JP2608718B2 - Dubbing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Application Field) The present invention relates to a recording system, in which a luminance signal input terminal for inputting a luminance signal, an RY component and a BY component are used. It has at least a line-sequencing signal input terminal for line-sequencing signal input in which color difference signals having different DC output levels are alternately arranged, and FM-modulates the line-sequencing signal and its luminance signal to perform magnetic recording. The present invention relates to a dubbing apparatus using a magnetic recording / reproducing apparatus for recording on a medium, and more particularly, to a dubbing apparatus capable of reducing image quality deterioration due to a clamp timing of a DC output level in a dubbing process.

(Prior Art) In a magnetic recording / reproducing apparatus, for example, an electronic still camera, a color difference signal (red color difference signal) composed of RY components and B
FM modulation of a line-sequential signal output from a line-sequencing circuit that alternately line-sequences a color difference signal (blue color difference signal) composed of a Y component with a different DC output level, and FM-modulates a luminance signal Then, a recording system that synthesizes the FM-modulated luminance signal and the FM-modulated line-sequentialized signal by frequency multiplexing and records it as a recording signal on a magnetic recording medium, and a recording signal already recorded on the magnetic recording medium. FM demodulation to extract the luminance signal and the line-sequentialized signal, and the demodulated line-sequentialized signal is synchronized by the synchronizing circuit that synchronizes the line-sequentialized signal, and is restored to the original color difference signal and reproduced and output. Some systems have a reproduction system (for example, see
No. 60-206397).

Here, the DC output levels V ₁ and V ₂ (see FIG. 8) differ between the RY component color difference signal and the BY component color difference signal, and the level difference is given when FM modulation is performed. Center frequency
If f ₁ and f ₂ are not different, R−
This is because the Y component and the BY component cannot be separated. The center frequency f ₁ is 1.2MHz, the center frequency f ₂ is determined to 1.3 MHz.

In such a magnetic recording / reproducing apparatus, as shown in FIG. 9, two magnetic recording / reproducing apparatuses 1 and 2 are prepared, and recording information of a magnetic recording medium set in one of the magnetic recording / reproducing apparatuses 1 is prepared. Is stored in a magnetic recording medium of another magnetic recording / reproducing apparatus 2 in some cases.

The conventional magnetic recording / reproducing devices 1 and 2 are provided with a luminance signal input terminal 4 and color difference signal input terminals 5 and 6 on the input side of the system 3 as connection terminals, and a luminance signal output terminal on the output side of the reproduction system 7. A terminal 8 and color difference signal output terminals 9 and 10 are provided. In the case of dubbing processing, the luminance signal output terminal 8 of one magnetic recording / reproducing device 1 is connected to the luminance signal input terminal 4 of another magnetic recording / reproducing device 2. And the color difference signal output terminals 9 and 10 of one magnetic recording / reproducing device 1 are connected to the other magnetic recording / reproducing device 2.
Are connected to the color difference signal input terminals 5 and 6.

Therefore, in the case of the conventional magnetic recording / reproducing apparatuses 1 and 2, the color difference signals synchronized by the synchronizing circuit of the reproducing system 7 of one magnetic recording / reproducing apparatus 11 (the magnetic recording / reproducing apparatus on which signal reproduction is performed). Is line-sequentialized again by the line-sequencing circuit of the recording system 3 of the other magnetic recording / reproducing apparatus 2, and the magnetic field set in the other magnetic recording / reproducing apparatus 2 (the magnetic recording / reproducing apparatus on which signal recording is performed). The dubbing process is performed according to a signal processing procedure of recording on a recording medium.

However, the synchronization of the color difference signals by the synchronization circuit of the reproduction system 7 of this one magnetic recording / reproducing device 1 and the line-sequencing of the color difference signals by the line-sequencing circuit of the recording system 3 of the other magnetic recording / reproduction device 2 Originally, the color difference signal is recorded in the magnetic recording medium in a line-sequential manner, so that it is essentially unnecessary in the dubbing process. Synchronization processing,
Since the line-sequencing processing is performed, there is a problem that the image quality is deteriorated accordingly.

