JPH01223601A - Digital voice recording video tape recorder - Google Patents

Abstract

PURPOSE:To record a video signal, an RCM sound signal and a two-channel sound signal of FM by providing a modulator for converting a sound signal and a video signal to an FM signal, a digital signal processor for converting the sound signal to a digital signal and three groups of magnetic heads whose azimuth angles are different, etc. CONSTITUTION:A two-channel sound signal which has been inputted to an input terminal 51 becomes main and sub-carrier waves by a modulator 53 and converted to an FM signal, passes through a changeover switch 55 and a rotary transformer 56 and applied to magnetic heads 58a, 58b of a rotary cylinder 57. A sound signal from the input terminal 51 is applied to a digital signal processor 59, as well, brought to A/D conversion to a sound signal using a PCM, passes through a switch 61 and a rotary transformer 62 and applied to magnetic heads 63a, 63b. A video signal which has been applied to an input terminal 64 is separated into a luminance signal and a chrominance signal, brought to frequency modulation by a modulator 66, passes through a switch 68 and a rotary transformer 69 as an FM signal and applied to magnetic heads 70a, 70b.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a digital audio recording video tape recorder for recording and reproducing video and audio signals.

BACKGROUND OF THE INVENTION In recent years, pulse code modulation (hereinafter referred to as PCB) has been used to record and reproduce audio with high quality. In video tape recorders (hereinafter referred to as VTRs),
In the so-called /%if1i VTR, the sound quality is improved because the audio signal is converted into a frequency modulation (hereinafter referred to as FM) signal and recorded on tape. The so-called 8mm video was developed by applying such technology, and can record audio using PCM and audio using FM at the same time.

An example of the conventional 8 mm video mentioned above will be described below with reference to the drawings.

FIG. 4 shows a block diagram of a conventional 8 mm video signal recording and reproducing section. FIG. 5 shows a spectral diagram of a signal recorded on a magnetic tape. In FIG. A first video processor converts the signal into a recordable signal; 3 is a second input terminal into which an audio signal is input; 4 is a video processor that converts the audio signal applied to the input terminal 3 into an FM signal, etc. 1 is an audio processor, 5 is a first digital signal processor that converts the audio signal applied to the input terminal 3 into a digital signal, and e is a controller 7 that controls the running of the magnetic tape 12. A tracking processor 8 supplies signals supplied from the first video processor 2 and the like to magnetic heads 11a and 11b attached to a rotary cylinder 10 through a rotary transformer 9. Amplify the reproduced signal,
A switching processor to be supplied to the next stage; 12 is a magnetic tape that is wound around the rotary cylinder 1o by a guide bin 13 and runs in the direction of arrow A; 14 is a converter that converts the signal supplied from the switching processor 8 into a video signal. second video processor, 15
1 is a first output terminal to which a video signal is output; 16 is a second audio processor that demodulates the FM signal supplied from the switching processor 8 into an audio signal; and 17 is a second output terminal to which an audio signal is output. 18 is a second digital signal processor that demodulates the signal modulated by the digital signal supplied from the switching processor 8 and converts it into the original audio signal; 19 is the audio signal obtained from the digital signal processor 18; This is the third output terminal to which a signal is output.

The operation of the 8mm video configured as described above will be explained below.

A video signal applied to a first input terminal 1 is converted by a first video processor 2 into an FM signal modulated by a luminance signal and a color signal converted to a low frequency signal. The FM signal output from the first video processor 2 and the color signal converted to low frequency are applied to the switching processor 8. Further, the two-channel audio signal applied to the second input terminal 3 is converted into a one-channel signal by the first audio processor 4, and then converted into an FM signal, and is then applied to the switching processor 8. It will be done. At the same time the second
The two-channel audio signal applied to the input terminal 3 of is also applied to the first digital signal processor 5, and is quantized by the
Conversion to a digital signal with a sampling frequency of 31.5 kHz is performed. This digital signal is then converted to 8 bits, added with an error correction code, compressed on the time axis, and further biphase modulated.

The biphase modulated signal thus obtained is applied to the switching processor 8. The switching processor 8 is also equipped with a tracking pilot signal generated by the tracking processor 6 for tracking during playback. The signals thus applied to the switching processor 8 are respectively summed and amplified. The signal amplified and output by the switching processor 8 is applied via a rotary transformer 9 to magnetic heads 11a and 11b attached to the rotary cylinder 1o. Here, when the magnetic head 11a or 11b is in the section indicated by arrow B, the signal shown in the recording signal spectrum of FIG. 5 is added, and when it is in the section indicated by arrow C,
The bi-phase modulation signal and tracking pilot signal are added. In FIG. 5, symbol a is a tracking pilot signal, b is a low frequency converted color signal, C is an audio signal converted to an FM signal, and d is a luminance signal converted to an FM signal. In this way, each signal is frequency-divided.

