JPS5916325B2 - Video signal recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention allows a rotating head to convey tape onto a tape that is diagonally placed on a guide drum and transported in one direction, or placed on a tape that is placed on a guide drum and transported in one direction. Regarding a device that records a video signal on a sheet that is transported in a direction and reproduces the video signal from this, it is particularly possible to reduce the diameter of the guide drum, thereby reducing the size of the recording device. This allows the density to be increased.

The present invention provides two or two sets of rotary heads that simultaneously scan a tape or sheet, one of which detects the low-frequency component of the video signal, and the other one of which detects the high-frequency component of the video signal. They are used for recording and reproducing, respectively, and when the diameter of the guide drum is made smaller, it is possible to record and reproduce good signals without any problems even if the relative linear velocity between the tape and the rotary head decreases and the signal recording band becomes narrower. It is something. ■0 Hereinafter, a specific example of this will be explained with reference to the diagram, taking as an example the case of recording on a tape and reproducing from it. In the example shown in FIGS. 1 and 2, the tape 1 is placed on the guide drum 2 over an angular range of its entire circumference, and the guide drum 2 is separated from the upper drum 2a and lower drum 2b. The lower drum 2b is fixed on the chassis 3, while the upper drum 2a is rotated by a motor 4.

Two rotating heads HA and Hc are attached to the upper drum 2a.
c are respectively mounted at positions separated by a certain distance Z in the direction of a common rotation axis. This distance Z is determined in relation to the angle of inclination of the tape 1, etc. so that the heads HA and Hc are always in 35-pair contact with the tape 1 over their respective rotational angle ranges of 3600 degrees. The heads HA and Hc, that is, the upper drum 2a, for example, rotates at 60H2 in the direction shown by arrow 5, and the scanning loci of the tape 1, for example) 1-, by the heads HA and Hc in the direction shown by arrow 6 are mutually They are transported at such a speed that they do not overlap.

Therefore, during recording, first tracks A1 and C1 are simultaneously formed by heads HA and Hc, then tracks A2 and C2 are simultaneously formed, and so on.
As shown in FIG. By making the size appropriate, a recording pattern can be obtained in which two tracks formed before and after two tracks formed at the same time are placed between two tracks formed at the same time, as shown in FIG. 3, for example. Here, as will be described later, the video signal is separated into low-frequency components and high-frequency components, and processing such as modulation and frequency conversion is performed so that each component occupies the lower frequency band. Head HA
is recorded on tracks Al, A2, ...... by
The high frequency component is tracked by the other head Hc,
It is recorded in C2, . . . That is, each field of the video signal is recorded with its low frequency components separated into two tracks formed simultaneously. In the example shown in FIGS. 4 and 5, the tape 1 is placed on the guide drum 2 at its 180
The upper drum 2a has two heads H extending along a somewhat larger angular range than the upper drum 2a and having an angular distance of 180 degrees from each other.
A and HB are mounted at the same position in the direction of the rotation axis, and two heads H are also spaced apart from each other by a certain distance Z in the direction of the rotation axis, with an angular spacing of 180 distances from each other.

and when an HD is installed. The distance Z is determined in relation to the angle of inclination of the tape 1 and the angular spacing between the heads HA and Hc, so that the heads HA and Hc are in simultaneous contact with the tape 1 over a rotational angle range of at least 1800° and the head H
B and HD are sized so that they simultaneously come into contact with the tape 1 over a rotation angle range of at least 180 tangents. The heads HA-HD rotate at 30[1z], and the tape 1 is transported at such a speed that the scanning trajectories of the heads HA-HD do not overlap with each other. Therefore, during recording, first tracks A1 and C1 are simultaneously formed by heads HA and Hc, and then tracks A1 and C1 are formed by heads HB and H.

