JPH052702A - Magnetic recording / reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] A high-frequency bias signal is superimposed on an audio signal, and the superimposed signal is recorded in the deep portion of the magnetic layer of the magnetic tape by an audio rotary magnetic head, and is recorded by a video rotary head.
To prevent deterioration of image quality of a magnetic recording / reproducing apparatus which records the M luminance signal and the low-frequency conversion carrier color signal on the surface layer portion of the magnetic layer of the magnetic tape. [Configuration] The frequency of the high frequency bias signal is set so that an interference signal does not occur in the frequency band of the color signal at least during the burst signal period when the high frequency bias signal leaks into the recorded video signal for magnetic recording and reproduction. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic recording in which a digital audio signal or FM audio signal is mixed with a high frequency bias signal and recorded in a deep portion of a magnetic layer of a magnetic tape, and a video signal is recorded in a surface portion of the magnetic layer. The present invention relates to a playback device.

[0002]

2. Description of the Related Art FIGS. 11 and 12 show, for example, JP-A-1-10.
FIG. 11 is a block diagram showing a conventional magnetic recording / reproducing apparatus disclosed in Japanese Patent No. 5301, FIG. 11 shows a recording system, and FIG. 12 shows a reproducing system.

A color video signal of a standard color system comes into the terminal 25 and is supplied to a video signal processing circuit 26. The video signal processing circuit 26 separates the luminance signal and the carrier color signal, frequency-modulates the carrier wave with the luminance signal to generate an FM luminance signal, and converts the carrier color signal into the low frequency band to convert the low frequency band into the carrier color signal. These signals are generated and frequency-division-multiplexed with these two signals to output a signal having a frequency spectrum as shown in FIG. In FIG. 13A, Y is an FM luminance signal, and its carrier frequency band is 5.4 MHz to 7.0 MHz. C
Is a low-frequency conversion carrier color signal, and its low-frequency conversion color subcarrier frequency is approximately 629 KHz. The above recording video signal is transferred to the video rotary heads 28a and 28b via the recording amplifier 27.
Is supplied to.

On the other hand, the left-channel audio signal and the right-channel audio signal input to the terminals 31a and 31b are sent to the noise reduction circuits 70a and 70b, and the dynamic range is reduced to 1/2, and then the pre-emphasis circuit 71a. , 71b are given a pre-emphasis characteristic, and limiters 72a, 72b cut signals of a predetermined level or higher. The outputs of the limiters 72a and 72b are sent to the FM modulators 73a and 73b, respectively, and 1.3M respectively.
It is FM-modulated with a carrier wave of Hz and 1.7 MHz, passed through bandpass filters 74a and 74b, and then sent to the mixer 75.

On the other hand, the switch means 69a, 6
When 9b is connected to the a side, terminals 31a, 31b
The left-channel audio signal and the right-channel audio signal that have come in are removed from unnecessary high-frequency components by the low-pass filters 32a and 32b, and then supplied to the A / D converters 34a and 34b via the sample hold circuits 33a and 33b. Here, after being linearly quantized to a quantization bit number of 16 bits, it is encoded to be a PCM audio signal. P of each of these left and right channels
The CM audio signal is supplied to the encoder 35 and subjected to processing such as adding an error correction code, and then an offset 4-phase difference P
It is modulated by the SK modulator (OQDPSK modulator) 36.
The carrier frequency of this modulated signal is selected to be about 3.0 MHz and has a frequency spectrum as shown in FIG. 13 (b). This modulated signal is input to the mixer 75 through the bandpass filter 37, frequency-division-multiplexed with the FM audio signal, and then supplied to the bias superimposing circuit 39, where a high frequency bias having a frequency of 10.8 MHz is superposed on the terminal 40. Is output. The superimposed signals extracted from the terminal 40 are supplied to the audio rotary heads 41a and 41b, respectively.

