JPH0572153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording and reproducing method, and in particular to a method for magnetic recording and reproducing, in which a rotating head is used to convert a total of three types of signals, a luminance signal, a color difference signal, and an audio signal, into predetermined signal formats. The present invention relates to a magnetic recording and reproducing method for recording on a magnetic tape after conversion and reproducing the same.

Conventional technology Currently, helical scan magnetic recording and reproducing devices (VTR) use 1/2 inch wide magnetic tape.
For home use, the band that can be recorded and reproduced is relatively narrow, so of the luminance signal and carrier color signal separated from the color video signal, the luminance signal is frequency-modulated and frequency-modulated, and the carrier color signal is subjected to low frequency conversion. It employs a so-called low-pass conversion color recording and reproducing method in which the frequency-division multiplexed signal is converted into a carrier color signal and then frequency-division multiplexed onto the frequency-modulated luminance signal, and this frequency-division multiplexed signal is recorded on a magnetic tape and reproduced. In order to improve tape usage efficiency, a guard bandless recording method is used in which the azimuth angles of each rotary head that records adjacent tracks are made to differ.

Problems to be Solved by the Invention However, the above-mentioned low frequency conversion color recording and reproducing method is somewhat insufficient for achieving higher image quality due to the limited recording and reproducing bands of luminance signals and carrier color signals. Conversion carrier color signal is NTSC system or
When recording a PAL color video signal, it is a balanced modulated wave, and due to uneven contact between the tape and the head, AM noise in the reproduced low-frequency conversion carrier color signal occurs and S/
The signal-to-noise ratio (N) deteriorates, and the residual time axis fluctuation component contained in the generated carrier color signal causes horizontal stripping noise on the screen. Furthermore, in the guard bandless recording method described above, the azimuth loss effect is not sufficient for low frequencies, and the low frequency converted carrier color signal of the adjacent track is mixed into the reproduced signal as a crosstalk component. During playback, the phase of the color subcarrier frequency of the low-pass conversion carrier color signal of the NTSC system or PAL system is shifted by about 90 degrees every horizontal scanning period (1H) (for example, Japanese Patent Publication No. 56-9073, 55-32273), or cross-stroke countermeasure processing such as inverting the phase of only the low-frequency conversion carrier color signal of one of the adjacent video tracks every 1H is required. In addition, since audio signals were recorded on magnetic tape with a fixed head along with bias signals,
The sound quality and S/N of the reproduced audio signal were not sufficient. It is known that high-quality reproduced audio signals can be obtained by recording and reproducing audio signals deep into the magnetic layer of a magnetic tape using a rotating head exclusively for audio. After-recording (so-called dubbing)
There was a problem that it was not possible.

Therefore, the present invention converts the luminance signal, color difference signal, and audio signal into predetermined signal formats, and then sequentially forms and records three tracks using three sets of rotary heads, and reproduces the tracks. It is an object of the present invention to provide a magnetic recording and reproducing method that solves the above-mentioned problems.

Means for Solving the Problems In the magnetic recording and reproducing method of the present invention, when the switch means is set to the first connection mode, a luminance signal and two types of color difference signals are sent to the first and second sets of rotating heads. A third set of rotary heads is supplied with a pulse code modulated or frequency modulated audio signal, and three parallel magnetic tapes are divided in the running direction of the magnetic tape. A recording track group is formed by repeating recording and forming tracks, and during reproduction, the three parallel tracks are separately scanned over the recording track group by the three sets of rotary heads, and the first and second sets are scanned separately. The frequency modulated video signal reproduced by the rotary head is demodulated to obtain a reproduced luminance signal and two types of reproduced color difference signals, and the modulated audio signal reproduced by the third set of rotary heads is demodulated to obtain reproduced audio. When the signal is obtained and the switch means is set to the second connection mode,
A frequency division multiplexed signal consisting of a frequency modulated luminance signal and a low frequency converted carrier chrominance signal which is frequency division multiplexed into an empty frequency region on the lower side thereof is transmitted only to the first set or the second set of rotating heads. A recording track group is formed by repeating the recording and formation of parallel tracks divided in the running direction of the magnetic tape, and during reproduction, frequency division multiplexing is reproduced by the first set or the second set of rotating heads. The signal is processed and a reproduced luminance signal and a reproduced carrier color signal returned to the original band are output.