A magnetic tape 12 is attached to a guide bin 1 in a rotating cylinder 10.
3, the magnetic tape is wound obliquely to the running direction of the magnetic tape. The magnetic tape 12 is running in the direction of arrow A by a magnetic tape running device (not shown) controlled by the control device 7, and since the rotation of the rotary cylinder 1o is controlled, the magnetic tape 12 is Each signal is recorded on diagonal tracks.

Next, let's talk about playback.

The magnetic tape 12 is run by a magnetic tape running device, and signals are reproduced from the magnetic heads 11a and 11b. This reproduced signal passes through a rotary transformer 9, is applied to a switching processor 8, and is amplified. Of the reproduced signals, a tracking pilot signal is applied to the tracking processor 6, and is a control signal that controls the controller 7 so that the magnetic heads 11a and 11b rotate along the tracks on the magnetic tape 12 where signals are recorded. Output. In this way, reproduction tracking is performed and the signal is correctly reproduced.

Of the reproduced signals, the luminance signal converted into an FM signal and the color signal converted into a low frequency signal are applied to the second video processor 14, converted into video signals, and then sent to the first output terminal 15. Output. Also, among the reproduced signals, the audio signal converted to the FM signal is applied to the second audio processor 16, and after being converted to a 1-channel audio signal, the audio signal is sent to the second output terminal 17.
is output to. The biphase modulated signal, which is intermittently reproduced due to the time axis being compressed, is applied to the second digital signal processor 18, where signal processing such as demodulation and error correction is performed, and then digital-to-analog conversion is performed. channel audio signal. Then, the signal is output from the third output terminal 19iC of two channels.

In this way, video and audio can be recorded and played back simultaneously.

Problems to be Solved by the Invention However, although the above configuration can record audio signals using PCM, the quantization is 10 bits and the sampling frequency is approximately 31.5kHz.
Therefore, it is difficult to say that the best sound quality can be obtained. Also,
Recording of audio signals using FM is only for one channel,
Recording of music, etc. was unsatisfactory.

In view of the above-mentioned problems, the present invention records a video signal and at the same time records a high-quality audio signal, for example, an audio signal using 16-pit quantization, a sampling frequency of 48 kHz (t7) PCM, and a two-channel audio signal using FM. The present invention provides a digital audio recording video tape recorder capable of recording both signals.

Means for Solving the Problems In order to achieve the above object, the digital audio recording video tape recorder of the present invention has three groups of magnetic heads each having a different azimuth angle attached to a rotating cylinder, and a first input signal having a frequency a first modulator for converting into a modulated signal; a first amplifier for supplying an output signal of the first modulator to a first magnetic head group; and a first amplifier for supplying an output signal of the first modulator to a first magnetic head group; a first demodulator for demodulating; a first digital signal processor for converting the first input signal or the second input signal into a digital signal and adding an error correction code; a second amplifier for supplying the output signal of the signal processor to the second magnetic head group; and a second amplifier for performing error correction on the signal reproduced by the second magnetic head group and converting it into an analog signal. 2 digital signal processor and cylinder 1 in synchronization with the rotation of the rotary cylinder.
and a signal generator that generates a signal that serves as a reference signal for the second digital signal processor; a first signal processor that separates the input video signal into a luminance signal and a color signal; a second modulator for converting the output signal into a frequency-modulated luminance signal and a low-frequency converted color signal; and a third modulator for supplying the output signal of the second modulator to a third magnetic head group. an amplifier, a second demodulator that converts the signal reproduced by the third magnetic head group into an intensity signal and a color signal, and a second signal processing that converts the output signal of the second demodulator into a video signal. Detects the detected portion provided on the magnetic tape cassette and the output device.The output signal of the first digital signal processor can be supplied to the second magnetic head group by the detection output of the director and the detector. a second switch for switching the carrier frequency of the frequency-modulated luminance signal of the second modulator to a higher frequency according to the detection output of the detector; a first frequency converter connected to the control device to reduce the rotational angular velocity of the rotary cylinder and the running speed of the magnetic tape to 1/N; and a signal generator. a second frequency converter for multiplying the period of the signal generated by the first frequency converter by eight;
and a third switch for driving the second frequency converter.