The audio rotary heads 41a and 41b are mounted on the rotary surface of a rotary cylinder (not shown) so as to face each other by 180 degrees, and are mounted ahead of the video rotary head by a predetermined angle. Further, one of the azimuth angles of the rotary heads for voice 41a and 41b is +30.
And the other is -30 degrees, and the rotary head 2 for image
The azimuth angles of 8a and 28b are +6 degrees on the one hand and -6 degrees on the other hand. By the rotary heads for voice 41a and 41b, the digital voice signal and the FM voice signal are high-frequency bias-recorded even in the deep portion of the magnetic tape 43 which runs while being wound around the rotary cylinder over an angle range of slightly over 180 degrees. After the track is formed, the video rotary head 28 is formed on the surface of the magnetic layer above the audio track.
A video signal for recording is recorded by a and 28b to form a video track.

Next, the modulated digital audio signal and FM audio signal alternately reproduced by the audio rotary heads 41a and 41b from the audio track formed in the deep portion of the magnetic tape 43 recorded by the recording system are preamplifier 55. Is supplied to. At the same time, the video signals alternately reproduced from the video tracks on the magnetic tape 43 by the rotary heads 28a and 28b are supplied to the switching amplifier 56.
The reproduced signal is amplified and switched to be a continuous signal, which is supplied to the video processing circuit 58 via the preamplifier 57. The video signal processing circuit 58 band-divides and extracts the FM luminance signal and the low-frequency conversion carrier color signal from the reproduced signal, and outputs the FM signal.
It demodulates to obtain a luminance signal and also obtains a carrier color signal by frequency conversion, superposes the carrier color signal on the luminance signal and outputs the reproduced color video signal of the standard color system from the terminal 59.

On the other hand, the preamplifier 55 is the rotary head 41.
The reproduced audio signal in which the digital audio signals from a and 41b and the FM audio signal are mixed is amplified and switched to form a continuous signal. The frequency spectrum of the output signal of the preamplifier 55 is shown in FIG. Since the high frequency bias signal is superimposed on the recorded audio signal, the noise generated in the low range of the reproduced audio signal is suppressed to a low level.

This reproduction signal is supplied to the reproduction equalizer 80 and the bandpass filters 81a and 81b. Bandpass filter 81
The outputs of a and 81b are subjected to FM demodulation in FM demodulators 83a and 83b via limiters 82a and 82b,
After passing through the de-emphasis circuits 84a and 84b, the noise reduction circuits 85a and 85b restore the original dynamic range, and the left and right channels are output from the output terminals 86a and 86b, respectively.

The regenerative equalizer 80 enhances the attenuated high frequency component and supplies it to the band pass filter 60. Bandpass filter 6
The output of 0 is demodulated by the OQDPSK demodulator 61 and converted into a digital audio signal, which is supplied to the decoder 62, where it is subjected to processing such as error correction, and separated into left channel and right channel digital audio signals. The digital audio signals of the left and right channels are respectively D / A converters 63a, 6a.
After being analogized by 3b, the deglitcher circuit 64a,
64b and low-pass filters 65a and 65b, and the terminal 6
The sound of the left channel and the sound of the right channel are output to 6a and 66b.

[0011]

The conventional magnetic recording / reproducing apparatus is constructed as described above, and the frequency of the high frequency bias signal is 10.8 MHz (JP-A-1-105301) or 11 MHz (DIGITAL SOUND SYSTEM OF). S-
VHS VCR IEEE Transactions on Consumer Electronics,
Vol.36, AUGUST 1990, pp.642-646). Since this high frequency bias signal has a high frequency and a high level, it is easy to cause crosstalk, and it is very difficult to suppress mixing in the recording video signal.

In the above magnetic recording / reproducing apparatus, the recording video signal has the frequency spectrum shown in FIG.
The carrier frequency band of the luminance signal is 5.4 MHz to 7.0 MH
z, and the low-frequency conversion color subcarrier frequency is approximately 629 KHz.
Is. When magnetic recording / reproduction is performed with a high-frequency bias signal of, for example, 10.8 MHz mixed in this recording video signal, an interference signal is generated in the color burst of the recorded / reproduced color video signal due to the non-linearity of the magnetic recording, and the color signal However, there is a problem in that the S / N of the above-mentioned is lowered and the quality of the reproduced color video signal is remarkably lowered.

