JPH0824365B2 - Reference signal generator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference signal generation device that can be used in video signal recording / reproducing devices such as VTRs, time base correctors (TBC), peripheral devices such as frame synchronizers.

2. Description of the Related Art When a video signal recording / reproducing apparatus such as a VTR is used to record / reproduce a video signal, a time base fluctuation occurs due to various causes such as uneven rotation of a cylinder and uneven running of a tape. TBC is used as a device for correcting this. In TBC, the correction range is limited by the amount of memory, so the VTR output signal is corrected during normal playback with respect to the timing of the signal to be obtained as TBC output (for example, the same timing as the external reference signal). Servo is applied so that the position is advanced half the width. The servo reference signal for this purpose is created by TBC. Further, in the TBC, various reference signals such as a read reference signal, a synchronization signal for switching to an output signal, and a burst signal are created.

FIG. 2 shows a block diagram of an example of a conventional reference signal generating apparatus which receives and operates a signal from a VTR, and FIG. 3 shows a diagram showing a head arrangement on a cylinder of the VTR. In FIG. 2, 1 is a composite sync signal input terminal separated from the input video signal, 2 is a composite sync signal input terminal separated from the reference video signal, 3 and 4 are frame detectors, 5 to 8 are delay devices,
9 to 12 are switches, 13 to 16 are control signal input terminals representing the VTR mode and the reproducing head and their signals, 17, 18
Is a reference signal generator, and 19 and 20 are reference signal output terminals.
Now, as shown in FIG. 3, as the VTR, the rotation erasing heads A and A ', the recording / reproducing heads B and B', and the reproducing heads C and C'are
Each is placed on a rotating cylinder at intervals of 60 °, 180
Consider that one field is recorded during rotation and recording can be performed with C and C'while recording with B and B '. The TBC correction range will be described as ± 16H (H: 1 horizontal scanning period). The VTR mode is a mode in which the input video signal is output only by electrical processing during recording or standby (EE), and a mode in which the signal reproduced by the C head during recording is output (simultaneous Playback), normal playback, and playback during editing. ， Mode of the VTR
The output video signal of is synchronized with the input video signal. However,
In the mode, the mounting angles of the B, B'heads and the C, C'heads are 60 °, that is, 1/3 V (V: 1 vertical scanning period) delayed from the input video signal. Further, in this mode, the servo is applied in synchronization with the input video signal in order to obtain continuity at the joint of editing, so that the output video signal is also synchronized with the input video signal in this mode. In the mode, in order to synchronize (match) the video signal of the TBC output with the external reference video signal or internal reference signal, the VTR is servoed with the reference signal 20 created from the external or internal reference signal, and the external or external VTR output is used. A signal that is 16H ahead of the internal reference signal as the center value is obtained. Furthermore, in the mode of ,, TB which is delayed by 16H as the center value from the VTR output video signal
A reference signal 19 for replacing the C reading force synchronization signal is created.

