JPH04321902A - Magnetic tape recorder - Google Patents

Abstract

PURPOSE:To constitute the magnetic tape recorder so that its circuit configuration for supplying a recording video signal to a rotary magnetic head is simplified, and also, the recorder is provided with interchangeability with a standard video tape recorder, even in the recorder in which the diameter of a tape guide cylinder is smaller than that of the standard video tape recorder in which the diameter of the tape guide cylinder is, for instance, 40mm. CONSTITUTION:A recording video signal based on a video signal subjected to time base compression with prescribed time compressibility is recorded in a magnetic tape (45) for running through the outside peripheral surface part of a tape guide cylinder (43) by two pieces of rotary magnetic heads (41, 42), and a recording amplifying part (35) and a switch (36) supply successively and alternately a unit section signal component subjected to time base compression and connected intermittently in the recording video signal, to each of two pieces of rotary magnetic heads (41, 42).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a magnetic tape recording system in which a recording video signal formed based on a video signal is recorded on a magnetic tape running on the outer peripheral surface of a tape guide cylinder using two rotating magnetic heads. Regarding equipment.

0002

2. Description of the Related Art A so-called video tape recorder, which is a device for recording a video signal on a magnetic tape or reproducing a video signal from a magnetic tape on which the video signal has been recorded, is
The tape guide cylinder includes a tape guide cylinder having an outer circumferential surface portion that serves as a running guide for the magnetic tape, and a rotating magnetic head disposed inside the tape guide cylinder. It is assumed that the magnetic tape runs on the outer circumferential surface of the tape guide cylinder, and in this case, the magnetic tape is wound around the outer circumferential surface of the tape guide cylinder at a preset wrapping angle. It is assumed to take on a state. The tape guide cylinder is, for example, divided in the direction of its central axis to form a fixed part and a rotating part, and the rotating part is rotated with respect to the fixed part at a preset rotation speed. The rotating magnetic head is, for example, attached to the rotating part of the tape guide cylinder and positioned between the fixed part and the rotating part of the tape guide cylinder, and rotates with the rotation of the rotating part of the tape guide cylinder. ,
With the magnetic gap forming portion facing the outer circumferential surface of the tape guide cylinder, the magnetic tape running on the outer circumferential surface of the tape guide cylinder during one rotation is scanned obliquely to the traveling direction of the magnetic tape. Record signals on a magnetic tape or read signals from a magnetic tape.

Recording of video signals on a magnetic tape using such a tape guide cylinder and rotary magnetic head involves the recording of a large number of tapes, each extending at a predetermined angle of inclination with respect to the longitudinal direction of the magnetic tape. Recording tracks are arranged in parallel, and usually one field period of a video signal is recorded on each recording track. Therefore, during a recording operation, a rotating magnetic head that scans a magnetic tape diagonally with respect to the traveling direction during one rotation period records one field period of video signals on the magnetic tape for each rotation. A recording track of a book is formed, and during a reading operation, the magnetic tape is scanned along the recording track formed on the magnetic tape every rotation to read one field period of the video signal.

[0004] Regarding such video tape recorders, many systems have been proposed with different specifications regarding the mechanism, specifications regarding signal recording and signal playback operations, specifications regarding operation control, etc., but one of them is For a standard video tape recorder that complies with The number of rotations of the rotating part in the tape guide cylinder (hereinafter referred to as cylinder rotation number), that is, the number of rotations of the rotating magnetic head is approximately 2.
There is one in which the speed is 9.97 rps, and the number of rotating magnetic heads is two, which are arranged with a rotation angle interval of 180 degrees. Such a standard video tape recorder belongs to a category in which the diameter of the tape guide cylinder is relatively small, and the tape guide cylinder and rotary magnetic head employed therein are different from the standard tape guide cylinder and the rotary magnetic head, respectively. It is considered a standard rotating magnetic head.

[0005]

[Problem to be Solved by the Invention] In order to further reduce the size and weight of the standard video tape recorder as described above, the diameter of the tape guide cylinder is made smaller than the diameter of the standard tape guide cylinder. Moreover, it has been proposed to construct a compact video tape recorder that is compatible with standard video tape recorders. For such a compact video tape recorder, from the viewpoint of compatibility with a standard video tape recorder, (1) the length of the recording track formed on the magnetic tape by the compact video tape recorder should be (2) the period for one field period of the video signal recorded on the magnetic tape is equal to the length of the recording track formed on the magnetic tape by a standard video tape recorder; It is required that two conditions be satisfied: the period should be equal to the period of one field period of the video signal.