The present invention has been made in order to solve the above problems, and magnetic recording in which the quality of a reproduced color video signal is not deteriorated even when a high frequency bias signal is mixed with a recording video signal. The purpose is to obtain a playback device.

[0014]

In the magnetic recording / reproducing apparatus according to the present invention, when a high frequency bias signal is mixed in a recorded video signal, an interfering signal generated in the reproduced video signal by the magnetic recording / reproducing system is excluded except for a synchronizing signal period. The frequency of the high frequency bias signal is set lower than the frequency obtained by the following equation so that the frequency becomes higher than the highest frequency of the effective frequency band of the low frequency conversion carrier color signal. 2Fyp-Fcu However, Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcu: Maximum frequency in the effective frequency band of the low-frequency conversion carrier color signal

Further, in the magnetic recording / reproducing apparatus according to the present invention, when the high frequency bias signal is mixed in the recording video signal, the disturbing signal generated in the reproduced video signal by the magnetic recording / reproducing system is converted into the low frequency band at least during the color burst period. The frequency Fb of the high frequency bias signal is set in the range of the following equation so that the frequency is lower than the lowest frequency of the effective frequency band of the color signal. 2Fyp-Fcl <Fb <2Fyp + Fcl where Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcl: lowest frequency of effective frequency band of low-frequency conversion carrier color signal

Further, in the magnetic recording / reproducing apparatus according to the present invention, when the high frequency bias signal is mixed in the recorded video signal, the disturbing signal generated in the reproduced video signal by the magnetic recording / reproducing system is converted into the low frequency band at least during the color burst period. The frequency of the high frequency bias signal is set higher than the frequency obtained by the following equation so that the frequency is higher than the maximum frequency of the effective frequency band of the color signal. 2Fyp + Fcu However, Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcu: Maximum frequency in the effective frequency band of the low-frequency conversion carrier color signal

Further, in the magnetic recording / reproducing apparatus according to the present invention, even if the carrier frequency of the FM luminance signal is switched, the carrier frequency of the FM luminance signal is adjusted so that the frequency of the high frequency bias signal satisfies a predetermined condition. The frequency of the high frequency bias signal is switched in synchronization with the switching.

[0018]

According to the present invention, the interfering signal generated in the reproduced video signal occurs at a frequency higher than the highest frequency of the effective frequency band of the low-frequency conversion carrier color signal except the synchronizing signal period, so that the S / N ratio of the color signal is increased. Is not deteriorated and the image quality is not substantially deteriorated.

Further, according to the present invention, the disturbing signal generated in the reproduced video signal occurs at a frequency lower than the lowest frequency of the effective frequency band of the low frequency conversion carrier color signal in the burst period of the color signal, so that the burst is generated. It is not disturbed, and since it is completely outside the FM modulation luminance signal band, there is substantially no deterioration in image quality.

Further, according to the present invention, the disturbing signal generated in the reproduced video signal occurs at a frequency higher than the highest frequency of the effective frequency band of the low frequency conversion carrier color signal in the burst period of the color signal, so that the burst occurs. There is no interference, and there is substantially no deterioration in image quality.

Further, according to the present invention, even when the carrier frequency of the FM luminance signal is switched, the frequency of the high frequency bias signal can be set so as to satisfy a predetermined condition by switching the frequency of the high frequency bias signal. Therefore, the image quality of the video signal does not deteriorate.

[0022]

【Example】

Example 1. 1 and 2 are block diagrams showing the structure of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. FIG. 1 shows a recording system and FIG. 2 shows a reproducing system. First, the basic operation of this magnetic recording / reproducing apparatus will be described.