In addition, the input two-channel audio signals are converted into digital signals and recorded on the magnetic tape. At the same time, the input video signal is converted into a luminance signal converted into an FM signal and a color signal converted into a low frequency signal, and then recorded on the magnetic tape. In this way, high-quality audio and video signals can be recorded simultaneously, but since the tracks on the magnetic tape where each signal is recorded can be overlapped, the running speed of the magnetic tape can be increased, and the tracks on which the signals are recorded can be There is no need to narrow the width and divide it into video and audio, and the problems of the conventional technology can be solved simply by increasing the recording density.

Embodiment Hereinafter, a digital audio recording video tape recorder according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram in one embodiment of the present invention.

In FIG. 1, 51 is a first input terminal into which two-channel audio signals are input, 62 is a first amplifier that amplifies the input two-channel audio signals, and 53 is a first amplifier 5.
A first modulator 54 amplifies the output signal of the first modulator 63 and outputs a frequency-modulated two-channel modulation signal using the output signal of the first modulator 63 as a modulation wave. a second amplifier 59 for supplying magnetic heads 68a and 58b constituting a first magnetic head group attached to a rotary cylinder 57 through a rotary transformer 56;
is a first digital signal processor 60 which converts the output signal of the first amplifier 52 into analog-to-digital (hereinafter abbreviated as AD), adds an error correction code, interleaves, etc.
amplifies the output signal of the first digital signal processor 59, and sends the magnetic head e3a constituting the second magnetic head group to the rotary cylinder 57 through the second switch 61 and the second rotary transformer 62. , e3b.

64 is a second input terminal into which a video signal is input; 65 is a first signal processor that separates the input video signal into a luminance signal and a color signal; 66 is a terminal that receives the output signal of the first signal processor 65; A second modulator that receives as input and outputs a frequency-modulated luminance signal and a low-frequency converted color signal; 67 is a second modulator e;
A magnetic head 70 that constitutes a third magnetic head group attached to the rotary cylinder 57 is amplified through a third switch 68 and a third rotary transformer 69.
71 is a magnetic tape, 80 and 81 are guide bins, and 82 is a control device that controls the rotation of the rotary cylinder 57 and the running of the magnetic tape.

Reference numeral 83 denotes a magnetic head 58a constituting the first magnetic head group.
, a fifth amplifier 84 amplifies the signal reproduced by the second amplifier 83 and supplied via the first switch 55, and a fifth amplifier 84 demodulates the output signal of the sixth amplifier 83 and outputs a two-channel audio signal. 1 demodulator, 85 a sixth amplifier that amplifies the audio signal demodulated by the first demodulator 84, and 86 a sixth amplifier.
This is the first output terminal to which the two-channel audio signal output from the amplifier 85 is output.

Reference numeral 87 denotes a magnetic head 63a constituting the second magnetic head group.
, e3b and amplifies the signal supplied via the second switch 61. A seventh amplifier 88 obtains a digital signal from the output signal of the seventh amplifier 87, and performs deinterleaving, error correction, Performs interpolation, etc., and converts the digital
A second digital signal processor 89 converts analog (hereinafter abbreviated as DA) and outputs a two-channel audio signal.
an eighth amplifier 90 for amplifying the audio signal of the channel;
A second output terminal 91 outputs the audio signal of the channel, and magnetic heads 70a and 70 forming the third magnetic head group.
a ninth amplifier 92 for amplifying the signal regenerated by b and supplied via the third switch 68;
93 is a second signal processor that converts the output signal of the second demodulator 92 into a video signal; 94 is a video signal; is the third output terminal from which is output.

95 is a detector that detects a hole, which is a detected part provided in a magnetic tape cassette, and outputs a detection signal; 96 is a first detector that enables the third amplifier 60 to operate based on the output signal of the detector 96; A switch 97 is a second switch for switching the frequency of the carrier wave frequency-modulated by the luminance signal of the second modulator 66 to a higher frequency according to the output signal of the detector 95; This is the third switch for switching to double the amount.

99 is a fifth switch for operating the first switch 96 and a fourth switch 100 for stopping the amplification operation of the fourth amplifier 67; 101 is the control device 82;
connected to the first and second digital signal processors 5
a signal generator for generating an operating reference signal of 9.88, 102;
is a sixth switch for driving the first and second frequency converters 104 and 103.

The operation of the digital audio recording video tape recorder constructed as described above will be explained below with reference to FIG.

