JP2548937B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is directed to a recording system, on which a luminance signal input terminal to which a luminance signal is input and a color difference signal provided with a DC level difference are alternately arranged. A magnetic recording / reproducing apparatus which has at least a line-sequential signal input terminal for inputting a line-sequential signal and which FM-modulates the line-sequential signal and its luminance signal to record them on a magnetic recording medium. More specifically, the present invention relates to a magnetic recording / reproducing apparatus capable of reducing image quality deterioration during dubbing processing.

(Prior Art) In a magnetic recording / reproducing apparatus, for example, an electronic still camera, the line-sequential signal output from a line-sequential circuit for alternately line-sequencing the color difference signals is FM-modulated and the luminance signal is FM-modulated.
A recording system that modulates and synthesizes an FM-modulated luminance signal and an FM-modulated line-sequentialized signal by frequency multiplexing and records as a recording signal on a magnetic recording medium, and a recording signal already recorded on the magnetic recording medium. The FM signal is demodulated to extract the luminance signal and the line-sequential signal is extracted. The demodulated line-sequential signal is synchronized by the synchronization circuit that synchronizes the line-sequential signal, and the original dye signal is restored and reproduced. Some have a reproduction system for outputting (for example, Japanese Patent Laid-Open No. 60-206397).
(See the official gazette).

By the way, in such a magnetic recording / reproducing apparatus, as shown in FIG. 7, two magnetic recording / reproducing apparatuses 1 and 2 are prepared and the magnetic recording medium set in the one magnetic recording / reproducing apparatus 1 is used. A dubbing process of recording recorded information on the magnetic recording medium of another magnetic recording / reproducing apparatus 2 may be performed.

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 recording system 3 as connection terminals, and a luminance signal output on the output side of the reproducing system 7. A terminal 8 and color-difference signal output terminals 9 and 10 are provided. During dubbing processing, the luminance signal output terminal 8 of one magnetic recording / reproducing apparatus 1 is connected to the luminance signal input terminal 4 of another magnetic recording / reproducing apparatus 2. , And the color difference signal output terminals 9 and 10 of one magnetic recording / reproducing apparatus 1 are connected to the other magnetic recording / reproducing apparatus 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 signal synchronized by the synchronizing circuit of the reproducing system 7 of one magnetic recording / reproducing apparatus 1 (the magnetic recording / reproducing apparatus on the side where signal reproduction is performed). Is re-line-sequentialized by the line-sequencing circuit of the recording system 3 of the other magnetic recording / reproducing apparatus 2 and is set in the other magnetic recording / reproducing apparatus 2 (the magnetic recording / reproducing apparatus on the side where the signal is recorded). The dubbing process is performed by following the signal processing procedure of recording on the magnetic recording medium.

However, the synchronization of the color difference signals by the synchronization circuit of the reproduction system 7 of the one magnetic recording / reproducing apparatus 1 and the line sequentialization of the color difference signals by the line sequential circuit of the recording system 3 of the other magnetic recording / reproducing apparatus 2 are not possible. Originally, since the color difference signals are line-sequentially recorded on the magnetic recording medium, it is originally unnecessary in the dubbing process, and in the conventional magnetic recording / reproducing apparatus, this originally unnecessary color difference signal is used in the dubbing process. Synchronization processing of
Since the line-sequentialization process is performed, there is a problem that the image quality deteriorates accordingly.

Therefore, a line-sequential signal output terminal for extracting the FM-demodulated line-sequential signal at the time of dubbing processing is provided on the input side of the reproduction system synchronization circuit, and on the output side of the recording system line-sequential circuit. , Magnetic recording / reproducing with a line-sequential signal input terminal for inputting a line-sequential signal output from the line-sequential signal output terminal by switching the connection with the line-sequential circuit during dubbing processing Apparatus and another magnetic recording / reproducing apparatus are prepared, and a recording signal already recorded on the magnetic recording medium set on the one magnetic recording / reproducing apparatus is transferred to the magnetic recording medium set on the other magnetic recording / reproducing apparatus. During the dubbing process, the line-sequential signal before being input to the reproducing system synchronization circuit of the one magnetic recording / reproducing device is led to the output side of the recording system line-sequentializing circuit of the other magnetic recording / reproducing device. Other magnetic based 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 originally-unnecessary color-difference signal synchronization processing and line-sequential processing at the time of the dubbing processing, and thus it is possible to reduce deterioration in image quality due to these processings.

