproduction is performed in which field signals of one recording track recorded by a recording head having the same azimuth angle as the reproducing heads 2A and 2B are alternately reproduced by the two heads 2A and 2B. In this case, the relationship of the center locus of the scanning of the heads 2A and 2B with respect to the recording track on the tape 1 at this time is shown in FIG.
It becomes as shown in. That is, in FIG. 4 (A), the solid line indicates the center locus of the recording track of the field signal recorded by the recording head having the same azimuth angle as the heads 2A and 2B, and the broken line indicates the azimuth different from the heads 2A and 2B. The center trajectory of the recording track of the field signal recorded by the recording head having a corner, the white arrow is the head 2A and
The center trajectory of the scanning of 2B, and the CTL indicates the recording trajectory of the CTL signal (this is the same in FIG. 4B), and the scanning of the heads 2A and 2B is performed as shown in FIG. The center locus (hereinafter, head locus) C of the track to be reproduced is a pair of the center locus (hereinafter, track locus) a of the track to be reproduced with the start end of the track locus a and the end of the track locus b of the adjacent track on the left side. It becomes a line segment connecting angularly. Therefore, in order to correct this and adjust the head trajectory c to the track trajectory a, if the heads 2A and 2B are set so that the traveling direction of the tape 1 at the time of recording is + and the opposite direction is-, within one field of scanning. 0
It can be seen that it is only necessary to make the transition continuously from to -1 TP.

From the above, it can be seen that the stale pattern signal from the stale pattern generator 24 shown in FIG. 3 (c) can satisfy the necessary transition of the heads 2A and 2B for the field stale reproduction.

On the other hand, the capstan FG signal output from the frequency signal generator 12 with the rotation of the capstan 10 by the capstan motor 11 is applied to the counters 20 and 22 in the pattern signal generating circuit 15 shown in FIG. The counters 20 and 22 count the capstan FG signal. However, since the counter 20 is reset every frame by the CTL signal from the CTL head 9, the counting is performed. The output is as shown in FIG. 3 (e) since the CTL signal becomes as shown in FIG. 3 (d) during 1.5 × speed reproduction with the count value for the +2 track pitch being the upper limit. And, in contrast, the presettable counter
Reference numeral 22 denotes a count output (or D / A) for counting the capstan FG signal while presetting the output of the counter 20 at that time by the timing signal (FIG. 3 (b)) from the timing signal generation circuit 21. The output of the converter 23 is as shown in FIG. Accordingly, the adder 25 outputs the D / A converter 23 at this time.
Is added to the output of the stale pattern generator 24, as a result, a pattern signal as shown in FIG. 3 (g) is output during 1.5 × speed reproduction.

Note that the outputs of the counters 20 and 22 and the adder 25 include small stepwise changes because the counters 20 and 22 actually count the capstan FG signal. is there.

Here, at 1.5 × speed reproduction, the head trajectories of the heads 2A and 2B with respect to the track trajectory on the tape 1 are shown in FIG. 4 (B).
It becomes as shown in.

That is, in _{FIG., A 1, A 2, A} 3 ...... is a head trajectory of the head 2A, the head trajectory of _{B 1, B 2, B 3} ...... head 2B, also a _1, a
_2, a ₃ ...... are those indicating a track locus of the field track recorded by the recording head of the same azimuth angle as the head 2A and 2B, the first field to align the head locus A ₁ to track the trajectory a ₁ to have a transition from 0 in the scanning of the first field to + 0.5TP content needs to continuously provide to a head 2A, in the second field head 2B in order to adjust the head locus B ₁ also to track the trajectory a ₁ , It is necessary to continuously apply the transition from +1.5 TP to +2 TP within the scan of the second field.
Field must give continuously the displacement of the head locus A ₂ to + 1TP know + 1.5TP minute in scan of the punching 3 fields against head 2A to match the next to the next track locus a _2, which fourth head 2B in order to match the head locus B ₂ to the next following track locus a ₃ a field
It is necessary to continuously give a transition from +0.5 TP to +1 TP within the scanning of the fourth field, and the above will be repeated in a four-field cycle. Such heads 2A and 2B It can be seen that the pattern signal shown in FIG. 3 (g) satisfies the required transition.