The main and sub-channel audio signals input to the first input terminal 51 are amplified by the first amplifier 52 and applied to the first modulator 53 . In the first modulator 53, as shown in FIG. 3A, the main channel audio signal has a carrier wave of 1.3 MHz, and the sub channel audio signal has a carrier wave of 1.7 MHz, similar to the conventional so-called VHS format VTR. carrier wave and maximum frequency deviation of plus or minus 150 k
It is converted into an FM signal in Hz. After these two carrier waves are mixed, they are amplified by a second amplifier 54, and passed through a first switch 55 switched to the R side and a first rotary transformer 56, and then passed through a first rotary transformer 56 attached to a rotary cylinder 57. A magnetic head 58 a constituting one magnetic head group,
Added to esab. Note that the magnetic heads 58a and sa
b is attached around the rotating cylinder 57 at a positional relationship of 180 degrees.

The output signal of the first amplifier 52 is also applied to a first digital signal processor 59 and subjected to signal processing. This content will be explained below. The signals of the main and sub-channels are subjected to AD conversion using 1e bit quantization and a sampling frequency of 48 kHz. After that, addition of an error correction code and interleaving are performed, and the rotation of the rotary cylinder 5 is controlled by a reference signal from a signal generator 101 that generates a signal synchronized with the rotation of the rotary cylinder 67 under the control of the control device 82. Converted to a synchronized signal, the transmission rate is approximately 2.6M
It becomes a bit/second digital signal. This digital signal was applied to a modulator and was
It is converted into a phase-phase modulated signal.

The frequency band is limited to 2.5 MHz 7' las minus 1.3 MHz by bandpass filtering and output. When the detector 95 detects a hole provided in the magnetic tape cassette and generates a detection output, the four-phase phase modulation signal obtained in this way is activated, and the first switch 96 is operated to pass the signal to the third amplifier 60. performs an amplification operation, and after being amplified, via the second switch 61 which is switched to the R side and the second rotary transformer 62, it constitutes the 20th air head group attached to the rotary cylinder 6. magnetic head 63a.

Added to esb.

Note that the holes provided in the magnetic tape cassette indicate that the magnetic tape wound therein has a large coercive force, and that the tape is capable of recording digital audio. Moreover, the magnetic heads 63a and 83b are arranged around the rotary cylinder 5.
It is attached with a 0 degree positional relationship, and the magnetic head 58
a and 63a and 5sb and esb are attached very close to each other.

Next, we will discuss the flow of video signals.

The video signal applied to the second input terminal 64 is separated into a luminance signal and a chrominance signal by a first signal processor 65, and a frequency-modulated luminance signal and a low frequency signal are converted by a second modulator 66. color signal.

Here, if the detector 95 does not generate a detection output,
Similar to the conventional so-called VHS format VTR,
A low frequency converted color signal with a carrier wave of s 29 kHz and a luminance signal as an FM signal with a sync chip of 3.4 MHz and a white peak of 4.4 MHz are obtained, and the detector 96
is generating a detection output, the second switch 97 operates, and the sync chip changes to 5.4MHz as shown in FIG. 3C.
A luminance signal with a white peak of 7 MHz is obtained as an FM signal. The luminance signal and the low frequency conversion color signal, which have become the FM signal obtained in this way, are mixed and sent to the fourth amplifier 67.
The magnetic head 70a, which constitutes the third magnetic head group attached to the rotary cylinder 5, is amplified by the third switch 68 and the third rotary transformer 69, which are switched to the R side. 70b. The magnetic heads 70a and 70b are mounted around the rotary cylinder 57 in a 180 degree positional relationship, and the angular difference from the magnetic heads 58a and ssb constituting the first magnetic head group is selected to be 46 degrees to 60 degrees. I'm here. In addition, the detector 96
If the detection output is generated, the magnetic head 70a constituting the third magnetic head group is more sensitive than when it is not generated.
, 70b is increased by about 2 degrees.

A magnetic tape 71 is wound around the rotary cylinder 67 diagonally with respect to the running direction of the magnetic tape 71 using guide bins 80 and 81. It is traveling in the direction of E, and the rotation of the rotating cylinder 57 is also controlled, so that it is traveling in the direction of arrow F.
, the respective signals are recorded on the magnetic tape 71 in tracks oblique to the running direction of the magnetic tape γ1. Rotating cylinder 5
The magnetic head group 7 is attached to the magnetic head 58a, which constitutes the first magnetic head group, so that the recorded tracks overlap each other.

A magnetic head 63a later overlaps the trunk recorded by the ssb to form a second magnetic head group.