Therefore, for a small video tape recorder, let the ratio of the diameter of the tape guide cylinder to that of a standard video tape recorder be a, the ratio of the tape winding angle be b, and the ratio of the cylinder rotation speed be c. (1) and (2)
In order to satisfy the following conditions, it is necessary that the relationship a·b=1, b/c=1 hold, and that the number of rotating magnetic heads be an even number of 4 or more. So, for example,
a = 2/3, b = c = 3/2, and the number of rotating magnetic heads was selected to be 4, thereby making the diameter of the tape guide cylinder 40 mm 2/3 ≒ 26.67 m.
m, tape wrapping angle is 180 degrees 3/2 = 270 degrees, cylinder rotation speed is 29.97 rps 3/2 ≒ 44.95
A small video tape recorder with a speed of 5 rps and four rotating magnetic heads will be constructed.

However, in a small video tape recorder constructed in this way, the number of rotating magnetic heads is
This is an increase compared to a standard video tape recorder, and it is necessary to provide four tape guide cylinders. Assembling four independent rotating magnetic heads will involve considerable difficulty, and there is a risk that the mounting accuracy of the four rotating magnetic heads will not be good. This results in the disadvantage that the circuit configuration for supplying the recording video signal to each of the rotating magnetic heads becomes complex, including a plurality of recording amplification units individually corresponding to each rotating magnetic head. Furthermore, in addition to the tape guide cylinder to which four independent rotating magnetic heads are assembled, there is also a review
w) It is extremely difficult to add a rotary magnetic head for variable speed playback that should be used in playback mode, still playback mode, etc., and as a result, so-called noise rescue playback, noiseless review playback, etc. Alternatively, noiseless still playback will not be performed.

[0008] In view of these points, the present invention provides, for example, a tape guide cylinder with a diameter of 40 mm and a tape winding angle of 180 mm.
Even though the diameter of the tape guide cylinder is smaller than that of a standard video tape recorder in which the cylinder rotation speed is approximately 29.97 rps and the number of rotating magnetic heads is two, The compact design simplifies the circuit configuration for supplying recording video signals to the rotating magnetic heads without increasing the number of rotating magnetic heads, and is said to be compatible with standard video tape recorders. The object is to provide a magnetic tape recording device forming a video tape recorder.

[0009]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a magnetic tape recording device according to the present invention includes a video signal time axis processing unit that compresses the time axis of a video signal with a predetermined time compression ratio, and a video signal a recording signal forming section that forms a recording video signal in which time-domain compressed unit division signal components are intermittently linked based on the time-domain compressed video signal obtained from the time-domain processing section; and a tape guide cylinder. two rotating magnetic heads that scan a magnetic tape running on the outer circumferential surface of the magnetic tape, and a recording signal supplying section disposed to the rotating magnetic head, the recording signal supplying section receiving information from the recording signal forming section. It is configured to be common to the two rotary magnetic heads, and alternately supplies time-base compressed unit division signal components of the recorded video signal to each of the two rotary magnetic heads.

0010

[Operation] In the magnetic tape recording device according to the present invention configured as described above, based on the video signal which has been time-axis compressed with a predetermined time compression ratio, the time-axis compressed unit segment signal component is intermittently transmitted. A recording video signal consisting of a series of images is formed, and is recorded on a magnetic tape running on the outer circumferential surface of the tape guide cylinder by two rotating magnetic heads. A recording signal supply unit including one recording amplification unit arranged in common with the recording amplification unit sequentially supplies each of the time-axis compressed unit division signal components forming the recording video signal to each of the two rotating magnetic heads. are supplied alternately. As a result, even if the diameter of the tape guide cylinder is made smaller than that of a standard video tape recorder, the number of rotating magnetic heads does not increase, and video signals for recording are supplied to the rotating magnetic heads. The circuit configuration is simplified and compatibility with standard video tape recorders is provided.

[0011]

[Embodiment] FIG. 1 shows an example of a magnetic tape recording device according to the present invention. This example is supposed to record a color television signal conforming to the NTSC system. A video signal including a signal and a color signal is recorded on a magnetic tape together with an accompanying audio signal.

In FIG. 1, video signal input terminals 11 and 12 are supplied with a luminance signal Y and a carrier color signal C, which constitute a video signal in a color television signal based on the NTSC system, respectively. In addition, the audio signal input terminal 13
is supplied with an audio signal AU in a color television signal conforming to the NTSC system.

The luminance signal Y from the video signal input terminal 11 is digitized in an analog/digital (A/D) converter 14, and a digital luminance signal DY is obtained from the A/D converter 14 and stored in the field memory 15. supplied to Further, the carrier color signal C from the video signal input terminal 12 is digitized in the A/D converter 16, and
A digital carrier color signal DC is obtained from the /D converter 16 and supplied to the decoder 17. In the decoder 17, the digital red color difference signal DR and the digital blue color difference signal DB are individually taken out from the digital carrier color signal DC, and the digital red color difference signal DR and the digital blue color difference signal DB obtained from the decoder 17 are stored in the field memory 18, respectively. and is supplied to the field memory 19. Furthermore, the audio signal AU from the audio signal input terminal 13 is digitized by the A/D converter 20 , and the digital audio signal DA is obtained from the A/D converter 20 and supplied to the field memory 21 .

