JPH11110706A - Signal transmitting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal transmitting apparatus having a rotary transformer capable of surely reducing crosstalk noises in a power supply line. SOLUTION: This apparatus includes a rotary transformer 11 having signal transmitting lines 12 and 13 and a power supply line 14, a power supply driving circuit 14b connected to the power supply line 14 on the stator side of the rotary transformer 11 and a signal generating circuit 14c for outputting a driving pulse to the power supply driving circuit 14b. By providing attenuaters 15a and 15b, the pulse signal from the dispatch circuit 14c is attenuated while its phase is inverted, so that the resultant signal is added, as a noise cancel signal, to the signal transmitting lines on the stator side of the rotary transformer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal transmission device using a rotary transformer, and more particularly, to a signal transmission device having a signal transmission system and a power supply system.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording / reproducing apparatus such as a rotary magnetic head for a video tape recorder, a rotary transformer is used to connect a rotary magnetic head mounted on a rotary drum to a fixed-side amplifier, power supply circuit and the like. Is used.

[0003] Such a signal transmission device is configured, for example, as shown in FIG. In FIG. 4, the signal transmission device 1 includes a recording signal transmission system 3, a reproduction signal transmission system 4, and a power supply system 5 connected via a rotary transformer 2. The rotary transformer 2 has a known configuration, and includes coils (not shown) of transmission systems (a recording signal transmission system 3, a reproduction signal transmission system 4, and a power supply system 5) provided on a fixed-side stator. And coils disposed on the rotating rotor so as to be opposed to the respective coils on the stator, so that transmission of a signal or supply current is performed for each of the transmission systems 3, 4, and 5. Has become.

The recording signal transmission system 3 includes a recording head 3a attached to a rotating drum and connected to a coil on the rotor side of the rotary transformer 2, and a recording amplifier 3b connected to a coil on the stator side of the rotary transformer 2. A recording signal output unit 3c for inputting a recording signal to the recording amplifier 3b
And is composed of

The reproduction signal transmission system 4 includes a reproduction head 4a attached to a rotating drum, a reproduction amplifier 4b to which a reproduction signal from the reproduction head 4a is input and connected to a coil on the rotor side of the rotary transformer 2; Output amplifier 4 connected to stator-side coil of rotary transformer 2
c.

The power supply system 5 includes a rotary transformer 2
And the reproduction amplifier 4b
Rectifier circuit 5a for supplying a drive voltage to the power supply, a power supply drive circuit 5b connected to a coil on the stator side of the rotary transformer 2, and a transmission circuit 5c for outputting a pulse signal to the power supply drive circuit 5b. I have.

According to the signal transmission apparatus 1 having such a configuration, the signal is recorded first through the rotary transformer 2 after the recording signal from the recording signal output unit 3c is amplified by the recording amplifier 3b. The data is transmitted to the head 3a. As a result, a signal is recorded from the recording head 3a to the magnetic tape.

In reproducing a signal, a very small reproduction signal from the reproduction head 4a is amplified by the reproduction amplifier 4b, input to the output amplifier 4c via the rotary transformer 2, and amplified again by the output amplifier 4c. After that, it is sent to an external playback device (not shown). As a result, the signal is reproduced by the reproducing head 4a. Here, the reproduction amplifier 4b receives an alternating current supplied from the power supply driving circuit 5b based on the pulse signal from the transmission circuit 5c, and inputs the alternating current to the rectification circuit 5a via the rotary transformer 2, and the rectification circuit 5a It is rectified. And the rectifier circuit 5a
The rectified DC current is supplied to the reproduction amplifier 4b, so that the reproduction amplifier 4b is supplied with power and can operate.

[0009]

By the way, in the signal transmission device 1 having such a configuration, the rotary transformer 2
The power supply current leaks from the power supply system 5 and jumps into the signal transmission systems 3 and 4 as crosstalk noise. For this reason, if the crosstalk noise jumps into the reproduction signal, distortion occurs in the reproduction signal, resulting in a problem that the quality of the reproduction signal is reduced and the error rate is deteriorated. Also, if crosstalk noise enters the recording signal, the recording signal will be distorted, so that a signal having distortion will be recorded on the magnetic tape. Therefore, when this signal is reproduced, the reproduced signal is distorted, and there is a problem that an error rate is deteriorated. Further, when the crosstalk noise into which the recording signal enters is large, there is a problem that the magnetic tape is demagnetized.