The height is determined so that the esb records, and then the magnetic heads 70b and 70a, which overlap to form the third magnetic head group, record. That is, the first. Magnetic heads 58a, ssb, 63 constituting the second magnetic head group
a and esb are mounted at the same height, and magnetic heads 70a and 70b constituting the third magnetic head group are mounted at the same height but lower than the magnetic head 58a.

A conceptual diagram of a trunk recorded on the magnetic tape 71 in this manner is shown in FIG. 10 shown in Figure 2
1a, 101b, 102a, 102b, 103a.

103b are magnetic heads 58a and 5sb, respectively.

These are the tracks recorded by 63a, 63b, 70a, and 70b.

The tracks recorded on the magnetic tape 71 overlap, but since the azimuth angles of the magnetic heads are different, signals with different azimuth angles are attenuated by azimuth loss during reproduction. A magnetic head 70a is used to maintain compatibility with conventional VTRs.

The azimuth angles of the magnetic heads 70b are set to plus 6 degrees and minus 6 degrees, the azimuth angles of the magnetic heads 58a and sab are set to plus 30 degrees and minus 30 degrees, and the azimuth angles of the magnetic heads 63a and 63b are set to plus 20 degrees and minus 20 degrees. I am choosing. In this way, crosstalk between tracks is suppressed and deterioration of video and audio playback characteristics is prevented.

Furthermore, the frequency of the carrier wave is selected so that parts of high signal energy do not overlap in the frequency band of the signals recorded by each magnetic head group.

This situation is shown in the recorded signal spectrum diagram of FIG.

In FIG. 3, A indicates the magnetic heads 58a and ssb constituting the first magnetic head group, B indicates the magnetic heads 63a and 63b constituting the second magnetic head group, and C indicates the third magnetic head 58a and ssb.
The magnetic heads 70a and 70b forming the M1 head group of
This shows the recording signal level)/y.

As a result, mutual interference can be reduced, and at the same time, even if recording tracks are overlapped, the degree of attenuation of previously recorded signals can be reduced. Further, the second and third magnetic head groups also record on the tracks recorded by the magnetic heads 68a and sab that constitute the first magnetic head group, but the signal level that can be reproduced by the magnetic heads 58a and 58b is different from that of the first magnetic head group. A magnetic head 63a constitutes the second magnetic head group.

After the esb records, it is more than 10 d compared to before recording.
However, even if the magnetic heads 70a and 7ob constituting the third magnetic head group subsequently record, there is an effect that the increase in attenuation can be suppressed to about 1 dB.

A magnetic head 63a constitutes a second magnetic head group.

The level of the signal reproduced by the ESB is also attenuated by more than 10 dB due to recording by the magnetic heads 70a and 70b forming the third magnetic head. However, the signal-to-noise ratio necessary to obtain the original audio signal from the audio signal converted to a digital signal can be secured, which is about 20 dB.
The symbol error rate before correction is less than or equal to 1o to the minus fourth power.

Further, a magnetic head 63a constituting the second magnetic head group
, 63b uses the four-phase f-key modulation method for the signal recorded, so the modulated signal has a narrow band, and the attenuation can be suppressed to a dozen or more dB. If a modulation method such as FM requires a wider band than 4-phase phase modulation, a higher frequency signal must be recorded, and in this case, the degree of attenuation of the signal in this higher frequency band during playback is large. Therefore, the error rate of the digital signal increases. In other words, such a modulation method cannot be used.

On the other hand, the magnetic head 58a constituting the first magnetic head group
, the signal-to-noise ratio of the signal reproduced by sab is the same as that of the conventional V
It can secure the same value as TR, so-called high-fidelity VTR.
The playback performance is as follows.

Next, the playback operation will be described.

The signals reproduced by the magnetic heads 58a and ssb are applied to the fifth amplifier 83 via the first rotary transformer 56 and the first switch 56 switched to the P side, and are amplified. The signal amplified by the fifth amplifier 83 is
The signal is demodulated by the first Enoki modulator 84 and converted into a two-channel audio signal. The two-channel audio signal thus obtained is amplified by the sixth amplifier 85 and output to the first output terminal 86. As mentioned above, this audio signal is of high quality, as is called a high-fidelity VTR.

On the other hand, the signals reproduced by the magnetic heads e3a and s3b are applied to the seventh amplifier 87 via the second rotary transformer 62 and the second switch 61 switched to the P side. The signal amplified by the seventh amplifier 87 is
The digital signal processor 88 converts the signal into an audio signal, the contents of which will be explained next.