The above description has been made by taking the case of 1.5 × speed reproduction as an example. However, the pattern signal for controlling the head 2A and 2B corresponding to the reproduction speed is not limited to 1.5 × speed, and the pattern signal generation circuit 15 Obtained from

The pattern signal thus obtained from the pattern signal generating circuit 15 is applied to a conversion element driving circuit 16, which drives the conversion element driving circuit 16 and outputs the pattern signal and the HSW signal from the rotation phase detector 6.
The electro-mechanical transducers 3A and 3B are driven so that the heads 2A and 2B are turned on the track to be reproduced based on the signal.

As described above, in the conventional apparatus, a pattern signal for head control corresponding to the reproduction at an arbitrary speed is obtained as described above. Still pattern generator 24 is indispensable for signal formation. The still pattern generator counts clock pulses of a predetermined frequency according to a timing signal, and counts the count value.
The configuration is such that D / A conversion is performed and output, which hinders simplification of the circuit.

On the other hand, the present invention is intended to obtain a pattern signal for head control corresponding to reproduction at an arbitrary speed without specially providing a stale pattern generator. I do.

FIG. 5 is a block diagram mainly showing an outline of the configuration of a special reproduction system section of a VTR as one embodiment of the present invention. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description will be omitted. That is, for numbers 1 to 14, CT
Since no L signal is used, the components are very similar to those of the conventional VTR shown in FIG. 1 except that the CTL head 9 is not provided.

In the VTR of the embodiment shown in FIG. 5, the following method is used instead of the tracking method using the CTL signal. That is, a plurality of types (for example, four types) of pilot signals having mutually different frequencies are recorded on a recording medium by superimposing them one by one on video signals for one field. And this is reproduced by the reproduction head,
Only the pilot signal component is separated. Then, the levels of pilot signals obtained from tracks (both adjacent tracks) on both sides of the track (main track) mainly traced by the reproducing head are obtained to obtain track deviation information of the reproducing head, and this is used for tracking control. It's a signal. That is, tracking of the well-known 4f method is performed.

 Hereinafter, the function of each unit in FIG. 5 will be briefly described.

The reproduction signals obtained from the reproduction heads 2A and 2B include the video signal and the tracking pilot signal as described above. This reproduction signal is amplified by the reproduction amplifier 51 and converted into a continuous signal by the HSW signal, and supplied to the video signal reproduction processing circuit 52 and the tracking signal generation circuit 53. The video signal reproduction processing circuit 52 separates the video signal from the output signal of the reproduction amplifier 51, performs processing such as demodulation, and supplies the reproduced video signal in the original signal form to the output terminal 50. On the other hand, the tracking signal generation circuit 53 performs a known process of separating a pilot signal component from the output of the reproduction amplifier 51, comparing the levels of pilot signals obtained from both adjacent tracks, and obtaining a tracking control signal. It is.

Numeral 54 denotes a system control circuit for controlling the operation of each section of the apparatus according to the drive mode of the apparatus. For example, the operation of the head motor control circuit 7, the capstan motor control circuit 13, the tracking signal generation circuit 53, the pattern signal generation circuit described later, and the like differs between recording and reproduction, and further depending on the specified tape speed and the like. These generate a control signal so that a desired operation can be performed in each operation mode.

A conversion element control circuit 55 includes a pattern signal generation circuit 56, a low-pass filter (LPF) 57, a subtraction circuit 58, a DC component removal circuit 59, and a conversion element drive circuit 60. The output of the conversion element control circuit 55 drives the above-described electro-mechanical conversion elements 3A and 3B so that the reproducing heads 2A and 2B accurately trace one recording track in each scanning field.

FIG. 6 is a diagram showing a detailed configuration of the conversion element control circuit 55. Hereinafter, the operation of generating conversion element control pattern signals and driving them will be described with reference to FIG.

The pattern signal generation circuit 56 has a counter P101 and a counter A10
2 and a counter B103. These counters are up-down parallel input up-down counters. The input indicated by CD of each counter indicates a countdown input terminal, and CU indicates a countup input terminal. In this example, a binary counter is used.

Now, the fixed pattern signal necessary for realizing the noiseless special reproduction as described above includes information (phase information) for accurately adjusting the entry position of the reproduction head with respect to the reproduction track that changes along with the running of the tape. And information for matching the inclination between the reproduction track and the trace of the reproduction head corresponding to the running speed of the tape (speed information)
Must be included at least. In the pattern signal generating circuit 56 shown in FIG. 6, the counter P101 is for obtaining phase information, and the counters A102 and B103 are for obtaining speed information.