(Problems to be Solved by the Invention) However, the deterioration of the image quality during the dubbing process is not limited to this, and the luminance signal of the reproducing system of the magnetic recording / reproducing apparatus on the side where the signal is reproduced is line-sequential. When the digitized signal has a level fluctuation, it also occurs when the luminance signal and the line-sequentialized signal having the level fluctuation are directly input to the recording system on the signal recording side. Regarding the level fluctuation of the luminance signal, there is a conventional structure that performs automatic gain control (AGC) in order to suppress this level fluctuation, but in order to suppress the level fluctuation of the line-sequentialized signal, automatic gain control is performed. There is no configuration for performing this, and if the level of the line-sequentialized signal fluctuates, the image quality deteriorates during the dubbing process, making it difficult to obtain a faithful color reproduction image.

Therefore, the present invention provides 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. It is an object of the present invention to provide a magnetic recording / reproducing apparatus capable of reducing image quality deterioration due to a level variation of a line sequential signal at the time of dubbing processing.

Structure of the Invention (Means for Solving Problems) According to the present invention, a luminance signal input terminal to which a luminance signal is input and a color difference signal provided with a DC level difference are alternately arranged on the recording system side. And a line-sequential signal input terminal for inputting a line-sequential signal, wherein the line-sequential signal and the luminance signal are FM-modulated and recorded on a magnetic recording medium. A detection circuit for detecting a DC level difference of the serialization signal, and a gain control amplifier for controlling the DC level difference of the line-sequentialization signal to a prescribed value based on the output of the detection circuit, and the detection circuit, A sample and hold circuit that samples and holds the output of the gain control amplifier, a capacitor that removes a DC component from the output of the sample and hold circuit, and the sample and hold in which the DC component is removed by this capacitor. A magnetic recording / reproducing apparatus having a rectifying circuit for rectifying the output of the circuit and a differential amplifier for comparing the output from the rectifying circuit with a reference potential and performing a required output.

(Embodiment) An embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described below with reference to the drawings shown in FIGS. 1 to 6.

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, and 14 is a magnetic recording medium. Is a spindle motor for driving the magnetic disk, 15 is a magnetic head, and 16 is a recording / reproducing switching switch.

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 an output signal output from a solid-state image sensor of an electronic still camera.

The luminance signal input terminal 17 is connected to the FM modulation circuit 23. The luminance signal Y is FM-modulated by the FM modulation circuit 23. The color difference signal input terminals 18 and 19 are connected to the line sequentializing circuit 24. The color difference signals R-Y and B-Y are simultaneously (parallel) input to the line-sequentializing circuit 24, and the line-sequentializing circuit 24 outputs the color-difference signals simultaneously input to R-Y and B-Y.
-Y is recorded on the magnetic disk 13 alternately every horizontal scanning period, so that the color difference signals RY and BY are alternately switched every 1H, and the color difference signal RY and the color difference signal are alternated every 1H. B-
It has a function of outputting a line sequential signal in which Y and Y are sequentially arranged. The switching is performed in synchronization with the horizontal synchronizing signal S. Further, the color difference signals R-Y and B-Y are given a DC level difference in order to facilitate the identification of the color difference signals at the time of line-sequential reproduction.

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-sequential 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. To be 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 performing FM demodulation on 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 synchronizing circuit 31 has a function of returning the FM-demodulated line-sequential signals 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.

The output side of the FM demodulation circuit 30 and the input side of the synchronization circuit 31 are connected to a line-sequential signal output terminal 32 for taking out the FM-demodulated line-sequential signal during dubbing processing.
A line-sequential signal input terminal 33, which is connected to the line-sequential signal output terminal 32 during the dubbing process, is connected to the changeover switch 25. When performing the dubbing process, as shown in FIG. 4, the line-sequential signal output terminal of one magnetic recording / reproducing apparatus 1 is used.
32 and other magnetic recording / reproducing apparatus 2 line-sequential signal input terminal 33
And the cable through the auto gain control circuit 34
In addition to the connection by the cable 35, the brightness signal output terminal 20 of one magnetic recording / reproducing apparatus 1 and the brightness signal input terminal 17 of the other magnetic recording / reproducing apparatus 2 are connected by the cable 36 via the auto gain control circuit 34.

The changeover switch 25 is a connection terminal for the line sequential circuit 24.
25a, a connection terminal 25b for connecting to the FM modulation circuit 26, and a switch piece 25c. For example, as shown in FIGS. 5 and 6, the push-off type is adopted, and the plug 37 of the cable 35 is a jack type wire. When inserted into the serialization signal input terminal 33, the pressing piece
38 is displaced in the direction of the arrow (see FIG. 5) by the body portion 37a of the plug 37, and the movable piece 39 is displaced in the direction of the arrow (see FIG. 6) based on it, and automatically by the connection of the cable 35. The switch piece 25c is switched from the connection side of the line-sequentialization circuit 24 to the connection side of the line-sequentialization signal input terminal 33. In FIGS. 5 and 6, reference numeral 40 is a housing forming a part of the switching circuit 25, 41 is a spring for urging the movable piece 38 toward the pressing side 37, and a changeover switch.
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. Further, the gain control amplifier 43 is provided with a DC level difference L, and a color difference signal RY and a color difference signal B-
A line-sequentialization signal in which Y and Y are arranged alternately is input. The gain control amplifier 42 has a function of maintaining the output level of the luminance signal Y at a predetermined level.
A clamp circuit 45 is connected to the output stage of the. The clamp circuit 46 has a function of clamping the sync tip level of the sync signal S. The luminance signal Y output from the clamp circuit 45 is input to the differential amplifier 46. The differential amplifier 46 uses the sync pulse Φ of the sync pulse generation circuit 44.
Controlled by _A. 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. Based on the synchronizing pulse Φ _A , the differential amplifier 46 compares the pedestal level PD at the time when the synchronizing pulse Φ _A is output with the reference potential, and the luminance signal Y output from the gain control amplifier 42 is predetermined. The gain control amplifier 42 is controlled so as to attain the level. In FIG. 1, reference numerals E ₁ and E ₂ are power supplies for applying a reference potential to the clamp circuit 45 and the differential amplifier 46.

A sample hold circuit 47 is connected to the output side of the gain control amplifier 43. The sample and hold circuit 47 has a function of sampling and holding the color difference signals BY and RY, and the synchronizing pulse generating circuit 44 outputs the color difference signals, RY and BY in synchronization with the horizontal synchronizing signal S. It has a function of outputting a synchronization pulse Φ _B for sample-holding the level to the sample-hold circuit 47. The output SH of the sample hold circuit 47 is input to a rectifier circuit 49 via a capacitor 48, rectified by the rectifier circuit 49, and a differential amplifier.
It is compared by 50 with the reference potential E ₃ . Its differential amplifier 50
Compares the reference potential E ₃ with the rectified output of the rectifier circuit 49, controls the gain control amplifier 43 so that the difference becomes small, and holds the sample hold circuit 47, the capacitor 48, and the rectifier circuit.
The differential amplifier 50 and the differential amplifier 50 function as a detection circuit for detecting the DC level difference of the line-sequential signal, whereby the DC level difference L of the line-sequential signal output from the gain control amplifier 43 is controlled to a specified value. It

As described above, in the embodiment, the automatic gain control circuit 34 is provided between the magnetic recording / reproducing devices 1 and 2, but the reproducing system 12 of the magnetic recording / reproducing device 1 or the recording of the magnetic recording / reproducing device 2 is performed. The system 11 may be provided.

As described above, the magnetic recording / reproducing apparatus according to the present invention includes a detection circuit for detecting the DC level difference of the line-sequentialized signal in order to keep the DC level difference of the color difference signals in the recording system at a specified value. , A gain control amplifier that controls the DC level difference of the line-sequentialized signal to a specified value based on the output of the detection circuit is provided, and the DC level difference of the line-sequentialized signal is maintained at the specified value. In the processing, it is possible to reduce the image quality deterioration due to the level variation of the line sequential signal. Moreover, in the present application, the detection circuit includes a sample and hold circuit that samples and holds the output of the gain control amplifier, a capacitor that removes a DC component from the output of the sample and hold circuit, and the sample from which the DC component is removed by the capacitor. Since it has a rectifier circuit that rectifies the output of the hold circuit and a differential amplifier that compares the output from this rectifier circuit with a reference potential and performs the required output, there is an advantage that the circuit configuration is simplified. .

[Brief description of drawings]

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 a dubbing process, FIG. 5 is an external view of a changeover switch used in the magnetic recording / reproducing apparatus, and FIG. FIG. 7 is a cross-sectional view of a part and shows a connection state when a dubbing process is performed using a conventional magnetic recording / reproducing apparatus. 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 generation circuit 47 …… Sample hold circuit 50 …… Differential amplifier

Claims (1)

(57) [Claims] 1. A line-sequential signal for inputting a line-sequential signal in which a luminance signal input terminal for inputting a luminance signal and color difference signals given a DC level difference are alternately arranged on the recording system side. A magnetic recording / reproducing apparatus which has at least an input terminal and FM-modulates the line-sequentialized signal and the luminance signal to record on a magnetic recording medium, the detection circuit detecting a DC level difference of the line-sequentialized signal. And a gain control amplifier that controls the DC level difference of the line-sequentialized signal to a specified value based on the output of the detection circuit, and the detection circuit samples and holds the output of the gain control amplifier. A circuit, a capacitor for removing a DC component from the output of the sample and hold circuit, a rectifying circuit for rectifying the output of the sample and hold circuit from which the DC component is removed by the capacitor, and A magnetic recording / reproducing apparatus, comprising: a differential amplifier that compares the output from the flow circuit with a reference potential to perform a required output.