Operation The switching means causes the recording track of the frequency-modulated luminance signal by the first set of rotary heads and the recording track of the frequency-modulated luminance signal by the second set of rotary heads in the first connection mode. A recording track of a frequency division multiplexed signal consisting of a color difference signal, and a third
A recording track of a modulated audio signal obtained by subjecting a pulse code modulated audio signal to frequency modulation, four-phase PSK modulation, or four-phase DPSK modulation using a set of rotary heads is separately formed. Therefore, the three types of information signals consisting of a luminance signal, two types of color difference signals, and an audio signal are recorded in a wide band without being restricted in band by other information signals. Further, only the audio signal can be recorded later on the recorded magnetic tape by the third set of rotary heads (so-called dubbing can be performed).

Further, in the case of the second connection mode, the same frequency division multiplexed signal can be recorded and reproduced using the same track pattern as that of a conventional low frequency conversion color recording and reproduction system VTR.

Embodiments Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.

FIG. 1 shows a block system diagram of a first embodiment of the recording system of the present invention. In the figure, input terminal 1 is connected to a conventional low-frequency conversion color recording generation VTR (hereinafter referred to as
A brightness signal with a wider band than the brightness signal recorded and reproduced by a conventional VTR (hereinafter referred to as a VTR) comes in, and after being band-limited to, for example, about 4MHz by a low-pass filter (hereinafter referred to as LPF) 2, it is supplied to an FM modulator 3. , here, for example, as shown in Figure 2A, the carrier wave shift band is
It is converted into a frequency modulated luminance signal (FM luminance signal) of approximately 5MHz to 6MHz. This FM luminance signal is supplied to the first set of rotating heads 4a and 4b, respectively, through a recording amplifier and a rotary transformer (neither shown). Note that conventional VTR luminance signal recording systems are provided with a high-pass filter on the output side of the FM modulator, but this is unnecessary.
This is because only the FM luminance signal is recorded on only one track.

On the other hand, two types of color difference signals R-Y and B-Y taken out from a color television camera are supplied to input terminals 5 and 6, respectively, and further passed through LPFs 7 and 8 with a cutoff frequency of about 1 MHz to FM modulators 9 and 8. 10. The FM modulator 9 outputs a first frequency-modulated color difference signal (FM color difference signal) having a frequency spectrum as shown in FIG. . Further, from the FM modulator 10, a second FM color difference signal having a frequency spectrum as shown in FIG. 2B obtained by frequency modulating a 1.5 MHz carrier wave with the color difference signal B-Y is taken out. As can be seen from FIG. 2B, the first FM color difference signal and the second FM color difference signal have different bands. The first FM color difference signal is passed through a high-pass filter (hereinafter referred to as
HPF) 11 to an adder 13. On the other hand, the second FM color difference signal is passed through the LPF 12 with a cutoff frequency of about 2.5MHz to the adder 13.
supplied to As a result, a frequency division multiplexed signal with a frequency allocation as shown in FIG. supplied respectively.

In this way, frequency modulated video signals relating to a luminance signal and two types of color difference signals are supplied to the first and second sets of rotating heads, respectively.

In addition, the left input terminals 15a and 15b,
The analog audio signal of the right channel is supplied to the PCM processor 16, where it is subjected to pulse code modulation (PCM) based on, for example, Electronics Industries Association of Japan (EIAJ) standards, and a vertical blanking period is provided, and the two channels are The time axis is compressed to time-division multiplex the PCM signal and transmit it, and then an error correction code and an error check code are added.
It is converted into a digital audio signal in block units,
Furthermore, a composite synchronization signal is added to the signal, and the signal is converted into a signal compliant with a composite video signal (this is referred to as a PCM audio signal). This PCM audio signal passes through LPF17 with a cutoff frequency of about 3.5MHz.
The signal is supplied to the FM modulator 18, where it is frequency modulated so that the carrier wave shift band is 3.5MHz to 4.5MHz, as shown in FIG.
- PCM audio signals) and then supplied to the third set of rotary heads 19a and 19b, respectively, through a recording amplifier and a rotary transformer (none of which are shown).

Note that the luminance signal input to input terminal 1 may be obtained separately from the composite color video signal, and the color difference signals R-Y and B supplied to input terminals 5 and 6 may also be obtained separately from the composite color video signal.
-Y may be obtained by demodulating the carrier color signal separated from the composite color video signal, and the I signal and Q
It can be a signal.

