JPH029001A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce the disturbance caused by a frequency which appears on a reproducing screen and to improve the quality of a reproducing image by controlling a level of power supplied to an amplifier from a power source use oscillator so that it becomes lower than that in other period, when an image appears on the reproducing screen. CONSTITUTION:A reproducing voltage which passes through an amplifier and a rotary transformer from a video head and applied to a signal processing circuit 4 is demodulated, and a reproducing luminance signal is outputted to an output terminal 14. This reproducing luminance signal is inputted to a synchronizing separator circuit 15, as well, and a horizontal synchronizing signal (b) is inputted to a gate circuit 17 of a power source use oscillator OSC 5. The gate circuit 17 gates an output of high frequency power (c) from an oscillator 16, whenever the horizontal synchronizing signal (b) is inputted. In such a way, the output is provided to the rotary transformer from the OSC 5 only in a synchronizing signal period, therefore, in a recording and reproducing period for information, a level of power supplied to the amplifier can be made lower than that in a blanking period accompanied with a synchronizing signal, and the disturbance caused by a frequency on a reproducing screen can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information recording/reproducing device such as a rotary head type magnetic recording/reproducing device, and in particular to a power supply unit for an amplifier that rotates together with a transducer. It is.

[Prior Art] Fig. 4 is a block diagram of a conventional information recording/reproducing device disclosed in, for example, Japanese Patent Publication No. 57-37924. In the figure, (1) is a video head, and (2) is an amplifier. ,(3
) is a rotary transformer, (4) is a signal processing circuit, (5)
is a power supply oscillator (hereinafter referred to as O3C), (6),
(7) is a power transmission coil, (8) is a rectifier diode, (9) is a smoothing capacitor, (10) and (11) are signal transmission capacitors, and the video head (1) and amplifier (2) are connected to each other. The signal transmission capacitor (10), rectifier diode (8), and smoothing capacitor (9) rotate as one unit.

In addition, the high frequency power of 08C (5) passes through the power transmission coils (6), (7), the rotary transformer (3), and is further rectified by the diode (8) and smoothing capacitor (9), and is then rectified by the amplifier. (2).

Next, the operation of the above configuration will be explained.

The signal from the video head (1) is amplified by the amplifier (2) and then input to the signal processing circuit (4) via the signal transmission capacitor (10), rotary transformer (3), and signal transmission capacitor (11). be done.

At this time, high frequency power having a frequency separable from the frequency of the signal reproduced by the video head (1) is transmitted from the osc(s) to the power transmission coil (6),
After passing through a rotary transformer (3), a power transmission coil (7), and then being rectified by a diode (8) and a smoothing capacitor (9), it is supplied to the amplifier (2). ) or be operated. In this way, by amplifying the signal from the video head (1) and inputting it to the rotary transformer (3), a drop in the level of the reproduced signal is prevented, the S/N ratio is improved, and the reproduced image quality is improved.

[Problem to be solved by the invention] The conventional information recording/reproducing device was configured as described above, and although it is effective in improving the S/N, the amplifier (
2) There was a problem in that frequency-based interference appeared on the playback screen due to the influence of the high-frequency power supplied to the playback screen.

That is, the power supplied from o s c (s) to the amplifier (2) requires at least about 0.1 W.

On the other hand, the reproduction voltage from the video head (1) is 0.1 m
There is a weak power on the order of V, and the output power from the amplifier (2) is on the order of 0.001W. Therefore, even if the frequency of the reproduced signal and the frequency of the power supplied from OS C (s) can be separated, OS C (5)
It is unavoidable that the high frequency output from the signal processing circuit (4) mixes with the signal processing circuit (4). In the past, there was a problem in which frequency interference appeared on the playback screen, degrading the quality of the playback image.

This invention was made in order to solve the above-mentioned problems, and by taking into account the period of supply of high-frequency power to the amplifier, it is possible to reduce the interference that appears on the playback screen and improve the quality of the playback image. The purpose of this invention is to provide an information recording and reproducing device that can perform the following functions.

[Means for Solving the Problems] The information recording/reproducing device according to the present invention is configured such that the level of power supplied from the OSC to the amplifier is lower during the information recording/reproducing period than during the flanking period accompanied by the synchronization signal. The present invention is characterized in that a power supply control means for controlling the power supply is provided.

[Operation] According to the present invention, the level of high-frequency power supplied from the OSC to the amplifier is automatically controlled so that it becomes high during the blanking period accompanied by a synchronizing signal and becomes low during the period when information is recorded and reproduced. Especially,
When information is reproduced, it is possible to avoid as much as possible the introduction of high-frequency power into the signal processing circuit, etc., thereby reducing the appearance of frequency interference on the reproduction screen.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of the main parts of an information recording and reproducing apparatus according to an embodiment of the present invention.
4) is a signal processing circuit, and this signal processing circuit (4) is the fourth signal processing circuit.
As shown in the figure, it is coupled to the rotary transformer (3) via the signal transmission capacitor (11), is connected to the limiter (I2) and the FM demodulator (13), and is ) has an output terminal (14) that outputs a reproduced luminance signal having a waveform as shown in FIG.

(I5) is a synchronization separation circuit which separates a horizontal synchronization signal as shown in FIG. 2(b) from the reproduced luminance signal (a).