On the other hand, in order to reduce crosstalk noise from the power supply system 5 to the signal transmission systems 3 and 4,
For example, as shown in FIG. 5, a so-called short ring 2c is provided between the signal line 2a and the power supply line 2b of the rotary transformer 2, or as shown in FIG. 6, the signal line 2a and the power supply line of the rotary transformer 2 are provided. Countermeasures such as increasing the distance d between the first and second electrodes 2b are adopted.

However, as a countermeasure against the provision of the short ring 2c shown in FIG. 5, the provision of a plurality of short rings 2c causes a problem that the coupling coefficient of each of the signal transmission systems 3 and 4 is reduced and the frequency characteristics are deteriorated. . Also,
The measure for increasing the distance d shown in FIG. 6 has a problem that, in the case of a small rotating drum, the rotary transformer 2 itself is also small, so that substantially no space is taken and it is difficult to realize. .

In view of the above, it is an object of the present invention to provide a signal transmission device including a rotary transformer, which can surely reduce crosstalk noise in a power supply system.

[0013]

According to the present invention, there is provided a rotary transformer having at least one signal transmission system and a power supply system, and a power supply connected to the power supply system on a stator side of the rotary transformer. A signal transmission device, comprising: a driving circuit for driving and a transmitting circuit for outputting a driving pulse to a driving circuit for a power supply, wherein the pulse signal from the transmitting circuit is attenuated and the phase is inverted to generate a noise canceling signal. This is achieved by a signal transmission device comprising means for adding to the signal transmission system on the stator side of the rotary transformer.

In the signal transmission apparatus according to the present invention, preferably, the means for providing the noise cancellation signal to the signal transmission system is an attenuator, and the attenuator converts the noise cancellation signal contained in the signal of the signal transmission system into a power supply system. The attenuation is adjusted so that it becomes the same level as the crosstalk noise leaking from the signal transmission system to the signal transmission system.

According to the above configuration, the pulse signal from the transmission circuit for driving the power supply driving circuit of the power supply system is:
The signal is attenuated through the attenuator and inverted in phase, and is added to the signal transmission system as a noise canceling signal.
Accordingly, in the signal transmission system, a noise cancellation signal having the same phase as the crosstalk noise from the power supply system is added, so that the crosstalk noise included in the signal is canceled out by the noise cancellation signal and reduced. Will be.

In the case where the attenuator adjusts the attenuation of the noise cancellation signal included in the signal of the signal transmission system so that the noise cancellation signal has the same level as the crosstalk noise leaking from the power supply system to the signal transmission system, the attenuation of the signal is reduced. The included crosstalk noise is completely canceled and removed by the noise cancellation signal.

When a plurality of signal transmission systems are provided and attenuators are provided for each of the signal transmission systems, a noise canceling signal is added to each signal transmission system by the corresponding attenuator. , The crosstalk noise included in the signal is reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows the configuration of an embodiment of a signal transmission apparatus to which the present invention is applied. In FIG. 1, a signal transmission device 10 is incorporated in a magnetic recording / reproducing device such as a rotary magnetic head for a video tape recorder, and has a recording signal transmission system 12 connected via a rotary transformer 11.
It includes a reproduction signal transmission system 13, a power supply system 14, and a noise cancellation circuit 15.

The rotary transformer 11 has a well-known structure, and includes transmission systems (a recording signal transmission system 12, a reproduction signal transmission system 13, and a power supply system 1) provided on a fixed stator.
4) and a coil disposed on the rotor on the rotating side so as to face each coil on the stator. Each of the transmission systems 12, 13, and 14 has a signal. Alternatively, the supply current is transmitted.

The recording signal transmission system 12 includes a recording head 12a attached to a rotating drum and connected to a rotor-side coil of the rotary transformer 11, and a recording amplifier 1 connected to a stator-side coil of the rotary transformer 11.
2b and a recording signal output unit 12c for inputting a recording signal to the recording amplifier 12b.

