JPS61117702A - Power supply system of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a system by transmitting power to a rotary drum with an AC signal having a frequency sufficiently higher than that of a reproduced signal to supply power into the drum without influences upon the reproduced signal. CONSTITUTION:Recording signals detected by video heads 5a-5n of a magnetic recording and reproducing device are amplified by regenerative amplifiers 7a-7n and are applied to a pair of rotary transformers 12c and 13c of a rotary transformer group 4 as a continuous reproduced signal by a switch circuit 11. The output of the transformer 13c is processed by a filter 18 and a signal processing circuit 19 and is converted to a signal required in each part and is outputted. The switching control signal of the circuit 11 is generated by a switch signal generating circuit 17 and is inputted to the circuit 11 through a converter 16, rotary transformers 13b and 12b, and an inverse converting circuit 10. The AC signal generated by an oscillator 15 is used as power required for the rotary drum and is amplified by a power supply circuit 14 and passes rotary transformers 13a and 12a and is processed by a smoothing circuit 9 and a stabilizing circuit 8 and is supplied to a regenerative amplifier group 4 as the AC signal having a high frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic recording/reproducing device, and particularly to a power supply system used to supply power to a circuit mounted within a rotating drum.

[Background of the invention]

In a magnetic recording and reproducing device that records and reproduces signals on a magnetic tape etc. using a magnetic head mounted on the rotating drum while rotating the rotating drum, circuits such as a recording amplifier and a reproducing amplifier are installed in the rotating drum. Conventionally, methods for supplying power to those circuits include using a slip ring or attaching a magnet to a fixed part that supports the rotating drum, as described in Japanese Patent Application Laid-Open No. 58-211306. A generator was constructed by installing coils on each side of the rotating drum, and the power was supplied by the generator.

However, when using a slip ring, there are problems in terms of life and reliability due to mechanical rotating contact, and
When constructing a generator as in the latter case, there was a problem in that the cost of the coils and magnets themselves and the cost of mounting them were extremely high.

[Purpose of the invention]

The purpose of the present invention is to solve the problems of the prior art described above,
To provide a power supply method that can supply power without mechanical contact, can be realized at low cost, and can supply power without affecting a reproduced signal. It is in.

[Summary of the invention]

In order to achieve the above object, the present invention includes an oscillator that oscillates at a frequency higher than the maximum frequency of the reproduced signal, an amplifier circuit that amplifies the output from the oscillator, and a rotary drum. is provided with a smoothing circuit for smoothing the output from the amplifier circuit and a stabilizing circuit for stabilizing the smoothed output so that it can be used as a power source in the rotating drum. The output is transmitted to the conversion circuit via a rotary transformer.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a sectional view of a rotating drum and a fixed part used in the present invention.

The rotating drum mechanism in the magnetic recording/reproducing apparatus is as shown in FIG. That is, the rotating drum 1 is rotatably supported by the fixed part 2 and rotationally driven by the motor part 5.

Note that this is a 4Vi rotary transformer group.

Next, the configuration of this embodiment will be explained.

In FIG. 1, numerals 5α to 5 are video heads for recording and reproducing signals on magnetic f-7' (not shown), and 6 is a group of reproduction amplifiers, each of which is composed of reproduction amplifiers 7a to 7F&. Also, 8 is a stabilizing circuit, 9 is a smoothing circuit, 1
0 is an inverse conversion circuit, and 11 is a switch circuit. Each of the circuits described above is mounted within the rotating drum 1 shown in FIG. 2, and is driven together with the rotating drum 1 by the motor section 3.

Next, 12α to 12C and 13α to 13C are rotary transformers, respectively, and constitute the rotary transformer group 4 shown in FIG. 12α and 13g, 126 and 13A, and 12C and 13C form pairs, respectively. In addition, 14 is a power supply circuit, 15 is an oscillator, 1
6 is a converter, 17 is a switch signal generation circuit, 18 is a filter, and 19 is a signal processing circuit, these circuits are as follows:
It is arranged at or around the fixed part 2.

Next, the operation of this embodiment will be explained.

First, signals recorded on a magnetic tape (not shown) are detected by the outside of the video heads 5a to 5. The detection signals from each of the heads 5α to 51 are amplified by the reproduction amplifiers 74 to 74 corresponding to the respective heads, and then input to the rotary transformer 12c by the switch circuit 11 as one continuous signal (reproduction signal). Since the rotary transformers 12c and 15c form a pair, the reproduced signal is input to the rotary transformer 13c, and then passed through the % filter 18 and converted by the signal processing circuit 19 into signals necessary for each section.

On the other hand, the aforementioned switch circuit 11 is a circuit that sequentially switches the output signals of the respective reproduction amplifiers 76 to 7+s to produce one reproduction signal.

A control signal for performing such an operation is generated by the switch signal generation circuit 17, converted by the converter 16 into a signal that can be transmitted from the rotary transformer 12b to the public 13, and then converted into a signal required by the inverse conversion circuit 1o. After being returned to , it is input to the switch circuit 11 .

In this way, when a circuit as described above is disposed inside the rotating drum 1 and a signal is to be transmitted between the rotating drum 1 and the fixed part 2, it is necessary to supply power to the rotating drum 1 once. Therefore,
The oscillator 15 generates an AC signal, the signal is amplified by the power supply circuit 14, and the α-tally transformer 13g,
12a f to transmit signals into the rotating drum 1.

In the rotating drum 1, the signal is smoothed by a smoothing circuit 9, and stabilized by a stabilizing circuit 8) so that it can be used as a power source.

Next, regarding VC and this power supply, see Figure 3.

This will be described in more detail using FIG.

FIG. 5 is a circuit diagram showing a specific circuit configuration of the smoothing circuit and power supply circuit shown in FIG. 1.

