JPH01236404A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To realize the reproduction of sound signals during the recording of video signals by setting the resonance frequency of a resonance circuit in accordance with the frequency component of the video signal. CONSTITUTION:The resonance frequency of a resonance circuit 7 is set about the center of the band of the video signal. At the same time, the Q is reduced to extremely attenuate the frequency component of the video signal which has the crosstalk over a sound signal transmission line after trapping the frequency component covering approximately the entire band of the video signal. Then the resonance frequency of a resonance circuit 7 is set in accordance with the frequency component of the video signal to be recorded. As a result, the saturation of a sound signal recording/reproducing circuit 6 that is caused by the video signal having the crosstalk can be avoided. Thus it is possible to record the video signals during the recording of the sound signals.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording/reproducing device such as a high-fidelity VTR (video tape recorder).

(Prior Art) As is generally known, in a VTR, a magnetic tape is wound diagonally around a rotating cylinder to which a magnetic head is attached, and the magnetic tape is run while the rotating cylinder is rotated to generate signals. Perform recording and playback.

In addition, the so-called high-fidelity VTR is equipped with a video head for recording and reproducing video signals as a magnetic head attached to a rotating cylinder as described above, and an audio head for recording and reproducing audio signals.
In R, the video head records video signals on the surface layer of the magnetic tape, and the audio head records audio signals on the deep layer of the magnetic tape.

Incidentally, in such a VTR, a rotary is used to connect the video head and the audio head attached to the rotary cylinder to each recording/reproducing circuit without interfering with the rotation of the rotary cylinder to form a signal transmission path. A transformer is used.

In such a rotary transformer, the coil for the video signal transmission path and the coil for the audio signal transmission path are distributed in the radial direction of the rotary transformer in a state where they are quite close to each other due to dimensional restrictions.

Conventionally, therefore, a short ring is placed between the video path coil and the audio signal transmission path coil to attenuate the crosstalk between the respective coils.

(Problem to be Solved by the Invention) As a new function of the high-fidelity VTR as described above, the present applicant has developed a system that reproduces and listens to (monitors) pre-recorded audio signals while also outputting appropriate video signals. We are working diligently to develop an editing function that allows you to record in the desired location.

However, when attempting to realize such an editing function, the following problems arise in the conventional high-fidelity VTR as described above.

That is, in general, when recording a video signal, the video signal is amplified to a certain level, so that the amplified video signal causes crosstalk to the audio signal transmission line at the rotary transformer.

Even if the crosstalk component of such a video signal is attenuated by the short ring, it is at a considerably higher level than the weak reproduced audio signal, so the audio signal reproduction circuit becomes saturated. It becomes impossible to output an audio signal from this reproduction circuit.

(Means for Solving the Problems) The present invention has been made in order to solve the problems as described above, and an object of the present invention is to provide a magnetic recording/reproducing device capable of reproducing audio signals while recording video signals. purpose.

In order to achieve this object, the present invention includes a video head for recording video and audio signals, an audio head for reproducing audio signals, each attached to a rotating cylinder, and a rotary transformer provided in the rotating cylinder. A video signal recording circuit and an audio signal reproducing circuit are respectively connected to the video head and the audio head via a resonant circuit, and a resonant circuit is connected between the rotary transformer and the audio signal reproducing circuit. The present invention provides a magnetic recording/reproducing device characterized in that the frequency is set to a frequency corresponding to the frequency component of a video signal.

(Embodiment) Hereinafter, a preferred embodiment of the magnetic recording/reproducing Vt device according to the present invention will be described in detail with reference to FIGS. 1 and 2.

In this embodiment, the present invention is applied to a magnetic recording and reproducing device such as a high-fidelity VTR, and this magnetic recording and reproducing device is arranged at a predetermined angular position of a rotary cylinder that is rotatably attached to the main body of the device. It is equipped with a projection head 1 for recording and reproducing video signals and an audio head 2 for recording and reproducing audio signals.

The video head 1 and the audio head 2 are arranged close to each other in a predetermined position W1 relationship such that they trace the same track as the rotary cylinder rotates. After magnetically recording the video signal in the deep part of a predetermined track of the magnetic tape, the video head 1 magnetically records (overlaps) the video signal in the surface part of the same track.

The video head 1 and the audio head 2 are connected to a video signal recording circuit 5 and an audio signal recording/reproducing circuit 6 arranged on the fixed part side of the main body of the device via a rotary transformer 4 equipped with a general short ring 3. are connected to each.

Here, in this embodiment, between the video head 1 and the video signal recording/reproducing port N5, a band of about 5, 4 [MH2] to 7 [MH2] is formed by superimposing the FM luminance signal and the low-frequency conversion color signal. Video signals are exchanged, and these video signals are recorded on the magnetic tape with a recording current of about 25 IIAP-P.