A color video signal of the standard color system is input to the terminal 25 and supplied to the video signal processing circuit 26 to perform the following operation. First, the Y / C separation circuit 260 separates the luminance signal and the carrier color signal, and the luminance signal is passed through the pre-emphasis circuit 261 and the clamp circuit 262, and then the carrier wave is frequency-modulated by the FM modulator 263. To generate. Further, the recording color signal processing circuit 264 converts the carrier color signal into a low frequency band to generate a low frequency conversion carrier color signal. Both signals are frequency-division-multiplexed by the mixer 265 to output a signal having a frequency spectrum as shown in FIG. In FIG. 3A, Y is F
The carrier frequency band of the M luminance signal is 5.4 MHz to 7.
It is 0 MHz. C is a low-frequency conversion carrier color signal, and its low-frequency conversion color subcarrier frequency is approximately 629 KHz. The recording video signal is supplied to the video rotary heads 28a and 28b via the recording amplifier 27.

On the other hand, the left-channel audio signal and the right-channel audio signal that have entered the terminals 31a and 31b are sent to the noise reduction circuits 70a and 70b, and their dynamic range is reduced to 1/2, and then the pre-emphasis circuit 71a. , 71b are given a pre-emphasis characteristic, and limiters 72a, 72b cut signals of a predetermined level or higher. The outputs of the limiters 72a and 72b are sent to the FM modulators 73a and 73b, respectively, and 1.3M respectively.
It is FM-modulated with a carrier wave of Hz and 1.7 MHz, passed through bandpass filters 74a and 74b, and then sent to the mixer 75.

On the other hand, switch means 69a, 6
When 9b is connected to the a side, terminals 31a, 31b
The left-channel audio signal and the right-channel audio signal that have come in are removed from unnecessary high-frequency components by the low-pass filters 32a and 32b, and then supplied to the A / D converters 34a and 34b via the sample hold circuits 33a and 33b. Here, after being linearly quantized to a quantization bit number of 16 bits, it is encoded to be a PCM audio signal. P of each of these left and right channels
The CM audio signal is supplied to the encoder 35 and subjected to processing such as adding an error correction code, and then an offset 4-phase difference P
It is modulated by the SK modulator (OQDPSK modulator) 36.
The carrier frequency of this modulated signal is selected to be about 3.0 MHz and has a frequency spectrum as shown in FIG. This modulated signal is input to the mixer 75 through the bandpass filter 37, frequency-division-multiplexed with the FM audio signal, and then supplied to the bias superimposing circuit 39, where a high frequency bias of, for example, a frequency of 10.6 MHz is superposed. Is output to. The superimposed signals extracted from the terminal 40 are supplied to the voice rotary heads 41a and 41b, respectively.

The audio rotary heads 41a and 41b are mounted on the rotary surface of a rotary cylinder (not shown) so as to face each other by 180 degrees, and are mounted ahead of the video rotary head by a predetermined angle. Further, one of the azimuth angles of the rotary heads for voice 41a and 41b is +30.
And the other is -30 degrees, and the rotary head 2 for image
The azimuth angles of 8a and 28b are +6 degrees on the one hand and -6 degrees on the other hand. As a result, the rotary head 41a for voice,
By 41b, the digital audio signal and the FM audio signal are high-frequency bias-recorded to a deep portion of the magnetic tape 43 which runs while being wound around the rotary cylinder over an angular range of slightly over 180 degrees to form an audio track. In the upper part of the magnetic layer above the audio track, a video signal for recording is recorded by the video rotary heads 28a and 28b to form a video track.

Next, the modulated digital audio signal and FM audio signal which are alternately reproduced by the audio rotary heads 41a and 41b from the audio track formed in the deep layer portion of the magnetic tape 43 recorded by the above recording system are preamplifier 55. Is supplied to. At the same time, the video signal reproduced alternately by the rotary heads 28a and 28b from the video track of the magnetic tape 43 is supplied to the preamplifier 56, which amplifies the reproduced signal and switches it to the video processing circuit 58 as a continuous signal. It is supplied and the following processing is performed. The high-pass filter 580 extracts the FM luminance signal from the reproduced signal, passes the equalizer 581 and the limiter 582, and then outputs the FM signal.
A demodulator 583 performs FM demodulation and a luminance signal is obtained by passing through a de-emphasis circuit. Further, the band-pass filter 585 extracts the low-frequency conversion carrier color signal, the reproduction color signal processing circuit 586 obtains the carrier color signal, and the superimposition circuit 587 superimposes the carrier color signal on the luminance signal to reproduce the standard color reproduction color. The video signal is output from the terminal 59.