Field memories 15, 18, 19 and 2
1 are supplied with a write clock pulse PW and a read clock pulse PR sent from the timing pulse generator 22. The timing pulse generator 22 is supplied with a vertical pulse Pv synchronized with the vertical synchronization signal of the luminance signal Y supplied to the video signal input terminal 11 through the terminal 22A, and the timing pulse generator 22 receives the write clock pulse PW. is continuously sent out as having a frequency ft, and the readout clock pulse PR is as having a frequency 2·ft, and from the start point synchronized with the vertical pulse Pv in each field period of the luminance signal Y, for example, From time t after a period Tf·3/4 (Tf represents a field period, for example, 1/60 seconds), the signal is transmitted for a period Tf/2.

Therefore, in the field memory 15, in accordance with the write clock pulse PW, the digital luminance signal DY is changed over one field period F(n-1), F(n) as shown by A in FIG. ,F(n+1)
, F(n+2), . . . and written for one field period F(n-1).
, F(n), F(n+1), F(n+2), . . . are read out in accordance with the readout clock pulse PR. At this time, the frequency of the reading clock pulse PR is 2·f
Since t is twice the frequency ft of the write clock pulse PW, one field period F(n-
1), F(n), F(n+1), F(n+2),...
It is assumed that the time axis of each of these is compressed with a time compression rate of 1/2, and furthermore, since the readout clock pulse PR is sent out for a period Tf/2 from time t, 2, one field period F(n
-1), F(n), F(n+1), F(n+2),...
. is obtained by time-base compressing each of
, F(n)', F(n+1)', F(n+2)',...
. . are sequentially and intermittently sent out, and the signals as a whole form a digital time-base compressed luminance signal DY' and are supplied to the digital/analog (D/A) converter 23.

Further, in the field memories 18 and 19, the digital red color difference signal DR and the digital blue color difference signal DB are divided and written for each one field period according to the write clock pulse PW, and the written Each of the digital red color difference signal DR and the digital blue color difference signal DB for one field period is read out in accordance with the read clock pulse PR. In such a case, the frequency 2·ft of the read clock pulse PR is equal to the frequency ft of the write clock pulse PW.
field memory 18
It is assumed that the time axis of each one field period of the digital red color difference signal DR read out from 1 is compressed with a time compression rate of 1/2, and furthermore, the readout clock pulse PR is set for a period Tf/2 from time t. As a result, from the field memory 18, the period Tf/, which is obtained by time-base compressing each field period of the digital red color difference signal DR at a time compression rate of 1/2, starting from time t, is transmitted. The digital segmented time-base compressed color difference signal that continues for 2 times is intermittently sent out, and is supplied to the encoder 24 as a whole forming a digital time-base compressed red color difference signal DR'. Also,
Since the frequency 2·ft of the read clock pulse PR is twice the frequency ft of the write clock pulse PW, each one field period of the digital blue color difference signal DB read from the field memory 19 is as follows.
It is assumed that the time axis is compressed with a time compression rate of 1/2, and furthermore, by sending out the readout clock pulse PR for a period Tf/2 from time t, the field memory 19 outputs a digital blue color difference signal. The period Tf/starting from time t is obtained by compressing the time axis of one field period of DB at a time compression rate of 1/2.
The digital time-base compressed color difference signal that continues for 2 times is intermittently sent out, and is supplied to the encoder 24 as a whole forming a digital time-base compressed blue color difference signal DB'. In the encoder 24, both the digital time-base compressed red color difference signal DR' and the digital time-base compressed blue color difference signal DB' are combined to form a digital time-base compressed carrier color signal DC' which is obtained intermittently. The digital time-base compressed carrier color signal DC′ obtained from the encoder 24 is supplied to the D/A converter 25 .

Furthermore, in the field memory 21, according to the write clock pulse PW, the digital audio signal DA is divided and written for each one field period, and the digital audio signal DA that has been written is written for one field period. Each clock pulse P for reading
It is read out according to R. In such a case, the frequency 2·ft of the read clock pulse PR is twice the frequency ft of the write clock pulse PW, so that one field period of the digital audio signal DA read from the field memory 21 is The time axis of each minute is assumed to be compressed with a time compression rate of 1/2, and furthermore, by sending out the reading clock pulse PR for a period Tf/2 from time t, the data from the field memory 21 is ,
The digital segmented time-base compressed audio signal, which is obtained by time-base compressing each field period of the digital audio difference signal DA at a time compression rate of 1/2 and which starts at time t and continues for a period Tf/2, is intermittent. are transmitted as a whole into a digital time-base compressed audio signal DA'
is supplied to the D/A converter 26.

In the D/A converter 23 , the digital time axis compressed luminance signal DY' is converted into an analog signal to obtain a time axis compressed luminance signal Y', which is supplied to the luminance signal recording processor 27 . In the luminance signal recording processing unit 27, frequency modulation (FM) processing is performed based on the time axis compressed luminance signal Y', and based on the time axis compressed luminance signal Y', for example, the carrier frequency shift band is time axis compressed. A time-base compressed FM luminance signal Yf' is formed in which the leading edge of the synchronization signal of the luminance signal Y' has a frequency of 5.7 MHz and the white peak has a frequency of 7.7 MHz. Then, from the luminance signal recording processing section 27, the cut-off frequency is, for example, about 2 MH.
A time-base compressed FM luminance signal Yf' is obtained through a high-pass filter (HPF) 28 set to z, and is supplied to a signal synthesis section 29.

In the D/A converter 25, the digital time-base compressed carrier color signal DC' is converted into an analog signal to obtain a time-base compressed carrier color signal C', which is supplied to the color signal recording processor 30. In the color signal recording processing section 30, a low-pass conversion time-domain compressed color signal Cc' having a color subcarrier frequency of approximately 743 KHz is formed based on the time-domain compressed carrier color signal C', Color signal recording processing section 3
0 through a bandpass filter (BPF) 31 to obtain a low-pass conversion time-base compressed color signal Cc', which is supplied to the signal synthesis section 29.

In the D/A converter 26, the digital time-base compressed audio signal DA' is converted into an analog signal to obtain a time-base compressed audio signal AU', which is supplied to the audio signal recording processor 32. In the audio signal recording processing section 33, FM processing is performed based on the time-domain compressed audio signal AU', and based on the time-domain compressed audio signal AU', for example, the carrier frequency is 1.5 MHz and the frequency deviation width is ±100~150
A time-domain compressed FM audio signal Af' having a frequency of approximately 1.5 MHz is formed, and a time-domain compressed FM audio signal Af' is obtained from the audio signal recording processing unit 32 through a BPF 33 whose passband center frequency is approximately 1.5 MHz. and is supplied to the signal combining section 29.

In the signal synthesis section 29, the time-domain compressed FM luminance signal Yf' from the HPF 28, the low frequency converted time-domain compressed color signal Cc' from the BPF 31, and the time-domain compressed FM audio signal Af' from the BPF 33 are processed. Frequency multiplexing is performed to form a composite recording signal Sm. As shown in A in FIG. 3, such a composite recording signal Sm has a period Tf starting from time t of the time-axis compressed FM luminance signal Yf'.
For one field period lasting for /2, the period Tf/2 starts from time t of the low frequency conversion time axis compressed color signal Cc'.
and time axis compression F
The period Tf/2 starts from the time t of the M audio signal Af'.
One field period Sm (n-1), which is time-axis compressed and starts from time t and continues for a period Tf/2, is formed by frequency multiplexing and combining one field period that lasts for Tf/2.
, Sm(n), Sm(n+1), Sm(n+2),...
. . are successively and intermittently connected, and are supplied to the movable contact 36a of the switch 36 through the recording amplification section 35.

The switch 36 opens its movable contact 36 in response to a switch control signal SW supplied from a control terminal 37.
The connection state between a and the selection contacts 36b, 36c and 36d is controlled. The switch control signal SW is B in FIG.
As shown in , every other time-axis compressed field period Sm(n), Sm
(n+2), . . . takes a high level H in the period corresponding to each of the fields Sm(n-1) for every other time-axis compressed field period in the composite recording signal Sm.
, Sm(n+1), . . . , and Sm(n-1) and Sm(n
), Sm(n) and Sm(n+1), Sm(n+1) and Sm(n+2), . Movable contact 36 when taking high level L
selection contact 3 connected to the rotating transformer 38
6b, and when the switch control signal SW takes the intermediate level M, the movable contact 36a is set as an empty contact.
6c, and when the switch control signal SW takes a low level L, the movable contact 36a is connected to the selection contact 36d connected to the rotary transformer 39. As a result, from the selection contact 36b of the switch 36, Sm for one field period compressed in the time axis as shown in C in FIG.
(n), Sm(n+2), . , selection contact 3 of switch 36
6d, the time axis compressed one field period Sm(n-1) and Sm(n
+1), . Further, the switch control signal SW takes an intermediate level M,
When the movable contact 36a of the switch 36 is connected to the selection contact 36c, the recording amplifier 35 is in a state where no output current flows, and as a result, the power consumption in the recording amplifier 35 is reduced.