The four-phase phase modulation signal, which is the output signal of the seventh amplifier 87, is demodulated by a demodulator and converted into a digital signal.

After that, deinterleaving, error correction, and correction are performed to correct the time axis, and then DA conversion is performed to obtain an audio signal. The two-channel audio signal obtained in this way is output from the second digital signal processor 88, and is then sent to the eighth amplifier 8.
After being amplified at 9, the signal is output to a second output terminal 90.

The audio signal output to the second output terminal 90 is 48
Since it is sampled at -kHz, quantized and recorded at 16 bits, it has a dynamic range of over 90 dB, and the distortion is less than o, oos%, so it can be said to be of the highest quality.

The signals reproduced by the magnetic heads 70a and 7ob are
The third rotary transformer 69 and the third
The signal is applied to the ninth amplifier 91 via the switch 68 . The signal amplified by the ninth amplifier 91, that is, the FM
The luminance signal converted into a signal and the chrominance signal converted into a low frequency band are applied to a second demodulator 92, where they are demodulated into a luminance signal and a chrominance signal.

At this time, the detector 95 detects the hole provided in the magnetic tape force sector, and if a detection output is generated, the second switch 9
7 operates to switch the pull-in frequency range of the phase-locked loop for demodulating the luminance signal of the second demodulator 92 to a higher side (if the pull-in frequency range of the phase-locked loop is wide, this is not necessary). . The luminance signal and color signal obtained from the second post-tone device 92 are converted into video signals by the second signal processor 93 and output to the third output terminal 94. In this way, the recorded video signal can be played back, but in the case of the magnetic tape 71 on which the detector 95 operates, the carrier wave frequency of the luminance signal is set high, so the frequency of the luminance signal that can be recorded is It has a wide band, high resolution, and can provide high-quality video signals.

Next, we will talk about recording that allows for so-called dubbing, in which only the audio signals on the recorded magnetic tape are re-recorded.

When set to the mode that allows dubbing, the third switch 9
8 operates and switches the control device 82 to finish the magnetic tape 1.
Double the running speed of. Then, the magnetic tape ends 1.
At the top, a magnetic head 58a constituting the first magnetic head group is shown.
, sab and the tracks recorded by the magnetic heads 70a and 70b forming the third magnetic head group no longer overlap. Therefore, each track can be erased and recorded independently.

Incidentally, since the magnetic heads 68a, 58b and 63a, 63b constituting the first and second magnetic head groups have the same height and are mounted very close to each other, the tracks overlap in this case as well. Therefore, when rewinding and playing back the magnetic tape 71 recorded in a mode that allows dubbing, if the audio section is put into the recording state, the magnetic heads 58a, 58
b, 63a.

The magnetic head 58 overlaps the track recorded by the magnetic head 63b.
a, sab, 63a, and asb record signals.

Then, the magnetic head 63a forming the second magnetic head group and the magnetic head 58a forming the first magnetic head group are placed on the track recorded by the ESB.

58b will record. In this case, since the frequency of the signals recorded by the magnetic heads 58a and 58b is lower than the frequency of the signals recorded by the magnetic heads 63a and sab, the signals previously recorded by the magnetic heads 63a and 63b are significantly reduced. In other words, the magnetic head 58a constitutes the first magnetic head group.

ssb is a magnetic head 63 constituting the second magnetic head group.
a, 63b operates as an erase head.

Therefore, it is not necessary to provide a special magnetic head for erasing, and this is very effective. Magnetic head 58a.

The frequency of the signal supplied to 58b may be lowered and used only for erasing.

In this way, the recorded video signal can be left intact and only the audio can be re-recorded. The playback operation can be performed in the same manner as described above.

Next, a case will be described in which digital audio is recorded on a conventional magnetic tape in which the magnetic tape cassette has no holes and the detector 95 does not generate a detection output.

Conventional magnetic tape has a small coercive force, so it requires four-phase phase modulation signals to record audio signals converted to FM signals, audio signals converted to digital signals, and FM signals to record video signals. It is not possible to record a mixed wave of a luminance signal converted into a chrominance signal and a chrominance signal converted into a low frequency band as described above. Only audio signals can be recorded. This can be understood from the fact that it is possible to record a mixed wave of an audio signal converted to an FM signal with a conventional VTR, a luminance signal converted to an FM signal for recording a video signal, and a color signal converted to a low frequency band. Ru. Therefore, when it is desired to record only audio signals on a conventional magnetic tape, the fifth switch 99 is switched and recorded. The output signal of the fifth switch 99 operates the first switch 96 and switches the four-phase phase modulation signal output from the first digital signal processor 59 so that it can be amplified by the third amplifier 6Q. . Thereafter, the same operation as described above is performed, and the audio signal converted into a digital signal is recorded as a four-phase phase modulation signal on the magnetic tape 71.