Next, the above rotating heads 4a, 4b, 14a, 1
The arrangement relationship among 4b, 19a, and 19b will be explained. In FIG. 3A, a magnetic tape 27 running in the direction of arrow A is wound diagonally around the outer peripheral side of a rotating body 21 such as a rotating drum over an angular range of over 180°, and is also wound counterclockwise, for example A rotating head 4a is mounted on the rotating surface of the rotating body 21 that rotates at 30 rps.
and 4b, 14a and 14b, and 19a and 19b are mounted and fixed facing each other. The rotary heads 4a and 4b are arranged at positions that precede the rotary heads 14a and 14b by a slight angle .theta. in the direction of rotation. The above angle θ is such that the rotating heads 4a and 14a, 4b and 14b are close enough to each other that crosstalk is not a problem, and the tape running speed is 66.7 mm/
sec, which is a value of, for example, an interval of about 2.5 mm (corresponding to 7 horizontal scanning periods at the recording wavelength), as shown in FIG. 3B, when the diameter of the rotating body 21 is 62 mm. Also,
The rotary heads 19a, 19a are located behind the rotary heads 14a, 14b by, for example, about 50 degrees in the rotational direction.
19b are arranged respectively. Rotating head 4a,
4b, 14a, 19a and 19b are connected to the rotating heads 4a, 4, respectively, so that three parallel tracks are formed as will be described later.
b, 19a and 19b are the same height, and
Rotating heads 14a,
14b is at a height approximately 40 μm lower.
The height position relationship is set optimally.

The track width of the rotating heads 4a and 4b is, for example,
47 μm, rotating heads 14a and 14b, and 1
9a and 19b are each selected to have a track width of 27 μm, and each of the rotary heads 4a and 14b has an azimuth angle gap of, for example, +6°.
The rotary heads 4b and 14a each have an azimuth angle gap of, for example, -6°, the rotary head 19a has an azimuth angle gap of, for example, +30°, and the rotary head 19b has an azimuth angle gap of, for example, -30°. has. That is, three sets of rotating heads 4a and 4b, 14a and 14b, and 19a and 19b are mounted facing each other on the rotating surface of the rotating body 21.
have different azimuth angle gaps.

The magnetic tape 20 has a track pitch of, for example,
Assuming that the magnetic tape 20 is run at a speed of 116 μm, the track pattern on the magnetic tape 20 is as shown in FIG _. At the same time, the rotary head 14a converts the first frequency division multiplexed signal with the frequency allocation shown in FIG.
A track T _C1 of 27 μm is recorded and, after a delay, an FM-PCM audio signal with a frequency spectrum shown in FIG.
During the next one field period, the rotary head 4b forms an FM luminance signal recording track T _Y2 with a width of 47 μm, and at the same time, the rotary head 14b forms a track T _A1 with a width of 27 μm. A first frequency division multiplexed signal recording track T _C2 is formed, and later a modulated audio signal recording track T _A2 having a width of 27 μm is formed by the rotary head 19b. Thereafter, in the same manner as above, a total of three parallel tracks, the FM luminance signal recording track, the first frequency division multiplexed signal recording track, and the FM-PCM audio signal recording track, are sequentially formed at a track pitch of 116 μm for each field. . A guard band of 5.0 μm is formed between each track.

Note that since a guard band is formed between each track as described above, each rotary head 4a, 4b, 1
4a, 14b, 19a, and 19b are not necessarily required to have azimuth angles, but the guard band is relatively narrow, approximately 5 μm, and this embodiment, which has the above-mentioned azimuth angles, makes it possible to reduce the distance from adjacent tracks. It is desirable to reduce crosstalk more fully. Furthermore, when using a wider rotating head, or when the tape running speed is insufficient and a guard band cannot be obtained, it is necessary to set each rotating head so that it has the required azimuth angle as described above. .

According to this embodiment, the wideband FM luminance signal as shown in FIG. 2A has a width as shown in FIG. 4A.
Since it is recorded on tracks T _Y1 and T _Y2 as wide as 47 μm, the required S/N of the reproduced luminance signal can be ensured.
On the other hand, the first and second FM color difference signals and FM-PCM
The audio signal is on the narrower tracks T _C1 and T _C2 with a width of 27 μm.
Alternatively, it is recorded on T _A1 and T _A2 , but the band of the color difference signal is narrower than that of the luminance signal, so it does not require as much C/N as the luminance signal, and the PCM audio signal is less susceptible to interference from noise in the transmission system. Therefore, even with a track width of 27 μm, a reproduced signal can be obtained with no problem in practical use. Note that tracks recorded by fixed heads such as control tracks and audio tracks are not shown in FIG. 4A (the same applies to FIGS. 4B, C and 5, which will be described later).