Each of the rotating magnetic heads 41 and 42 has a mutually different gap azimuth, and is attached to a rotating part of the tape guide cylinder 43.
It is disposed between the rotating part and the fixed part of the tape guide cylinder 43, rotates with the rotating part of the tape guide cylinder 43, and travels through the magnetic gap forming part on the outer circumferential surface of the tape guide cylinder 43. tape 45
The magnetic tape 45 is scanned in a direction forming a predetermined angle of intersection with the running direction of the magnetic tape 45. The attachment state of the rotating magnetic heads 41 and 42 to the rotating part of the tape guide cylinder 43 is as shown in FIG. It is meant to be.

The magnetic tape 45 is made to run by a capstan 47 which is rotationally driven by a capstan drive motor 46 and a pinch roller 48 which is in contact with the capstan 47 with the magnetic tape 45 sandwiched therebetween. It is controlled by the stun servo control circuit 49 to cause the magnetic tape 45 to take a predetermined running speed. In addition, the rotating magnetic heads 41 and 4
The rotating part of the tape guide cylinder 43 to which 2 is attached is rotationally driven by a cylinder drive motor 50, and the cylinder drive motor 50 is driven by a cylinder servo control circuit 5.
1, the rotating portion of the tape guide cylinder 43, and thus the rotating magnetic heads 41 and 42, are controlled to have a predetermined rotation speed.

The diameter of the tape guide cylinder 43, the tape wrapping angle for the tape guide cylinder 43, and the cylinder rotation speed, that is, the rotation speed of the two rotating magnetic heads 41 and 42, are based on a standard diameter of 40 mm. It is equipped with a tape guide cylinder and two standard rotary magnetic heads, and the tape winding angle for the standard tape guide cylinder is 180 degrees, and the cylinder rotation speed, that is, the rotation speed of the standard rotary magnetic head is approximately 29.97 rps. The diameter of the tape guide cylinder 43 is determined based on the standard video tape recorder known as the standard video tape recorder (40 m).
m), that is, approximately 26.67 mm,
The tape wrapping angle for the tape guide cylinder 43 is the tape wrapping angle for the standard tape guide cylinder (180
degree), that is, 270 degrees, and furthermore, 2
The rotational speed of the two rotating magnetic heads 41 and 42 is set to three times the rotational speed of the standard rotating magnetic head (approximately 29.97rps), that is, approximately 89.91rps. The scanning state of the magnetic tape 45 by the rotating magnetic heads 41 and 42, which are rotated at a rotational speed of about 89.91 rps, is as shown in E in FIG. During each period of every other rotation, the first composite recording signal component Sm supplied
Sm(n) for one field period compressed on the time axis in a
, Sm(n+2), . During the period, when each of the time-axis compressed one field period Sm(n-1), Sm(n+1), . 45 is assumed to be scanned. As a result, each time each of the rotating magnetic heads 41 and 42 scans the magnetic tape 45 during one rotation every two rotations, one field period compressed in the time axis of the first composite recording signal component Sma is scanned. Sm(n), Sm(n+2),...
・ and one field period Sm(n-1), S which is time-axis compressed in the second composite recording signal component Smb.
Each of m(n+2), .

With the above settings, the ratio of the diameter of the tape guide cylinder 43 to the diameter of the standard tape guide cylinder is AA, and the ratio of the tape guide cylinder 43 to the tape winding angle of the standard tape guide cylinder is AA.
BB is the ratio of the tape winding angle for , CC is the ratio of the rotational speed of the rotating magnetic heads 41 and 42 to the rotational speed of the standard rotating magnetic head, and EE is the time compression ratio of the composite recording signal Sm. For the example shown in FIG. 1 with magnetic heads 41 and 42, in order to provide compatibility with standard video tape recorders, the length of the recording track formed on magnetic tape 45 is longer than that of a standard video tape recorder. The length of the recording track formed on the magnetic tape by a standard video tape recorder is equal to the length of the recording track formed on the magnetic tape, and the period for one field period of the composite recording signal Sm recorded on the magnetic tape 45 is equal to the length of the recording track formed on the magnetic tape by a standard video tape recorder. The condition for the period to be equal to the period of one field period of the signal is as follows: AA・BB=1 (
a) BB/(CC·EE)=1 (b) The following two relationships hold true.

[0027] Then, looking at the respective values of AA, BB, CC and EE, AA=2/3, BB=3/2, CC=3
, EE=1/2, so the above equations (a) and (b
) is established. Therefore, the example shown in FIG. 1 employs a tape guide cylinder with a smaller diameter than that of a standard video tape recorder, and the number of rotating magnetic heads is reduced to two without increasing the number of rotating magnetic heads. A color television signal consisting of a video signal including a luminance signal and a carrier color signal and an audio signal can be recorded on a magnetic tape while maintaining compatibility with a standard video tape recorder. become. Then, only one recording amplifying section 35 needs to be provided in common to the two rotating magnetic heads 41 and 42, thus simplifying the configuration of the recording video signal supply circuit to the rotating magnetic heads 41 and 42. It turns out.