Next, the operation of FIG. 2 in each mode will be described.
In the E-E mode, the VTR video output signal has almost the same timing as the input video signal. Therefore, a signal obtained by delaying the frame signal generated by the frame detector 3 by the 16H delay device 5 from the input synchronization signal applied to the terminal 1 is passed through the H side terminal of the switch 11 and the H side terminal of the switch 12 and then the reference signal. It leads to a generator 17 and creates various reference signals 19 for TBC reading and synchronizing signal replacement, which are delayed by 16H from the input video signal. Further, the output signal of the frame detector 3 is guided to the reference signal generator 18 via the H-side terminal of the switch 9 to generate the servo reference signal 20. During simultaneous playback of, the VTR output video signal is delayed by 1 / 3V from the input video signal. Therefore,
The switch 11 is connected to the L side and the switch 12 is connected to the H side, and the signal 19 is created from the signal delayed by 1 / 3V + 16H by the delay unit 6. Signal 19 is the same as mode. At the time of editing and reproducing of, the signal 19 is the same as in the previous two modes. Therefore, the VTR output video signal is almost the same as the input video signal when reproduced by the recording head (however, there is a time axis fluctuation), so the switch 11 is connected to the H side,
12 is connected to the H side and is 1 as the center value from the VTR output signal
A reference signal 19 delayed by 6H is obtained. Also, when the playback head is playing, the VTR output video signal is delayed by 1 / 3V from the input video signal (with time axis fluctuation). Therefore, the switch 11 is L
Side, the switch 12 is connected to the H side, and a similar reference signal 19 is obtained. Next, during normal reproduction of, the switch 9 is connected to the L side. When reproducing the recording / reproducing head, switch 10 is L
The frame signal generated by the frame detector 4 from the sync signal of the reference video signal applied to the terminal 2 (internal reference sync signal when not applied)
The signal advanced by 16H (actually delayed by 1V-16H) is applied to the reference signal generator 18,
The servo reference signal 20 advanced by 16H is obtained. Since the servo is applied based on the position of the recording / playback head, the VTR output video signal and the servo reference video signal have almost the same timing when the recording / playback head is played back, and the VTR output video signal is Almost 1 / 3V from servo reference signal
Running late. Therefore, when reproducing the reproducing head, the switch 10 is connected to the H side, and the signal advanced by 1 / 3V + 16H by the delay device 8 from the output signal of the frame detector 4 is the reference signal generator 1.
8 is applied to produce a servo reference signal 20. In this way, a signal that is approximately 16H ahead of the reference video signal is obtained at the VTR output. In the mode, the switch 12 is connected to the L side, and the reference signal 19 has the same timing as the reference synchronizing signal of the terminal 2.

In this example, the control signals 13-16 are sent from the VTR.
The control signal 16 is a signal indicating that the VTR outputs a video signal synchronized with the input video signal.

By the way, in the reference signal generating apparatus as described in the example of FIG. 2, it is necessary to exchange many control signals with the VTR main body. In the case of a TBC with a built-in VTR, there is no big problem, but when connecting an external TBC to a portable VTR, for example, in terms of the space of the connector,
It is preferable to exchange as few signals as possible.

From this point of view, we have previously proposed an example of a method for reducing the exchange of signals with the VTR. A block diagram of this example is shown in FIG. 4 and will be described. In FIG. 4, the same numbers as in FIG. 2 represent the same items. 21 is a signal application terminal (or its signal) related to the signal indicating that the VTR is outputting a video signal synchronized with the input video signal and the vertical synchronizing signal of the input video signal at that time, and 22 is the presence or absence of the signal 21. A detector 23 for detecting the signal, 23 is an application terminal (or a signal thereof) of a signal indicating the mode of the VTR and the selection of the reproducing head.

In the configuration in which the VTR and TBC are connected and used as separate devices, it is necessary for the VTR to operate independently, and a signal related to the vertical synchronizing signal of the input video signal, that is, a frame signal is created inside the VTR, It has a function to apply. Therefore, in the embodiment of FIG. 4, when the VTR outputs a video signal synchronized with the input video signal to the terminal 21 (mode in the description of the example of FIG. 2,), the frame signal is received, In other cases (mode), no signal is transmitted. The signal received at the terminal 21 is guided to the signal detector 22 and outputs a high level when there is a signal at the terminal 21 and a low level when there is no signal at the terminal 21. The switch 12 is connected to the H side when the output of the signal detector 22 is at a high level, and based on the signal obtained by delaying the signal 21, various reference values for TBC reading and video output signal replacement by the reference signal generator 17 are provided. Signal 19 is created.
Further, to the terminal 23, a control signal 23 of a high level in the mode, a low level in the mode, a high level in the case of the recording / reproducing head and a low level in the case of the reproducing head is transmitted in the cases of and. The signal 23 is inverted by the inverter 25 and applied to one input of the NAND gate 24. NA
The output of the signal detector 22 is applied to the other input of the ND gate 24, and its output is high level in the mode, low level in the mode, and is not reproduced by the recording / reproducing head in the mode. High level, low level when reproducing head. The switch 11 is controlled by the output of the NAND gate 24, and is connected to the H side when the level is high and the L side when the level is low.
Therefore, when the recording / reproducing head is reproduced in the modes and modes, the reference signal 19 is created by the signal 16 delayed by the delay device 5 by the delay device 5, and when reproducing the reproducing head in the modes and modes, the signal 21 is generated by the delay device 6. The reference signal 19 is created by the signal delayed by 1 / 3V + 16H. In either case, the reference signal delayed by 16H (median value of the correction range of TBC) as the central value from the output video signal of the VTR is obtained.

When the VTR outputs a video signal synchronized with the internal reference signal applied to the external reference signal applied to the terminal 2 or externally applied to the terminal 2, that is, in the mode, the signal is applied to the terminal 21. Since it is not transmitted, the output of the signal detector 22 becomes low level, and the switch 12 is connected to the L side. Therefore, the reference signal from the frame signal generated by the frame detector 4 is calculated from the reference synchronization signal applied to the terminal 2.
Is created. In the mode, the signal 23 becomes high level when the recording / reproducing head is reproduced, the switch 10 is connected to the L side, and the output signal of the frame detector 4 is delayed by the delay device 7.
Servo reference signal 20 created from 16H advanced signal is terminal 2
Output from 0 to VTR. Further, when reproducing the reproducing head, the signal 23 becomes low level, the switch 10 is connected to the H side,
The reference signal 20 for the servo created from the signal that the output signal of the frame detector 4 is advanced by 1 / 3V + 16H by the delay device 8 is from the terminal 20.
Output to VTR. In either case, the servo is applied based on the position of the recording / reproducing head by the reference signal 20, and the VTR
The output video signal is at a position 16H ahead of the center value of the terminal 2 or the reference signal inside.

A VTR that does not have a read-only head but has only a recording / playback head is also possible.
In, it is not necessary to transmit the signal 23. At this time, the input of the inverter 25 automatically becomes high level, and the switch 10
Becomes the L side and the switch 11 becomes the H side, and the recording / reproducing head mode is set.

Problems to be Solved by the Invention According to the configuration of FIG. 4, the required operation can be performed with a connection with a small number of VTRs and TBCs. However, in order to perform the most complete operation in the points described below, another control signal from VTR is required.

The first problem is that the reference signal generator based on the signal obtained by advancing the frame signal produced by the frame detector 4 by the delay device 7 or 8 from the composite sync signal separated from the reference video signal applied to the terminal 2. The present invention relates to control of switching (switch 10) between the delay devices 7 and 8 when the servo reference signal 20 is generated by 18. In the example of FIG. 4, the switch 10 is connected to the L-side contact (signal 23: high level) in the above-mentioned mode (EE). This is necessary to connect the switch 11 to the H side in the EE mode.

When shifting from EE (mode) to normal reproduction (mode) by the reproducing head, the switch 10 switches from the L side to the H side and supplies the servo reference signal to the VTR. This time,
Since the phase of the servo reference signal changes, it takes time for the cylinder to lock, and the image is disturbed during this time.

The second problem is that the signal for switching the switches 11 and 12 is created by detecting the presence or absence of the signal 21 of 30 Hz by the signal detector 22, so that when the signal 21 is applied, it passes at substantially the same time. The output signal can be obtained, but when the signal 21 disappears, it takes some time to detect it, and a delay occurs in switching the switches 11 and 12.

The reference signal generating device of the present invention is a signal related to a first external or internal reference signal to be synchronized with a video output signal reproduced from a video signal recording / reproducing device having a rotary head cylinder. Delay means for delaying, a reference signal generating means for generating a second reference signal which is advanced from the output video signal by a predetermined time from the output of the delay means, a switching means for switching the delay amount of the delay means, and a recording / reproducing operation. An identification information input terminal for inputting the identification information of the head used when the device mode and playback are being performed, and a selection information input terminal for inputting the selection information of the head to be used for playback. If the selection information is not applied to the selection information input terminal, it is used when reproduction is performed only by the information applied to the identification information input terminal. Depending on the mounting position of the head on the rotating cylinder, and when the selection information is applied to the selection information input terminal, by both the selection information and the information applied to the identification information input terminal, Depending on the mounting position on the rotating cylinder of the head that is being played during playback, or the head that is going to be used for playback when playback is not running,
It is characterized in that the delay amount of the delay means is switched.

Further, the reference signal generating apparatus of the present invention is an input video signal output by the video signal recording / reproducing apparatus when the video signal recording / reproducing apparatus having the rotary head cylinder outputs the video signal synchronized with the input video signal. Of the vertical synchronizing signal as an input, delay means for delaying the related signal, discriminating means for discriminating the presence or absence of the related signal, and an input signal to the reference signal producing means according to the result of the discriminating means. And the determination means determines that the vertical synchronization signal is present at the timing of a signal delayed from the output of the delay means by a predetermined time from the output video signal of the video signal recording / reproducing apparatus. If the means determines that the third reference signal has a vertical synchronizing signal at the timing of the first reference signal applied from the outside or internally generated When the reference signal creating means to be created and the information indicating whether or not the video signal recording / reproducing apparatus outputs the video signal synchronized with the input video signal are input, the video signal recording / reproducing apparatus uses the information to inform the video signal recording / reproducing apparatus. When the video signal synchronized with the input video signal is being output, the vertical synchronizing signal is provided at the timing of the signal delayed from the output of the delay means by the predetermined time from the output video signal of the video signal recording / reproducing device. The switching is performed so as to generate a third reference signal having a vertical synchronizing signal at the timing of the first reference signal applied from the outside or internally generated when the video signal synchronized with It is characterized in that it is provided with a switching means for performing.

With the configuration of the present invention as described above, it is possible to obtain a substantially satisfactory function from the device shown in FIG.
From a device with sufficient space, output the head selection information and a signal indicating that the video signal synchronized with the input video signal is output together to switch the switch in the TBC, and the state to be played next. The servo can be locked in advance, and the signal that is the basis for creating the reference signal can be switched quickly.

Embodiment An explanation will be given of a block diagram of an embodiment of the present invention in FIG. In FIG. 1, the same numbers as those in FIGS. 2 and 4 represent the same items and operate in the same manner. 26 is the head selection information (or its application terminal) at the time of reproduction, 27 is the information (or its application terminal) indicating that the VTR is outputting the video signal synchronized with the input video signal, and 28 and 29 are the gates. Is.

In the E-E mode, the signal 23 is at a high level and a signal related to the vertical synchronizing signal of the input video signal is applied to the terminal 21,
The output of the signal detector 22 is at high level. Further, a signal 27 that is high level when the VTR outputs a video signal synchronized with the input video signal and is low level otherwise is applied to the terminal 27. That is, the signal 27 is at a high level during EE. Therefore, in the EE mode, the output of the NAND gate 24 becomes high level, the output of the AND gate 29 becomes high level, the switch 11 is connected to the H side, the switch 12 is connected to the H side, and the output of the reference signal generator 17 is output. The signal 19 is delayed by 16H from the signal 21, and a video signal delayed by 16H from the input is obtained at the TBC output. Immediately after this, when shifting to the normal reproduction (mode) by the reproducing head, the signals 23, 21 and 27 are kept in the above-mentioned state until the servo is locked, the image of EE is output, and the terminal 26 In advance, the head selection information during playback (playback head: low level, recording / playback head:
(High level) is applied (currently it is low level because of reproducing head reproduction), the output of the NAND gate 28 is set to high level, the switch 10 is connected to the H side, and the output of the frame detector 4 is 1 / 3V +
Servo reference signal 2 with reference signal generator 18 from the signal advanced by 16H
Create 0 to lock the servo before the video output switches to playback. If the output terminal for the signal 26 cannot be provided in a small VTR, the level of the terminal 26 automatically becomes high level, and the switch 10 is controlled by the signal obtained by inverting the signal 23 with the gate 28, the same as in FIG. To work.

In addition, since a high level is applied to the terminal 27 when the VTR outputs a video signal synchronized with the input video signal, and a low level is applied when the VTR outputs the video signal in reverse, for example, when switching from EE to normal playback. Immediately, the signal 27 becomes low level, and therefore the output of the AND gate 29 becomes low level, the switches 11 and 12 are immediately switched to the L side, and the timing of the VTR output video signal and the synchronizing signal or burst signal added to it are matched. Can be made. In connection with a VTR which does not have an output terminal for the terminal 27, the level of the terminal 27 automatically becomes high, and the switches 11 and 12 perform the same operation as in the example of FIG.

When miniaturization is required, the VTR can be configured with one that has a control signal output terminal as shown in the example in Fig. 4, and when space is available, the signal 26 and signal 27 are further output to achieve high performance. Can be changed.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to add a control signal when the video signal recording / reproducing apparatus which is required to be downsized has a sufficient function and further high performance is required. Due to
A reference signal having a more sufficient function can be created to perform servo and TBC operations.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG.
FIG. 4 is a block diagram showing an example of a conventional reference signal generator, and FIG. 3 is a plan view showing an example of head arrangement on a head cylinder used in the present invention and the conventional example. 5,6,7,8 …… Delay device, 17,18 …… Reference signal generator, 21,23,
26,27 …… Control signal input terminal, 28,29 …… Gate, 10,11,
12 ... switch.

Claims (2)

[Claims] 1. A first video output signal reproduced from a video signal recording / reproducing apparatus having a rotary head cylinder should be synchronized.
Of delaying means for delaying a signal related to an external or internal reference signal, reference signal producing means for producing a second reference signal advanced from the output video signal by a predetermined time from the output of the delaying means, and the delay means. Switching means for switching the delay amount,
An identification information input terminal for inputting information for identifying the mode of the recording / reproducing apparatus and a head used during reproduction, and a selection information input terminal for inputting selection information of a head to be used for reproduction. And when the selection information is not applied to the selection information input terminal, only on the information applied to the identification information input terminal, on the rotary cylinder of the head being used during reproduction. When the selection information is applied to the selection information input terminal in accordance with the mounting position of, the reproduction is performed at the time of reproduction by both the selection information and the information applied to the identification information input terminal. The amount of delay of the delay means depending on the mounting position on the rotating cylinder of the head to be used for reproduction when reproduction is not being performed. Reference signal generating apparatus according to claim. 2. A video signal recording / reproducing apparatus having a rotary head cylinder outputs a video signal synchronized with an input video signal, the video signal recording / reproducing apparatus outputs the video signal.
A signal related to the vertical synchronizing signal of the input video signal is input and a delay means for delaying the related signal, a judging means for judging the presence or absence of the related signal, and a reference signal creating means according to the result of the judging means. If the discriminating means discriminates that the input signal is switched, the vertical synchronizing signal is provided at the timing of the signal delayed from the output of the delay means by the predetermined time from the output video signal of the video signal recording / reproducing device. When the determination means determines that there is nothing, a reference signal generating means for generating a third reference signal having a vertical synchronizing signal at the timing of the first reference signal applied from the outside or internally generated. When information indicating whether or not the video signal recording / reproducing apparatus outputs a video signal synchronized with the input video signal is input, this information is used to determine the video signal recording / reproducing device. Has a vertical synchronizing signal at the timing of a signal delayed from the output of the delay means by a predetermined time from the output video signal of the video signal recording / reproducing device when the video signal synchronized with the input video signal is output. When the video signal synchronized with the signal is not output, the third reference signal having the vertical synchronization signal at the timing of the first reference signal applied from the outside or generated internally is generated. A reference signal generating device comprising switching means for switching.