In addition, the track pattern shown in FIG. 4A is not limited to the FM luminance signal recording track pattern as shown in FIG.
T _Y1 ′, T _Y2 ′ and the first frequency division multiplexed signal recording tracks T _C1 ′, T _C2 ′ are each formed by a rotating head having a gap of the same azimuth angle, and an FM-PCM signal is inserted between these tracks. A track pattern may be formed in which the audio signal recording tracks _TA1 ' and _TA2 ' are sandwiched between them.

Next, we will discuss the first embodiment of the regeneration system of the present invention in the sixth section.
This will be explained with figures. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.
In FIG. 6, assuming that the recording track pattern of the magnetic tape ₂₀ is as shown in _FIG .
Simultaneously, the rotary heads 19a and 14b sequentially scan the tracks T _C1 and T _C2 for each field, and later than these, the rotary heads 19a and 19b sequentially scan the tracks T _A1 and T _A2 for each field. Hereinafter, in the same manner as above, the rotary heads 4a, 14a and 19
a, 4b, 14b and 19b, three parallel tracks are scanned for each field. It goes without saying that the running speed of the magnetic tape 20 is selected to be the same speed as during recording.

As a result, the reproduced FM luminance signals alternately taken out for each field from the rotary heads 4a and 4b are transmitted to the rotary transformer, switch circuit, preamplifier, HPF, and limiter (all not shown).
are supplied to the FM demodulator 25 through the
It is FM demodulated and becomes a reproduced luminance signal, and then LPF2
6, the carrier is removed from the signal and the signal is output to the output terminal 27. Although not shown, the HPF normally provided on the input side of the FM demodulator 25 may be omitted.

Further, the reproduced first frequency division multiplexed signals alternately taken out for each field from the rotary heads 14a and 14b are passed through a rotary transformer, a switch circuit, and a preamplifier (none of which are shown) to the HPF 28 and LPF 29, respectively. Supplied.
The first FM color difference signal of the frequency spectrum shown as I in Fig. 2B separated by HPF28 is
The second FM color difference signal having the frequency spectrum shown in FIG. As a result, the FM demodulator 30 takes out the reproduced color difference signal RY, and the FM demodulator 31 takes out the reproduced color difference signal B-Y. The reproduced color difference signals R-Y and B-Y are outputted to output terminals 34 and 35 after carriers are removed by LPFs 32 and 33. Note that the difference in recording time between the luminance signal and the color difference signal is allowed within the vertical blanking period, so by considering the switching point within this period during playback, the recording time difference between the brightness signal and the color difference signal can be adjusted. Simultaneous operation can be achieved.

Furthermore, the FM-PCM audio signals reproduced by the rotary heads 19a and 19b are supplied to the FM demodulator 36 through a rotary transformer, a switch circuit, a preamplifier, and a limiter (all not shown), where they are demodulated into PCM audio signals. After LPF
The carrier is removed at step 37, and the signal is further supplied to a PCM processor 38. PCM processor 38
This circuit operates complementary to the PCM processor 16, and decodes the PCM audio signal in the form of a composite video signal using a known method and demodulates it into the original left channel playback audio signal and right channel playback audio signal. and simultaneously output to output terminals 39a and 39b.

Note that in the recording system shown in Figure 1, the emphasis and nonlinear emphasis for noise reduction, the white clip and dark clip for preventing overmodulation, and other circuits are not shown.
In the reproduction system shown in FIG. 6, circuits such as de-emphasis, non-linear de-emphasis, and RF equalizer for noise reduction are omitted. Also. In Figure 6, the reproduced second
The FM color difference signal has a low frequency as shown in FIG. It is preferable to perform FM demodulation using a high frequency conversion method, which converts the frequency to a high frequency range and then performs FM demodulation.

