JPH01303602A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a signal by equalizing the frequency of an erasing signal to flow at an erasing head and the frequency of a high frequency bias signal of a sound signal. CONSTITUTION:A core 95 for an erasing signal and sound signal winding and a core 96 for a video signal are separately provided, and a winding for a sound signal is provided between a winding for the erasing signal and a winding for the video signal. A high frequency bias signal from a bias oscillator 91 is supplied to a bias superimposing circuit 39 and supplied through a rotary transformer 100 to a rotation erasing head 92 as the erasing signal. A rotation erasing head 92 is provided on the rotation surface of a rotating cylinder together with other rotation head, the erasing signal is supplied at the time of recording, and thus, prior to the recording, a signal recorded beforehand on the magnetic tape is erased along the track on the magnetic tape. Consequently, by making the signal from the bias oscillator 91 into the erasing signal, the frequency of the erasing signal and the high frequency bias signal can be made coincident. Thus, the deterioration of the signal is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording/reproducing device, and in particular to an audio signal head that records an audio signal superimposed on a bias signal in a deep portion of a magnetic layer. The present invention relates to a magnetic recording/reproducing device having a video signal head and a rotary erasing head for recording video signals by forming a video track on the surface layer of a magnetic layer above the audio track.

Prior art The present applicant previously disclosed in Japanese Patent Application No. 62-261319 (title of invention [Magnetic recording device and magnetic recording/reproducing device]),
Frequency-multiplexed FM audio signals and PCM audio signals are superimposed and recorded on the deep layer of the magnetic tape, and then frequency-modulated luminance signals and low-frequency conversion carrier color signals are recorded on the surface layer of the magnetic tape. We have proposed a magnetic recording and reproducing apparatus that frequency-multiplexes video signals and records them, and further reproduces the previously recorded green signal recorded in this way.

Some of the rotating cylinders of the magnetic recording/reproducing apparatus and other VTRs are provided with a rotating erasing head for erasing previously recorded audio and video signals along recording tracks. This rotary erasing head has, for example, a 4M
The H7 erasure signal was supplied from outside the rotating cylinder via the I-tally 1-lance, and the winding for the rotating erasure head of the rotary transformer was wound between the audio signal windings. .

Problems to be Solved by the Invention As mentioned above, a high-frequency erasing signal current is supplied to the rotating erasing head, and this erasing current includes a signal that is recorded in the deep part of the magnetic layer in order to reliably erase the recorded signal. A larger current is required than the high frequency bias signal of the audio signal. Therefore, if no measures are taken, crosstalk will occur between this erasure signal 8 and the high-frequency bias signal for deep recording, and the audio signal recorded in the deep portion of the magnetic layer will suffer from cross-modulation distortion. occurs, degrading the signal quality.

One possible way to prevent this O-stalk is to add a short ring, but this increases cost and shortens the winding spacing of the rotary coil, causing crosstalk to other signals. There is a problem in that the signal deteriorates.

In addition, this erase signal causes crosstalk with the video signal, especially in the rotary transformer, and as a result, cross-modulation distortion occurs in the video signal as well, deteriorating the signal, and when the video signal recorded in this way is played back, moiré appears on the screen. There was a problem that occurred.

The present invention has been made in view of the above points, and is a magnetic recording device that can eliminate the influence of an erase signal on audio signals and video (i) and prevent signal deterioration without adding a short ring or the like. /The purpose is to provide a playback device.

Means for Solving the Problems The magnetic recording/reproducing apparatus according to the present invention sets the bias signal for superimposing an audio signal during recording and the erasing signal at the same frequency, and also superimposes the recorded audio signal and the recorded video signal through a rotary transformer. And when transmitting and receiving an erasure signal, among the windings constituting the rotary transformer, the first winding for the audio signal head is rotated, and the second winding for the erasure head and the third winding for the video signal head are rotated. A first core is provided between the wire and the first core and the second core is wound around the first and second windings, and a second core is separately provided around which the third winding is wound.