Therefore, a line-sequencing signal output terminal for extracting the FM-demodulated line-sequencing signal during dubbing processing is provided on the input side of the reproduction system synchronization circuit, and the output side of the recording system line-sequencing circuit is provided on the output side. A line-sequencing signal input terminal for inputting a line-sequencing signal output from a line-sequencing signal output terminal by switching the connection between the line-sequencing circuit during dubbing processing; A device and another magnetic recording / reproducing device are prepared, and a recording signal recorded on a magnetic recording medium set on one magnetic recording / reproducing device is transferred to a magnetic recording medium set on another magnetic recording / reproducing device. At the time of dubbing processing, the line-sequencing signal before being inputted to the synchronization circuit of the reproduction system of one magnetic recording / reproducing device is led to the output side of the line-sequencing circuit of the recording system of another magnetic recording / reproduction device, Other magnets based on it It is considered that a configuration for recording the recording signal on a magnetic recording medium set in the recording and reproducing apparatus. With such a configuration, it is possible to omit the color difference signal synchronization processing and the line sequential processing that are originally unnecessary during the dubbing processing, so that it is possible to reduce the deterioration of the image quality caused by these processings.

However, the image quality degradation during the dubbing process is not limited to this, and if there is a level change in the luminance signal and the line-sequentialized signal of the reproduction system of the magnetic recording / reproducing apparatus on the side where the signal is reproduced, the level may be degraded. This is also caused by the fact that a fluctuating luminance signal and a line-sequentialized signal are directly input to a recording system on which signal recording is performed. In order to suppress the level fluctuation of the luminance signal, there has conventionally been a configuration in which an automatic gain control (AGC) is performed to suppress the level fluctuation. However, in order to suppress the level fluctuation of the line sequential signal, the automatic gain control is performed. There is no configuration for performing this, and if the level of the line-sequentialized signal fluctuates, image quality deteriorates during dubbing processing, and it is difficult to obtain a faithful color reproduced image.

This point can be solved by performing automatic gain control so as to keep the level difference of the line sequential signal at a specified value.

(Problems to be Solved by the Invention) By the way, when a line-sequential signal is input via the line-sequential signal input terminal and FM-modulated and recorded on a magnetic recording medium, its DC output levels V ₁ , V _{When 2} fluctuates, the center frequencies f ₁ and f ₂ fluctuate, so that their DC output levels V ₁ and V ₂ must be fixed by a clamp circuit. In this case, since the reference DC output levels V ₁ and V ₂ alternately change every horizontal scanning period, a signal obtained by dividing the horizontal frequency by 2 may be used as the clamp timing signal. than with clamping tie ring signal horizontal frequency divided by 2, the specific what are the either clamp the DC output level V ₂ of the B-Y component that clamps the DC output level V ₁ of the R-Y component If the clamp timing is incorrect, the line sequential signal is recorded in the magnetic recording / reproducing device with the mistake, and the conventional magnetic recording / reproducing device may reduce the image deterioration due to the clamp timing of the DC output level in the dubbing process. However, there is still a problem that a faithful color reproduction image cannot be obtained during reproduction.

Therefore, the present invention uses a magnetic recording / reproducing apparatus in which a line sequential signal input terminal is provided on the recording system side for dubbing processing, and a line sequential signal is input from the line sequential signal input terminal. In such a case, an object of the present invention is to provide a dubbing apparatus capable of reducing image quality deterioration due to a clamp timing of a DC output level of a line sequential signal during a dubbing process.