First, an operation centered on the counter P101 for obtaining phase information will be described. When the counter P101 counts up twice (2n) of the number (n) of the capstan FG signals generated when the tape moves by 2TP, the digit stops and the CR shown in FIG.
Outputs the carry signal from the terminal. Then, this carry signal is supplied to a reset terminal (shown by R in the figure) to reset the counter P101. Similarly, the counter P101 is 2n
When the countdown is performed, the borrow signal is output from the BR terminal shown in FIG. This borrow signal is supplied to a preset terminal (indicated by PR in the figure), and presets the counter P101 to preset data (corresponding to 2n) generated by the preset data generator 104.

For example, in this example, it is assumed that the number (n) of occurrences of the capstan FG signal accompanying the movement of the tape for 2 TP is 24. Therefore, the counter P101 is a counter that repeats 0 → 48 when counting up, and a counter that repeats 48 → 0 when counting down.

Reference numeral 209 denotes an input terminal of the capstan FG signal, 111 denotes a frequency doubler that generates a pulse at the rise and fall of the capstan FG signal, and 112 denotes a pulse generator B that narrows the pulse width of the output pulse of the doubler 111. . 208 is a high level signal from the system control circuit 54 when the tape 1 is traveling in the positive direction (the same direction as during recording), and a low level signal when the tape 1 is traveling in the negative direction (the direction opposite to the recording direction). F / R
Signal). The F / R signal is supplied to the AND gate 115 via the AND gate 114 and the inverter 116. Accordingly, the output pulse of the pulse generator B112 is supplied to the CD terminal of the counter P101 via the AND gate 114 and the OR gate 138 when the tape is traveling in the positive direction, and is supplied to the AND gate 115 and the AND gate 115 when the tape is traveling in the negative direction. The signal is supplied to the CU terminal of the counter P101 via the OR gate 137.

With this configuration, the output data of the counter P101 is a relative value between the track to be reproduced on the running tape (the track recorded by the head having the same azimuth angle as the heads 2A and 2B) and the entry position of the reproducing head. This always indicates the actual positional deviation (relative phase information), whereby it is possible to control each entry position of each reproducing head. However, since this phase information is relative phase information to the last, it is effective only when the immediately preceding playback head entry position matches the playback track. On the other hand, as shown in FIG.
The rush phase of the reproducing head was obtained as absolute phase information according to the recording position of the TL signal. Therefore, in this example,
The relative phase information is generated in advance by the counter P101 as described above, and at the same time, the entry position of the reproducing head is matched with the reproducing track. This role is handled by the rush phase control circuit shown in FIG. 123, and the circuit 123 generates an absolute phase adjusting pulse to match the rush position of the read head even if the rush position of the read head does not match the read track. Control in the direction. The inrush phase control circuit 123 will be described in detail after the description of the entire pattern generation circuit 56.

By the way, the pulse signal to be counted up or down by the counter P101 is obtained by doubling the capstan FG signal, but this is performed to improve the accuracy of the phase information described above. In other words, TP
And the number of generated capstan FG signals with respect to TP is reduced to prevent coarse phase information.

Further, the reason why the pulse width is reduced by the pulse generation circuit B112 will be apparent from the following description, but there is a period in which each counter counts up or down a plurality of pulse signals. This is because it is configured to perform an operation corresponding to addition or subtraction.
In other words, the pulse generating circuit B112 is provided for the purpose of reducing the probability that a plurality of pulse signals are input at exactly the same timing and one cannot be counted. Further, the pulse generation circuit A131 and the pulse generation circuit C113 are provided for the same purpose, and a description thereof will be omitted in the following description.