The reproduction signal transmission system 13 includes a reproduction head 13a mounted on a rotating drum and a reproduction head 13a.
And a reproduction amplifier 13b connected to a rotor-side coil of the rotary transformer 11 and an output amplifier 13c connected to a stator-side coil of the rotary transformer 11.

The power supply system 14 is connected to a rotor-side coil of the rotary transformer 11 and supplies a drive voltage to the reproduction amplifier 13b, and a power supply connected to a stator-side coil of the rotary transformer 11. Drive circuit 14b, and a transmission circuit 14c that outputs a pulse signal to the power supply drive circuit 14b.

The means for providing a noise canceling signal plays a role of applying a predetermined signal to each or each signal transmission system and canceling a noise signal entering these signal systems. The present embodiment is characterized in that the means for exhibiting such an action is constituted by an electric circuit instead of a coil or the like formed on the core of the rotary transformer 11 as in the related art. 1
1 can be prevented from increasing. In the case of the present embodiment, the noise canceling circuit 15 as a means for giving the noise canceling signal is a transmitting circuit 14.
attenuators 15a to which the pulse signal from c is input,
15b. These attenuators 15a, 15b
Attenuates and inverts the phase of the pulse signal from the transmission circuit 14c, and applies it to each of the signal transmission systems 12 and 13 as a noise cancellation signal.

That is, the attenuator 15a outputs the noise cancel signal to the recording signal output unit 1 of the recording signal transmission system 12.
2c is applied to the recording signal. In this case, the attenuation of the attenuator 15a is adjusted so that the noise cancellation signal has the same level as the level of the crosstalk noise included in the recording signal.

The attenuator 15b applies a noise cancel signal to a reproduced signal input from the coil on the stator side of the rotary transformer 11 of the reproduced signal transmission system 13 to the output amplifier 13c. In this case, the attenuator 15b outputs the noise cancel signal
The attenuation is adjusted so that the level becomes the same as the level of the crosstalk noise included in the reproduction signal.

The signal transmission device 10 according to the present embodiment is configured as described above. First of all, the signal is recorded after the recording signal from the recording signal output unit 12c is amplified by the recording amplifier 12b, The data is transmitted to the recording head 12a via the transformer 11. As a result, a signal is recorded on the magnetic tape from the recording head 12a. Here, the recording signal from the recording signal output unit 12c is
Although crosstalk noise leaking from the power supply system 14 is included, a noise canceling signal having a phase opposite to that of the crosstalk noise is applied from the attenuator 15a, so that the crosstalk noise is canceled by the noise canceling signal. Reduced or completely eliminated. Thus, the recording signal from which the noise canceling signal has been reduced or completely removed is recorded on a magnetic tape or the like via the recording head 12a, so that the error rate is improved. Tape demagnetization will be eliminated.

FIG. 2 shows an attenuator 1 for a recording signal.
5A shows each signal waveform in the noise cancellation by 5a. FIG. 2A shows a pulse signal of the transmission circuit 14c, and crosstalk noise included in the recording signal is shown in FIG.
As shown in (b), it has a level Vn. On the other hand, the noise cancellation signal by the attenuator 15a has an opposite phase to the crosstalk noise and has a level Vnc, as shown in FIG. Therefore, when the noise cancellation signal is applied to the recording signal,
The crosstalk noise included in the recording signal is shown in FIG.
As shown in (1), the noise is canceled and reduced by the noise cancellation signal. Here, the level Vnc of the noise cancellation signal is equal to the level V of the crosstalk noise.
By performing the attenuation adjustment to be equal to n, the crosstalk noise is completely removed.

In reproducing a signal, a very small reproduction signal from the reproduction head 4a is amplified by the reproduction amplifier 4b, input to the output amplifier 4c via the rotary transformer 2, and amplified again by the output amplifier 4c. After that, it is sent to an external playback device (not shown). As a result, the signal is reproduced by the reproducing head 4a. Here, the reproduction amplifier 4b receives an alternating current supplied from the power supply driving circuit 5b based on the pulse signal from the transmission circuit 5c, and inputs the alternating current to the rectification circuit 5a via the rotary transformer 2, and the rectification circuit 5a It is rectified. And the rectifier circuit 5a
The rectified DC current is supplied to the reproduction amplifier 4b, so that the reproduction amplifier 4b is supplied with power and can operate.