Furthermore, between the audio head 2 and the audio signal recording/reproducing circuit 6, the frequency of 1, 3 [MHz] to 1.7 [MHZ
2] Audio signals of about ±150[KHz1 are exchanged, and the reproduction current of such audio signals is about 20μ^p-p.
The following is true.

On the other hand, between the audio signal recording and reproducing circuit 6 and the rotary transformer 4, a resonant circuit 7 comprising a coil L, a capacitor C, and a resistor R connected in series is connected to the audio signal recording and reproducing circuit 6.
are connected in parallel.

This resonant circuit 7 has a resonant frequency of approximately 6 [M
The inductance of the coil L and the capacitance of the capacitor C are respectively set so as to be approximately H2], and the Q value of the resonant circuit 7 is set to be relatively small by the resistor R.

Further, this resonant circuit 7 is grounded via a switch 8, and this switch 8 is turned on when the audio is being reproduced and the video is being recorded.

In the magnetic recording and reproducing apparatus having such a configuration, the video signal recording and reproducing circuit 5 is brought into the recording state, the audio signal recording and reproducing circuit 6 is brought into the reproducing state, and the switch 8 is turned on, thereby causing the rotary transformer 4 to be activated. The frequency component of the video signal that crosstalks to the audio signal transmission path is trapped in the resonant circuit 7.

That is, the resonant frequency of this resonant circuit 7 is approximately 6 [MHz
l, and the Q value is set small, so
The impedance of this resonant circuit 7 is considerably small over the entire video signal band around 6 MHzl.

Therefore, the frequency components of the video signal are grounded via the resonance circuit 7 and the switch 8, so that the frequency components entering the audio recording/reproducing circuit 6 are considerably attenuated.

Therefore, it is possible to prevent the reproduction amplifier of the audio recording and reproduction circuit 6 from being saturated by the crosstalked video signal, and it is possible to extract the reproduced audio signal.

By the way, although the series resonant circuit 7 was used in the above-described embodiment, the same effect can be obtained by using a parallel resonant circuit 10 as shown in FIG. 2 in the present invention.

That is, the resonant frequency of this parallel resonant circuit 10 is set to about 6[
MHz, and by setting the Q value small, this resonant circuit 1 for the video signal frequency component is
0 impedance can be increased, and this video signal frequency component can be prevented from entering the audio recording/reproducing circuit 6.

In addition, in this embodiment, by connecting a damping resistor R in series with the capacitor C, this resonant circuit 10
The Q value of can be made small, thereby making it possible to trap frequency components of a wide band of video signals.

In the parallel resonant circuit 10 as described above, the switch 11 connected in parallel with the resonant circuit 10 is turned off when the audio signal recording and reproducing circuit 6 is in the reproducing state and the video signal recording and reproducing circuit 5 is in the recording state. Ru.

As described above, according to the magnetic recording/reproducing apparatus according to each of the above embodiments, the resonant frequencies of the resonant circuits 7 and 10 are set approximately in the middle of the video signal band, and the Q is made small. It is possible to trap frequency components in almost the entire band.

As a result, the frequency components of the video signal that crosstalk into the audio signal transmission path can be significantly attenuated.

Note that the resonant frequency of each resonant circuit 7.10 above is 6 [MH
It is not limited to zl, and may be set according to the band of the video signal.

(Effects of the Invention) As is clear from the above description, the present invention provides a resonant circuit in the audio signal transmission path and sets the resonant frequency of this resonant circuit to a frequency corresponding to the video signal frequency to be recorded. It is possible to trap the frequency components of the video signal that crosstalk into the audio signal transmission path.

Therefore, according to the present invention, saturation of the audio reproduction circuit due to crosstalked video signals can be prevented, and a new function of recording a video signal while reproducing an audio signal can be realized.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of a magnetic recording/reproducing iu according to the present invention, and FIG. 2 is a circuit diagram showing another embodiment. 1... Video head, 2...: Audio head, 4... Rotary transformer, 5... Video signal recording and reproducing circuit (video signal recording circuit),
6...Audio signal recording and reproducing circuit (audio signal reproducing circuit),
7... Resonant circuit (series resonant circuit), 10... Resonant circuit (parallel resonant circuit). 2 concave

Claims (1)

[Claims] A video head for recording video signals and an audio head for reproducing audio signals, each attached to a rotating cylinder, and a rotary transformer provided in the rotating cylinder to connect the video head and the audio head to each other through a rotary transformer provided in the rotating cylinder. A video signal recording circuit and an audio signal reproducing circuit are connected to each other, and a resonant circuit is connected between the rotary transformer and the audio signal reproducing circuit, and the resonant frequency of the resonant circuit corresponds to the frequency component of the video signal. A magnetic recording/reproducing device characterized in that the frequency is set to 1.