Furthermore, the output of the PCM processor 16 includes a composite synchronization signal, but if it is asynchronous with the video signal, and the servo system of the VTR is controlled by the composite synchronization signal of the video signal, the data portion of the PCM audio signal is Rotating heads 4a, 4b and 14a, 14
There may be a switching position with b, and there is a possibility of data loss.
It is desirable to perform genlock with the video signal, and to add a time difference to the generation of the vertical synchronization signal in consideration of the time difference in head switching between the rotary heads 4a, 4b and 14a, 14b.

Furthermore, since the FM-PCM audio signal is recorded on a single track, the FM-PCM audio signal cannot be recorded on the recorded magnetic tape.
It is also possible to perform so-called post-recording, in which the PCM audio signal is recorded later, and therefore a circuit for this may be added.

Next, a second embodiment of the present invention will be described. FIG. 7 shows a block system diagram of the second embodiment of the recording system of the present invention. In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In FIG. 7, a standard television system composite color video signal inputted to an input terminal 41 has a luminance signal separated by an LPF 42, and a carrier color signal separated by a bandpass filter (hereinafter referred to as BPF) 43. Ru. The luminance signal from the LPF 42 passes through an FM modulator 44 and an HPF 45, respectively, and is converted into an FM luminance signal and supplied to an adder 46. On the other hand, BPF4
The carrier color signal from 3 is passed through a frequency converter 47 and
The signals are passed through the LPF 48 and converted into low-frequency conversion carrier color signals, which are then supplied to the adder 46.

As a result, the low frequency conversion carrier color signal obtained by the previously well-known low frequency conversion color recording and reproducing method described above is
A second frequency division multiplexed signal with the FM luminance signal is taken out from the adder 46 and supplied to the contact b of the switch 49 and the contact c of the switch 50, respectively. Further, the contact a of the switch 49 is connected to the output end of the FM modulator 3, and the contact c is an empty contact. A contact a of the switch 50 is connected to the output end of the adder 13, and a contact b thereof is an empty contact. In addition, the contact a of the switch 51 is connected to the FM modulator 1.
8, and contacts b and c are respectively empty contacts. The switches 49 to 51 are switched in conjunction with each other, and are roughly divided into cases in which all are connected to contact a (first connection mode) and cases in which none are connected to contact a (second connection mode). Ru.

In the case of the first connection mode, a track pattern as shown in FIG. 4A is formed on the magnetic tape 20 by the same operation as in FIG. 1.

In the second connection mode, when switches 49, 50, and 51 are all connected to contact b, the magnetic tape 20 is placed in the same position as in the standard mode of a conventional VTR, for example, with a track pitch of 58 μm. The vehicle is forced to run at a speed of . In this case, the second frequency division multiplexed signal output from the adder 46 is supplied to the first set of rotary heads 4a and 4b through a switch 49, and the switches 50 and 51 supply the first set of rotary heads 14a, 14b, 19a.
and 19b, no signal is supplied. Therefore, the track pattern on the magnetic tape 20 in this case is as shown in FIG.
a and 4b alternately every field, the second
The track on which the frequency division multiplexed signal of
They are formed sequentially as shown by T _S1 , T _S2 , and T _S3 . This track pattern has a track pitch of
58 μm, the width of tracks T _S1 to _{T S3} is 47 μm,
A guard band of 11 μm is formed between each track.

Next, among the second connection modes, switches 49 and 5
When all contacts 0 and 51 are connected to contact c, long-term mode recording is performed. That is, in this case, the magnetic tape 20 is run at the same low speed as in the long-time mode of a conventional VTR, for example, at a track pitch of 19 .mu.m. In this case, the switches 49 and 51 are used to control the rotary head 4.
Since no signals are supplied to the rotary heads 4a, 4b, 19a and 19b, the recording operation by the rotary heads 4a, 4b, 19a and 19b is stopped. frequency division multiplexed signals are provided to a second set of rotating heads 14a and 14b, respectively. As a result, the magnetic tape 20 in this case
The above track pattern becomes as shown in FIG. 4C, and the tracks on which the second frequency division multiplexed signal is recorded are alternately T _L1 , T _L2 , T _L3 for each field by the rotary heads 14a and 14b. As shown in the figure, the tracks are sequentially formed with a track pitch of 19 μm.
Here, the rotary heads 14a and 14b have different azimuth angles and the same azimuth angle gap as in the past, and their track width is 27 μm as described above, but one rotary head The first layer with a width of 27 μm was formed in advance.
The width of the track is 8 μm on the upstream side of the tape, then the width formed by the other rotating head.
The 8 μm width of the 27 μm second track is overwritten and erased, leaving a second track newly formed by the other rotary head. Below, in the same way as above, the width
Tracks of 19 .mu.m are sequentially formed at a track pitch of 19 .mu.m without a guard band, as shown in FIG. 4C.

Next, to explain the regeneration system, FIG. 8 shows a block system diagram of a second embodiment of the regeneration system of the present invention. In FIG. 8, switches 54, 55 and 5
6 are switched in conjunction with each other, and when they are all connected to contact a (first connection mode), when they are both connected to contact b (second connection mode), and when they are both connected to contact c. (second connection mode). These connection modes are selected according to the recording track pattern of the magnetic tape 20, and when the track pattern is as shown in FIG. 4A, the first connection mode is selected. As a result, each reproduced signal from the rotary heads 4a and 4b is supplied to the FM demodulator 25 through the switch 54, and the reproduced signals from the rotary heads 14
Each reproduction signal of a and 14b is passed through a switch 55.
The reproduction signals from the rotary heads 19a and 19b are supplied to the HPF 28 and the LPF 29, respectively, and the reproduction signals from the rotary heads 19a and 19b are supplied to the switch 5.
6 to the FM demodulator 36. Therefore, in this case, the same reproduction operation as in FIG. 6 is performed.

Next, when reproducing the magnetic tape 20 having the track pattern shown in FIG. It is switched and connected to. For this reason, the truck
Reproduction signals from the rotary heads 4a and 4b obtained by alternately scanning T _S1 , T _S2 and T _S3 are supplied to the HPF 57 and LPF 58 through the switch 54, while reproduction signals from the rotary heads 14a, 14b, 19a and 19b are Switches 55 and 56 block transmission to subsequent circuits. The FM luminance signal in the reproduced second frequency division multiplexed signal is separated by the HPF 57 and then passed through the FM demodulator 59 and LPF 60, respectively, to be converted into a reproduced luminance signal and supplied to the adder 61. On the other hand, the low frequency converted carrier color signal separated by the LPF 58 is supplied to the frequency converter 62, where it is returned to the original band and made into a reproduced carrier color signal, and then supplied to the adder 61 through the BPF 63. . As a result, the reproduced color video signal is taken out from the adder 61 and output to the output terminal 64.

Next, when reproducing the magnetic tape 20 having the track pattern shown in FIG. They are respectively switched and connected to the contact c side. As a result, the reproduction signals obtained by the rotary heads 14a and 14b alternately scanning the tracks T _L1 , T _L2 , T _L3 , etc. are passed through the switch 55 to the HPF 57 and
The signals are respectively supplied to the LPF 58 and thereafter subjected to the same signal processing as described above, and reproduced color video signals are taken out at the output terminal 64. On the other hand, the rotating heads 4a, 4
Each reproduction signal of b, 19a and 19b is transmitted through switch 5.
4 and 56 prevent transmission to subsequent circuits. In this way, compatibility with conventional VTRs can be achieved.

Note that in the recording and reproducing systems shown in FIGS. 7 and 8, circuits that can have the same characteristics, such as an FM modulator, may be used in common. Furthermore, although it has been described that the tape running speed is changed according to the switching of each switch, it may be maintained at a predetermined high speed. Furthermore,
PCM audio signals to be recorded and played back are not limited to frequency modulation, but also include, for example, 4-phase PSK modulation (phase shift keying).
Alternatively, recording and reproduction may be performed using four-phase DPSK modulation (differential phase shift keying). This 4-phase PSK modulation and 4-phase DPSK
Since one of the four types of information is transmitted in one of the four phases, modulation requires only one phase modulation for every two bits, and the carrier wave phase switching speed (symbol rate) can be half the bit rate. Therefore, it is possible to transmit in a narrow band.