In this case, the reproduction signal input from the rotary transformer 11 to the signal amplifier 13c is supplied to the power supply system 14
Crosstalk noise that leaks out of the
Since a noise cancel signal having a phase opposite to that of the crosstalk noise is applied from the attenuator 15b, the crosstalk noise is canceled by the noise cancel signal and is reduced or completely removed. Thus, the reproduced signal from which the noise canceling signal has been reduced or completely removed is reproduced by the reproducing head 13a, so that the error rate is improved.

The attenuation adjustment of the attenuators 15a and 15b described above is performed, for example, as shown in FIG. FIG.
In a state where there is no recording signal from the recording signal output unit 12c, the power supply system 14 transmits the signal
3 is monitored by the current probes 16 and 17, respectively. Then, in order to eliminate the cross toll noise of each of the signal transmission systems 12 and 13,
By adjusting the trimmers of the attenuators 15a and 15b, the attenuation adjustment of each of the attenuators 15a and 15b is completed.

In the above-described embodiment, the attenuators 15a and 15b are adjusted so that the noise cancellation signal is at the same level as the crosstalk noise, so that the crosstalk noise is completely removed. It is particularly suitable for the case of accurately reproducing a signal.
However, the attenuators 15a and 15b do not need to be of a type in which the noise cancellation signal is at the same level as the crosstalk noise by adjustment, and the crosstalk noise can be reduced to a practically sufficient level in accordance with the characteristics of the device to be incorporated. What is necessary is just to make it reduce.

[0033]

As described above, according to the present invention, there is no need to provide a short ring between wirings corresponding to each signal transmission system of the rotary transformer or to provide an interval between them, unlike the prior art. Is made small, and the manufacturing cost is reduced. Further, since a short ring is not required, the coupling coefficient of each signal transmission system can be increased, and the frequency characteristics of signal transmission are improved. Thus, according to the present invention, it is possible to provide a signal transmission device including a rotary transformer that can surely reduce crosstalk noise in a power supply system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a signal transmission device according to the present invention.

FIG. 2 is a time chart showing signal waveforms at various parts of the magnetic recording / reproducing apparatus of FIG.

FIG. 3 is a block diagram illustrating attenuation adjustment of each attenuator in the signal transmission device of FIG. 1;

FIG. 4 is a block diagram illustrating a configuration of an example of a conventional signal transmission device.

FIG. 5 is a schematic perspective view showing an example of an arrangement of signal lines and power supply lines of a rotary transformer in a conventional signal transmission device.

FIG. 6 is a schematic perspective view showing another example of an arrangement of signal lines and power supply lines of a rotary transformer in a conventional signal transmission device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Signal transmission device, 11 ... Rotary transformer, 12 ... Recording signal transmission system, 12a ... Recording head, 12b ... Recording amplifier, 12c ... Recording signal output part, 13 ... A reproduction signal transmission system, 13a reproduction head, 13b reproduction amplifier, 13c output amplifier, 14 power supply system, 14a rectifier circuit, 1
4b: power supply driving circuit, 14c: transmission circuit, 1
5. Noise cancellation circuit, 15a, 15b ...
Attenuator, 16, 17, ... current probe.

Claims (4)

[Claims] 1. A rotary transformer having at least one signal transmission system and a power supply system, a power supply drive circuit connected to a power supply system on a stator side of the rotary transformer, and a drive pulse output to the power supply drive circuit. A signal transmission device, comprising: attenuating and inverting the phase of a pulse signal from the transmission circuit, and adding the same to the signal transmission system on the stator side of the rotary transformer as a noise canceling signal. A signal transmission device comprising: 2. A means for providing the noise canceling signal to the signal transmission system is an attenuator, and the attenuator crosses the noise canceling signal included in the signal transmission system signal from the power supply system to the signal transmission system. 2. The signal transmission device according to claim 1, wherein the attenuation is adjusted so as to have the same level as the talk noise. 3. The signal transmission device according to claim 1, wherein a plurality of signal transmission systems are provided, and the attenuator is provided for each signal transmission system. 4. Each of the attenuators attenuates and adjusts a noise cancellation signal included in a signal of a corresponding signal transmission system so as to have the same level as crosstalk noise leaking from a power supply system to the signal transmission system. The signal transmission device according to claim 3, wherein: