JPH01248896A - Dubbing device - Google Patents

Abstract

PURPOSE:To simplify a signal route and to prevent a signal from deteriorating by separating a regenerative video signals into a luminance FM signal and a low band converting carrier chrominance signal, synthesizing the signal to identify the reproduced track and the low band converting carrier chrominance signal, and supplying the synthesizing signal and the equalization-processed luminance FM signal to a reproducer. CONSTITUTION:The regenerative video signals are supplied to a high pass filter HPF and a low pass filter LPF, and separated into the luminance FM signal and the low band converting carrier chrominance signal. A reproducing equivalent processing is executed to the luminance FM signal outputted from a HPF 25 by an equalization circuit 27. The low band converting carrier chrominance signal outputted from a LPF 26 is returned to chrominance sub-carrier frequencies by a balance modulating circuit 32. Further, it is made to pass through a 1H comb-line filter 33, and the stroke of the chrominance signal is eliminated. Further, it is supplied to an adder circuit 38, and added and synthesized with a track identifying signal and a dubbing period designating signal. Then, the regenerative video signal is supplied to a recording machine in the condition of the luminance FM signal and the low band converting carrier chrominance signal. Consequently, the signal route is simplified, and the signal can be prevented from deteriorating.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention uses, for example, two home-use helical scan video tape recorders (hereinafter, video tape recorders are referred to as VTRs). The present invention relates to a dubbing device suitable for dubbing video signals.

(Prior Art) When dubbing a video signal using a home helical scan type VTR, normally, as shown in FIG.
Prepare two TRs and play one! 111, and the other is used as a recording device 12. In this case, signals are generally received and passed between the reproduction 1fi 11 and the recording 1112 using a high frequency signal via a line input/output terminal or a VHF signal via a tuner.

However, in this configuration, the video signal passes through two signal processing circuits, a playback signal processing circuit and a recording signal processing circuit, and also passes through nonlinear circuits such as a nonlinear emphasis circuit and a noise canceller circuit, resulting in significant signal deterioration. There's a problem.

On the other hand, in a dubbing device using a U-matic type VTR, terminals of the dubbing device are provided in the playback device 11 and the recorder 12, and as shown in FIG. The signal is received and passed separately from the carrier color signal. In this case, the playback device 11
The drum servo reference signal for recording vs12 is obtained from the synchronization signal included in the luminance signal as usual.

According to such a configuration, the signal path of the color signal is simplified, so that deterioration of the color signal can be prevented.

However, although the configuration of FIG. 10 can prevent the deterioration of the color signal, it cannot prevent the deterioration because the signal path of the luminance signal is no different from that of FIG. 1.

In order to prevent the deterioration of the luminance signal and color signal,
No. 4879 and Japanese Patent Publication No. 61-24880 disclose a dubbing device that inputs and outputs a reproduced video signal by dividing it into a frequency-modulated luminance signal (hereinafter referred to as a luminance FM signal) and a low-frequency conversion carrier color signal. is disclosed.

According to such a configuration, the signal path of not only the color signal but also the luminance signal is simplified, so that deterioration of both signals can be prevented.

However, with this configuration, the level of the reproduced low-pass conversion carrier color signal is adjusted so that the color burst signal is constant, and only the level of the color burst signal in the carrier color signal is reduced (expanded by the amount However, in β■, VH83x mode, etc., there is a problem that the color signal crosstalk is large and a very large flicker beat remains.This crosstalk problem is caused by the U-matic type VTR. However, this is because this VTR uses the guard band recording method as the signal recording method, and it is necessary to consider other removal means for VTRs that use the azimuth recording method as the signal recording method. be.

In addition, the dubbing device described in the above publication must send a reference signal for the drum servo obtained from the drum servo related signals of the player through a separate channel in order to match the drum servo rotational phases of the player and the recorder. There was a problem that it had to be done.

Furthermore, in home VTRs that use the azimuth recording method as a signal recording method, color signals are generally recorded using a phase inversion (PI) method or a phase shift (PS) method in order to eliminate zero stalks in the color signal. It is set to play. Therefore, even during dubbing, in order to obtain the crosstalk removal effect of the PI method or PS method, it is necessary to match the playback track and the recording track so that the PI logic or PS logic of the playback device and the recorder match. . However, conventionally, no countermeasures have been taken for this purpose.

(Problems to be Solved by the Invention) As described above, in conventional dubbing III, deterioration of the luminance signal and color signal due to the complexity of the signal path can be prevented, but the color signal in azimuth recording It was not possible to eliminate crosstalk interference.

Furthermore, the reference signal for the drum servo must be sent on a separate channel, resulting in a problem that the transmission band becomes wider.

Furthermore, no measures have been taken to associate the reproduction tracks with the recording tracks so that the PI logic or PS logic of the reproduction machine and the recording machine match.

Therefore, this invention solves the problem of signal path? ! Not only is it possible to prevent signal deterioration due to noise, it is also possible to remove color signal crosstalk interference, and it is possible to prevent an increase in the transmission band due to the drum servo reference signal.
A further object of the present invention is to provide a dubbing device that can associate reproduction tracks and recording tracks so as to match PI logic or PS logic.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the present invention, a reproduced video signal is separated into a luminance FM signal and a low frequency conversion carrier color signal. The luminance FM signal is equalized so that it has almost the same signal state as when recording. The low-frequency converted carrier color signal is returned to the original high frequency according to the converted idler signal, and in this state, after crosstalk components from adjacent tracks are removed, it is converted back to the low frequency using the same signal as the idler signal. be done.

Further, in the present invention, a signal for identifying a playback track is generated in synchronization with a vertical synchronization signal of a playback video signal, and is combined with the low-frequency conversion carrier color signal. This composite signal and the equalized luminance FM signal are supplied to a regenerator.

(Function) According to the above configuration, since the reproduced video signal is supplied to the recording hoe in the state of a luminance FM signal and a low frequency conversion carrier color signal, these signal paths are simplified, and the problem caused by the complication of the signal path is simplified. signal deterioration can be prevented.

Further, since the low-pass converted carrier color signal is once returned to its original high-frequency range and passed through a comb filter, crosstalk of the color signal can be removed.

Furthermore, since the track identification signal is superimposed on the low frequency conversion carrier color signal, the tracks can be associated so that the PI logic and PS logic match.

Furthermore, since the track identification signal is synchronized with the reproduction vertical synchronization signal, this signal can be used as a reference signal for drum servo. Therefore, there is no need to transmit this reference signal on a separate channel from the reproduced video signal, and an increase in the transmission band can be prevented.

(Embodiments) Hereinafter, embodiments 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 this FIG. 1, 21 is a reproducing machine, and 45 is a recording machine. These reproducing device 21 and recording device 1145 are helical scan type VTRs.

In the reproducing device 21, the video signal reproduced from the video chip 722 by two rotary heads 23 (for convenience, one rotary head 23 is shown in the figure) is amplified by a reproducing amplifier 24. This amplified output is supplied to a bypass filter (hereinafter referred to as HPF) and a low-pass filter (hereinafter referred to as LPF), and is separated into a luminance FM signal and a low-pass conversion carrier color signal.

1-The i[FM signal output from the IPF 25 is subjected to reproduction equalization processing in the equalization circuit 27, and then passed through the automatic gain control circuit (
The amplitude is made constant by an AGC circuit (hereinafter referred to as an AGC circuit) 28. The output of this AGC circuit 28 is the FM equalization processing circuit 2
9, the signal is supplied to a delay circuit 30 for time alignment with the low frequency converted carrier color signal which has undergone equalization processing to become a signal equivalent to the luminance FM signal during recording.

The low frequency conversion carrier color signal output from the LPF 26 is as follows:
After the amplitude is made constant by the automatic color killer circuit (ACC circuit), it is returned to the color subcarrier frequency by the parallel modulation circuit (B, M, >32).The carrier color signal returned to the original high frequency is The crosstalk of the color signal is removed from the carrier color signal.The carrier color signal from which this crosstalk has been removed is passed through the parallel modulation circuit 34, which modulates the frequency in the low range. converted.

Idler signals for frequency conversion of the parallel modulation circuits 32 and 34 are output from the idler signal generation circuit 35. In this case, the idler signal generation circuit 35 generates a PI-converted (or PS-converted) idler signal. Further, this idler signal generation circuit 35 forms an automatic phase control circuit (APC circuit) together with the parallel modulation circuit 32.1H comb filter 33'' and the reference signal generation circuit 36, and the output from the reference signal generation circuit 36 is The idler signal is generated by aligning one phase of the carrier color signal output from the comb filter 33 with the reference signal.

The low frequency conversion carrier color signal output from the balanced modulation circuit 34 has unnecessary components removed by the LPF 37, and is then supplied to the adder circuit 38, where it is added and combined with the track identification signal and the dubbing period designation signal.

In this case, the track identification signal and the dubbing period designation signal are superimposed on the low frequency conversion carrier color signal using the vertical blanking period. ' The track identification signal is generated as follows.

In the figure, numeral 39 is a pulse generator that detects the rotational speed of a rotating drum on which two rotating heads 25 are provided.

The output of this pulse generator 39 is supplied to a servo circuit 40. This speed control circuit 40 generates head switching pulses for selectively selecting reproduction outputs of the two rotary heads 23- and controlling the rotational speed of the rotary drum according to one output of the pulse generator 39. Outputs various control signals such as speed control signals. Among these, the head switching pulse is supplied to the track identification signal generation circuit 41. This track identification signal generation circuit 41 generates a track identification signal indicating a reproduced track in accordance with the head switching pulse. In this case, the track identification signal generation circuit 41 outputs this track identification signal in synchronization with the reproduction vertical synchronization signal. This vertical synchronization signal is given as follows. That is, the AGC circuit 28
The luminance FM signal output from is further supplied to the luminance demodulation/reproduction processing circuit 42, where it is FM demodulated and
A predetermined regeneration process is performed. The luminance signal output from the luminance demodulation/reproduction processing circuit 42 is supplied to a vertical synchronization signal separation circuit 43, where the vertical synchronization signal is separated. This separated vertical synchronization signal is supplied to the track identification signal generation circuit 41 as a reproduced vertical synchronization signal.
゛The above dubbing period designation signal - microprocessor 4
Output from 4. This microprocessor 44 also serves to control various playback operations. Note that the dubbing period designation signal includes, for example, a start signal indicating the dubbing end timing and a stop signal indicating the dubbing end timing.

The luminance FM signal output from the delay circuit 30 and the addition circuit 3
The low-pass conversion carrier color signal output from 8145 is supplied to recording 8145.

The luminance FM signal supplied from the delay circuit 30 is sent to the recording equalization circuit 46 and then to the addition circuit 4.
7. On the other hand, the output of the adder circuit 38 is supplied to a color signal separation port 48, where the low frequency conversion carrier color signal is separated. This low-pass conversion carrier color signal is
The signal is added and synthesized with the luminance FM signal based on the input signal. ``The video signal obtained by this additive synthesis is amplified by the recording amplifier 49, and then supplied to two rotary heads 50 (for convenience, 111 rotary heads 50 are shown in the figure), and ``recorded on a video tape 51.'' Ru.

The output of the adder circuit 38 is further processed by a track identification number separation circuit 52 and a dubbing period designation signal separation circuit 53.
is supplied to The track identification signal separation circuit 52 separates the track identification signal from the input signal and supplies it to the servo circuit 54. This servo circuit 54 uses the track identification signal as a reference signal and controls the rotation of the two-rotation drum so that the rotational phase of the rotary head 50 matches the phase of this reference signal. In this case, since the track identification signal is synchronized with the vertical synchronization signal of the video signal to be recorded, the rotational phase of the rotary head 50 is synchronized with the recording signal. Also, since this track identification signal indicates the reproduced track, by controlling the rotation phase of the rotary spatula 1500 using this as a reference signal, the PI of the low frequency conversion carrier color signal is
It is possible to associate the reproduction track with the recording track so that the logic (or PS logic) matches.

The dubbing period designation signal separation circuit 53 separates the dubbing period designation signal from the input signal and supplies it to the microprocessor 54. By controlling the operations of the recording amplifier 49 and the rotary head 50 in accordance with this dubbing period designation signal from the microprocessor 54, the video signal is recorded only during the dubbing period.

The overall configuration and operation of the dubbing apparatus have been described above, and now the track identification signal and dubbing period designation signal will be described.

First, the track identification signal will be explained.

As mentioned above, this track identification signal (1) functions as a reference signal for controlling the rotational phase of the rotating cylinder (2) adjusts the azimuth of the reproduction track and recording track so that the PI logic (or PS logic) matches. It has two functions: a matching function.

In order to obtain the function (1), a track identification signal synchronized with the reproduction vertical synchronization signal is required.

In order to obtain the function (2), in the PI method, the logic of the idler signal supplied to the balanced modulation circuit 34 must be the same as that during recording (however, the logic of the idler signal supplied to the balanced modulation circuit 34 must be the same as that at the time of recording (however, the For channels (CH), the order of 0° and 180° is reversed, but this is corrected because the dubbing tape player has a burst ID). On the other hand, in the PS system, the 90° shift rotation is reversed from that during recording, so the playback device 21 and the recording I! At 145, a rotating head with reverse azimuth must be selected.

Therefore, in this embodiment, the track identification signal is synchronized with the reproduced vertical synchronizing signal, and is inserted into the low frequency conversion carrier color signal every vertical scanning period.

Also, regarding this insertion position, the opposite positions are selected between the PI method and the PS method. This situation is shown in the second cause. - In this FIG. 2, Sl is a track identification signal, and S2 is a low frequency conversion carrier color signal.

Although the track identification signal S1 is shown as a negative polarity signal in FIG. 2, it goes without saying that it may be a positive polarity signal. Further, in the PI system, either the track identification signal S1 indicating a 180° section or the track identification signal S1 indicating a 0° section may be used. Similarly, in the PS system, a track identification signal S1 indicating a positive polarity 90' shift interval (positive rotation), a track identification signal S1 indicating a negative polarity 90° shift interval (negative rotation)
It can be either. Further, although FIG. 2 shows a mode in which channel A is shown on the recording side, a mode in which channel B is shown may also be used.

FIG. 3, FIG. 4, and FIG. 5 show specific examples of the format of the track identification signal S1.

First, in the example shown in FIG. 3, an NTSC signal is prepared that includes a horizontal synchronizing signal HD and a vertical synchronizing signal VD, and also includes a luminance signal expressed as a DC signal. By setting the width to, for example, 6H, which is different from the original width of 3H, this is used as the track identification signal S1.

~ According to such a configuration, since the synchronization signals can be easily separated, there is an advantage that the track identification signal S1 inserted as the vertical synchronization signal VD can be easily separated.

The example shown in FIG. 4 is obtained by removing the horizontal synchronization signal HD from the example shown in FIG.

The example shown in FIG. 5 does not use the NTSC signal format, but instead inserts a sine wave burst signal with a frequency of 2 MHz or higher, for example, as the track identification signal S1. In this case, by setting the frequency of the sine wave burst signal to 2 MHz or more, since the frequency of the low-pass conversion carrier color signal is about 1.5 MHz, it can be easily separated with a filter.

The third factor and the track identification signal S1 shown in FIG. 4 can be easily generated by using a switching transistor with a pulse width changing circuit, for example, and the track identification signal S1 shown in FIG. It can be easily generated using a circuit.

Next, the dubbing period designation signal will be explained.

FIG. 6 shows the example of FIG. 2 in which a dubbing period designation signal S3 is inserted.

7 and 8 show the example of FIG. 5 in which a dubbing period designation signal S3 is inserted.

Further, FIGS. 6 and 7 show the dubbing period designation signal S
An example in which a sine wave burst signal is used as No. 3 is shown below. In the example shown in FIG. 8, P is set as $3 as the dubbing period designation signal.
A CM modulated signal is used.

Also, as a method for identifying the start and end of a dubbing period, for example, when instructing to start, insert a dubbing period designation signal into channel A, and when instructing to end, insert a dubbing period designation signal into channel A. This can be realized by inserting 83. In addition to this, identification can also be made by changing the insertion time width or frequency of the dubbing period designation signal S3.

The example of FIG. 8 has the advantage that the dubbing period designation signal S3 can be detected using the track identification signal @S1 as the clock run-in signal. This also applies when a PSK modulation signal or a FSKII' tone signal is used in addition to the PCMII tone signal as the dubbing period designation signal S3.

According to this embodiment described in detail above, the reproduced video signal is recorded in the state of the luminance FM signal and the low frequency conversion carrier color signal.
These signal paths are simplified, and signal deterioration due to complication of the signal path can be prevented.

Further, since the low-pass converted carrier color signal is once returned to its original high-frequency range and passed through the comb-shaped filter 33, crosstalk of the color signal can be removed.

In addition, since the track identification signal is superimposed on the low frequency conversion carrier color signal and supplied to the recorder 45, P1 logic and P
Tracks can be associated so that their S logics match.

Furthermore, since the track identification signal is synchronized with the vertical synchronization signal of the reproduced video signal, this signal can be used as a reference signal for drum servo. therefore,
There is no need to transmit this reference signal on a separate channel from the reproduced video signal.

Furthermore, since the same idler signal outputted from the idler signal generation circuit 35 is used to perform inverse frequency conversion and frequency conversion of the carrier color signal, the balanced modulation circuit 34 outputs
It is possible to obtain a low-pass conversion carrier color signal having the same frequency as the original low-pass conversion frequency, and a low-pass conversion carrier color signal having the same time base as the luminance FM signal.

Furthermore, since the dubbing period designation signal is transmitted, it is possible to improve the operability of editing.

Furthermore, since the dubbing period designation signal is transmitted while being superimposed on the low-frequency conversion carrier color signal, there is no need to transmit it on a separate channel.

Incidentally, in the present invention, it goes without saying that the reproducing device 1 and the recording device 45 may be made into an independent unit or may be made into an integral unit.

[Structure of the Invention] According to the present invention, it is possible to prevent signal deterioration caused by complication of the signal path, and also to eliminate crosstalk interference of color signals. It is possible to prevent the transmission band from increasing due to the reference signal, and furthermore, it is possible to associate the reproduction track and the recording track so as to match the PI logic or PS logic.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of one embodiment of the present invention, FIGS. 2 to 5 are signal waveform diagrams showing track identification signals of one embodiment, and FIGS. 6 to 8 are dubbing diagrams of one embodiment. A signal waveform diagram showing a period designation signal, the ninth factor is a circuit diagram showing the configuration of an example of a conventional dubbing device, and FIG. 10 is a circuit diagram showing another example of the conventional dubbing device. 21...Player, 22.51-...Video tape, 2
3.50... Video head, 25... Recording preamplifier, 25-) IPF, 26.37... LPF, 27
... Reproduction equalization circuit, 2 B-A G C circuit, 29.
-FM equalization circuit, 30-...delay circuit, 31...A
CC circuit, 32.34-...Equilibrium! Im circuit, 33-I
H< L-type filter, 35...Idler signal generation circuit, 36...Reference signal generation circuit, 38.47-...Addition circuit, 39...Pulse generator, 40.54...Servo circuit, 41...Track identification signal generation circuit, 42
...Brightness demodulation/reproduction processing circuit, 43...Vertical synchronization separation circuit, 36°55...Microprocessor, 45.
...Reproducing device, 46...Recording equalization circuit, 48...Low frequency conversion carrier color signal separation circuit, 49...Recording preamplifier, 52...Track identification signal separation circuit, 53...Dubbing Period specified signal separation circuit. Applicant's agent Patent attorney Takehiko Suzue 21A greige tJ1 diagram

Claims (1)

[Claims] Dubbing in which a video signal reproduced from a video tape for reproduction by a rotating head of a helical scan type player is recorded on a video tape for recording by a rotating head of a helical scan type recorder. In the apparatus, a signal separating means for separating a video signal reproduced from a videotape into a frequency-modulated luminance signal and a carrier color signal whose frequency is converted to a low frequency band; and the frequency-modulated luminance signal outputted from the signal separating means. an equalizing means for equalizing the signal so that it has almost the same signal state as when recording; and an equalizing means for equalizing the signal so that the signal state is almost the same as that at the time of recording; a frequency inverse conversion means for returning the frequency to the original high frequency signal; a crosstalk removal means for removing crosstalk components of adjacent tracks from the carrier color signal returned to the original high frequency by the frequency inversion means; frequency converting means for converting the carrier color signal from which crosstalk components have been removed to a lower frequency band using the same signal as the frequency converting idler signal used by the frequency inverse converting means; synchronized to the vertical sync signal,
and track identification signal generation means for generating a track identification signal indicating a playback track of the videotape; a low frequency conversion carrier color signal output from the frequency conversion means and a track identification signal output from the track identification signal generation means. a signal synthesis means for synthesizing the signals, and the output of the equalization means and the output of the signal synthesis means are supplied to the recording machine as outputs of the playback machine. .