(5) is the OSC, and this osc(s) is the oscillator (
I6), a gate circuit (17), and a power amplifier (18), and the high-frequency power having the waveform shown in FIG. 2(C) output from the oscillator (16) is transmitted to the gate circuit (17). This gate circuit (17) and the power amplifier (1
8) outputs high-frequency power having a waveform as shown in FIG. 2(d). The rest of the configuration is the same as the conventional example shown in FIG. 4, so illustration is omitted.

Next, the operation of the above configuration will be explained.

Reproduction voltage applied from the video head (1) to the limiter (12) of the signal processing circuit (4) via the amplifier (2), signal transmission capacitor (lO), rotary transformer (3), and signal transmission capacitor (11) is this limiter (1
After the amplitude is controlled in step 2), the FM demodulator (13)
It is input to the output terminal (14) and demodulated, and the output terminal (14) is
) is output.

This reproduced luminance signal (a) is also input to a synchronization separation circuit (15), which separates a horizontal synchronization signal as shown in FIG. s)
input to the gate circuit (17).

On the other hand, the 03C(5)(7) oscillator (1B) outputs high frequency power as shown in FIG. 2(c) and inputs it to the gate circuit (17). This gate circuit (17)
is the horizontal synchronization signal (b) from the synchronization separation circuit (15).
) is input, gates the output of high frequency power (C) from the oscillator (18), outputs power with a waveform as shown in FIG. Amplify and output. Therefore, the rotary transformer (3)
An output is given from the OS C (5) only during the synchronizing signal period (Dl), and no output is given during the other period (02).

In addition, upon receiving the output from the rotary transformer (3) as shown in Figure 2(d), the diode (8) and smoothing capacitor (3) operate, and the voltage of this smoothing capacitor (8) is as shown in Figure 2(d). e), i.e. diode (8
) is intermittent as shown in Fig. 2(d), but if the capacitance of the smoothing capacitor (9) is set large, even during periods when there is no input to the diode (8), Figure 2 (e) from the smoothing capacitor (9) to the amplifier (2).
) will be supplied with a DC voltage as shown below.

As described above, during the information recording/reproducing period (D2), by lowering the level of power supplied to the amplifier (2), it is possible to reduce frequency interference on one screen.

Note that by increasing the level of power supplied to the amplifier (2) during the horizontal synchronization signal period (old), its high frequency output mixes with the signal processing circuit (0) and causes interference on the screen, but during this period This is the ranking period and there is no visual problem.Also, when the video head (1), rotary transformer (3), etc. start rotating and there is no output from the FM demodulator (13), the gate circuit (17) However, in this case as well, there is no problem of interference with the screen.

FIG. 3 is a block diagram showing the configuration of the main parts of an information recording and reproducing apparatus according to another embodiment of the present invention. In the same figure, the difference from the embodiment shown in FIG. )
In this configuration, in addition to the gate circuit (17), there is a seven-tenutator (1) between the oscillator (18) and the power amplifier (18).
9) was inserted in parallel.

The rest of the configuration is the same as the embodiment shown in FIG.
The same reference numerals will be given, and the description thereof will be omitted.

Next, the operation of the configuration shown in FIG. 3 will be explained.

The output (c) of the oscillator (18) is directly applied to the power amplifier (18) during the synchronizing signal period (Dl), while attenuated by the attenuator (13) during the other periods (D2). Therefore, the power amplifier (18) outputs power having a waveform as shown in FIG. 2(f). That is, the OSC during the blanking period (D2)
The output from (5) is small, so that interference to the screen can be reduced, and the charge applied to the smoothing capacitor (9) can also be reduced.

According to the other embodiment shown in FIG. 3, the ability to supply power to the amplifier (2) can be increased, although somewhat more interference appears on the screen than in the embodiment shown in FIG. It becomes possible.

In the above embodiment, the output of the oscillator (16) is controlled using the gate circuit (17), but the oscillation intensity of the oscillator (16) itself is changed every time the oscillation of the oscillator (16) itself is intermittent. However, the same effects as in the above embodiment can be achieved.

Furthermore, in the above embodiment, one rotary transformer (3) is used to transmit the reproduced signal and to transmit power to the amplifier (2), but even if separate rotary transformers are used, the same effect as in the above embodiment can be achieved. It has a similar effect.

Furthermore, instead of the rotary transformer, a signal transmission means using capacitance or a signal transmission means using light may be used.

Furthermore, the period during which the output of the OS C (5) is reduced may be set slightly wider before and after the synchronizing signal period (Dl), and may be set to the full width of the blanking period.

[Effects of the Invention] As described above, according to the present invention, #! from O20! IV
By controlling the level of high-frequency power supplied to the A unit so that it is lower when an image appears on the playback screen than during other periods, the level of high-frequency power supplied to the amplifier is maintained at the necessary and sufficient level, while the playback screen It is possible to improve image quality by preventing frequency interference from occurring.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of essential parts showing the configuration of an information recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the operation, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a block diagram of the main parts of a conventional information recording/reproducing apparatus. (1)...Video head, (2)...Amplifier, (3
)...rotary transformer, (4)...signal processing circuit, (5)...0SC1 (16)...oscillator, (17
)...Gate circuit, (18)...Power amplifier. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A means for recording and reproducing information using a rotating transducer, an amplifier that rotates together with the transducer, a power supply oscillator that supplies high-frequency power to the amplifier, and a level of power supplied from the power supply oscillator to the amplifier. and power supply control means for controlling the information recording/reproducing period so that the information recording/reproducing period is lower than the blanking period accompanying a synchronization signal.