JPS60107760A - Video tape driving device - Google Patents

Abstract

PURPOSE:To widen an effective recording area, to simplify its constitution, and also to control a tape running phase at a high speed by executing an address comparison of reference address data with time code address data, receiving address error data, and controlling a tape reproducing running phase. CONSTITUTION:A time code address generator receives a synchronizing pulse S1 and a time code clock S2 and outputs time code address data S3. A reference address signal generator 14 receives a reference signal and a reference clock signal, generates reference address data and sends it out to an address comparator 22. The address comparator 22 compares said reference address data with time code address data and outputs address error data corresponding to a phase difference of the synchronizing pulse and the reference signal to a D/A converter 23. An analog address error outputted from the D/A converter is added to a rotating speed error signal obtained by a rotating speed detector 16, sent to a motor driving amplifier 17 and drives a capstan motor, by which a tape running phase is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a videotape drive, and more particularly to a videotape drive for controlling the tape playback running phase of a videotape on which a time code signal is recorded.

Generally, when playing back a recorded tape in a video, tape, or recorder, the video head is scanned along the trajectory of the recorded track at the same tape speed and tape running phase as during recording to produce a high-quality reproduced image. You can get it. However, if the tape speeds are slightly different, the scanning of the video head will gradually deviate from the recorded track trajectory, and if the tape running phase is slightly different, the scanning of the video head will constantly deviate from the recorded track trajectory by a certain amount. High-quality reproduced images cannot be obtained.

In a video tape recorder, such a failure in video-\rad scanning with respect to a recorded track locus is generally referred to as a tracking error.

In conventional videotape devices, in order to prevent such tracking errors, a signal synchronized with the video signal in the longitudinal direction of the tape is recorded at the same time as the video signal when recording the tape, and during playback, this signal is used to match the tape running phase and the video signal. This is achieved by comparing the phases of signals serving as speed standards and controlling the tape playback running phase fJIJ. A signal recorded in the longitudinal direction of the tape for this purpose is generally called a control I track signal.

In addition, conventional videotape devices mainly intended for editing using video tape recorders have video number codes for assigning numbers to each video, and clear separation between each video number code. A time code signal mainly composed of a synchronization code for the control and track signals is recorded on a longitudinal track separate from the control and track signals. Various types of such time code signals have been proposed, but are not currently in practical use.
Needless to say, it is.

In this way, in conventional devices, the aforementioned control track signal and time code signal are recorded on separate tracks, which not only reduces the effective recording area of the tape, but also allows two systems to be used for both signals. The disadvantage was that it was expensive because it required a recording/reproducing circuit.

In addition, in conventional devices, the control track signal that manages the tape running phase and the tie 2 code signal that manages the video number are treated separately. Due to various variations, the tape running phase control and video number control systems do not match, and various performance problems have been pointed out.

Furthermore, conventional devices have a problem in phase comparison using control track signals, and since the phase frequency is the same as the frequency of the synchronization signal of the video signal, and the comparison is at a relatively low frequency, it is necessary to increase the response speed. was difficult.

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks of conventional video devices, and to provide a video tape running phase that can be controlled at high speed by using synchronization pulses and time code clocks included in a time code signal, without requiring a conventional control signal. An object of the present invention is to provide a tape drive device.

According to the present invention, recording is performed in the longitudinal direction of the tape.

In a video tape recorder that plays back a videotape on which a time code signal consisting of a synchronization code corresponding to a simultaneous video signal, a video number, and a number code corresponding to the video tape is recorded, the recorded time code signal is played back. a time code reproducing means for amplifying the reproduced time code signal and outputting the reproduced time code signal; a synchronization pulse detecting means for receiving the reproduced time code signal, detecting the synchronization code, and outputting the reproduced synchronization pulse x'l; a time code clock detection means that receives a signal, detects a clock corresponding to a division of 1-bit data, and outputs a time code clock; and receives the synchronization pulse and the time code clock, and divides one period of the synchronization pulse into equal parts iN. area, i.e. T1
, 'r, yT3...... A time code address generator that outputs time code address data corresponding to TN, and a reference signal that serves as a reference for the video team playback speed and playback running phase, and receives the reference signal. An area that divides one period of 1 into N equal parts, that is, 1. R+2. R3...
A reference address generator that outputs reference address data 'elff' corresponding to R4, an address comparator that receives the reference address data and time code address data, compares both addresses, and outputs address error data, and an address comparator that outputs address error data. There is obtained a videotape drive device characterized in that it comprises means for receiving data and controlling the tape playback running phase.

Next, embodiments of the present invention will be described with reference to the drawings.

. FIG. 1 shows a videotape drive which is an embodiment of the present invention. In FIG. 1, in this embodiment, a capstan motor 1 rotates a capstan and pinches a video tape 14 using a pinch roller (not shown) to make it run.
1, a rotation detecting plate 12 attached to the rotating shaft of the capstan motor 11, and a rotation detecting plate 12 provided opposite to the rotating freezing plate 12, which detects the rotation of the capstan motor 11 and detects the rotation signal. The video tape device includes a transusert that supplies the speed detector 16, a rotation speed detector that measures the rotation speed of the capstan motor and feeds back the signal, and further reproduces and amplifies the time code from the time code recorded tape 14. , a time code reproducing means 18 for outputting a reproduced time code signal, a synchronization pulse detection means 19 for receiving the reproduced time code signal, detecting a synchronization code contained therein, and outputting a reproduction synchronization pulse; A time code clock detection means 20 receives the reproduced time code signal, detects a clock corresponding to a break of 1-bit data, and outputs a time code clock; is divided into N equal parts, i.e. 'r1eT2 yT3
...... A time code address generator 21 that outputs time code address data corresponding to TN, receives a reference signal that serves as a reference for the video tape playback speed and playback running phase, and receives one cycle iN of the reference signal, etc. A reference address generator 2 that outputs reference address data corresponding to the divided areas, that is, R1p, R2v, R3...
4, an address comparator 22 which receives the reference address data and time code address data, compares the two addresses, and outputs address error data; and means which receives the address error data and controls the tape playback running phase. include.

The magnetic head 13 recompresses the time code No. 8 recorded on the video tape 14, amplifies it with the reproduction amplifier 18, and then supplies it to the synchronization pulse detection means 19 and the time code clock detection means 20.

The pulse from the synchronization pulse detection means 19 is a synchronization pulse that is synchronized with the video signal that is recorded and reproduced at the same time, and has properties very similar to the control track signal in a conventional device. The tape running phase is controlled by controlling the phase of the reference signal of the reproduction phase, and the time code address data corresponding to the area equally divided by the synchronizing pulse = iN is shown in FIG. As shown in FIG. 1(b), the reference address data corresponding to the area where the signal t-N is divided into equal parts is a data string with a relatively low frequency and has the same information as the n synchronization pulse and the reference signal, respectively. be. Therefore, by comparing both address data, phase comparison between the synchronizing pulse and the reference signal can be performed at high speed.

In other words, when the synchronization pulse and the reference signal are in phase, as shown in Figure 1, if the values of the time code address data and reference address data at a certain timing are 'r and yR3, respectively, then the synchronization pulse If the data value is T 5 v "7, determine that the phase of the synchronization pulse is ahead by 12# address cycles. .

As described above, in this embodiment, by comparing the address data, it is possible to quickly compare the phase of the synchronizing pulse with respect to the reference signal r. For example, in this embodiment, as shown in the third column, a synchronization code included in the reproduced time code signal is detected and a synchronization pulse S1 is output. In the time code clock detection means 20, 1
A clock corresponding to a break in bit data is detected and a time code clock S2 is output. Furthermore, the time code address generator receives the synchronization pulse S1 and the time code clock S2 and outputs time code address data S3.

Here, the frequency relationship of 81.82.83 is 782 = m/83 (m, N is an integer greater than or equal to 1)'s
s""fs1 fxtle.

On the other hand, the reference signal is sent to the reference address generating means 24 and the reference clock signal generator 25. This reference clock signal generator 25 is means for generating a reference clock signal that is synchronized with the reference signal and has a frequency N times higher, and supplies the reference clock signal to the reference address generation means 24.

The reference address signal generator 14 receives the reference signal and the reference clock signal, generates reference address data, and sends it to the address comparator 22.

The address comparator 22 compares the reference address data with the time code address generator and sends address error data corresponding to the phase difference between the synchronization pulse and the reference signal to the DA converter 2.
Output to 3. The DA converter 13 is a DA converter that receives the address error data and outputs an analog signal, and outputs an analog address error. The analog address error is added to the rotational speed error signal obtained by the rotational speed detector 16 and the motor drive amplifier 17
The tape traveling phase is controlled by the capstan motor sent to the motor and the drive shaft.

As explained above, the present invention not only allows the tape playback phase to be controlled at high speed using the time code signal, and does not require the conventional control track signal, but also provides high-speed control using high-speed comparison that cannot be obtained with the control track signal. In addition, it is possible to record and reproduce other information using the tape area for control track signals, and it is also possible to create a tape format that does not require the control track itself. I'm worried.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing address data for detailed explanation of the present invention,
FIG. 3 is a diagram showing a timing chart of main waveforms of the embodiment. 16...Rotation speed detector, 17...Motor drive amplifier, 18...Time code reproduction amplifier, 19...Synchronization pulse detection means, 20.
...Time code clock detection means, 21...
...Time code address generator, 22...
Address comparator, 23...DA converter, 24.
. . .-Reference address generation means, 25 . . . Reference clock signal generator.

Claims (1)

[Claims] In a videotape recorder for playing back a videotape on which an evening code signal is recorded in the longitudinal direction of the tape and is composed of a synchronization code corresponding to a video synchronization signal, a video number, and a number code corresponding to the video number, a time code reproducing means for reproducing and amplifying the recorded time code signal and outputting a reproduced time code signal; and a synchronization pulse detector for receiving the reproduced time code signal, detecting the synchronization code, and outputting a reproduction synchronization pulse 'kffl'. means for receiving the reproduced time code signal, detecting a clock corresponding to a delimiter of 1-bit data, and outputting a time code clock; 1
A region dividing the period into N equal parts, i.e. 'r1eT2,'r3・
. . . A time code address generator that outputs time code address data corresponding to a reference address generator that outputs the base rate address data corresponding to the area to be processed, that is, "1 * R2y R3...R4, and a reference address generator that receives the reference address data and time code address data and compares the addresses between the two. 1. A video tape drive apparatus comprising: an address comparator for outputting address error data; and means for receiving the address error data and controlling a tape playback running phase.