JPS6184175A - Rotary head type reproducing device - Google Patents

Abstract

PURPOSE:To obtain an excellent playback signal by providing a manual detecting means which shifts a counted value or set value, and stopping a recording medium at an invariably ideal stop position even when the device has physical variance and variation in characteristics. CONSTITUTION:Playback signals reproduced by heads 5a and 5b are passed through a head switching HSW 9 to generate a continuous signal, which is supplied to a video signal processing circuit 14 and a tracking error ATF signal generating circuit 15. The HSW 9 is controlled with a head switching signal 30PG of 30Hz obtained from a detector 12 and a drum PG generator 13. On the other hand, only a four-frequency pilot signal component is separated by the circuit 15 with the continuous signal and processed by a known method to obtain a signal ATF. A variable speed playback control circuit 17 equipped with the manual detecting means which shifts a counted or set value performs rotation control over a capstan 10 during still reproduction and slow-motion reproduction by using 30PG, capstan FG, ATF signals, etc.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a rotary head type reproducing device, and in particular, the present invention relates to a rotary head type reproducing device, and in particular, by running a recording medium at a predetermined speed, the rotary head traces tracks formed at a predetermined pitch to generate recorded signals. This invention relates to a reproduction device.

<Description of the Prior Art> In the following description, a rotating two-head helical scan type video tape recorder (VT) will be described as a device of this type.
R) will be explained as an example.

Conventionally, in this type of VTR, in order to perform still image playback (FI/STILL) without producing noise on the screen, the control signal (CTL) recorded in the longitudinal direction of the magnetic tape is played back and 11) The rotational phase of the raw head was known and this phase information was used to stop the tape.

In contrast, in recent years, with the trend toward higher density recording, VTRs have been proposed that track CTL without recording and reproducing it.
It has been implemented. However, in this type of VTR, it is not possible to easily find the phase relationship between the head and the track as in the case of using the above-mentioned CTL, and it has not been possible to perform increased still playback in practice.

Furthermore, in conventional VTRs, one type of 4i has been commercialized, which alternately performs the above-mentioned fine still playback and normal playback, and is capable of noise-free slow motion playback (fine slow), but VTRs that do not record and play CTL In T and H, this fine throw could not be executed effectively.

In addition, the names of various parts of VTRs have become obsolete, and there is even more harassment between devices! 1
Since the stop position of the tape changes due to ``9'', it is difficult to always perform such accurate tracking.

<Purpose of the invention> Unfinished 91 was developed in consideration of the drawbacks such as HD, and even when there are variations or changes in the physical characteristics of the device, it is possible to always maintain the ideal stopping position. It is an object of the present invention to provide a rotary head type reproducing device that can stop a recording medium and obtain a good reproduced signal.

<Explanation based on examples> The present invention will be explained below based on examples.

In the embodiment described below, the present invention is applied to a VTR that employs a well-known four-frequency pilot system as a tracking method.

First, the relationship between the head trace locus and the trunk during still playback in a VTR, and the tracking error signal (ATFQ signal) indicating the deviation between the head and the touch at that time will be explained.

Here, a case will be described in which still playback (so-called frame still playback) in which two fields of video signals are sequentially played back in a rotating two-head VTR is performed.

11J (A) and (B) are diagrams showing the state on the magnetic tape and the timing of each signal when the tape is stopped without control. FIGS. 2A and 2B are diagrams showing the state on the tape and the timing of each signal when the tape end is stopped at an ideal position.

In Figure 1 (A) and ';lit, Figure 2 (A), 1
2 is the head trace locus, 2 is the tape running direction, 3 is the head trace direction, 4 is the tape, and fl to f4 are tracks on which pilot signals having frequencies of f1 to f4 are recorded. In addition, in Fig. 1 (B) and Fig. 2 (B), (A) is the head switching signal (30PG) of 30H2, which is synchronized with the rotation of the rotary head, (tff
) is the frequency of the pilot signal -) recorded on the track that is playing the video signal, (c) is the ATF Shinso, (
d) shows the enoherope waveform of the 11) raw signal.