Tracks B1 and D1 are formed simultaneously by heads HA and Hc, tracks A2 and C2 are formed simultaneously by heads HA and Hc, tracks B2 and D2 are formed simultaneously by heads HB and HD, and so on.
In this way, two tracks are simultaneously formed for one field section of the video signal. In this case, even if the moving amount W of the tape 1 during one rotation of the heads HA-HD is the same, the distance Z is made relatively small, so that two tapes are formed at the same time as shown in FIG. The recording pattern is such that two tracks formed before and after the book are inserted between the tracks of the book, and by making the distance Z larger than this, two tracks formed at the same time as shown in Fig. 7 are formed. A recording pattern is created in which four tracks are placed between tracks, and by increasing the distance Z, a recording is made in which five tracks are placed between simultaneously formed tracks as shown in Fig. 8. It becomes a pattern. In this case as well, the video signal is separated into low-frequency components and high-frequency components, and the low-frequency components are sent to one set of head HA.
and HB to track A,,Bl,A2,B2,...
. . . and its high frequency components are recorded on the tracks Cl, Dl, C2,
It is recorded in D2, . . . That is, each field of the video signal is recorded on two tracks formed at the same time, with its low-frequency components and high-frequency components separated. In the example of FIGS. 1 and 2, as shown in FIG. 9, if the angles formed by the width direction of the magnetic gap with respect to the respective scanning directions for the heads HA and Hc are made different from each other, the third As shown in FIG. 12 corresponding to the figure, by making the distance Z and the amount of movement W different, a recording pattern in which so-called guard bands are not formed between adjacent tracks can be created.
You can get the following information.

Similarly, in the examples of FIGS. 4 and 5, as shown in FIG. 10, between the heads HA, HB and the heads Hc, HD,
If the angles formed by the width direction of the magnetic gap with respect to each scanning direction are different from each other, as shown in FIG. 13 corresponding to FIG. 6, and as shown in FIG. 14 corresponding to FIG. 7. By making the distance Z and the amount of movement W different, respectively,
It is possible to obtain a recording pattern in which no guard band is formed between adjacent tracks. Furthermore, in the examples of FIGS. 4 and 5, as shown in FIG. 11, the angle formed by the width direction of the magnetic gap with respect to the scanning direction between heads HA, Hc and heads HB, HD is If they are different from each other, the 8th. As shown in FIG. 15, by varying the distance Z and the amount of movement W, it is possible to obtain a recording pattern in which no guard band is formed between adjacent tracks. During playback, heads HA and Hej or HA-HD rotate at the same speed as during recording, and tape 1 is transported at the same speed as during recording.・・・・・・
・The head HB tracks Bl, B2,...
..., the head Hc tracks Cl, C2,...
..., the head HD tracks D,, D2,...
A so-called tracking servo is applied to scan each of the .

Therefore, during recording, the head HA that recorded the low frequency component
Alternatively, the low-frequency components are reproduced from HA and HB, and the head Hc or Hc and H records the high-frequency components during recording. High frequency components are reproduced. And Figure 12~
Even when recording is performed at high density without forming a guard band as shown in Fig. 15, adjacent tracks are recorded and reproduced at heads that have different angles in the width direction of the magnetic gap with respect to the scanning direction. Therefore, no crosstalk occurs during reproduction due to azimuth loss.

Here, if the head is configured as shown in Figure 9 or 10 and the recording pattern is as shown in Figures 12 to 14, the low frequency and high frequency components are divided and recorded and reproduced at the same time. Since the angles formed by the width direction of the magnetic gap with respect to the scanning direction of the respective heads are different from each other, for example, as shown in FIG. 16 in the case of FIG. If the track is not scanned correctly and the tape is scanned at a position shifted in the longitudinal direction of the tape 1 as shown by the broken line, playback occurs because the amount of shift of the magnetic gap in the track extension direction is different in both heads. A time lag occurs between the low frequency component and the high frequency component.