On the other hand, the preamplifier 55 is the rotary head 41.
The reproduced audio signal in which the digital audio signals from a and 41b and the FM audio signal are mixed is amplified and switched to form a continuous signal. The frequency spectrum of the output signal of the preamplifier 55 is shown in FIG. Since the high frequency bias signal is superimposed on the recorded audio signal, the noise generated in the low range of the reproduced audio signal is suppressed to a low level.

The reproduced signal is supplied to the reproduction equalizer 80 and the bandpass filters 81a and 81b. Bandpass filter 81
The outputs of a and 81b are subjected to FM demodulation in FM demodulators 83a and 83b via limiters 82a and 82b,
After passing through the de-emphasis circuits 84a and 84b, the noise reduction circuits 85a and 85b restore the original dynamic range, and the sound is output from the output terminals 86a and 86b as left and right channel sounds, respectively.

The regenerative equalizer 80 enhances the attenuated high frequency component and supplies it to the band pass filter 60. Bandpass filter 60
Output is demodulated by the OQDPSK demodulator 61 to be a digital audio signal, which is supplied to the decoder 62, where it is subjected to processing such as error correction and separated into left channel and right channel digital audio signals. The digital audio signals of the left and right channels are respectively supplied to D / A converters 63a and 63a.
b after being analogized, the deglitcher circuits 64a, 6a
4b and low-pass filters 65a and 65b, and a terminal 66.
The left and right channel sounds are output to a and 66b.

Next, the reproduced video signal when the high frequency bias signal causes crosstalk, mixes with the recording video signal, and is magnetically recorded and reproduced will be described. As shown in FIG. 3, the carrier frequency band of the FM luminance signal is 5.4 MHz.
.About.7.0 MHz, the low-frequency conversion color subcarrier frequency is approximately 629 KHz, and the frequency of the FM luminance signal corresponding to a certain pedestal level of the color burst signal is 5.85.
There is MHz. That is, the frequency of the FM luminance signal in the period in which the color burst exists is 5.85 MHz.

FIG. 5 shows a recorded video signal whose frequency is 5.85M.
This is the spectrum of the reproduced video signal (output of the preamplifier 56) when recording and reproducing only the FM luminance signal of Hz and the recorded audio signal only by the high frequency bias signal. In the figure, Y is the FM luminance signal and B is the crosstalk. The high-frequency bias signal X recorded by means of X is an interference signal generated because the FM luminance signal Y and the high-frequency bias signal B interfere with each other due to the non-linearity of the magnetic recording system. Note that FIG.
(A) The frequency of the high frequency bias signal is 11.0 MHz
(DIGITAL SOUND SYSTEM OF S-VHS VCR IEEE Transact
ions on Consumer Electronics, Vol.36, AUGUST 1990, p
(value set in p.642-646), the frequency of the high frequency bias signal is 10.6M shown in FIG.
This is the case of Hz. As can be seen from FIG. 5, the frequency Fx of the interference signal X is the frequency of the following equation. Fx = | 2Fy−Fb | where Fy is the frequency of the FM luminance signal Y Fb is the frequency of the high frequency bias signal B

This is because the high frequency bias signal B leaking into the recorded video signal behaves like the upper sideband of the FM luminance signal Y, and due to the non-linearity (amplitude limiting effect) of the magnetic recording system, the upper sideband. A lower sideband corresponding to is generated. This is the cause of generation of the interference signal X. In the case of FIG. 5A, the frequency of the interference signal X is 0.7 MHz.
In the case of (b), the frequency of the interference signal X is 1.1 MHz. FIG. 6 shows the transfer characteristic of the bandpass filter 585. The filter 585 is for extracting the low-frequency conversion carrier color signal from the reproduced video signal as described above, and if the interference signal X is outside the pass band of the filter 585, it does not affect the reproduced color signal. There is no interference signal X but filter 5
If it is in the pass band of 85, it affects the reproduction color signal,
The S / N of the color signal decreases. That is, in the case of FIG. 5A, the color signal color burst is disturbed and the S /
Although N decreases, in the case of FIG. 5B, the S / N ratio of the color signal does not decrease.