The output signal of the fifth switch 99 is also applied to the fourth switch 100, and the fourth switch 100 operates to
The amplification operation of the amplifier 67 is stopped. For this reason, the magnetic heads Oa and Ob constituting the third magnetic head group
The signal is no longer applied to .

Recording of the audio signal converted into an FM signal is performed in the same manner as described above.

In this way, audio signals can be recorded, but since the amplification degree of the first and third amplifiers 8o is lowered, the magnetic heads 63a, e forming the second magnetic head group
The recording current value of the four-phase phase modulation signal supplied to sb decreases. In this way, since the coercive force of the magnetic tape 71 is small, the signal-to-noise ratio of the audio signal converted into an FM signal to be reproduced and the audio signal converted into a digital signal and turned into a four-phase phase modulation signal is reduced. improves. In this case as well, similarly to the above-mentioned recording in which post-recording is possible, the magnetic heads ssa and sab forming the first magnetic head group are replaced by the magnetic heads 63a forming the second magnetic head group.

It can be used as an erase head for 63b.

When recording only audio signals on the magnetic tape 71, the third
magnetic heads 70a and 7o constituting a magnetic head group of
The magnetic head 63a constitutes the second magnetic head group since no signal is recorded in the magnetic head 63a.

The reproduced signal of the four-phase phase modulation signal recorded by the ESB has a large S/N ratio, and the recording density can be further increased. Therefore, the running speed of the magnetic tape 71 was changed to a fraction of that,
It becomes possible to lengthen the recording time. Next, this content will be explained.

When the sixth switch 102 is operated, the first frequency converter 104 connected to the control device 82 is operated, and the reference signal which is the reference for the running of the magnetic tape 71 and the rotation of the rotary cylinder 5 is activated. The frequency becomes 1/2 (N is an integer), for example, 1/2. As a result, the rotational angular velocity of the motor for running the magnetic tape 71 is halved,
Further, the rotational angular velocity of the rotary cylinder 57 is reduced to one-half.

The sixth switch 102 also operates the second frequency converter 103. First and second digital signal processors 59.8
8 operates based on a signal from a signal generator 101 that generates a signal synchronized with the rotation of the rotary cylinder 57, but since the rotation of the rotary cylinder 57 is 1/N, the signal generator The signal frequency generated by 101 becomes 1/N. Therefore, the frequency converter 10 of coffin 2
3, the frequency of the signal generated by the signal generator 101 is multiplied by N times (in the above example, twice), and the first and second digital signal processors 59 and 88 are operated normally. Since both the running speed of the magnetic tape 71 and the rotational angular velocity of the rotary cylinder 57 are 1/N, when recording in this state,
Tracks are formed on the magnetic tape 71 with the same track width as before changing the magnetic tape running speed. However, the recording wavelength becomes N times larger. In this way, if the first and second magnetic head groups record audio signals as described above,
The recording time is increased by N times, or twice in the above example, and the magnetic tape can be used effectively.

Although the third magnetic head group has been described so far as a pair of magnetic heads 70a and 70b, it may also be composed of two pairs of magnetic head groups placed very close to each other, as has been the case in the past. good. In this case, one pair is the magnetic head s mentioned above.
8a and ssb, and the other pair is used for long-term recording.

The appearance of overlapping recording tracks is similar to that of conventional No-Fi VT.
Same as R. However, three tracks overlap.

Effects of the Invention As described above, the present invention provides a modulator that converts an audio signal into an FM signal, a digital signal processor that similarly converts an audio signal into a digital signal and processes the signal, and a digital signal processor that converts a video signal into an FM signal.
A modulator for converting into a signal, etc., three groups of magnetic heads each having a different azimuth angle, a first frequency converter that converts the rotational angular velocity of the rotating cylinder and the running speed of the magnetic tape to 1/N, and a signal generator. By providing a second frequency converter for increasing the period of the signal generated by the device by N times, it is possible to simultaneously record and reproduce a video signal and a high quality audio signal. Moreover, by increasing the recording density of the recording tracks of conventional VTRs, it is possible to record audio signals converted to high-quality digital signals.
Channel audio signals can be added and recorded. Furthermore, when only audio signals are recorded, the recording time is increased by N times by the third switch, and the magnetic tape can be used effectively. Furthermore, since the magnetic tape on which audio signals converted to digital signals can be recorded can be automatically inspected and recorded, there is no error in handling and the operability is good.

[Brief Description of the Drawings] Fig. 1 is a block diagram of a digital audio recording video tape recorder according to an embodiment of the present invention, Fig. 2 is a conceptual diagram of tracks on a recorded magnetic tape, and Fig. 3 is a magnetic head. The spectrum diagram of the signal recorded by the group, Figure 4 is the conventional 8
FIG. 5, a block diagram of a millimeter video, is a spectrum diagram of a signal recorded by a conventional 8 millimeter video. 51.64...Input terminal, 53,6θ・°...
...Modulator, 52, 54, 60, 67. 83, 85, 8
7゜89, 91 --- Amplifier, 58a, ssb
, 63a. 63b, 70a, 70b...magnetic head, 71
...Magnetic tape, 59.88 ...Digital signal processor, 84.92 ...Demodulator, 8
6.90.94... Output terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person51
．． 54-Each person's kakajishi product,'? 0.94- Output Hanako Fig. 2 7/03b Fig. 3

Claims (4)

[Claims] (1) A first magnetic head group, which is attached to a rotating cylinder and is composed of at least one pair of magnetic heads each having a different azimuth angle, and which is attached at a different position from the first magnetic head group; a second magnetic head group that is different from the azimuth angle of each magnetic head in the first magnetic head group and is composed of at least one pair of magnetic heads each having a different azimuth angle; At least one magnetic head mounted at a different position from the head group and having an azimuth angle different from that of each magnetic head of the first and second magnetic head groups, and having a different azimuth angle, respectively.
a third magnetic head group composed of a pair of magnetic heads; a first modulator that converts a first input signal into a frequency modulation signal; and a third magnetic head group configured of a pair of magnetic heads; a first amplifier for supplying the signal to the head group; a first demodulator for demodulating the signal reproduced by the first magnetic head group; and a first demodulator for demodulating the signal reproduced by the first magnetic head group; a first digital signal processor that converts the signal into a digital signal and adds an error correction code; and a second digital signal processor that supplies the output signal of the first digital signal processor to the second magnetic head group. an amplifier, a second digital signal processor for performing error correction on the signal reproduced by the second magnetic head group and converting it into an analog signal; and a signal generator that generates a signal serving as a reference signal for a second digital signal processor; a first signal processor that separates an input video signal into a luminance signal and a chrominance signal; a second modulator for converting the output signal into a frequency-modulated luminance signal and a low-frequency converted color signal; and a second modulator for supplying the output signal of the second modulator to the third magnetic head group. a second demodulator that converts the signal reproduced by the third magnetic head group into a luminance signal and a color signal;
a second signal processor that converts the output signal of the demodulator into a video signal; a detector that detects the detected portion provided on the magnetic tape cassette; and a detection output of the detector that converts the first digital signal into a video signal. A first switching device that enables the output signal of the signal processor to be supplied to the second magnetic head group, and a carrier wave frequency of the frequency-modulated luminance signal of the second modulator based on the detection output of the detector. a second switch for switching to a higher frequency, and a control device for controlling the rotation of the rotary cylinder and the running of the magnetic tape, the control device being connected to the control device and configured to control the rotational angular velocity of the rotary cylinder and the magnetic tape. a first frequency converter for reducing the running speed of the signal generator to a fraction of N (N is an integer); a second frequency converter for multiplying the period of the signal generated by the signal generator by N; 1st
and a third switch for driving the second frequency converter. (2) A two-channel signal is used as the first input signal, the first modulator outputs two types of carrier waves corresponding to each input signal, and the first digital signal processor outputs the four-phase phase modulation signal. Claim 1 characterized in that the invention is configured to output
A digital audio recording videotape recorder as described in . (3) The frequency of the carrier wave output from the first modulator is selected to be a higher frequency near the frequency of the low-band-converted color signal, and the frequency of the modulation signal output from the first digital signal processor is adjusted. 2. The digital audio recording video tape recorder according to claim 1, wherein a higher frequency is selected in the vicinity of the frequency of the carrier wave output from the first modulator. (4) A fourth switch for stopping the supply of the output signal of the second modulator to be supplied to the third magnetic head group, and for operating the first switch and the fourth switch. 2. The digital audio recording video tape recorder according to claim 1, further comprising a fifth switching device.