Furthermore, the bias signal or the erase signal ( The 1° effect cancellation signal, which is provided with a bias signal trapping means for trapping the frequency (both have the same frequency), is at a human level higher than the high frequency bias signal r of the audio signal recorded in the deep part of the magnetic layer. However, by matching the frequency of this cancellation signal and the frequency of the high-frequency bias signal, even if crosstalk occurs between the two signals, it is possible to prevent cross-modulation distortion caused by the cancellation signal from occurring in the audio signal. .

In addition, the configuration of the windings constituting the rotary transformer has been changed by arranging the audio signal winding between the high-level cancellation signal winding and the video signal winding. It is possible to make a large distance between the image signal and the video signal winding, and the influence of the erasing signal on the video signal can be reduced.

Furthermore, since the frequencies of the cancellation signal and the high-frequency bias signal of the audio signal are the same, the core around which the cancellation signal winding and audio signal winding are wound is separated from the core around which the video signal winding is wound. By doing so, cross-modulation distortion of the video signal due to crosstalk between the erasure signal and the audio signal and the video signal is further reduced.

Even with the above configuration, even if the video signal is affected by the erasure signal or audio signal via the winding of the rotary coil, the rotary coil must be placed before the rotary coil on the transmission path of the recorded video signal. The cancellation signal and the high-frequency bias signal are trapped by the bias signal trap means provided in one or both of the closed loops consisting of the winding of the video signal head and the winding of the video signal head. The influence on the signal is further reduced.

Embodiment FIG. 1 is a block system diagram showing an embodiment of the apparatus of the present invention. In the figure, the part above the - dotted chain line is the magnetic recording device M.
(Recording system) The portion below A is a magnetic recording/reproducing device including a reproducing system.

To explain this embodiment, a standard color one-way color video signal is input to the terminal 25, and the video signal processing circuit 26 receives a standard color video signal.
supplied to The video signal processing circuit 26 separates the r4 degree signal and the carrier color signal by known means, and frequency-modulates the carrier wave with this luminance signal to obtain frequency-modulated luminance No. 18 (
FM luminance signal), and converts the carrier color signal to a low band to generate a low band converted carrier color signal, and frequency division multiplexes these two signals to create a frequency spectrum as shown in Figure 2 (A). Output a signal. In Figure 2 (A), l is FMtf
The carrier frequency band is 5.4M l-(Z ~ 7
．． It is 0MH2. (2) is a low-band conversion carrier color signal, and its low-band conversion color subcarrier frequency is approximately 629 kHz. The above video signal for recording is transmitted to the recording amplifier 27 and -1 of the present invention.
The signal is supplied to the image rotating heads 28a and 28b via a trap circuit 90a which is a main part. This trap circuit 90
Further, the video signal processing circuit 26 supplies the standard color one-way color video signal to the sync signal separation circuit 29 as it is. The synchronization signal separation circuit 29 separates the vertical synchronization signal and supplies it to a servo circuit 30, which will be described later.

Further, the left channel analog audio signal and the right channel analog audio signal input to each of the terminals 31a and 31b are connected to a switch means 69a.

Noise reduction (NR) circuit 70a via 69b
, 70b, and after the dynamic range is halved, a pre-emphasis characteristic is imparted to the pre-emphasis circuit 718 and 71b, and the limiter 72a, 72
At b, signals above a predetermined level are cut. The outputs of the limiters 72a and 72b are sent to the FM modulators 73a and 73b.
For example, 1.3MHz and 1.7M, respectively.
FM modulated with a carrier wave of Hz, and passed through bandpass filters 74a, 7.
4b is sent to the mixer 75.

On the other hand, after unnecessary high-frequency components exceeding the audible frequency band are removed by the low-pass filters 32a and 32b via the switch means 69a and 69b, respectively, the sampling frequency is changed to, for example, 47.952 kllz (=48 k)-IZ.
÷1.001) sample hold circuits 33a, 33b
The signal is then supplied to A/D converters 534a and 34b, where it is linearly quantized to 16 bits and then encoded into a PCM audio signal. The PCM B voice signals of the left and right channels are supplied to an encoder 35.

The encoder 35 converts the even-numbered samples ES and the odd-numbered samples O8 in one field period into a sample shown in FIG. 3 (A).
) error detection and n-plus codes P, Q in the format shown in
generate.