During still playback, the trace locus of the video track and the head causes a undulation of one tran period in one field. Now, if the tape stops in the state shown in Figure 1 (A), the maximum point of one head's output will be the video signal on the screen, but the minimum point of the other head's output (indicated by an x in the figure) will be the video signal on the screen. After all, since it is a video signal within the screen, noise appears on the reproduced image.

Therefore, in order to prevent /Eve/S- from appearing on the screen, the maximum output point of the head and the minimum output point of the head should be made to match the head vJ exchange point as shown in Figure 2.
In other words, it is sufficient to stop the head so that the entry position matches the track to be reproduced or its adjacent track L. Also, considering the ATFQ signal at this time, the ATFQ signal is at O level (accurately is the level determined by the difference in frequency characteristics (VJ), which indicates that the head is accurately tracing the recorded track trajectory. A T F +, if number i is O and hell, it's good f
This shows that it is possible to achieve a still playback.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention. In Figure 3, 4 is a magnetic tape 5a
, 5b are rotary playback heads. Heads 5a, 5b
have different magnetization directions. 6 is the rotating head 5
a, 5b, and guides the magnetic tape 4 on its outer peripheral surface. Head 5a, 5b tel
'f was born 11) His birth name was Hatsuto Switchinog Circuit (
H5W) is converted into a continuous signal and supplied to the video signal 1 processing circuit 14 and the ATF (j signal generation circuit 15.
5W9 is 30 obtained by detector 12 and generator 13
Controlled by PG.

21 obtained in H5W9! The subsequent signal is sent to the video signal processing circuit 14.
After the video signal components are separated, they are returned to the original signal form (for example, a video signal conforming to the NTSC signal) and output. On the other hand, from this continuous value 5; the ATF signal generation circuit 15
Only the four-frequency pilot signal components are separated, and an ATF signal is obtained by well-known signal processing. To briefly explain this signal processing, the reproduction pilot No. 43 included in the reproduction signal from the head, the pylon No. signal) and compares the level of the difference frequency signal with the pilot signal reproduced from the tracks on both sides adjacent to the main track to detect a truck error.
It is something that earns a number.

The ATF signal thus obtained is supplied to the capstan motor control circuit 8 and is normally at 111 hours. The capstan lO is controlled via a capstan drive circuit 7. As is well known, the capstan lO moves the tape 4 in conjunction with a pitch roller (not shown). Further, this rotation is detected by a detector 11, and the detector 11 generates, for example, X pulses per one rotation of the capstan 10, which is a so-called capstan 7FG that controls the capstan motor, the circuit 8 and The signal is supplied to a variable speed regeneration control circuit 8, which will be explained in detail later. This capstan FC is supplied to a capstan/motor control circuit 8 to form a speed control loop.

The variable speed regeneration control circuit 17 includes the aforementioned 30PG, capstan FG, ATF signal, and system controller 16.
This is a circuit for controlling the rotation of the capstan 10 during still playback and slow motion playback using signals obtained from the above, and the variable speed playback control circuit 17 will be explained below using a specific circuit example. do.

Figure 4 is a diagram showing a specific example of the variable speed regeneration control circuit 17 in the A3M. Figures 5 (a) to (g) are shown in Figure 4 (
a) to (g) are timing charts showing waveforms of various parts, and the operation of the circuit shown in FIG. 4 will be described below using FIG. 5.

In Figure 4, 20 is the capstan FG during recording.
22 is a terminal to which the ATF signal (b) is input, 26 is a terminal to which 30PG is input, 28 is a terminal to which a clock signal of the same frequency as Terminal 30 is the terminal to which the level (number) is supplied.

32 is the level when the head is on track fE, (shown in Figure VJ) [; is used as the threshold value for 1 comparator, and 34 is for obtaining the pulse generated at the rise of the conoparator. 36 is a flip-flop CFF set by a pulse generated from the monomulti 34. The 3oPG(a) supplied to the -power terminal 26 is supplied to the monomulti 38.

The pulse generated at the rising edge is obtained. This pulse resets F F 36 via OR gate 40.