Table 1 shows a summary of the color S / N and the frequency Fx of the interference signal X when the frequency of the high frequency bias signal B is changed.

[0035]

[Table 1]

From this, when the frequency of the high frequency bias signal is approximately 10.8 MHz to 11.3 Hz, the interference signal X generated by the pedestal level of the luminance signal enters the pass band of the filter 585, and the low frequency conversion carrier color signal, In particular, it interferes with the color burst signal, causing the color S / N (P
(M property) is significantly reduced.

In this embodiment, as shown in FIG. 7, the interference signal X
Is higher than the maximum frequency of the pass band of the filter 585. For example, if the frequency of the high frequency bias signal is set to 10.6 MHz as described above, the color S / N is not reduced. . In order to prevent the interference signal X from interfering with the color burst signal, the frequency of the high frequency bias signal B may be set lower than the frequency obtained by the following equation. 2Fyp-Fcu where Fyp: F corresponding to the brightness of the pedestal level
Frequency of M luminance signal Fcu: Maximum frequency of effective frequency band of low-frequency conversion carrier color signal (upper limit of pass band of band filter 585)

However, if the frequency of the high frequency bias signal B is set too low, the interfering signal X enters the effective band of the FM luminance signal Y (pass band of the high-pass filter 580).
Beat-like noise may occur in the reproduced video signal, and image quality deterioration different from that described above may occur. Therefore, if the frequency of the high frequency bias signal is set lower than the frequency obtained by the above equation by several tens KHz to several hundred KHz,
It is possible to obtain a reproduced image without image quality deterioration.

Example 2. Although the interference signal X has a frequency higher than the highest frequency of the pass band of the filter 585 in the first embodiment as shown in FIG. 7, the interference signal X has a pass band of the filter 585 as shown in FIG. The frequency may be lower than the lowest frequency. In order that the interference signal X does not interfere with the color burst signal,
The frequency Fb of the high frequency bias signal B may be set to a frequency within the range of the following equation. 2Fyp-Fcl <Fb <2Fyp + Fcl where Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcl: The lowest frequency of the effective frequency band of the low-frequency conversion carrier color signal (the lower limit of the pass band of the band filter 585) For example, if the frequency of the high frequency bias signal is set to 11.6 MHz, interference occurs during the color burst period. Since the signal X never enters the pass band of the filter 585, a large S /
N drop does not occur.

However, the frequency of the high frequency bias signal is set to 1
At 1.6 MHz, when the luminance signal is other than the pedestal level, especially when the frequency of the FM luminance signal is around 6.1 MHz, the interference signal X falls within the pass band of the filter 585, so that a slight color S / N ratio occurs. Occurs. However, this decrease in the color S / N occurs only when the level of the luminance signal reaches a specific value, so there is no practical problem. In addition, within the range of the above equation, the frequency F of the high frequency bias signal is
When b is set, the interfering signal X does not enter the FM modulation luminance signal band, so that there is an effect that the S / N of the luminance signal does not decrease.