As described above, the counter P101 counts down the pulse related to the capstan FG signal at the time when the tape is traveling in the forward direction, and counts up the pulse when the tape is traveling in the reverse direction. Regardless, the relative phase information of the entry position when the playback head enters the playback track at that moment is output.
For example, when performing slow motion playback in which the tape is run at a tape speed that is 1/3 times faster than when recording in the forward direction,
(Hereinafter referred to as 1/3 slow) 1/3 when recording in the opposite direction
When the tape is run at twice the tape speed and thrown (hereinafter referred to as "inverted 1/3 slow"), for example, in the case of forward 1/3 slow, the output of the counter P101 is every six field scanning periods. 48 → 0 is repeated, and in the case of a reverse 1/3 throw, 0 → 48 is repeated every 6 field scanning periods.
Now, as the output of the head entry counter P101, for example, 16
Is obtained, the inrush position of the reproducing head with respect to the reproducing track at that time is negative from the reproducing track both in the case of positive 1/3 slow and in the case of reverse 1/3 slow, assuming that the displacement amount of the conversion element is 0. Is shifted by 2 / 3TP in the direction of.

In the case of a binary counter, the necessary number of bits of the counter P101 is the number of bits (6 bits in this example) necessary to represent 2n (48 in this example) in binary.

By reading out the data obtained by the counter P101 at a predetermined timing according to the rotation of the rotary head, it is possible to obtain the rush phase information of the reproduction head with respect to the reproduction track.

Therefore, next, the operation of the counters A102 and B103 that operate using this will be described.

The counter A102 and the counter B103 are counters for outputting a fixed pattern signal including the above-described phase information and speed information as digital data. In addition to the phase information obtained by the counter P101, the counter A102 and the counter B103 determine the reproduction track and the trace trajectory of the reproduction head generated when the tape runs at a speed different from that at the time of recording when the reproduction heads 2A and 2B scan over the tape. This is for generating the above-mentioned speed information for correcting the difference between the inclination and the inclination. The number of bits of the counter A102 and the counter B103 has a 10-bit configuration in this example, but is determined by the necessary amount of conversion of the conversion element, that is, the maximum tape speed at the time of high-speed search reproduction to be enabled. .

The counter A102 and the counter B103 respectively operate the counter P101 at a predetermined timing related to the rotation of the head 2A and the head 2B.
Is loaded as lower 6-bit data.
A signal for determining the load timing is obtained according to the HSW signal. The load signal (PUL, A) of the counter A102 is input from a terminal 302, and the load signal (PUL, B) of the counter B103 is input from a terminal 204. . PUL, A and PUL, B
Are input to the preset terminals of the counters A102 and B103 (represented by PR in the figure, respectively). When the head 2A and the head 2B are rotating 180 degrees out of phase, PUL,
It goes without saying that A, PUL, and B are also input with a phase difference of 180 °.

When PUL, A, PUL, and B are input to PR, respectively, the counter A1
02, counter B103 is loaded with initial data.
As described above, the initial data of the lower 6 bits is a counter.
Although the output data of P101 is used, the above four bits are generated by the preset data generation circuit 105. In this embodiment, the data supplied from the circuit 105 is 1000. This is because the output data of the counter A102 and the counter B103 is D / A as so-called offset binary data.
When conversion is performed, the output is intended to be close to the 0 level. That is, in this case, the initial data to be loaded is from 10000000 to 1000110000, and the initial data is near 0, which is desirable because a DC component as described later does not occur so much. By the way, from the viewpoint that the output data of the preset data generation circuit 105 does not generate a DC component, it is more preferable to change the output data in accordance with the designated tape traveling speed. That is, for example, when running the tape at 10 times the normal speed
1011 is generated by the circuit 105, and when the tape runs at 6 times the speed in the reverse direction, 0101 may be generated by the circuit 105.

The counter A102 to which the initial data has been input as described above.
Similarly, the counter B103 counts, as in the case of the above-described counter P101, a milled rice pulse having a pulse width twice the frequency of the capstan FG signal generated by the pulse generation circuit B112. Further, the counter A102 and the counter B103 count the clock pulse signal (CL) irrelevant to the tape traveling speed input from the terminal 210 via the pulse generating circuit C113.

Here, the clock pulse output from the pulse generation circuit C113 is always guided to the CU terminals of both counters A and B. The output pulse of the pulse generation circuit B112 is configured to be guided to the CD terminals of the counters A and B when the tape is traveling in the positive direction and to the CU terminals of the counters A and B when the tape is traveling in the negative direction. .
This is because, as is well known, even if the tape traveling speed is the same, the difference between the trace locus of the reproducing head and the inclination of the reproducing track differs depending on the traveling direction. For example, when the tape traveling speed at the time of recording is v, the tape speed at the time of reproduction is Nv (N indicates a positive direction speed, and N indicates a negative direction speed, respectively).
And the amount of head displacement required by the reproducing head during one field period is proportional to (N-1) times TP. This means that the inclination of the fixed pattern signal to be obtained is proportional to (1-N) in order to correct the inclination.