FIG. 4 shows a luminance signal, a carrier color signal, and an audio signal forming a color television signal from a magnetic tape 45 on which a composite recording signal Sm has been recorded using the example of the magnetic tape recording device shown in FIG. An example of a signal reproducing device for reproducing a signal is shown, and in this example, the two rotary magnetic heads 41 and 42 in the example of the magnetic tape recording device shown in FIG. 1 are used as the rotary magnetic head for reading. Therefore, the tape guide cylinder 43 is also used, and the rotary transformers 38 and 39 are also used.

In the example of the signal reproducing device shown in FIG. 4, the rotating portion of the tape guide cylinder 43 is driven to rotate in the same manner as during the recording operation, and the magnetic tape 45 is caused to run in the same manner as during the recording operation. The two rotating magnetic heads 41 and 42 having mutually different gap azimuths generate a first composite recording signal component from among the recording tracks on the magnetic tape 45 whose gap azimuths correspond during recording. Sma and second composite recording signal component Sm
b is read out alternately for one field period compressed in the time axis, and as shown in G in FIG. (n), Sm(n+2),
. . . and one field period Sm(n-1), Sm(n+1) of the read second composite recording signal component Smb which is time-axis compressed, as shown by H in FIG.
), . . . are the rotary transformers 38 and 3, respectively.
9, and is supplied to selection contacts 63b and 63c in switch 63 after passing through regenerative amplification units 61 and 62. As shown by I in FIG. 3, the switch 63 is supplied with signals Sm(n), Sm for one field period of the time-base compressed first composite recording signal component Sma to the selection contact 63b, as shown by I in FIG. (n+2), . . . , the selection contact 63
c, one field period Sm(n-1), Sm(n+1), which is time-base compressed of the second composite recording signal component Smb;
When the switch control signal SW' takes a high level H, the movable contact 63a is connected to the selection contact 63b, and the switch Control signal SW
When ' is a low level L, the movable contact 63a is connected to the selection contact 63c. Thereby, the read first signals obtained alternately from the regenerative amplification sections 61 and 62 are
As shown in J in FIG. , to form a series of composite recording signals Sm, the movable contact 63a of the switch 63
It is derived from

The composite recording signal Sm obtained from the movable contact 63a of the switch 63 is the time-axis compressed FM luminance signal Yf'
HPF71 compatible with low frequency conversion time axis compressed color signal Cc
BPF72 and time axis compressed FM audio signal A corresponding to '
The signal is supplied to the BPF 73 corresponding to f'. And HP
The time axis compressed FM luminance signal Yf' in the composite recording signal Sm is obtained from F71 and supplied to the luminance signal reproduction processing section 74. In the luminance signal reproduction processing section 74, the time axis compression F
Various processes including demodulation processing are performed on the M luminance signal Yf', and the luminance signal reproduction processing section 74 outputs a time-axis compressed FM signal.
A time-base compressed luminance signal Y' based on the luminance signal Yf' is obtained and supplied to the A/D converter 75. A/D converter 7
5, the time axis compressed luminance signal Y' is digitized to obtain a digital time axis compressed luminance signal DY',
It is supplied to field memory 76.

[0031] Furthermore, a low frequency converted time axis compressed color signal Cc' in the composite recording signal Sm is obtained from the BPF 72 and is supplied to the color signal reproduction processing section 77. In the color signal reproduction processing section 77, various processes including frequency conversion processing are performed on the low frequency conversion time axis compressed color signal Cc'. The time axis compressed carrier color signal C' based on
8. In the A/D converter 78, the time-base compressed carrier color signal C' is digitized to obtain a digital time-base compressed carrier color signal DC', which is sent to the decoder 7.
9. In the decoder 79, a digital time axis compressed red color difference signal DR' which is formed by intermittently connecting digital time axis compressed color difference signals from the digital time axis compressed carrier color signal DC' and a digital time axis compressed red color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals and a digital time axis compressed color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals A series of digital time-base compressed blue color difference signals DB' are individually extracted and sent to a decoder 79.
Digital time-base compressed red color difference signal DR' obtained from
, and digital time-base compressed blue color difference signal DB' are supplied to field memory 80 and field memory 81, respectively.

Furthermore, the composite recording signal Sm is output from the BPF 73.
The time-base compressed FM audio signal Af' is obtained and supplied to the audio signal reproduction processing section 82. Audio signal reproduction processing section 82
, various processes including demodulation processing are performed on the time-domain compressed FM audio signal Af', and a time-domain compressed audio signal AU' based on the time-domain compressed FM audio signal Af' is obtained from the audio signal reproduction processing section 82. and is supplied to the A/D converter 83. In the A/D converter 83, the time axis compressed audio signal AU' is digitized to obtain a digital time axis compressed audio signal DA', which is stored in the field memory 8.
4.

Field memories 76, 80, 81 and 8
A write clock pulse QW and a read clock pulse QR sent from the timing pulse generator 85 are supplied to each of the clock pulses 4 and 4. The timing pulse generator 85 is supplied with a synchronizing pulse Pv' synchronized with the level change portion of the switch control signal SW' through a terminal 85A, and the timing pulse generator 85 receives a write clock pulse QW.
has a frequency of 2·ft, and the synchronization pulse Pv
Based on the timing of ', the digital segmented time axis compressed luminance signal F(n-1)', F which forms the digital time axis compressed luminance signal DY' sent out from the A/D converter 75
(n)', F(n+1)', F(n+2)', . Continuously send out the information as if it were held.

Thereby, in the field memory 76, the digital time-base compressed luminance signal DY' is converted into the digital segmented time-base compressed luminance signal F(n-1)', F(n)' according to the write clock pulse QW. ,F(n+1)
', F(n+2)', .
Each of F(n+2)', . . . is read out in accordance with the reading clock pulse QR. At this time, the frequency ft of the read clock pulse QR is equal to the write clock pulse QW.
Therefore, the field memory 76 outputs the written digital segmented time-base compressed luminance signals F(n-1)', F(n)', F(n
+1)', F(n+2)', ... are digital segmented luminance signals F(n-1), F(n), F( n+1)
, F(n+2)... and are sent out sequentially and continuously,
The signal as a whole is supplied to the D/A converter 86 to form a digital luminance signal DY.

In the D/A converter 86, the digital luminance signal DY is converted into an analog signal to obtain a luminance signal Y.
It is reproduced as the luminance signal Y at the video signal output terminal 8.
7.

Furthermore, in the field memory 80,
According to the write clock pulse QW, each of the digital segmented time-base compressed color difference signals forming the digital time-base compressed red color difference signal DR' is sequentially written, and each of the written digital segmented time-base compressed color difference signals is read out. Each of the digital segmented time-domain compressed color difference signals forming the digital time-domain compressed blue color difference signal DB' is sequentially read out in accordance with the clock pulse QR and sequentially written in the field memory 81 in accordance with the write clock pulse QW. At the same time, each of the written digital segmented time-base compressed color difference signals is sequentially read out in accordance with the readout clock pulse QR. In this case, since the frequency ft of the read clock pulse QR is set to 1/2 the frequency 2·ft of the write clock pulse QW, the field memory 80 reads the written digital division time axis. Each of the compressed color difference signals is expanded at a twice the expansion rate on the time axis and is continuously sent out as a digital segmented color difference signal, thereby obtaining a digital red color difference signal DR. Each of the written digital segmented time-base compressed color difference signals is intermittently transmitted as a digital segmented color-difference signal obtained by expanding its time axis at a double expansion rate, thereby producing a digital blue color difference signal DB. can get. Both the digital red color difference signal DR and the digital blue color difference signal DB are supplied to the encoder 88, and the encoder 88 outputs the digital red color difference signal DR and the digital blue color difference signal DB.
Both are combined to form a digital carrier color signal DC, and the digital carrier color signal DC obtained from the encoder 88 is supplied to the D/A converter 89.

In the D/A converter 89, the digital carrier color signal DC is converted into an analog carrier color signal to obtain a carrier color signal C, which is outputted to the video signal output terminal 90 as a reproduced carrier color signal C.

Further, in the field memory 84, the digital time-base compressed audio signal DA' is divided and written for each one field period according to the write clock pulse QW, and the written digital time-base compressed audio signal DA' is written in accordance with the write clock pulse QW. Each of the signal DA' for one field period is read out in accordance with the read clock pulse QR. In such a case, the frequency f of the reading clock pulse QR
t is 1/of the frequency 2·ft of the write clock pulse QW.
Since it is assumed to be twice as large, from the field memory 84,
1 of the written digital time-base compressed audio signal DA'
The time axis of each field period is expanded at twice the expansion rate and is continuously transmitted as a digital segmented audio signal, which collectively forms the digital audio signal DA. The signal is supplied to the A conversion section 91.

Then, in the D/A converter 91, the digital audio signal DA is converted into an analog audio signal AU.
is obtained and output to the audio signal output terminal 92 as a reproduced audio signal AU.

In this way, the signal reproducing apparatus shown in FIG. 4 which reproduces the luminance signal Y, the carrier color signal C, and the audio signal AU forming the video signal from the magnetic tape 45 is adapted to the above-mentioned standard video tape recorder. Although the tape guide cylinder 43 has a smaller diameter than the standard tape guide cylinder, two rotary magnetic heads 4 are used.
It is considered that it is sufficient to have only 1 and 42, so 2
In addition to the rotating magnetic heads 41 and 42, it is easy to provide a rotating magnetic head for variable speed playback to be used in cue playback mode, review playback mode, still playback mode, etc. It will be possible to easily perform noise rescue playback, noiseless review playback, noiseless still playback, etc.