In FIG. 5, 20, 25, 28 are capacitors, 21.22 are diodes, 25, 27,
51ti transistors, 24, 26, 29 respectively
, 30 and 32 are resistors, respectively.

Further, FIG. 4-1 is a graph showing the frequency characteristics of the reproduction signal 1 rooting signal and noise, and FIG. 4(B) is a graph showing the frequency characteristics of the filter of FIG. 1.

First, the oscillator 15 oscillates a signal at a frequency suitable for transmission. This oscillation signal is transmitted to the rotary transformer group 4.
Since the influence on the reproduction amplifier group 6, etc. can be easily predicted, it is necessary to select a frequency that does not affect the reproduction signal as the oscillation frequency. Therefore, if an attempt is made to transmit using a lower frequency than the reproduced signal, the harmonics will become noise to the reproduced signal, so it is necessary to oscillate a frequency higher than the reproduced signal and use it for transmission. shall be. Furthermore, considering that the oscillation signal is transmitted into the rotary drum 1, interference within the reproduction amplifier group 6 can be easily expected, and there is a possibility that the reproduction signal will be modulated. In other words, the highest frequency 12I2n in the band of the reproduced signal is f”
When the % oscillation frequency is fc (fc>fx), as a particularly large noise component, f noi ## = f c :l:7m''-
-. (11 is considered. If fnOilg is higher than f, it is possible to separate the reproduced signal and the noise component using the filter 18 shown in FIG. 1. In other words, as shown in FIG. 4 (A) , if the frequency of the oscillation signal S and the spectrum of the noise C are higher than the spectrum of the reproduced signal α, only the reproduced signal can be obtained by using a filter having frequency characteristics as shown in Figure 4 (Bl). I can do it.

Therefore, from this condition, fnoizm = fcthfyx > frn...
'・””・(2), and in the end, f, > 2f, ・・・・・・・・・(3
). That is, the oscillation frequency of the oscillator 15 needs to be twice or more the highest frequency of the reproduced signal.

Next, the oscillation signal from the oscillator 15 is transmitted to a transistor 51 constituting an emitter follower, as shown in FIG.
．． It is received by the resistor 30. Note that at this time, the resistor 32 is matched with the oscillator 15. The signal is then input to the transistor 27 via the speed-up capacitor t28 and the protective resistor 29, and is converted into a rectangular wave by the resistor 26 and transistor 27. Next, the resistor 24, capacitor 1 and 25 are High Pa5t Filters to prevent the DC signal from inputting to the base of the transistor 25 and destroying the transistor 23. , the above-mentioned rectangular wave is input to the base of the transistor 230 and drives the rotary transformer 13α.Here, the diode 22
Fi is a M-# key diode for speeding up the transistor 23. Next, the signal is transmitted from the rotary transformer 13α to the rotary transformer 12α, and is smoothed by the diode 21 and capacitor 2o that constitute the smoothing circuit 9. Then, it is stabilized in a stabilizing circuit 8 and sent to various circuits as a stable power source. Although the configuration of the stabilizing circuit 8 is not shown, it can be easily realized by stacking diodes or the like.

In this way, this embodiment does not require a large amount of equipment such as a generator, so the cost is low, and it is possible to supply power to the rotating drum without affecting the reproduced signal. .

In the above explanation, only the time of playback was explained, but
Power can be supplied in the same way during recording.

In this case as well, it is possible that a noise component may be included in the recording signal when power is supplied, but this noise component may be present immediately before the video heads 58 to 5 or on the rotary drum 1.
Immediately after the transmission into the interior, a filter can be provided and removed by the filter.

〔Effect of the invention〕

According to the present invention, power can be supplied to the rotating drum without affecting the reproduced signal by transmitting power to the rotating drum using an AC signal with a sufficiently high frequency compared to the reproduced signal. Furthermore, since a large amount of equipment such as a generator is not required, it can be realized at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. Figure 2 is a sectional view of the rotating drum and fixed part used in the present invention, Figure 5 is a circuit diagram showing the specific circuit configuration of the smoothing circuit and power supply circuit of Figure 1, and Figure 4 (V) is a regeneration circuit. Signal 2 is a graph showing the frequency characteristics of the oscillation signal and noise, and v3+ in the same figure is a graph showing the frequency characteristics of the filter in FIG. 1... Rotating drum 2... Fixed part 8... Stabilizing circuit 9... Smoothing circuit 121! , 13a
... Rotary transformer 14 ... Power supply circuit 15 ... Oscillator Fig. 2

Claims (1)

[Scope of Claims] 1) Consisting of a rotating drum and a fixed part that rotatably supports the rotating drum, a group of magnetic heads for reproducing signals recorded on a magnetic recording medium on the rotating drum, and a group of magnetic heads for reproducing signals recorded on a magnetic recording medium; a reproduction amplifier for amplifying a reproduction signal from the group, and an output from the reproduction amplifier is inputted to a reproduction signal processing circuit provided in the fixed part via a first rotary transformer. In the device, the fixed part is provided with an oscillator that oscillates at a higher frequency than the maximum frequency of the reproduction signal, and an amplifier circuit that amplifies the output from the oscillator, and the rotating drum is provided with an output from the amplifier circuit. and a stabilizing circuit that stabilizes the smoothed output so that it can be used as a power source in the rotating drum, and transmits the output from the amplifier circuit to the smoothing circuit. Power supply for a magnetic recording and reproducing device, characterized in that power is supplied from the fixed part to the inside of the rotating drum through a second rotary transformer, without affecting the reproduced signal. method. 2) A power supply system for a magnetic recording/reproducing apparatus according to claim 1, characterized in that a filter for attenuating the oscillation frequency of the oscillator is provided at a stage upstream of the reproduction signal processing circuit. Supply method.