Since the frequency of the output pulse from the pulse generation circuit B112 is proportional to the absolute value of the running speed of the tape, an inclination proportional to N is obtained by counting the frequency.
At this time, if the tape running is in the positive direction, the counter is decreased, and if the tape running is in the negative direction, the tape is counted up to obtain a slope proportional to (-N). On the other hand, since the slope required to displace the reproducing head by 1 TP in one field period is proportional to 1, the number of pulses corresponding to 1 TP (48 in this example) is counted up in one field period, and the slope is increased. Get +1. And if these are done simultaneously, (1-N)
Can be obtained. Therefore, the frequency of the clock pulse generated by the pulse generation circuit C is
fv x 48 (Hz). Where fv is the field scanning frequency.

A terminal 206 is a terminal to which a rectangular wave signal (PUL.C) for designating a period during which the counter A 102 counts each pulse described above is supplied. PUL, C are AND gates 117 and 119.
To gate each pulse. The other terminal 207 is a terminal to which a rectangular wave signal (PUL.D) for specifying a period during which the counter B103 counts each pulse is supplied.
The LD similarly gates each pulse by AND gates 118 and 120. Reference numeral 121 denotes an OR gate for guiding both the output pulse of the pulse generation circuit B112 and the clock pulse output from the pulse generation circuit C113 to the counters A102 and B103.

In this manner, the count A102 and the counter B103 take in the initial data for determining the entry position of the head from the counter P101 during the period when the reproducing heads 2A and 2B trace the recording track on the tape, respectively, and then read the reproducing head. By counting each pulse so as to obtain an inclination proportional to the inclination between the trace locus and the recording track, a fixed pattern signal for the reproducing head to accurately trace the desired recording track when the tape is running at an arbitrary speed. Can be generated as digital data.

Next, the state of generation of each timing signal in this example is shown in FIG.
This will be described in detail with reference to the timing chart shown in FIG. In FIG. 7, (a) is an HSW signal, in which the reproducing head 2A reproduces a video signal for one field on each recording track when the reproducing head 2A is at a high level and the reproducing head 2B is at a low level. Are shown respectively. This HSW signal is 30H when fv is 60Hz
This is a rectangular wave signal of z, which is supplied to each unit of the apparatus as a timing pulse of 30 Hz related to the rotation of the head, so-called 30PG. (B) is a capstan FG signal, and (c) is a pulse (FGP) generated by the pulse generation circuit B112 related to the capstan FG signal, and shows a waveform at the time of a positive 1/3 slowdown. I have. (D) is a pulse (CLP) generated by the pulse generation circuit C113 by narrowing the clock pulse (CL) input from the terminal 210, and (E) is a 60 Hz timing pulse (60PG) phase-locked with the HSW signal. , (F) are square wave signals (PUL.C) supplied to the terminal 206, and (g) are terminals
The square wave signal (PUL.D) supplied to 207, (h) is a pulse (PUL.A) supplied to the terminal 202 for presetting the counter A102, and (l) is for presetting the counter B103. Pulse supplied to terminal 204 (PUL.B),
(Nu) is a sampling pulse supplied to the terminal 205,
(R) is an analog display of the output data of counter P101, (ヲ) is a pulse (PUL.E) output from terminal 203
It is.

The period during which the reproducing head 2A reproduces a video signal for one field of each recording track is a period in which the HSW signal (a) is at a high level. This period alone is sufficient. However, the electromechanical conversion element causes a resonance (ringing) phenomenon in response to a sudden change in the applied voltage. Further, in one recording track, there is an area in which another signal (for example, a digital audio signal) is recorded in addition to an area in which a video signal for one field is described. Further, it is necessary to obtain a tracking control signal from an area where other signals are recorded. For this reason, in this example, the valid period of the solid-state pattern signal, that is, the period in which the counter A102 can count the output of the pulse generation circuit B112 and the pulse generation circuit C113 is defined as the period in which the HSW signal is at a high level and immediately before. 1/2 field scanning period. This period is PUL.C
(F) is given as a high level period. This PUL.
C (f) can be easily formed by a logic circuit (not shown) by the HSW signal (a) and the 60PG (e). PUL.D (g) is formed as shown in FIG. 7 for the same reason.