Configuration of the Invention (Means for Solving the Problems) The present invention reads a luminance signal and a line-sequentialization signal recorded on one magnetic recording medium, and converts the read signal into an FM signal.
A reproduction system for demodulation, a recording system for FM-modulating the input luminance signal and the line-sequentialized signal, and recording the FM-modulated signal on the other magnetic recording medium, and a fluctuation between the luminance signal and the line-sequentialized signal. A dubbing apparatus comprising an auto gain control unit for suppressing, wherein the reproduction system includes a luminance signal output terminal for outputting a FM-demodulated luminance signal, and a line-sequentialized signal output for outputting an FM-demodulated line-sequentialized signal. A first amplifier circuit for amplifying the luminance signal from the luminance signal output terminal by the automatic gain control, and an R-signal of the line-sequentialized signal from the line-sequentialized signal output terminal. A detection circuit for detecting a level difference between the output level of the Y component and the output level of the BY component; and limiting the line sequential signal so that the level difference from the detection circuit becomes a specified value. And second amplifier circuit, in synchronization with the horizontal synchronizing signal of the luminance signal, the line sequential signal R-Y component and B-Y
A color signal identification circuit that identifies a component and generates a clamp timing signal corresponding to one of the RY component and the BY component; and a line based on the clamp timing signal from the color signal identification circuit. A clamp circuit for clamping a DC output level of the serialized signal, wherein the recording system is a luminance signal input terminal for inputting a luminance signal amplified by an auto gain control unit, and is limited and clamped by an auto gain control unit. And a line-sequencing signal input terminal for inputting a line-sequencing signal.

(Embodiment) An embodiment of the magnetic recording and reproducing apparatus according to the present invention will be described below with reference to the drawings shown in FIGS.

FIG. 3 is a circuit diagram showing a schematic configuration of a magnetic recording / reproducing apparatus according to the present invention. In FIG. 3, 11 is a recording system, 12 is a reproducing system, 13 is a magnetic disk as a magnetic recording medium, 14 Is a spindle motor for driving the magnetic disk, 15 is a magnetic head, and 16 is a switch for switching recording and reproduction.

On the input side of the recording system 11, a luminance signal input terminal 17 for inputting a luminance signal Y + horizontal synchronization signal S, a color difference signal R-
Color difference signal input terminals 18 and 19 for inputting Y and BY are provided, and a luminance for outputting a luminance signal Y including a vertical synchronization signal and a horizontal synchronization signal S is provided on the output side of the reproduction system 12. A signal output terminal 20 and color difference signal output terminals 21 and 22 for outputting color difference signals RY and BY are provided. The luminance signal Y and the color difference signals RY and BY input to the luminance signal input terminal 17 and the color difference signal input terminals 18 and 19 are, for example,
It is obtained by processing output signals output from an electronic still camera and a solid-state imaging device.

The luminance signal input terminal 17 is connected to the FM modulation circuit 23. The luminance signal Y is FM-modulated by the FY modulation circuit 23. The color difference signal input terminals 18 and 19 are connected to a line sequential circuit 24. The color difference signals RY and BY are simultaneously (parallel) input to the line-sequencing circuit 24, and the line-sequencing circuit 24 outputs the color difference signals RY and B-
In order to record Y on the magnetic disk 13 alternately every horizontal scanning period, the color difference signals RY and BY are alternately switched every 1H, and the color difference signals RY and B are alternately changed every 1H. -Y
And has a function of outputting a line-sequentialized signal sequentially arranged. The switching is performed in synchronization with the horizontal synchronization signal S. The color difference signals RY and BY are provided with a DC level difference in order to facilitate identification of the color difference signals at the time of reproduction in line-sequentialization.

The line-sequencing signal output from the line-sequencing circuit 24 is
It is input to an FM modulation circuit 26 via a dubbing changeover switch 25 whose configuration will be described later. The line-sequentialized signal is FM-modulated by the FM modulation circuit 26, combined with the FM-modulated luminance signal Y by frequency multiplexing, amplified by the recording amplifier 27, and recorded as a recording signal on the magnetic disk 13 by the magnetic head 15. Is done.