On the other hand, if the head is configured as shown in Fig. 11 and the recording pattern is as shown in Fig. 15, the low-frequency component and the high-frequency component will be shared and simultaneously recorded and reproduced in each scanning direction. Since the angles formed in the width direction of the magnetic gaps are equal to each other, as shown in FIG. Even if a position shifted in the longitudinal direction is scanned, there will be no time difference between the reproduced low-frequency and high-frequency components because the amount of displacement in the track extension direction of the magnetic gap is the same in both heads. Does not occur. To explain an example of a state in which a video signal is separated into low frequency components and high frequency components and recorded, for example, as shown in FIG. In the case of a color video signal, it is divided into a low frequency component YL of the luminance signal YO (B in the same figure), a high frequency component YH of the luminance signal YO (D in the same figure) and a carrier color signal Cs,
Each is recorded as a signal in a band of 2.8 MHz or less, for example. Specifically, as shown in FIG. 19, the color video signal from the input terminal 11 is supplied to the low-pass filter 12, and the low-frequency component YL (18th B) is taken out and supplied to the frequency modulator 13, where the derivation is 1.
The frequency is modulated in the range of 5 to 2.7 MHz, and the modulated signal YLF (FIG. 18C) is supplied to the head HA or to the heads HA and HB (FIG. 18C) through the recording amplifier 14 and the contact R side of the switch 15. In this case, it is preferable to perform frequency modulation in order to record the low frequency component YLOS/N extending to the DC region without dropping it.The input color video signal is also supplied to the bandpass filter 16 to The high-frequency component YH (FIG. 18D) in the band of 1.5 to 3.0 MHz is extracted and supplied to the frequency converter 17, while the 3.58 MHz component YH from the oscillator 18 is extracted.
z signal and the 0.5 MHz signal from the oscillator 19 are supplied to a multiplier 20 to generate the 3.08 MHz signals S1 and 4.
A signal S2 of 0.08 MHz is obtained, and the low pass filter 21
3.08MHz signal S1 is passed through high pass filter 2.
A signal S2 of 4.08 MHz is taken out from each of the frequency converters 17 and 1.5 to 3.
．． High frequency component YH of 0MHz band is 0.08 to 1.58
The frequency is converted into a signal YHL in the M11z band (FIG. 18E), this signal YHL is supplied to the phase modulator 23, where it is phase modulated with a carrier frequency of 2.8MHz, and the modulated signal is sent to the bandpass filter 24. 2.8MH supplied
A component YHp (FIG. 18F) below z is extracted and supplied to the synthesizer 25. In this case, since the high frequency component YH is once frequency converted to a low frequency band and subjected to phase modulation or amplitude modulation, the deviation of the high frequency component YH does not expand, and the center carrier of the modulation signal can be arbitrarily selected. The input color video signal is further supplied to a band pass filter 26 to extract a carrier color signal Cs, which is supplied to a frequency converter 27, and a 4.08 MHz signal S2 from the filter 22 is supplied to this frequency converter 27. The carrier color signal Cs is converted into a carrier color signal CL having a carrier frequency of 0.5 MHz (FIG. 18G), and this low-frequency-converted carrier color signal CL is supplied to the synthesizer 25. Further, the audio signal from the input terminal 28 is supplied to a frequency modulator 29, and the frequency is 1.05M.
The frequency is modulated in the range of Hz±50 KHz, and the modulated audio signal AF is supplied to the synthesizer 25. Then, in the synthesizer 25, the phase modulated high frequency component YHP of the luminance signal
, the carrier color signal CL that has undergone low frequency conversion, and the frequency-modulated audio signal AF are synthesized, and the synthesized signal ST (Fig. 18H
) is supplied to the head Hc or to the heads Hc and HD through the recording amplifier 30 and the contact R side of the switch 31. During reproduction, the frequency-modulated low-frequency component YLF (FIG. 18C) of the luminance signal reproduced by the head HA or by the heads HA and HB is passed through the contact P side of the switch 15 to the reproduction amplifier 32. is further supplied to the detector 34 through the limiter 33 to generate the low frequency component YL(
B) in Fig. 18 is detected, and this is detected by the low-pass filter 35.
is supplied to the synthesizer 36 through the