The initial data fetch timing of the counters A102 and B103 is determined by the pulse PU input to the PR terminal of each count.
Determined by LA (R) and PUL.B (H). This timing may be any timing as long as it is not included in the valid period of the fixed pattern signal.

In this embodiment, in consideration of the prevention of the ringing phenomenon described above, immediately before the effective period of the fixed pattern signal, the period is set immediately after the effective period so that a large level change does not occur in the fixed pattern signal. The PUL.A (L) and PUL.B (H) may be formed, for example, using the falling edges of PUL.C (F) and PUL.D (G). Note that PUL.S (nu) and PUL.E (ヲ) will be described later in detail.

Further, the fixed pattern signal generated according to the present embodiment is specifically shown and described with the tape running speed set. FIG. 8 is a timing chart in which the fixed pattern signals are set to (vi) and (vii) when the tape running speed is 0 (so-called still playback degree) and when the tape is running (so-called standard playback).
FG and FGP shown in FIGS. 8 (ii) and (iii) are those at the time of standard reproduction. 8 (vi) and (vii) show the counter A
The output data of 102 is displayed in analog form. At the time of still reproduction, no FGP is generated, and only the CLP is counted by the counters A102 and B103.
Therefore, the output of the counter A102 becomes as shown in FIG. 8 (vi). Since the output data of the counter P101 is always a constant number, the output of the counter B103 has the same waveform as that shown in FIG. 8 (vi) and a phase different by 180 °. On the other hand, at the time of standard reproduction, the FGP and the CLP have the same frequency as shown in FIG.
02 and the counter B103 are FGP within the valid period of the fixed pattern.
By counting down and counting up the CLP, their outputs are almost unchanged.
At this time, the output (vii) of the counter A102 is
Is a waveform shifted by the level at which the conversion element is driven by 1TP. This is because the timing of taking in the value of the counter P101 differs for one field scanning period, during which the counter P101
This is because FGP is counted for 1 TP.

9 (A) and 9 (B) show the relationship between the recording track on the tape at the time of forward and reverse 1/3 throws and the trace locus of the reproducing head, and FIG. 10 shows the fixed state at the time of forward 1/3 throw. FIG. 11 is a timing chart for setting the pattern signal to (v), and FIG. 11 is a timing chart for setting the fixed pattern signal at the time of reverse 1/3 throw to (v).

9 (A) and 9 (B), A ₀ , A ₁ and A ₂ are the center lines of the recording tracks recorded by the heads having the same azimuth angles as the reproducing heads 2A and 2B, respectively, and B ₀ and B Reference numeral ₁ denotes a center line of a recording track recorded by a head having a different azimuth angle from the reproducing heads 2A and 2B, respectively. Meanwhile, a ₁ ~a ₆ trace locus of the conversion element centerline trace locus of the head 2A when 3A and by the displacement is 0, b ₀ .about.B ₅ head 2B when the zero displacement by the conversion element 3B X is an arrow indicating the running of the tape.

As is well known, 1/3 slow and 1/3 slow reverse
Every other recording track is traced six times and reproduced. For example, In FIG. 9 (A) to trace over the recording tracks A ₁ to _{b 1, a 2, b 2} , a 3, b 3, a 4 of 6 times. Tenth
A and B in FIG. 5 (v) are the fixed patterns (the analog display of the output data of the counters A102 and B103) generated according to this example, and P is the analog display of the output data of the counter P. is there.

Taking as an example the operation to match Figure 9 the locus a ₂ of (A) to the track A _1, takes in output to the counter A counter P at the point u as shown in Figure 10, the counter at the point v A , The counting is stopped at the point w, and the output of the counter P is taken in again. It is apparent from the comparison with FIG. 9 (A) that the desired fixed pattern signal is obtained by this repetition.

Also in FIG. 11 (v), A and B are fixed patterns generated according to the present example, P is an analog display of the output data of the counter P, and similarly the output data of the counter P is output to the counter A at point u. The counting is started at the point v, the counting is stopped at the point w, and the output of the counter P is taken again. It is also clear from the comparison with FIG. 9B that the fixed pattern signal shown in FIG. 11 is a desired fixed pattern signal.