Example 3. In the first embodiment, as shown in FIG. 7, the frequency of the high frequency bias signal B is set to be lower than the frequency obtained by the following equation in order to set the interference signal X to a frequency higher than the maximum frequency of the pass band of the filter 585. . 2Fyp-Fcu where Fyp: F corresponding to the brightness of the pedestal level
M Luminance signal frequency Fcu: Maximum frequency of effective frequency band of low-frequency conversion carrier color signal (upper limit of pass band of band filter 585) However, interference signal X becomes higher than maximum frequency of pass band of filter 585. In order to achieve this, the frequency of the high frequency bias signal B may be set higher than the frequency obtained by the following equation, and almost the same effect can be obtained. 2Fyp + Fcu For example, if the frequency of the high frequency bias signal is set to 12.8 MHz, the interference signal X does not enter the pass band of the filter 585 during the color burst period, so that a large S /
N drop does not occur. This relationship is shown in FIG. However, when the frequency of the high frequency bias signal is set to 12.8 MHz, the interference signal X falls within the pass band of the filter 585 when the luminance signal is other than the pedestal level, particularly when the frequency of the FM luminance signal is around 6.1 MHz. Therefore, the color S / N is slightly lowered. However, this color S / N
There is no problem in practical use, because the decrease of P occurs only when the level of the luminance signal reaches a specific value.

In the above embodiment, the FM voice signal and the PC are
Although the case where the M audio signal is mixed and the high frequency bias signal is superimposed on this is shown, the frequency is similarly set when the high frequency bias signal is superimposed on either the FM audio signal or the PCM audio signal.

Although the frequency of the high frequency bias signal is fixed to one value in the above embodiment, there are a plurality of modes depending on the type of magnetic tape and the like, and the carrier frequency of the FM luminance signal is changed for each mode. Alternatively, the frequency of the high frequency bias signal may be changed for each mode so that the frequency of the high frequency bias signal satisfies any one of the conditions of the first to third embodiments. In this case, the bias superposition circuit has a configuration as shown in FIG. 10, for example. The oscillator 392 and the oscillator 393 generate high frequency bias signals of different frequencies, and the switch means 394 switches in synchronization with the switching of the carrier frequency of the FM luminance signal.
The mixer 395 superimposes the bias signal on the audio signal input from the terminal 391 and outputs the superimposed signal to the terminal 40. With such a configuration, there are a plurality of modes depending on the type of magnetic tape and the like, and it is possible to obtain a magnetic recording apparatus in which the image quality does not deteriorate even if the carrier frequency of the FM luminance signal is changed for each mode.

[0044]

As described above, according to the present invention, the frequency of the high frequency bias signal is set so that the interfering signal due to the non-linear distortion of the magnetic recording system does not affect the video signal, especially the color signal. The magnetic recording / reproducing apparatus can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a recording system of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a reproducing system of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram for explaining a frequency spectrum of a recording signal of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing measured values of a frequency spectrum of a reproduced audio signal of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 5 is a measured value (b) of the frequency spectrum of the reproduced video signal of the magnetic recording / reproducing apparatus according to the embodiment of the present invention;
It is a comparison diagram with the measured value (a) of the frequency spectrum of the reproduced video signal of the conventional magnetic recording and reproducing apparatus.

FIG. 6 is a diagram showing frequency characteristics of a pass band of a band filter of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the frequency characteristics of the pass band of the band filter of the magnetic recording / reproducing apparatus according to the embodiment of the present invention and the interfering signal X.

FIG. 8 is a diagram showing the relationship between the frequency characteristics of the pass band of the band filter of the magnetic recording / reproducing apparatus according to the second embodiment of the present invention and the interfering signal X.

FIG. 9 is a diagram showing the relationship between the frequency characteristics of the pass band of the band filter of the magnetic recording / reproducing apparatus according to the third embodiment of the present invention and the interfering signal X.

FIG. 10 is a diagram showing a configuration of a bias superimposing circuit of a magnetic recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a recording system of a conventional magnetic recording / reproducing apparatus.

FIG. 12 is a block diagram showing a configuration of a reproducing system of a conventional magnetic recording / reproducing apparatus.

FIG. 13 is a diagram for explaining a frequency spectrum of a recording signal of a conventional magnetic recording / reproducing apparatus.