On the other hand, at head Hc or at heads Hc and H. The signal ST (Fig. 18H) reproduced by The high frequency component YHL (FIG. 18E) which is supplied to the frequency converter 39 and converted to the low frequency side is detected, and is supplied to the frequency converter 41 through the band pass filter 40, and the 3.08 MHz signal from the filter 21 is detected.
The signal S1 is supplied to the frequency converter 41, and this high frequency component YHL is converted into the original high frequency component YH (FIG. 18D) in the band of 1.5 to 3.0 MHz, which is then sent to the synthesizer 3.
6 and is combined with the low frequency component YL to obtain a luminance signal YO (FIG. 18A) in a band of 0 to 3 MHz from a synthesizer 36, which is supplied to a synthesizer 42. Playback signal ST
The carrier color signal CL (FIG. 18G) is also supplied to the low-pass filter 43 and low-pass converted, and is supplied to the frequency converter 44.
．． 3. from the 58 MHz signal and the variable frequency oscillator 45.
A 58 MHz signal is supplied to the frequency converter 46 to obtain a 4.08 MHz signal, which is then supplied to the frequency converter 44 to convert the carrier color signal CL to a carrier whose carrier frequency has been changed to the original 3.58 MHz. Color signal Cs (Fig. 18A
), and this original carrier color signal Cs is sent to the combiner 42
is supplied to the output terminal 47, and is combined with the luminance signal YO to obtain a reproduced color video signal at the output terminal 47. In this case, the carrier color signal Cs from the frequency converter 44 is supplied to the burst gate circuit 48 to extract a burst signal, which is supplied to the phase comparison circuit 49 and compared in phase with the 3.58 MHz signal from the oscillator 18. , the oscillation frequency of the variable frequency oscillator 45 is controlled by the comparison output, and automatic phase adjustment of the carrier color signal Cs is performed. The reproduced signal ST is further supplied to a bandpass filter 50 to extract a frequency-modulated audio signal AF, which is supplied to a frequency demodulator 51 to obtain a reproduced audio signal at an output end 52. According to the present invention described above, the video signal is divided into low frequency components and high frequency components, and each component is simultaneously recorded or reproduced by separate heads, so that by reducing the diameter of the guide drum,
Even if the relative linear velocity between the tape and the rotary head decreases and the signal recording/reproduction band becomes narrower, the signal bandwidth supplied to each separate head is narrowed, and on the other hand, the total bandwidth of both heads is reduced. There is no decrease, and good recording and playback is possible without any inconvenience. As described above, according to the present invention, the diameter of the guide drum can be reduced, and the length of the track can be reduced. Therefore, it is possible to downsize the device. Incidentally, a normal TR requires a recording signal band of approximately 0 to 6.0 MHz, but the present invention requires a recording signal band of approximately 0 to 6.0 MHz.
3.0 MHz is sufficient and low frequency 1 drive TR is possible. Also, the structure of the head is changed to the first one as shown in Figures 9 to 11.
When creating recording patterns such as those shown in Figures 2 to 15,
At the same time, recording density can be significantly increased. Furthermore, in this case, if the head configuration is as shown in FIG. 11 and the recording pattern as shown in FIG. There is no time lag. Note that the method of signal separation processing can be modified in various ways other than the above-mentioned example.

The present invention can also be applied to a device in which a rectangular sheet rather than a tape is placed along a guide drum over a required angular range and is transferred in the direction of the rotating shaft of the head for recording or reproduction.

[Brief explanation of drawings]

1 and 2 are diagrams showing the states of the rotary head and tape in one example of the apparatus of the present invention, FIG. 3 is a diagram showing the recording pattern resulting from this, and FIGS. FIGS. 6 to 8 are diagrams showing examples of recording patterns, and FIG.
Figures 11 to 11 are diagrams showing examples of special configurations of rotating heads,
Figures 12 to 15 are diagrams showing examples of recording patterns resulting from this, Figures 16 and 17 are diagrams for explaining this case, and Figure 18 is a frequency spectrum for explaining an example of signal processing. FIG. 19 is a system diagram of an example of a recording and reproducing circuit system. 1 is a tape, 2 is a guide drum, and HA-HD is a rotating head.

Claims (1)

[Claims] 1. A set of first and second rotating heads that are spaced apart from each other by 180° and a set of third and fourth rotating heads that are spaced apart from each other by 180° share a common axis of rotation. The first and third rotary heads are mounted at positions separated by a certain distance in the direction of the rotation axis, and the angles formed in the width direction of the magnetic gap with respect to the scanning direction are the same. In addition, the second and fourth rotary heads are configured such that the angles formed by the width direction of the magnetic gap with respect to the scanning direction are the same and are different from those of the first and third rotary heads. and the tape or sheet is placed along the guide drum over an angular range of 180° or more,
The first and third rotary heads and the second and fourth rotary heads alternately scan the tape or sheet, and the tape or sheet scans the first, second and fourth rotary heads on the tape or sheet. The third and fourth rotary heads are transported in one direction at such a speed that the scanning trajectories are lined up in this order, and the set of the first and second rotary heads transfers the low-frequency components of the video signal to the third and fourth rotary heads. and a fourth set of rotary heads to record or reproduce high-frequency components of the video signal, respectively.