The trace trajectory of the head can be matched with the recording track as described above. However, as described above, the phase information is relative only by this.

Therefore, next, a description will be given of the rush phase control circuit 123 that matches the rush position of the read head to the recording track to be reproduced and brings the phase information closer to the absolute information.

In this example, a tracking control signal is used to match the rush phases. This tracking control signal is supplied from the above-mentioned tracking control circuit 53, but in this example, the reproduction head is used for performing the above-mentioned 4f type tracking.
During the period in which the reproduction signal is obtained from each of 2A and 2B, a tracking control signal can always be obtained for each head. Also in this example, as apparent from FIGS. 5 and 6, the tracking control signal (AT) obtained from the reproducing heads 2A and 2B is used.
FA, ATF.B) is subtracted from the fixed pattern signals for the heads 2A, 2B, respectively. This corrects the deviation between the trace trajectory and the track of the reproducing heads 2A and 2B when the conversion elements 3A and 3B are driven only by the fixed pattern signal. What is necessary is just to shift a signal.

ATF and A input to the terminal 201A are sampled and held by the sample and hold circuit (S / H) 132 using a timing pulse (PUL.S) indicating an intermediate timing of each scanning field as a sampling pulse. The timing of PUL.S is as shown in FIG.

The output of the S / H 132 is supplied to a voltage detection circuit composed of comparators 133 and 134 and resistors R ₁ , R ₂ and R _{3. When the} voltage is equal to or higher than a predetermined voltage E ₁ , a high level output is obtained from the comparator 133 and lower than E _1. predetermined voltage E ₂ following the time comparator
Get a higher level output than 134.

The output of the comparator 133 is supplied to the AND gate 135, and the output of the comparator 134 is supplied to the AND gate 136, and gates the pulse from the pulse generation circuit A131. The pulse generation circuit A131 narrows the pulse width of PUL.A and supplies it to AND gates 135 and 136. ATF, the AND gate 135 if E ₁ or more at the timing of A PUL.S is a pulse counter P1
01 CD terminal. On the other hand, ATF, A supplies the AND gate 136 is a pulse if E ₂ or less at the timing of PUL.S the CU terminal of the counter P101.

This ATF, A is based on the determination that when E ₁ or more is progressing reproducing head 2A is relative to the track, almost on-track when the E ₁ below E ₂ or more, when the E ₂ or less delayed . That is, if the head 2A advances with respect to the track, the counter P101 is counted down once every two field scanning periods, and since the output of the counter P101 shifts downward, the fixed pattern signal also shifts downward, so that both the heads 2A and 2B are turned on. Approaching track state. If the head 2A lags behind the track, the fixed pattern signal is similarly shifted upward and approaches the on-track state. This is a counter
While the P101 is counting the FGP, it is executed in the form of counting interrupt pulses one by one in two field scanning periods. For example, if the entry position of the head with respect to the track is shifted by 1/2 TP in the initial stage, the counter P101 counts 24 interrupt pulses, and the on-track state is set. That is, in this case, the time required for the on-track state is 48 × 1 / fv, and the track can be pulled into the on-track state within one second. Further, according to the configuration of the present embodiment, it is possible to correct the displacement of the entry position caused by the slip of the capstan with the tape.

Also, by adopting such a configuration, in the stale reproduction, the fixed pattern signal can be shifted to the on-track state by shifting the fixed pattern signal, so that extremely good tracking can be performed. In addition, there is no need to take timing when stopping the tape, and control of the entire apparatus can be simplified.

In this manner, the pattern signal generation circuit 56 generates a fixed pattern signal for driving the conversion elements 3A and 3B so that the reproducing heads 2A and 2B can trace a desired recording track at an arbitrary tape running speed. It can be generated via the / A converters 106,107.

The OR gate 151 in FIG. 6 outputs a pulse signal when a carry signal or a borrow signal of the counter P101 is generated. This means that the reproduction track is updated, and the tracking control circuit 53 supplies the track update pulse (PU
L, E). In the case of the 4f tracking, the pilot signal obtained from the track and the pilot signal obtained from both adjacent tracks are different each time the reproduction track is updated, so that the signal processing method is different. For example, when a pilot signal component in a reproduction signal is multiplied by a predetermined reference signal for processing, the frequency of the reference signal to be multiplied is different. This switching is performed using this PUL.E.

Next, the remaining part of the conversion element control circuit 55 will be described with reference to FIG. The LPFs 161 and 162 remove high frequency components of the fixed pattern signal in order to further prevent the ringing phenomenon described above. The subtracters 171 and 172 subtract ATF, A and ATF and B from the fixed pattern signals for the heads 2A and 2B, respectively. 59 detects the average of the DC component included in the output signal of the subtraction circuit 58 by the integrator 180, and
This is a DC component removing circuit that removes the signal using the components 1,182. The output signals of the differential amplifiers 181 and 182 are amplifiers 191 and 192 and LPF19, respectively.
The voltage is applied to the electro-mechanical conversion elements 3A and 3B from the terminals 211 and 212 via 3,194 and the high voltage amplifiers 195 and 196.

Note that in the above example, the inrush phase control circuit 123 sets the counter P101
The pulse to be supplied to is supplied during one two-field period, but is not limited to this. For example, it is possible to set one pulse every two field periods, or to determine the supply interval and the number of pulses according to ATF.A. The same circuit 12
The sampling timing of the S / H 132 of 3 is arbitrary, and the S / H 132 may not be provided.

Also, the method of shifting the fixed pattern is a method of changing the number of pulses counted by the counter P101 as described above, but it can also be performed by changing the preset data generated by the preset data generator 104. It is.

<Description of Effects> As described above with reference to the embodiments, according to the present invention, by effectively using the up / down counter, the rotating head can be moved in the direction crossing the rotating surface with a simple circuit configuration. By controlling the displacement means for displacing, good tracking can be performed at an arbitrary recording medium phase velocity.

[Brief description of the drawings]

FIG. 1 shows a VT as an example of a conventional rotary head type reproducing apparatus.
FIG. 2 is a block diagram showing a specific example of a pattern signal generating circuit in FIG. 1; FIG. 3 is a block diagram showing a specific example of a pattern signal generating circuit in FIG. 1; FIGS. 4A and 4B are diagrams showing input / output waveforms at 1.5 × speed reproduction of FIG.
FIG. 5 is a diagram showing the relationship between the center locus of the head scanning and the center locus of the recording track on the tape during 5 × speed playback. FIG. 5 is a diagram showing the main configuration of a VTR as one embodiment of the present invention. FIG. 5 is a diagram showing a concrete circuit example of the conversion element control circuit shown in FIG. 7, FIG. 7 is a timing chart showing how each timing signal is generated in FIG. 6, and FIG. 9 (A) and 9 (B) are diagrams showing the relationship between the recording track on the tape and the trace locus of the reproducing head at the time of forward and reverse 1/3 throws. FIG. 11 is a timing chart showing a fixed pattern signal at the time of forward 1/3 throw, and FIG. 11 is a timing chart showing a fixed pattern signal at the time of reverse 1/3 throw. Numeral 1 is a magnetic tape as a recording medium, 2A and 2B are rotating heads for reproduction, 3A and 3B are electro-mechanical transducers as shifting means, 10 is a capstan included in the phase means, and 12 is a capstan FG signal. , 55 is a conversion element control circuit, and 102 and 103 are up-down counters, respectively.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Susumu Kozuki 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. (72) Inventor Masahiro Takei 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. ) Inventor Kenichi Nagasawa 770 Shimonoge, Takatsu-ku, Kawasaki

Claims (1)

(57) [Claims] An apparatus for reproducing a video signal by tracing a recording track formed on a recording medium at a predetermined track pitch by a rotating head displaced in a direction intersecting a rotation plane by a displacement means. Driving means for transferring the recording medium, means for obtaining tracking error information indicating tracking error between the rotary head and the recording track using a signal reproduced by the rotary head, and driving the displacement means Drive signal forming means for forming a drive signal, wherein the drive signal forming means counts up or counts down a pulse obtained in association with the recording medium transfer operation of the transfer means, and adjusts the rotation period of the rotary head. Count down or up pulse with related frequency A rotary head type video signal reproducing device, comprising a pull-down counter, wherein the drive signal is formed based on information indicating the tracking shift and an output of the up-down counter.