FIG. 14 is a diagram showing measured values of a frequency spectrum of a reproduced audio signal of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

26 Video signal processing circuit 263 FM modulator 28 Video rotating head 35 Bias superposition circuit 36 OQDPSK modulator 41 Voice rotating head 43 magnetic tape 58 Video signal processing circuit 585 bandpass filter 586 reproduction color signal processing circuit 61 OQDPSK demodulator 73 FM modulator 75 Mixer

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[Procedure amendment]

[Submission date] May 21, 1992

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Next, the modulated digital audio signal and FM audio signal alternately reproduced by the audio rotary heads 41a and 41b from the audio track formed in the deep portion of the magnetic tape 43 recorded by the recording system are preamplifier 55. Is supplied to. At the same time, the video signals alternately reproduced from the video tracks on the magnetic tape 43 by the rotary heads 28a and 28b are supplied to the switching amplifier 56.
The reproduced signal is amplified and switched to form a continuous signal, which is supplied to the video signal processing circuit 58 via the preamplifier 57. The video signal processing circuit 58 band-divides and extracts the FM luminance signal and the low-frequency conversion carrier color signal from the reproduction signal,
FM demodulation is performed to obtain a luminance signal, and a carrier color signal is obtained by frequency conversion, and the carrier color signal is superimposed on the luminance signal and output from the terminal 59 as a standard color reproduction color video signal.

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FIG. 11

Claims (4)

[Claims] 1. A high-frequency bias signal is superposed on an audio signal, and the superposed signal is recorded in a deep portion of a magnetic layer of a magnetic tape by a rotary magnetic head for audio, and the magnetic layer surface layer formed above the audio track is formed. In a magnetic recording / reproducing apparatus, a video track is formed by a video rotary head having an azimuth angle different from that of the audio rotary magnetic head to record an FM luminance signal and a low-frequency conversion carrier color signal.
A magnetic recording / reproducing apparatus wherein the frequency of the high frequency bias signal is lower than the frequency obtained by the following equation. 2Fyp-Fcu However, Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcu: Maximum frequency in the effective frequency band of the low-frequency conversion carrier color signal 2. A high-frequency bias signal is superimposed on an audio signal, and the superimposed signal is recorded in a deep portion of a magnetic layer of a magnetic tape by a rotary magnetic head for audio, and the surface of the magnetic layer formed above the audio track is formed. In a magnetic recording / reproducing apparatus, a video track is formed by a video rotary head having an azimuth angle different from that of the audio rotary magnetic head to record an FM luminance signal and a low-frequency conversion carrier color signal.
A magnetic recording / reproducing apparatus wherein the frequency Fb of the high frequency bias signal is set in the range of the following equation. 2Fyp-Fcl <Fb <2Fyp + Fcl where Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcl: lowest frequency of effective frequency band of low-frequency conversion carrier color signal 3. A high-frequency bias signal is superposed on an audio signal, and the superposed signal is recorded in a deep portion of a magnetic layer of a magnetic tape by a rotary magnetic head for audio, and a magnetic layer surface layer formed above the audio track is formed. In a magnetic recording / reproducing apparatus, a video track is formed by a video rotary head having an azimuth angle different from that of the audio rotary magnetic head to record an FM luminance signal and a low-frequency conversion carrier color signal.
A magnetic recording / reproducing apparatus wherein the frequency of the high frequency bias signal is set higher than the frequency obtained by the following equation. 2Fyp + Fcu However, Fyp: FM corresponding to the brightness of the pedestal level
Luminance signal frequency Fcu: Maximum frequency in the effective frequency band of the low-frequency conversion carrier color signal 4. A high frequency bias signal is superposed on an audio signal, and the superposed signal is recorded in a deep portion of a magnetic layer of a magnetic tape by a rotary magnetic head for audio, and a magnetic layer surface layer formed above the audio track is formed. In a magnetic recording / reproducing apparatus, a video track is formed by a video rotary head having an azimuth angle different from that of the audio rotary magnetic head to record an FM luminance signal and a low-frequency conversion carrier color signal.
A magnetic recording / reproducing apparatus comprising: switching means for switching a carrier frequency of the FM luminance signal, and the frequency of the high frequency bias signal is switched in cooperation with the switching means.