JPS62230275A - Special reproducing device - Google Patents

Abstract

PURPOSE:To store the video signals which belong to a period where most suitable video signals are obtained by setting the storing-timing for the video signals based on plural reference signals generated in accordance with a tape carrying speed. CONSTITUTION:Reproduction outputs from rotary heads 11A and 11B are made consecutive signals by a switch 12, and a pilot signal P is drawn out from a BPF 13. This pilot signals P is multiplied by a reference signal R from a reference signal generating circuit 28 in a multiplier 14. And thus the pilot signal conponent to be reproduced as a crosstalk component can be obtained from the neighboring two tracks. The generation of the reference signal R is controlled by a control circuit 29, and made into the plural reference signals. Output from the multiplier 14 undergoes the wave detection BPFs 15 and 16, and wave detecting circuit 17 and 18, and is amplified by a differential amplifier (19). The polarity between the tracks of the output SD of the differential amplifier is made coherent by an inversion circuit 20 and switch 21. As a result, a tracking error signal SE can be obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a video tape recorder (hereinafter referred to as VTR) that uses the motherboard method as a tracking method.
This invention relates to a special playback device.

(Prior Art) For helical scan VTRs, various types of special playback devices that play back images at a speed different from that during recording have been proposed and realized. For example, (1) a special playback device that uses a double azimuth head to perform noise-free slow playback and still playback (2) a special playback device that uses a four-head format to perform noise-free slow playback and still playback (3) a piezoelectric element Special playback device that performs dynamic tracking using field memory (4) There is a special playback device that uses field memory.

Now, focusing on the special playback device (4), this device is used in VTRs that control tracking using a so-called control signal, but it controls tracking using a nokilot signal (hereinafter referred to as
This pilot type tracking control (hereinafter referred to as ATF control) type is not adopted for VTRs. One reason for this is that no effective method for applying special playback using field memory to pilot-type VTRs has yet been considered.

By the way, special playback using field memory is very superior in that it does not require a special head. Therefore, it is very important to realize special playback using field memory in this e-pilot type VTR.

(Problems to be solved by the invention) As mentioned above, conventionally, the pilot method (7) V
In TR, special playback using field memory was not performed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a special playback device that can perform special playback using field memory in a pilot type VTR.

[Structure of the Invention (Means for Solving the Problems)] In order to achieve the above object, the present invention provides a tape transporting means for transporting a magnetic tape at a speed different from that during recording, and a tape transporting means for this tape transporting means. a control means for controlling the generation of the plurality of reference signals according to the speed; a storage means for storing a specific section of the reproduced video signal according to the order in which the plurality of reference signals are generated; and an image reproducing means for reproducing an image using a video signal.

(Function) As described above, according to the configuration in which the storage timing of the video signal is set according to the generation control of the reference signal, it is possible to store the video signal in a section where an optimal video signal is obtained. Therefore, the special playback used for the field memo IJ' can be performed without any problem even in a Noquilot type VTR.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention.

In the embodiment shown in FIG. 1, access to the field memory 27 is controlled in response to the generation of a reference signal (8).

In FIG. 1, first, ATF control in a pilot type VTR will be explained. In the rotating head 11, I
The reproduced output of the IB is made into a continuous signal by a switch 12. Pantone 4 filter 131t'! The reproduced output of the pilot signal Φ) is extracted from this continuous signal, and the multiplier 14
give to The multiplier 14 multiplies the pilot signal (P) and the reference signal (8) to detect a pilot signal component reproduced as a crosstalk component from both adjacent tracks. The multiplication output of these crosstalk components is f□
, has a frequency of 3fH. However, it is f-1 horizontal frequency. These two multiplication outputs (hereinafter referred to as difference frequency signals)
are level-detected through band-pass filters 15 and 16 and detection circuits 17 and 18, respectively. Then, both transverse wave outputs are differentially amplified by a differential amplifier circuit 19, and the polarity of the differential amplified output SD between tracks is unified by an inverting circuit 20 and a switch 21, thereby generating an ATF error signal indicating a tracking deviation. s2 is obtained. This signal S-ma,
The speed control signal obtained from the speed sensor 22, the frequency dividing circuit 23, and the frequency discriminator 24 is synthesized by the differential amplifier circuit 25,
Controls the capstan motor 26. This controls the running speed of the magnetic tape and eliminates tracking deviation.

Next, the features of this embodiment will be explained.

As described above, in this embodiment, access to the field memory 26 is controlled in response to the generation of the reference signal (6). Here, the reference signal @ is output from the reference signal generation circuit 28, but its generation is controlled by the control circuit 29. That is, the control circuit 29 controls the generation of a plurality of reference signals (odors) according to the slow reproduction speed and the head switching signal (swp) indicating the rotational phase of the rotary heads 11A and IIB. Haslo one playback speed, head switching noculus (
s), and a reference signal (controls the read mode and write mode of the memory 27 according to the order in which smells occur).

As a result, the signal of the specific section of the video signal output from the video signal reproduction processing circuit 26 is stored in the memory 27. Then, the image reproduction circuit 30 reproduces the image according to the video signal stored in the memory 27.

Access to the memory 27 will now be described in more detail with reference to FIGS. 2 and 3. In addition, the second
In the figure, f1 to f4 indicate the frequencies of the pilot signal (P) and the reference signal (A) and (B), respectively.
) respectively indicate tracks traced by IIB on the rotary head 11.

Figure 2 shows the scanning loci of the rotary heads IIA and JIB (however, the track width of the heads is drawn equal to the track pitch) and the distinction between the A channel and B channel of the playback head, taking single-speed playback and τ-times playback as an example. , playback envelope, field memory 27 write/read signal (R
/W)'f, as shown.

In the case of 1x speed playback, the envelope reaches its maximum every third track. However, due to skew, only the signals to be played by heads on the same channel (azimuth) are written.
When reading, signals from every six tracks that satisfy the condition are written into the memory 27 (see the shaded area in the figure). - Even when playing at 7x speed, 8x
Signals from tracks satisfying the above conditions for each track are written into the memory 27.

FIG. 3 shows an example of ATF control in this case. Unlike tracking control that uses control signals, ATF control automatically selects the optimal tracking position, so tracking like this tracking control is not possible. There is no particular need for heels (however, to improve heel performance, a simple twist is required).

Rucking? (There are also ATF-controlled VTRs equipped with a volume.)

For this reason, the generation sequence of the reference signal (6) during reproduction is important. In the case of i-times speed playback in Figure 2, when taken on the gold side, the reference signal (8) corresponds to the scanning track from f3 to f.
3 to f3 is repeated 3 times, then f4 is repeated 3 times, and fl is repeated 3 times.
Times... and so on.

At this time, the difference frequency signal of frequency 3fH9fH and the AF
The signal SD, which can be called the original form of the F error signal, is as shown in the figure. When the tracking position changes, the level of the signal SD changes and maintains a stable point (tracking stable point). Therefore, if the reference signal (odor) is monitored, the interval in which the optimum reproduction signal can be obtained is the frequency fs=
It can be seen that this is the second track in the section that provides the fx reference signal (8). This also matches the trace in FIG.

Similarly, at −x speed, the reference signal (8
) is the second head switching section of the four head switching sections that are output. 11 in the interval determined as the interval in which the optimum reproduced signal can be obtained.

The control circuit 29 sets the memory 27 to write mode,
The video signal from the reproduction processing circuit 26 is written into the memory 27. In other sections, the memory 27 is set to reading mode, and images are reproduced using the stored video signals.

According to this embodiment described in detail above, in the pilot type VTR, according to the generation control of the reference signal (8),
With a simple configuration for controlling access to the memo 27, special playback using the memo 27 can be realized.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other modifications can be made.

[Effects of the Invention] As described above, according to the present invention, the pilot system VTR
Accordingly, it is possible to provide a special playback device that can perform all special playback using field memory.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
This figure and FIG. 3 are diagrams for explaining the operation of FIG. 1. 11 people-, 11B... Rotating head, 13, 15° 16
...Band pass filter, 14...Kake'lL device, J
y. 18...Detection circuit, 19.25...Differential amplifier circuit,
20... Inverting circuit, 12.21... Switch, speed sensor, 23... Frequency dividing circuit, 249 Frequency discriminator, 2
6... Video signal reproduction processing circuit, 27... Field memory, 28... Reference signal generation circuit, 29... Control circuit, 30... Image reproduction circuit.

Claims (1)

[Claims] A tracking deviation is detected from the reproduction output of a plurality of pilot signals having different frequencies that are cyclically recorded one by one on a video track and a plurality of reference signals having different frequencies, and the detected output is Accordingly, in a special playback device for a video tape recorder that performs tracking control between a rotary head and a magnetic tape, a tape transport means for transporting the magnetic tape at a speed different from that during recording, and a tape transport speed according to the tape transport speed of the tape transport means are provided. a control means for controlling the generation of the plurality of reference signals, a storage means for storing a specific section of the reproduced video signal in accordance with the generation control of the plurality of reference signals, and a storage means for storing the video signal stored in the storage means. and an image reproducing means for reproducing images using the special reproducing device.