The output (d) of the FF 36 is supplied to the ant gate 42,
While this FF 36 is set, the counter 46 counts (counts up) the clock signal supplied from the terminal 20. When the counter 46 stops counting up by the clock signal, the clock signal generated by the monomulti 38 is generated. The pulse is passed through the OR gate 40.7 and the F gate 44.
Set F48. The FF 48 is reset when the il value becomes smaller than the output data of the analog-to-digital converter (A/D) 56 while the counter 46 is counting down. That is, it is reset by the output of the monomulti 60 which is triggered by the fall of the output signal of the comparator 58. 54 is a polyurethane for adjusting the output data of the A/D 56.

During the period when the FF 48 is set, a clock signal is supplied to the output terminal 52 via the seventh gate 50.

A step-by-step explanation will be given below. When a command for still reproduction is issued from the nostem controller 16, the rotation of the capstan 10 is temporarily stopped at an arbitrary timing. The ATF signal at this time is shown in Figure 5 (b
), and by making this ATF signal become C in FIG. 5(b), fine still (field still) can be realized.

Now, the ATF signal - (b) is at the above-mentioned level V
The period after exceeding Jt- until the rise of the primary 30PG (a) is the period when the output signal (d) of FF36 is at the /\I level, and this (d) is the ideal period for the ATF signal (b) and 30PG (a). It shows the phase difference from the state. During this period, the counter 46 is counting the clock signal, but this FF
36 output signal (d) during recording (=
The tape length when the tape is transported at the tape running speed (during normal playback) corresponds to the distance of the tape position shift to the ideal tape stop position. Therefore, if the clock signal input from the terminal 20 is set as the frequency of the capstan FC during recording in advance, the count value of the counter 46 will be generated from now until the capstan 10 is rotated and the tape reaches the ideal stop position. The number of capstan FCs used is reduced. In other words, after the clock signal is counted up by the counter 46 in this way, the capstan is rotated and the capstan FG generated at that time is counted down by the counter 46. If the counted value becomes zero, it is ideal. It is sufficient to judge that the tape is at the stop position and stop the tape running. mchi,: FF in fS5 diagram
When the output signal (g) of 48 is high level, the capstan l
0 will be driven by a clock signal via a 7-note gate 50. However, as mentioned above, due to changes in the physical characteristics of the capstan and irregularities, the time when the jl number (a) of the counter 46 becomes zero is not necessarily the ideal timing to stop driving the capstan. Therefore, the user manually operates the Porium 54 to perform A/D.
By changing the output data of the tape 56, the user can freely adjust the stop position, and once the polyurethane is adjusted, the tape can always be stopped at the ideal stop position. Also, this polyum 54 and A/D
Adjustment of the I'+"+L angle by 56 is extremely easy for the user to handle because the stopping position changes as the polyurethane moves.

According to a VTR having a variable speed playback control circuit as described above, A
By counting the signal at the same frequency as the capstan FC during recording for a period corresponding to the phase difference between the TF signal and 30PG, the deviation from the ideal stopping position can be accurately calculated as distance information. I can do it. Furthermore, when driving the tape accordingly, the tape stop position can be adjusted freely by manual operation in response to variations and changes in the physical characteristics of the JA machine.

The tape can always be stopped at an ideal stopping position.

FIG. 6 is a diagram showing another specific example of the variable speed regeneration control circuit 17 in FIG. Further, FIG. 7 is a timing chart for explaining the operation of the iS6 diagram.

In Figure 6, 27 is 30PG (shown in Figure 7(a))
is the terminal to which 30PG is supplied, and this 30PG is a mono multi 3
5.37, the phase is shifted and the waveform is shaped, and the pulse as shown in FIG. 7(b) (hereinafter referred to as PG pulse) is generated.
is output from the monomulti 37. The terminal 29 is a terminal to which a tape stop command signal is supplied from the system controller 16, and this command signal is kept at a high level for approximately one frame (=two fields) period.

Now, when a tape stop command is supplied from the terminal 29, the PG pulse generated from the monomulti 37 while the command signal is at a high level is gated by the 7 note gate 41, and this pulse (Fig. 7 (m) ) is supplied as a trigger pulse to a monomulti 43 consisting of a T flip-flop. Monomulti (MM) 43 is a monomulti for tracking adjustment, and is R11CRx.