The reproduction system 13 includes a reproduction amplifier 28, FM demodulation circuits 29 and 30, and a synchronization circuit 31. Magnetic head 15
The reproduced signal reproduced by the amplifier 28 is used for reproduction.
, And input to the FM demodulation circuits 29 and 30. FM
The demodulation circuit 29 has a function of FM demodulating the luminance signal Y based on the reproduced signal. The output side of the FM demodulation circuit 29 is connected to the luminance signal output terminal 20. The FM demodulation circuit 30 has a function of FM demodulating the line sequential signal based on the reproduced signal. The output side of the FM demodulation circuit 30 is connected to the input side of the synchronization circuit 31. The synchronization circuit 31 has a function of returning the FM-demodulated line sequential signal to the original color difference signals RY and BY. The output side of the synchronization circuit 31 is connected to the color difference signal output terminals 21 and 22. Its color difference signal output terminal 21,
22 outputs color difference signals RY and BY as parallel signals. For example, when the luminance signal output terminal 20 and the color difference signal output terminals 21 and 22 are connected to a connection terminal of a color television (not shown), a color still image is displayed on a screen.

A line sequential signal output terminal 32 for extracting the FM demodulated line sequential signal at the time of dubbing processing is connected to the output side of the FM demodulation circuit 30 and the input side of the synchronization circuit 31. The changeover switch 25 has a line-sequencing signal input terminal connected to the line-sequencing signal output terminal 32 during dubbing processing.
33 is connected. At the time of the dubbing process, as shown in FIG. 4, the line sequential signal output terminal 32 of one magnetic recording / reproducing apparatus 1 and the line sequential signal input terminal 33 of the other magnetic recording / reproducing apparatus 2 are connected to the automatic gain. While connected by a cable 35 via a control circuit 34, the luminance signal output terminal 20 of one magnetic recording / reproducing device 1 and the luminance signal input terminal 17 of another magnetic recording / reproducing device 2 are connected to an auto gain control circuit 34.
And connected by cable 36.

The changeover switch 25 is a connection terminal for the line sequential circuit 24.
25a, a connection terminal 25b with the FM modulation circuit 26, and a switch 25c. For example, as shown in FIGS. 5 and 6, a push-off type is used, and a plug 37 of the cable 35 is a jack type line sequential. When it is fitted into the coded signal input terminal 33, the pressing piece 38
Is displaced in the direction of the arrow (see FIG. 5) by the body 37a of the plug 37, and the movable piece 39 is displaced in the direction of the arrow (see FIG. 6) based on the displacement. The switch piece 25c is switched from the connection side of the serialization circuit 24 to the connection side of the line sequential signal input terminal 33. In FIGS. 5 and 6, reference numeral 40 denotes a housing constituting a part of the switching circuit 25, and reference numeral 41 denotes a spring for urging the movable piece 38 toward the pressing piece 37.
The 25 configurations are not limited to this.

The auto gain control circuit 34 includes gain control amplifiers 42 and 43 and a synchronization pulse generation circuit 44 as shown in FIG. The luminance signal Y including the horizontal synchronization signal S shown in FIG. 2 is input to the gain control amplifier 42 and the synchronization pulse generation circuit 44.

The gain control amplifier 43 is supplied with a line-sequential signal in which color difference signals RY provided with a DC level difference L and color difference signals BY are alternately arranged. Gain control amplifier 42
Has a function of maintaining the output level of the luminance signal Y at a predetermined level, and a clamp circuit 45 is connected to an output stage of the gain control amplifier. This clamp circuit 45 has a function of clamping the sync tip level of the synchronization signal S. The luminance signal Y output from the clamp circuit 45 is input to the differential amplifier 46. Its differential amplifier 46 is controlled by the synchronization pulses [Phi _A sync pulse generator 44. In this embodiment, the gain control amplifier 42, the clamp circuit
45 and a differential amplifier 46 constitute a first amplifier circuit. Its sync pulse [Phi _A, in order to synchronize the pedestal level PD of the luminance signal Y, which is intended to be outputted from the horizontal sync signal S a certain period delayed. The differential amplifier 46 has its synchronization pulse Φ
_A , the pedestal level PD at the time when the synchronization pulse Φ _A is output is compared with the reference potential, and the gain control is performed so that the luminance signal Y output from the gain control amplifier 42 becomes a predetermined level. It controls the amplifier 42. The first
In the figure, symbols E ₁ and E ₂ are a clamp circuit 45 and a differential amplifier.
A power supply for applying a reference potential to 46.