In the example shown in FIG. 1, the two rotating magnetic heads 41 and 42 are arranged such that the rotation angle interval between them is 180 degrees.
The arrangement of the rotating magnetic heads 41 and 42 is not limited to this example, and the rotation angle interval between them is 1.
It can be made smaller than 80 degrees. At that time, the digital luminance signal DY and the digital red color difference signal DR from the field memories 15, 18, 19 and 21 are
, the digital blue color difference signal DB, and the digital audio signal DA, the reading period during each field period forming each frame period of the luminance signal Y, and the number of cylinder rotations, that is, the rotating magnetic head. 41 and 42 are the rotational speeds of the rotating magnetic heads 41 and 42.
It changes according to the rotation angle interval between.

Furthermore, two rotating magnetic heads 41 and 4
2 can also be constructed in the form of a double-gap rotary magnetic head having two magnetic gap forming portions having mutually different gap azimuths. When such a double-gap rotary magnetic head is used, this corresponds to the fact that the rotation angle interval between the rotary magnetic head 41 and the rotary magnetic head 42 is substantially zero.

[0043]

As is clear from the above description, in the magnetic tape recording device according to the present invention, based on a video signal that has been time-axis compressed with a predetermined time compression ratio, time-axis compressed unit segments are A recording video signal consisting of an intermittent series of signal components is formed, and is recorded on a magnetic tape running on the outer peripheral surface of the tape guide cylinder by two rotating magnetic heads. A recording signal supply section including one recording amplification section arranged in common with respect to the rotating magnetic head sequentially supplies each of the time-axis compressed unit division signal components forming the recording video signal to two rotational magnetic heads. It is supplied alternately to each of the magnetic heads. Therefore, the magnetic tape recording device according to the present invention has a tape guide cylinder with a diameter of 40 mm and a tape winding angle of 180 mm.
Even though the diameter of the tape guide cylinder is smaller than that of a standard video tape recorder in which the cylinder rotation speed is approximately 29.97 rps and the number of rotating magnetic heads is two, The number of rotating magnetic heads is not increased, the circuit configuration for supplying recording video signals to the rotating magnetic heads is simplified, and it is said to be compatible with standard video tape recorders. .

Furthermore, the magnetic tape recording device according to the present invention may have a function of reproducing video signals recorded on the magnetic tape in addition to the function of recording video signals on the magnetic tape. In this case, even though a tape guide cylinder with a smaller diameter than that of a standard video tape recorder is adopted, the number of rotating magnetic heads does not increase, so the review It is said that it is easy to add a rotary magnetic head for variable speed reproduction to be used in reproduction mode, still reproduction mode, etc., and therefore, so-called noise rescue reproduction, noiseless review reproduction, noiseless still reproduction, etc. can be easily performed. It is assumed that it can be done.

[Brief explanation of drawings]

FIG. 1 is a block connection diagram showing an example of a magnetic tape recording device according to the present invention.

FIG. 2 is a time chart for explaining the operation and other explanations of the example shown in FIG. 1;

FIG. 3 is a time chart for explaining the operation and other explanations of the example shown in FIG. 1;

FIG. 4 is a block connection diagram showing an example of a signal reproducing device for reproducing signals from a magnetic tape recorded according to the example shown in FIG. 1;

[Explanation of symbols]

11 Video signal input terminal 12 Video signal input terminal 13 Audio signal input terminal 15 Field memory 18 Field memory 19 Field memory 21 Field memory 22 Timing pulse generation section 27 Luminance signal recording processing section 29 Signal synthesis section 30 Color signal recording processing section 32 Audio signal recording processing section 35 Recording amplification section 41 Rotating magnetic head 42 Rotating magnetic head 43 Tape guide cylinder 45 Magnetic tape 47 Capstan 50 Cylinder drive motor

Claims (1)

[Claims] Claims: 1. A video signal time axis processing unit for time axis compressing a video signal at a predetermined time compression rate; and a time axis compressing unit based on the time axis compressed video signal obtained from the video signal time axis processing unit. a recording signal forming unit that forms a recording video signal in which the unit segmented signal components are intermittently connected;
The two rotating magnetic heads that scan the magnetic tape running on the outer circumferential surface of the tape guide cylinder and the time-axis compressed unit division signal components of the recording video signal obtained from the recording signal forming section are sequentially A magnetic tape recording device comprising: a recording signal supply unit provided in common to the two rotating magnetic heads, and supplying signals alternately to each of the two rotating magnetic heads.