The time constant determined by the variable resistor R2 and the capacitor C is adjusted by the variable resistor R2 to adjust the pulse width of the pulse generated by the monomulti 43 (shown in Figure 7 (C)), and tracking can be done manually to some extent. Can be adjusted. In addition, the output of this monomulti 43 is 30PG
so that it almost coincides with the rise of .

The Q output of the monomulti 43 (shown in FIG. 7(C)) is supplied to the ck terminal of a D flip-flop (DFF) 47, thereby changing the Q output of the DFF 47 from low level to high level.

A clock signal with the same frequency as the capstan FG during recording is supplied from terminal 21, and the clock signal is 0FF47.
When the Q output of the clock becomes high level, the counter 53 starts counting up the clock number 3 via the ant gate 55 and the off gate 59. On the other hand, an ATF signal (shown in FIG. 7(e)) is supplied to the terminal 23, and this ATF signal is compared by a comparator 33 with the level (VJ) when the head is in an on-track state. Therefore, when the output of the comparator 33 (shown in FIG. 7(f)) falls and rises, the reproducing head is on-track. These falling and rising edges are detected by an edge detection circuit comprising an i/putter 39a and an exclusive OR circuit 39b, and are converted into narrow pulses. This edge pulse resets the DFF 47 via the seventh gate gate 45.

Therefore, the Q output of the DFF 47 (shown in FIG. 7(d)) is high from the rise of the Q output of the monomulti 43 (shown in FIG. 7(C)) to the aforementioned edge pulse (shown in FIG. 7(tl)). level. The counter 53 counts up the clock signal during this period.

Further, while the Q output of the DFF 47 is at a high level, the tape length when the tape is transported at the tape running speed during recording corresponds to the distance of the tape position from the ideal tape position. That is, it shows the number of capstan FCs that occur after the tape passes the ideal stop position.

Therefore, after the counter 53 counts up the clock signal in this way, the capstan is rotated, and the counter 53 further counts and amplifies the capstan 7FG generated at that time, so that :l1ffff〆( is nF((
If H and F are a) of Capstar 7FG, which occurs when the tape is transferred by one track pitch, it is sufficient to stop the tape running assuming that the tape is at the ideal stop position.

Output of the monomulti 49 (shown in FIG. 7(g)) More than one frame period (approximately l) from the rise of the Q output of the monomulti 43
(preferably a frame period) becomes high level,
The counter 53 should stop counting up the clock signal at least during this high level period. The fall of the output of the monomulti 49 triggers the DFF 51, and the Q output of the DFF 51 changes to high level. Further, the Q output (shown in FIG. 7(i)) is supplied to the capstan motor control circuit 8 via the terminal 61, and the capstan 10 is activated. In response to this, the capstan FG which is manually input from the terminal 31 is counted and amplified by the counter 53 via the ant gate 57° and the OR gate 59. If we assume that the number of capstan FGs generated when the tape is transferred by one track is 16, and the stop position is set in units of 2 frames, the count value of the counter 53 will be 6.
4, the tape is at the ideal stopping position.

Therefore, if the data output from the A/D 63 is set as the addressee 64 and the DFF 51 is reset by the output of the monomulti 65 that occurs at the falling edge of the output of the comparator 64,
When the tape is at the ideal stop position, the Q output of the DFF 51 will be at a low level. In other words, the counter 53 counts the capstan FC while the Q output of the DFF 51 is at a high level (shown at t2 in FIG. 7).

When the Q output of DFF51 turns to low level, counter 5
3 stops the count amplifier of the capstan FG, and the Q output of the DFF 51 changes to a high level, which is supplied to the capstan motor control circuit via the terminal 61, thereby stopping the capstan 10, and the tape becomes ideal. The vehicle will stop at the desired stopping position. Figure 7 ('')
indicates the current (output of the capstan motor drive circuit 7) applied to the capstan motor when χ, and:? Figure J7 (k) shows a signal detecting the actual rotational force direction of Capsta/10, and Figure 757 (text) shows the period during which the brake is applied to Capsta/10. That is, when the DFF 51 is reset, the brake is applied to the capstan 10,
Immediately before stopping, an extremely weak driving current is applied again in the forward direction. If the capstan 10 is stopped in this manner, the capstan/10 will not be reversed and will stop very stably.

It should be noted that the polium 62 is used for tracking adjustment by the user, similar to the polium 54 in FIG. That is, the resistance R2 is initially adjusted, and the A/D6
Even if the tape is configured to stop at the ideal stop position when the output data of No. 3 is 64, the tape will not stop at the ideal stop position due to physical changes as described above.

Therefore, the user adjusts the value of the polyum 62 to adjust this stop position. This adjustment results in a change in the stopping position due to the adjustment of the polyurethane 62 as described above, resulting in one linear position. Therefore, it is much easier for the user to handle than adjusting the stop position by changing the value of the resistor R2.

As mentioned above, even in a VTR equipped with a variable speed playback control circuit as shown in FIG. 6, the tape could always be stopped at a good stopping position regardless of changes in the physical characteristics of the device.

Although the above explanation does not specifically mention slow-motion playback, for example, when using the circuit shown in Figure 6, when stopping the tape as described above, the capstan for the E2 period is the same as during normal playback. Similarly, while driving,
This can be achieved by setting the pulse width of the output of the monomulti 49 to two field periods and repeating this stopping operation many times.

In addition, manual Afi of the stop position by the user was performed by adjusting the output data of the A/Ds 56 and 63 supplied to the comparators 58 and 64, but the counter 4
6.53 When setting glue This can also be done by using this as a preset and Jlfi this preset data.

Further, as a means for obtaining a tracking error signal, a well-known four-frequency tracking error signal is used, but it goes without saying that the tracking error signal can also be obtained by, for example, a simple envelope detection circuit.

As explained above, according to the present invention, even when there are variations or changes in the physical characteristics of the device, the recording medium can always be stopped at the ideal stopping position, and a good result can be achieved. A rotary head type reproducing device capable of obtaining a reproduced signal was obtained.

[Brief explanation of the drawing]

Figures 1 (A) and CB) show the state on the magnetic tape and the timing of each signal when the tape is stopped without write control in a VTR. Figures 2 (A) and (B) show the timing of each signal. FIG. 4 is a diagram showing the state on the tape and the timing of each signal when the tape is stopped at an ideal position. FIG. 3 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention, and FIG. 4 is a diagram showing an example of a variable speed playback control circuit in the wS3 diagram. FIG. 5 is a timing chart for explaining the operation of the circuit shown in FIG. 4. The sixth factor is a diagram showing a specific example of the variable speed regeneration control circuit in FIG. 3. FIG. 7 is a timing chart for explaining the operation of the circuit shown in FIG. 4. l is a trace locus, 4 is a magnetic tape as a recording medium,
8 is a capstan motor control circuit, IO is a capstan included in the transfer means, 13 is a drum PG generation circuit, 15
are A T F (, i number generation circuit, 16 is a system controller, 17 is a variable speed regeneration control circuit, 46.53 are respective counters, 54.62 are polyols included in each manual operation stage, 56.63 are each A /D, 58° and 64 are comparators respectively.

Claims (1)

[Claims] A device for reproducing recorded signals by running a recording medium at a predetermined speed and tracing tracks formed at a predetermined pitch with a rotary head, the apparatus comprising: means for generating a first periodic signal, means for generating a second periodic signal related to a fluctuation period of a tracking error signal indicating a deviation between the track and the head, and a transporting means for causing the storage medium to travel;
means for generating a first pulse signal in connection with the medium transport operation of the transport means, and having a frequency equal to the frequency of the first pulse signal when the medium is transported by the transport means at the predetermined speed; means for generating a second pulse; and a counter for counting the second pulse and the first pulse signal generated in a period according to the phase difference between the first periodic signal and the second periodic signal. means, a detection means for detecting that the count value of the counting means has reached a predetermined set value, a means for controlling the transfer means based on the output of the detection means, and the count value or the setting. A rotary head type playback device comprising manual operation means for shifting values.