A sample and hold circuit 47 is connected to an output side of the gain control amplifier 43 as a second amplifier circuit. The sample and hold circuit 47 has a function of sampling and holding the color difference signals BY and RY, and the synchronizing pulse generation circuit 44 synchronizes with the horizontal synchronizing signal S to output the color difference signals BY and RY. Pulse Φ _B for sampling and holding
Is output to the sample-and-hold circuit 47. Output SH of the sample-hold circuit 47 is input to the rectifier circuit 49 via the capacitor 48, it is rectified by the rectifier circuit 49 is compared with a reference potential E ₃ by the differential amplifier 50. Its differential amplifier 50, rectifier circuit 49 and the reference potential E ₃
The gain control amplifier 43 is controlled so that the difference becomes smaller, and the sample and hold circuit 47, the capacitor 48, the rectifier circuit 49, and the differential amplifier 50 reduce the DC level difference of the line sequential signal. It functions as a detection circuit for detecting, whereby the DC level difference L of the line sequential signal output from the gain control amplifier 43 is controlled to a specified value.

The line-sequential signal output from the gain control amplifier 43 is
It is input to the clamp circuit 51 shown in FIG. The clamp circuit 51 has a function of clamping either the DC output level V _1, V ₂ of the line sequence signals, code E ₄
Is a power supply for determining the clamp level. The clamp circuit 51 uses the clamp timing signal CRAMP (see FIGS. 2 and 7) output from the AND circuit 52 (corresponding to the clamp timing signal generation circuit of the present invention) to control the DC output level V of the RY component. clamping one of the DC output level V ₂ of ₁ and B-Y component.

The AND circuit 52 functions as a color difference signal discriminating circuit for discriminating the RY component and the BY component of the line-sequentialized signal together with the comparator 53 (corresponding to the comparison circuit of the present invention). One terminal a is a capacitor 48
, And the output of the sample and hold circuit 47 is input after the DC component is removed by the capacitor 48. Also,
The other terminal a 'of the comparator 53 is grounded. When one terminal a is a negative terminal and the other terminal a 'is a positive terminal, the comparator 53 outputs the identification signal K' shown in FIG.
When one terminal a is a positive terminal and the other terminal a 'is a negative terminal, the comparator 53 is configured to output an identification signal K shown in FIG. I have.

(I) The identification signal to the terminal K of the AND circuit 52, K 'either is input to the other terminal synchronous pulses [Phi _B
Is input, and the clamp timing signal CRAMP is
The identification signal K, when K 'is the synchronization pulses [Phi _B at the high level is inputted to the AND circuit 52, intended to be outputted to the clamp circuit 51, to output the identification signal K as shown in Figure 2 when the things, the DC output level V ₁ for each R-Y component of the line sequential signal is clamped, when configured to output an identification signal K 'as shown in FIG. 7 is
DC output level V ₂ is clamped to the respective B-Y component of the line sequential signal.

As described above, in the embodiment, the automatic gain control circuit 34 and the color difference signal discriminating circuit are provided between the magnetic recording / reproducing apparatuses 1 and 2, but the reproducing system 12 of the magnetic recording / reproducing apparatus 1 or the magnetic recording / reproducing apparatus 1 It is also possible to adopt a configuration provided in the recording system 11 of the playback device 2.