Effects of the Invention As described above, according to the present invention, the three types of information signals, the luminance signal, the color difference signal, and the audio signal, are recorded and reproduced separately on three tracks.
The moiré and cross colors that occur in conventional VTRs, which frequency-division multiplex the FM luminance signal and the low-frequency conversion carrier chrominance signal and record and reproduce them on the same track on a magnetic tape, do not occur, and the luminance signal and color difference signal are Both recording and reproduction bands can be made sufficiently wide, and since the low frequency conversion carrier color signal is not recorded biased by the FM luminance signal, it is possible to reproduce equal reproduction color difference signals without causing side-scanning noise. It is possible to improve the S/N and obtain a reproduced color video signal of higher image quality, and since the PCM audio signal is recorded and reproduced using a rotating head, compared to the conventional method of recording audio signals using a fixed head, It is possible to significantly improve the S/N, bandwidth, etc., and since it is recorded on a dedicated track, there is no rotary head dedicated to audio in the depths of the conventional tape magnetic layer.
This was not possible using the method of recording FM audio signals. So-called post-recording is also possible, and when the switch means is set to the first connection mode, recording is repeatedly performed on three parallel tracks divided in the magnetic tape running direction to form a recording track group. When using the second connection mode, which corresponds to the recording and playback method of a video tape recorder, the frequency division multiplexed signal is supplied only to the first set or the second set of rotating heads, and is divided in the magnetic tape running direction. Since parallel tracks are recorded, the first connection mode that allows high-quality reproduced color video signals to be obtained with a single device and the second connection mode that is compatible with conventional video tape recorders are selected as appropriate. In particular, the rotary head of the first set or the second set can be used for both, so the structure can be simplified.

[Brief explanation of drawings]

FIG. 1 is a block system diagram showing a first embodiment of the recording system of the present invention, FIGS. 2A to C are diagrams showing frequency spectra of three types of recording signals of the present invention, and FIG.
Figures A and B are diagrams each illustrating the arrangement of the rotary head in the present invention, Figures 4A to C are diagrams each showing examples of recording track patterns according to the present invention, and Figure 5 is a diagram illustrating the recording track pattern according to the present invention. FIG. 6 is a block system diagram showing a first embodiment of the reproducing system of the present invention, and FIGS. 7 and 8 show a second embodiment of the recording system and reproducing system of the present invention, respectively. FIG. 1... Luminance signal input terminal, 2... Low pass filter (LPF), 3, 9, 10, 18, 44... FM modulator, 5, 6... Color difference signal input terminal, 4a, 4b...
...first set of rotary heads, 13, 46...adder, 14a, 14b...second set of rotary heads,
15a, 15b...analog audio signal input terminal,
16, 38...PCM processor, 19a, 19
b... Third set of rotating heads, 20... Magnetic tape, 21... Rotating body, 25, 30, 31, 36,
59...FM demodulator, 27...Reproduction luminance signal output terminal, 34, 35...Reproduction color difference signal output terminal, 3
9a, 39b...playback audio signal output terminal, 41...
...Composite color video signal input terminal, 47, 62...
Frequency converter, 49-51... switch, 64...
...Playback color video signal output terminal.

Claims (1)

[Claims] 1. A pair of rotating heads that are mounted opposite to each other on the rotating surface of a rotating body around which a running magnetic tape is wound obliquely over a predetermined angle range, and that have different azimuth angles. A magnetic recording and reproducing method for recording and reproducing information signals using one or all of a set of first to third sets of rotating heads, the switch means being set in a first connection mode. In this case, the first and second sets of rotating heads are supplied with frequency modulated video signals of a luminance signal and two types of color difference signals, and the third set of rotating heads is supplied with pulse code modulated or frequency modulated video signals. A recording track group is formed by repeatedly recording and forming three parallel tracks divided in the magnetic tape running direction by supplying a frequency-modulated modulated audio signal, and during playback, the three sets of rotating heads The recording track group is separately scanned by three parallel tracks, and the frequency modulated video signals reproduced by the first and second sets of rotary heads are demodulated to produce a reproduced luminance signal and two types of reproduced color differences. get a signal,
The modulated audio signal reproduced by the third set of rotary heads is demodulated to obtain a reproduced audio signal, and when the switch means is set to the second connection mode, the frequency modulated luminance signal and its lower frequency side are demodulated. A frequency division multiplexed signal consisting of a low frequency converted carrier chrominance signal frequency division multiplexed into an empty frequency region is supplied only to the first set or second set of rotating heads and divided in the magnetic tape running direction. A recording track group is formed by repeating recording and forming parallel tracks, and during reproduction, the frequency division multiplexed signal reproduced by the first set or the second set of rotary heads is subjected to signal processing to determine the reproduction brightness. A magnetic recording and reproducing method characterized by outputting a signal and a reproduction carrier color signal restored to the original band.