In FIG. 3(A), data DATAI.

DATA2 is, for example, samples ES and O8 which have been subjected to time reduction and interleaving, respectively, and data DATA in each row in the middle of a word in the horizontal direction (one word is 8 bits).
I, DATA2 (8 x 50 bits each), each row is 8 x 30 (=
8x6x5) bit parity Q is obtained. The encoder 35 also encodes eight columns in the vertical direction, that is, one word in each row (
-8 bits) data DATA1. A predetermined operation is performed for every 32 words of DATA2° parity Q to generate 8×4 bit parity P for each column of 4 words.

Next, the above data DATA1. DATA2 and parity P, Q are divided into 8 columns of 36 words, and immediately before each of the 36 words, an 8-bit (-1 word) synchronization signal 5YNC and an identification signal are placed as shown in FIG. 3(B). ID,
Address signal ADDR.

A block parity signal PARITY is added to form a data block of 40 words in total.

Synchronization signal 5YNC indicates the start of each data block. Address signal ADDR indicates the order of each data block in one track of digital audio signals (ie, 130 data blocks). Block parity signal PARl
rY is an error detection signal obtained by PARITY=IDeADDR. Here, e is an additive operator modulo 2.

The data D A T A1, DA shown in FIG. 3 (A) in the 130 data block of the data area shown in FIG. 3 (C)
TA2 and parity P and Q are transmitted, but before that, 4
Two data blocks [one postamble] are added after a preamble for clock recovery for data blocks.

In this way, the encoder 35 encodes a total of 136 data blocks (=43,520 bits) as shown in FIG. 3(C).
A digital audio signal of the signal format is generated and transmitted in one field period (=1159.94 seconds). Therefore, the transmission bit rate of digital audio number n is 2.6086 (= 136x 320x59.
94) M bps.

Note that the encoder 35 is field synchronized with the video signal to be recorded by the output signal of the servo circuit 30.

The offset four-phase differential PSK modulator (OQDPSK modulator) 36 includes a conversion circuit that converts this digital audio signal into serial-parallel signals and outputs them alternately as two code strings, and a conversion circuit that converts these two code strings into 172 bits of one time slot each. A phase shifting means receives two code strings from this phase shifting means as modulation signals, and the phases are 90" from each other at a predetermined frequency fc.
A well-known synthesis circuit includes a balanced modulation means that separately performs carrier suppression amplitude modulation on two different carrier waves, and a synthesis circuit that synthesizes two amplitude modulated waves from the balanced modulation means and outputs a 0QDPSK modulated digital Δ voice signal. It is said to be composed of

As an example, the carrier wave frequency t'c is selected to be about 3.0 MHz, which is 191 times the horizontal scanning frequency fH. Therefore, the frequency spectrum of the output digital audio signal of this 0QDPSK modulator 36 has a maximum level at carrier frequency t'c, and since the transmission bit rate is 2.6086 Mbps, ±nx1.30 MHz (= 2
．． 6086 MHz /2) A well-known comb-like spectrum with O at distant frequency positions is obtained. However, the above n is a natural number. Therefore, the output digital audio signal of the 0QDPSK modulator 36 has a band v1 limit for removing unnecessary frequency components, and a passband width centered around about 3.0 MH7 that does not cause code amount interference. After passing through a bandpass filter 37 selected to be about 0.1 times the transmission bit rate and band-limiting the digital audio signal with a frequency spectrum as shown in (8) in FIG. The signal is inputted to a mixer 75, frequency-division multiplexed with the FM audio signal, and then supplied to three bias superimposition circuits, where it is superimposed with the high frequency bias signal generated in the bias superimposition circuit 91.

The bias superimposition circuit 39 has a configuration as shown in FIG. 4 or FIG. 5, for example. 4 and 5, the same constituent parts as in FIG. 1 are given the same reference numerals, and in FIG. 5, the same constituent parts as in FIG. 4 are given the same reference numerals.

The bias weight/reduction circuit 39 shown in FIG.
, the bias oscillator 4 is applied to the audio signal which is a mixture of the 0QDPSK modulated digital audio signal and the frequency modulated FM audio signal from the terminal 38.
A high frequency bias signal of, for example, 10.8 MHz is superimposed on the terminal 6, and this superimposed signal is sent to the terminal 4 through the recording amplifier 47.
Output to 0.

On the other hand, the bias superimposition circuit 39 shown in FIG.
The 0QDPSK modulated digital audio signal and the frequency modulated FM audio signal are sent to the coil 50.
The high frequency bias signal taken out from the bias oscillator 46 through the capacitor 52 is combined (superimposed) with the high frequency bias signal taken out from the bias oscillator 46 through the trap circuit consisting of the capacitor 51 and the capacitor 51, and then outputted to the terminal 40.

The circuit shown in FIG. 5 is a well-known circuit V4 configuration for bias recording, and the trap circuit prevents transmission of the high frequency bias signal to the recording amplifier 47 side, and the capacitor 5
2 prevents the digital audio signal and FM audio signal from being transmitted to the bias oscillator 46 side. As the recording amplifier 47 of the bias superimposing circuit 39 shown in FIG. 5, an inexpensive recording amplifier can be used as compared to the broadband, high-output, expensive recording amplifier required in the bias superimposing circuit 39 shown in FIG.

Next, the noise spectrum reduction effect of high frequency bias recording will be explained. Approximately 3. OMH2
0QDPSK with ±1.3MHz frequency spectrum
Modulated digital audio signal ■ and frequency modulated F
The M audio signal ■ is magnetically converted to -1 by the audio rotary head without superimposing a high frequency bias signal as in the conventional device.
- Reproduced modulated digital audio signal and FM audio when a recorded magnetic tape, in which video signals are recorded directly in the deep layer of the magnetic layer of the tape and video signals are recorded in the surface layer of the magnetic layer, is played back by an audio rotary head. The frequency spectrum of the signal is as shown in FIG. 7(A).

In FIG. 7(A), fsc is the color subcarrier frequency of the low-pass conversion carrier color signal, which is, for example, 629 kHz, and the low-pass conversion carrier color signal band includes the variable w4 distortion, as shown by the broken line V. The noise spectrum exists at a large level, and this occurs in the low frequency region where the azimuth loss effect is reduced. l! 11
It also occurs in the signal, degrading the color S/N. Furthermore, such cross-modulation distortion occurs due to the nonlinearity of the tape, and the resulting distortion degrades the error rate of the digital signal as described above, and increases the ratio of the carrier wave to the noise of the FM audio signal. It also deteriorates the C/N ratio.

On the other hand, in the frequency spectrum shown in Figure 6 above, 0
When a QDPSK-modulated digital audio signal and an FM audio signal are recorded by superimposing a high frequency bias signal of, for example, 10.8 MH2 according to the present invention, the frequency spectrum of the reproduced modulated digital audio signal is as shown in FIG. 7(B).
As shown in , among the noise spectrum due to cross-modulation distortion in the low-pass conversion carrier color signal band surrounded by the broken line ■, the noise spectrum in the vicinity of the low-pass conversion color subcarrier frequency f'sc is significantly reduced. was confirmed by experiment.

Note that the high-frequency components in FIG. 7(B) are equalized to the spectrum in FIG. 2(B) by the reproduction equalization type.

Also, instead of 0QDPSK modulation, 4-phase differential PSK modulation (
A digital audio signal with a frequency spectrum similar to that shown in Figure 6 obtained by QDPSK12 tone) is directly deep recorded without superimposing a high frequency bias signal, and the frequency spectrum when played back is similarly low-frequency converted. color hi'
The noise spectrum in the vicinity of l carrier frequency f'sc is significantly reduced.

Therefore, it can be applied not only to the 0QDPSK modulated digital audio signal described above, but also to the QDPSK modulated digital audio signal.
In addition to modulation formats such as and QDPSK, the present invention can be similarly applied to digital audio signals subjected to two-phase or eight-phase offset 0PSK modulation or 0PSK modulation.

The superimposed signal of the audio signal and the high frequency bias signal taken out from the terminal 40 is sent to the audio rotary head 41 in FIG.
a and 41b, respectively.

The audio rotating heads 41a and 41b are attached to the rotating surface of a rotating cylinder (not shown) so as to face each other at 180 degrees, and are attached at a certain angle ahead of the mounting position of the video rotating heads 28a and 28b. It is being Further, the azimuth angle of the audio rotating heads 41a and 41b is +30° for one and 130° for the other, and the azimuth angle of the rotating heads 28a and 28b for video is +6 for one.
1 and the other is selected to be 16°.

The motor (not shown) that rotates the above rotating cylinder is
Based on the output signal of the servo circuit 30 to which the vertical decimation signal from the synchronization signal separation circuit 29 is supplied, it rotates in phase synchronization with the vertical synchronization signal.

As a result, the audio rotary heads 41a and 41b,
The digital audio signal and the FM audio signal are recorded with a high frequency bias into the deep part of the magnetic layer of the magnetic tape 43 that is running while being wound around the rotating cylinder over an angular range of over 180 degrees to form an audio track, After that, a rotating video head 2 is placed on the surface layer of the magnetic layer on the audio track.
8a.

A recording video signal is recorded by 28b to form a video track.

At the same time, the control head 42 generates a control pulse generated from the vertical synchronization signal taken out from the servo circuit 30 to form a control [1-Rack] along the longitudinal direction of the magnetic wave. and record it.

Next, the main parts of the present invention will be explained. The high frequency bias signal from the bias oscillator 91 is sent to the bias superimposition circuit 3.
In addition to being supplied to the rotary erase head 92 via the rotary transformer 100 (see FIG. 9), the erase signal is also supplied to the rotary erase head 92 as an erase signal. The rotary erasing head 92 is provided on the rotating surface of the rotary cylinder together with other rotary heads, and is supplied with an erasing signal during recording, thereby erasing signals previously recorded on the magnetic tape onto the magnetic tape prior to recording. Erase along the track.

This cancellation signal is normally at a higher level than the high frequency bias signal superimposed in the bias superimposition circuit 39, so setting the cancellation signal to an arbitrary frequency will cause crosstalk between the audio signal and the video signal in the rotary transformer. This causes deterioration of the signal. However, as shown in FIG. 1, by using the signal from the bias oscillator 91 as the cancellation signal, the frequencies of the cancellation signal and the high-frequency bias signal can be made to match, for example, 10.8MH2, so that they cross each other in the rotary transformer. Even if talk occurs, cross-modulation distortion does not occur and signal deterioration can be reduced.

Historically, the core of a rotary transformer provided in the lower drum of a rotating cylinder (the portion of the rotating cylinder that is fixed to the chassis) has been constructed as shown in FIG.

In the figure, a core 95 is a core for winding erase signals and audio signals, and a core 96 is a core for winding video signals, and both are magnetically separated by a protruding member 97 of the lower drum. A winding for erasing signals is located on the inner circumferential side of the surface of the core 95.
It is wound concentrically over several turns, and a winding for audio signals is similarly wound on the outer circumferential side.

Further, on the surface of the core 96 (the outer periphery of the protruding member 97), a video signal winding is wound several times concentrically with the core 96 (and A 95).

As described above, the core 95 for the erasure signal and actual signal winding and the core 96 for the video signal are provided separately, and in addition, the core 95 for the erasure signal and the actual signal winding is provided separately, and in addition, the audio By providing a signal winding, crosstalk between the video signal and the cancellation signal can be effectively reduced.

FIG. 9(A) shows the trap circuit 90; 1 provided at the rear stage of the recording amplifier 27 (between the recording amplifier 27 and the rotary transformer 100) as shown in FIG. FIG. 2B shows the video signal winding of the rotary transformer 100 in the rotating cylinder, the video signal head 28a (or 28b), and the trap circuit 90b provided in the closed loop. In the figure, the side to the right of the line m is the inside of the rotating cylinder (the inside of the upper drum rotating above the lower drum), and the side k is the outside of the rotating cylinder (including the lower drum).

The above [・Wrap circuits 90a and 90b are both 8'! j
The values of the coil and capacitor are set to trap the large signal frequency of 10.8 MH2 (i.e., the bias signal frequency), and by trapping the cancellation signal and high frequency bias signal induced in the rotary transformer 100, the impedance for this frequency is , thereby reducing the effect on the video signal.

By taking the above measures, it is possible to automatically reduce the influence of the cancellation signal (and high-frequency bias signal) on the video signal, and it is possible to prevent cross-modulation distortion caused by the cancellation signal from occurring in the video signal. can.

Next, the operation of the reproducing system for reproducing the magnetic tuner 743 recorded by the recording system will be described.The rotary head 41a is read from the audio track formed in the deep part of the magnetic layer of the magnetic tape 43 for two recordings.

The modulated digital audio signal and the F M g re-signal alternately reproduced by the preamplifier 55 are supplied to the preamplifier 55 . At the same time, video signals alternately reproduced from the previous video track of the magnetic tape 43 by the rotary heads 28a and 28b are supplied to the switching amplifier 56. In addition, the control pulse reproduced from the control head 42 from the control rack of the magnetic tape 43 is transmitted to the servo circuit 3.
o. The water circuit 30 controls the rotation of the rotary cylinder so that the regeneration control pulses are synchronized with the reference frequency signal.

The switching amplifier 56 is the rotating head 28a.

28b, the reproduced video signals of the people are amplified and switched to a continuous signal, and this signal is supplied to the video signal processing circuit 58 via the preamplifier 57.

The video signal processing circuit 58 uses known means to separate the bands of the FM f1 degree in and low frequency converted carrier color signals and extracts them from the reproduced signal, performs FM demodulation to obtain a luminance signal, and performs frequency conversion to obtain a carrier color signal. A carrier color signal is superimposed on the degree of color signal and output from a terminal 59 as a standard color one-way reproduced color video signal.

On the other hand, the preamplifier 55 is a rotary head 41a.

41b and the digital audio signals from each FM'It
The reproduced product signal, which is 8-combined with the voice signal, is amplified and switched to a continuous signal, which is supplied to the reproduction equalizer 80 and the bandpass filter 818.81b. Band filter 81a
, 81b output from the limiter 82a.

82b and then in FM demodulators 83a and 83b, respectively.
After being demodulated and given a de-emphasis characteristic by a de-emphasis circuit 84a and 684b, the dynamic range is restored to the original state by noise reduction circuits 85a and 85b, and left channels are output from output terminals 86a and 86b, respectively. It is extracted as the right channel audio signal.

The regenerative equalizer 80 enhances the attenuated high-frequency components and then supplies them to the bandpass filter 60 . The reproduced liquid modulated gain audio signal having the frequency spectrum shown in FIG. 2(B) extracted by band separation by the bandpass filter 60 is supplied to each 0QDPSK demodulator 61, where it is subjected to the known 0QDPSK demodulation and converted into a digital audio signal. and is supplied to the decoder 62.

The decoder 62 is supplied with a synchronization signal generated from pulses phase-synchronized with the rotation of the rotary cylinder from the servo circuit 30 in order to know the first reproduction position of the digital audio signal of each track. This decoder 62 performs processing on the reproduced digital audio signal such as error correction, 2 clock axis corrections, 1 time axis extension, and deinterleaving, and each sample is combined in the order of A/D conversion station 1, and left channel a digital audio signal of the right channel and a digital fame signal of the right channel.

After the digital audio signals of the left and right channels are converted into single signals by D/A converters 63a and 63b, noise components generated by D/A conversion valves are removed by deglitcher circuits 64a and 64b, and further reduced. Area Noir Taro 5a, 65
In b, unnecessary high-frequency components exceeding the audible frequency band are removed. As a result, the left channel and right channel alilog 8-voice signals are separately outputted by 1ε to the terminals 66a and 66b.

Effects for valves As described above, according to the present invention, since the frequency of the erasing signal sent to the erasing head and the frequency of the high frequency bias signal of the audio signal are equal, cross-modulation distortion due to the erasing signal does not occur in the audio signal, and the audio signal In addition, by magnetically separating the rotary transformer's erase signal and audio signal cores from the video signal core, the rotary transformer's audio signal winding is separated from the erase signal winding and video signal core. By placing the bias signal trap between the signal windings, the effect of a high-level erasure signal on the video signal is reduced, and furthermore, by providing a bias signal trap means in the transmission path of the recorded video signal, the signal is Since the slightly picked up cancellation signal or high frequency bias signal can be trapped, the influence of the cancellation signal and audio signal on the video signal is further reduced, cross-modulation distortion of the video signal is reduced, and the so-called moire that appears on the screen is reduced. It has the advantage of being able to prevent

[Brief explanation of the drawing]

Figure 1 is a block system diagram of one embodiment of the present invention;
The figure is a diagram showing an example of the frequency spectrum of the signal of each part of the block system illustrated in Figure 1, and Figure 3 is a signal format diagram for explaining the operation of the encoder in the block system illustrated in Figure 1.
4 and 5 are block system diagrams showing each bias superimposition circuit in the block system shown in FIG. 1, FIG. 6 is a diagram showing an example of the frequency spectrum of a signal recorded on an audio track, Figures (A) and (B) are diagrams showing a comparison of the frequency spectra of the reproduced signals when 0QDPSK modulated digital audio signals are deeply recorded with the conventional device and the device of the present invention, and are reproduced. The figure is a perspective view showing the core of the rotary transformer, and FIG. 9 is a circuit diagram of the trap circuit. 25...Color video signal input terminal, 28a, 28b.
...Rotary head for video, 31a, 31b...Analog audio signal input terminal, 34a, 34b...A/D converter, 35...Encoder, 36...0QDPSK modulator, 39...Bias Superposition circuit, 418.41b...
・Audio rotary head, 43...magnetic tape, 45...
- Addition Q circuit, 46... Bias oscillator, 47... Recording amplifier, 50... Trap circuit coil, 51...
・For trap circuit] Capacitor, 73a, 73b... Frequency modulation, 74 a, 74b, 81 a, 81'
O-... Bandpass filter, 75... Mixer, 80...
Regenerative isolator, 83a. B3b-mFAZ <FM recovery FAFS>, 90a, 9
0b... Trap circuit, 91... Bias oscillator,
92... Rotating erase head, 95.96... Core, 9
7...Protruding member, 100...Rotary transformer. Patent applicant: Victor Japan Co., Ltd. Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Q Figure 7 fscIM 2M 3M 4M
Hz) One frequency, (Hz)

Claims (4)

[Claims] (1) An audio signal head that records or reproduces the audio signal superimposed on the bias signal in the deep layer of the magnetic layer, and a video track formed on the surface layer of the magnetic layer above the audio track formed by the audio signal head. A magnetic recording/reproducing device comprising: a video signal head for recording or reproducing a video signal by using the magnetic recording medium; and a rotating erasing head for erasing the audio signal and video signal recorded on the magnetic layer by supplying an erasing signal of a predetermined frequency. In the apparatus, the frequency of the erasing signal supplied to the rotary erasing head is made equal to the frequency of the bias signal, and a rotary transformer for transmitting and receiving the recorded audio signal, recorded video signal, and erasing signal is provided, and the rotary transformer is configured. A first winding for an audio signal head is provided between a second winding for a rotary erasing head constituting the rotary transformer and a third winding for a video signal constituting the rotary transformer. A magnetic recording/reproducing device characterized by: (2) The rotary transformer includes a first core around which a first winding for an audio signal head and a second winding for a rotary erasing head are wound, and a third winding for a video signal head. 2. The magnetic recording/reproducing device according to claim 1, further comprising a second core magnetically separated from the first core around which the magnetic recording/reproducing device is wound. (3) The magnetic recording/reproducing apparatus according to claim 1 or 2, further comprising a first bias signal trap means provided upstream of the rotary transformer on the recorded video signal transmission path. (4) Any one of claims 1 to 3, characterized in that a second bias signal trap means is provided in a closed loop formed by the winding of the video signal head and the rotary transformer on the recorded video signal transmission path. The magnetic recording/reproducing device according to item 1.