Effect of the Invention The dubbing device according to the present invention, as described above,
A clamp circuit for clamping the DC output level of the line-sequencing signal;
A color signal discriminating circuit for discriminating the Y component and the BY component and outputting a clamp timing signal for clamping the line-sequentialized signal to the clamp circuit is provided. Since the simultaneous processing and the line sequential processing are not performed, the deterioration of the image quality due to these processing can be reduced. In addition to this, the output level of the RY component and the B-
A level difference between the output level of the Y component and the output level of the Y component is detected, the line-sequential signal is limited so that the level difference becomes a specified value, and the RY component and the BY component are identified. Since the clamping is performed using the clamp timing signal corresponding to one of the Y component and the BY component, it is possible to reduce the image quality deterioration due to the clamp timing of the DC output level of the line sequential signal during the dubbing process. It works. In addition, the color difference signal identification circuit includes a gain control amplifier, a sample and hold circuit, a capacitor, a comparison circuit, and a clamp timing signal generation circuit. Has the advantage that the circuit configuration is simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main circuit of a magnetic recording / reproducing apparatus according to the present invention, FIG. 2 is a signal waveform diagram of the main circuit, and FIG. 3 is an overall circuit configuration diagram of the magnetic recording / reproducing apparatus according to the present invention. FIG. 4 is a diagram showing a connection state of the magnetic recording / reproducing apparatus according to the present invention during dubbing processing, FIG. 5 is an external view of a changeover switch used in the magnetic recording / reproducing apparatus, and FIG. FIG. 7 is a signal waveform diagram of another example of the main circuit shown in FIG. 2, FIG. 8 is a characteristic diagram showing the relationship between the DC output level of the color difference signal and the frequency, and FIG. FIG. 10 is a diagram showing a connection state when dubbing is performed using the magnetic recording / reproducing apparatus of FIG. DESCRIPTION OF SYMBOLS 1 ... One magnetic recording / reproducing apparatus 2 ... Other magnetic recording / reproducing apparatus 11 ... Recording system, 12 ... Reproducing system, 13 ... Magnetic disk 23, 26 ... FM modulation circuit, 24 ... Line sequential Circuit 25… Changeover switch, 29, 30… FM demodulation circuit 31… Simultaneous circuit, 32… Line sequential signal output terminal 33… Line sequential signal input terminal 34… Auto gain control circuit 43… Gain control amplifier 44 Synchronous pulse generator 47 Sample hold circuit 50 Differential amplifier 51 Clamp circuit 52 AND circuit 53 Comparator

Claims (1)

(57) [Claims] 1. A luminance signal and a line-sequentialized signal recorded on one magnetic recording medium are read, and the read signal is
A reproduction system for demodulation, a recording system for FM-modulating the input luminance signal and the line-sequentialized signal, and recording the FM-modulated signal on the other magnetic recording medium, and a fluctuation between the luminance signal and the line-sequentialized signal. A dubbing device comprising an auto gain control unit for suppressing the luminance, wherein the reproduction system comprises: a luminance signal output terminal for outputting an FM demodulated luminance signal; and a line sequential signal output for outputting an FM demodulated line sequential signal. A first amplifier circuit for amplifying a luminance signal from the luminance signal output terminal by automatic gain control, and an R-signal of a line-sequentialized signal from the line-sequentialized signal output terminal. Y
A detection circuit for detecting a level difference between the output level of the component and the output level of the BY component; and a second amplifier circuit for limiting the line-sequentialized signal so that the level difference from the detection circuit becomes a specified value. And the line-sequentialized signal R in synchronization with the horizontal synchronization signal of the luminance signal.
-The Y component and the BY component are identified, and the RY component and BY
A color signal identification circuit that generates a clamp timing signal corresponding to one of the components, and a clamp circuit that clamps the DC output level of the line sequential signal based on the clamp timing signal from the color signal identification circuit. The recording system comprises: a luminance signal input terminal for inputting a luminance signal amplified by an auto gain control unit; a line sequential signal input terminal for inputting a line sequential signal limited and clamped by the auto gain control unit; A dubbing device comprising: