JP3066212B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high definition VTR.

In particular, the present invention relates to a high-definition VTR capable of recording and reproducing a high-definition baseband signal in a VTR for recording and reproducing a current television signal.

[0003]

2. Description of the Related Art As a VTR for recording and reproducing a high-vision baseband signal, a commercial VTR called UNIHI has been commercialized.

In July 1991, three domestic companies (Hitachi,
Matsushita, Sony) has proposed a standard for a high-definition baseband VTR intended for consumer use. The outline is VH
Using a cassette one size larger than the size of the S cassette, rotating a rotary drum having a diameter of 62 mm at 3600 rpm, and dividing one field of the Hi-Vision signal into two intersecting two-track tracks for recording. . Therefore, one frame of the Hi-Vision signal is divided into eight tracks and recorded. The details of the three-company high-vision baseband VTR are described in "Consumer High-Vision VTR Specifications" (published on September 26, 1991, Technical Report of the Institute of Television Engineers of Japan).

[0005] The three-company high-vision baseband VTR has not been commercialized at present.

[0006] For high-definition broadcasting, MU
Satellite broadcasting by the SE (Multiple Sub-Nyquist Sampling Encoding) method is performed as a test broadcasting for about 8 hours a day. The MUSE system is described in detail in "MUSE-Hi-Vision Transmission System-" (by Ninomiya, edited by the Institute of Electronics, Information and Communication Engineers, published by Corona).

[0007]

However, UNIHI is very expensive because it is a commercial VTR.

[0008] The above-mentioned three-company high-vision baseband VTR is widely used worldwide in VHS-V.
The TR and the drum diameter are the same, but the cassette size is different, so there is no compatibility and there is a problem that the huge software assets of VHS cannot be reproduced.

[0009] Also, since a high-vision baseband VTR of the three-company system has not been commercialized, there is currently no means for recording a high-definition broadcast in a general home.

[0010] The magnetic recording / reproducing apparatus of the present invention is compatible with the existing NT.
It is an object of the present invention to record a Hi-Vision baseband signal on a VHS standard VTR for SC.

[0011]

According to the present invention, a sampling frequency for A / D conversion of a luminance signal Y of a Hi-Vision baseband signal is determined by a sampling frequency of the luminance signal Y of the Hi-Vision studio standard. 24.75MHz which is 1/3 of 74.25MHz
And the color difference signal P _B ,
The sampling frequency of the P _R to A / D conversion, as 7.425MHz is 1/5 of 37.125MHz is the sampling frequency of the color difference signal of the HDTV studio standards, line sequence chrominance signal data converted A / D After that, the signal is time-division multiplexed with the luminance signal data, and a data such as a negative polarity synchronizing signal is added thereto, so that the number of 1H samples of the recording signal is 910 as a recording signal. Further, the number of recording lines for one track is 262.5H, and the sampling clock of the recording signal is 14.318 MHz (N
238 of the field frequency of 59.94 Hz of the TSC signal,
875 times) so that the recording signal is similar to the NTSC signal. Also, the number of lines in one frame of the HDTV baseband signal is 1125H,
Of these, the number of active lines is 1035H, so 1035H
Is divided into four tracks, and a number H is added as an area necessary for head switching, so that the number of recording lines in one track becomes 262.5H, which is the same as VHS-VTR.

In addition, the tape pattern at the time of recording is secured so that 1H immediately before the start of the video signal in the recording signal is secured as a time code area for recording a frame address and at least 2H is secured as a head switching area. We are devising.

Further, in order to improve the accuracy of time axis correction at the time of reproduction, a burst signal adding means for adding a burst signal serving as a phase reference signal of a clock of a time base collector is provided. The frequency is set to half of the clock.

[0014]

According to the structure of the present invention , the sampling frequency for A / D conversion of the luminance signal Y of the Hi-Vision baseband signal is 1/3 of 74.25 MHz, which is the sampling frequency of the Hi-Vision studio standard luminance signal Y. Since the frequency is 24.75 MHz, the band of the luminance signal Y is 12.
The effective number of samples at 375 MHz and 1H is 640.
Also, the color difference signals PB,
Since the sampling frequency for A / D conversion of PR is 7.425 MHz, which is 1/5 of 37.125 MHz, which is the sampling frequency of the color difference signal of the HDTV standard, the band of the color difference signals PB and PR is 3.7125 MHz.
The effective number of samples for z and 1H is 192. When the color difference signal is line-sequentialized and then time-division multiplexed with the luminance signal, the number of samples becomes 640 + 192 = 832. If a recording signal is obtained by adding 78 samples as data such as a negative polarity synchronization signal, the number of 1H samples of the recording signal is 832 + 78 = 910. At this time, the sampling clock of the recording signal is set to 14.318 MHz (238,875 of the 59.94 Hz field frequency of the NTSC signal).
Double), the recording signal can be a signal similar to the NTSC signal.

Further, by dividing the HDTV baseband signals time-axis-multiplexed into two channels, since the number of recording lines of one track and 262.5 H, and the tape pattern of the VHS-VTR tape pattern recorded on a magnetic tape It is possible to make them similar.

Also , since a frame address generating means is provided so that a frame address can be recorded at the head of a recording track, head cueing and editing of a tape can be easily performed.

Also , a synchronizing signal adding means for adding a negative synchronizing signal and a burst signal is provided, and the frequency of the burst signal is set to a frequency which is 1/2 of the sampling clock of the recording signal for D / A converting the recording data. Therefore, the burst signal can be used as a phase reference signal of the clock of the time base collector at the time of reproduction, and highly accurate time axis correction can be performed at the time of reproduction.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of the present invention. In FIG. 1, the low-pass filter immediately before the A / D converter and the low-pass filter immediately after the D / A converter are omitted.

The luminance signal Y of the Hi-Vision baseband signal is input to the A / D converter 1 where it is 24.75 MH
A / D conversion is performed at a sampling frequency of z. On the other hand, the color difference signals P _B and P _R of the HDTV baseband signal are input to A / D converters 2 and 3, respectively.
A / D conversion is performed at a sampling frequency of Hz. 24. The sampling frequency of the A / D converter 1
75 MHz is one third of 74.25 MHz which is the sampling frequency of the luminance signal Y of the HDTV standard. Further, 74.25 MHz is the sampling frequency of the A / D converter 2 is the frequency of the HDTV studio standard of the color difference signal P _B, 1/5 of 37.125MHz is the sampling frequency of the P _R. As described above, in the present invention, the sampling frequency of the A / D converter is selected so as to be a simple integer ratio of the sampling frequency of the HDTV studio standard. By the way, 74.2 which is the sampling frequency of the HDTV studio standard
5 MHz is 5.5 times the sampling frequency of CCIR Recommendation 601 of 13.5 MHz.

The luminance signal Y data converted into digital data by the A / D converter 1 stores one frame, which is two fields of the luminance signal Y, for converting a timing from an input signal to a recording signal. Input to the Y frame memory 4 which is a
The frame data is temporarily stored. On the other hand, the data of the color difference signals P _B and P _R converted into digital data by the A / D converters 2 and 3 are respectively supplied to the vertical filter / line sequential circuit 5.
Where the two types of color difference signals are thinned out in half for each line to obtain a line-sequential color difference signal (hereinafter referred to as a C signal).
It is converted to P _B / P _R data. The configuration of the vertical filter / line sequentialization circuit 5 will be described later in detail. Vertical filter
As for the C signal data output from the line-sequencing circuit 5, data for one frame is temporarily stored in the C frame memory 6 for timing conversion, similarly to the data of the luminance signal Y.

Y frame memory 4 and C frame memory 6
Is intermittently read out at a frequency of 28.636 MHz (NTSC: 8f _H : f _H is a subcarrier frequency) and input to the synchronization addition / two-channel conversion circuit 7. The synchronization addition / two-channel conversion circuit 7 adds data such as a negative polarity synchronization signal, multiplexes the C signal data and the Y signal data on the time axis, and divides the data into two-channel signals.
Output at a sampling frequency of 14.318 MHz (4f _H of NTSC). The details of the synchronization addition / two-channel conversion circuit 7 will be described later.

The data converted into two channels by the synchronization addition / two-channel conversion circuit 7 are converted into D / A converters 8 and 9 respectively.
Is converted into an analog signal by the emphasis circuits 10 and 1
1, emphasis processing suitable for magnetic recording
The frequency is modulated by the modulators 12 and 13 and the recording amplifiers 14 and
At 15, current amplification for recording is performed and the magnetic head 1 is amplified.
Recording is performed on the magnetic tape 18 at two tracks 6 and 17 simultaneously.

The reproduction is basically the luminance signal Y and the color difference signal P _B is made processing during recording and conversely, outputs the P _R. Signals reproduced by the magnetic heads 16 and 17 from the magnetic tape 18 are amplified by reproduction amplifiers 21 and 22, and are reproduced by FM demodulators 21 and 22.
2 and the reverse of the emphasis processing performed during recording by the de-emphasis circuits 23 and 24 is performed.
The data is converted into digital data by the / D converters 25 and 26. The two-channel digital data is input to time base collectors 27 and 28, where the fluctuation of the time axis such as jitter at the time of reproduction is corrected, and input to a one-channel Y / C separation circuit 29. . In the 1-channel / Y / C separation circuit 29, the processing reverse to that performed by the synchronization addition / 2-channel conversion circuit 7 at the time of recording is performed. Further, data such as a synchronization signal added at the time of recording is removed, and the Y signal data is removed. And C signal data are separated, and the Y signal is input to the Y frame memory 30 and the C signal is input to the C frame memory 31. At this time, since recording and reproduction are not performed simultaneously, the Y frame memory 30 and the C frame memory 31 may be shared with the Y frame memory 4 and the C frame memory 6 used at the time of recording. Then, the data temporarily stored in the C frame memory is input to the interpolation filter 32.

The data of the luminance signal Y is read from the Y frame memory 30, converted into an analog signal by the D / A converter 33, and output as the luminance signal Y of the Hi-Vision baseband signal. On the other hand, the interpolation filter 32 separates the line-sequential data of P _B and P _R , and compensates for the lines thinned out by interpolation processing such as taking the average value of the preceding and succeeding lines. The separated P _B and P _R data are converted into analog signals by D / A converters 34 and 35, respectively, and the color difference signals P _B and P _{R of the} HDTV baseband signal are converted.
Is output to a monitor (not shown).

FIG. 2 is a block diagram showing an example of the configuration of the vertical filter / line sequential circuit 5. The vertical filter / line sequentialization circuit 5 includes two vertical filters 36 and 37 and a switch 38. If two types of color difference signals are line-sequentialized into one signal, the original signal is thinned out by half. It is well known that transmitting a chrominance signal by decimating it by half does not cause a visual problem, but decimating it by half means that it is sampled. Otherwise, aliasing distortion will occur when the signal is reproduced. Therefore, before the signals are selected line by line by the switch 38 and line-sequentialized, the color difference signals are band-limited by the vertical filters 36 and 37, respectively. As shown, the vertical filters 36 and 37 have exactly the same configuration. If the vertical filter is configured as shown in the figure,
Since the information of the middle line is １ ／ and the information of the upper and lower lines is ず つ from each of the three consecutive signals, even if the signal is halved, some of the decimated signals are lost. Is included, which means that the band is limited, and even if the signal is reproduced after being sampled, aliasing does not occur.

FIG. 3 is a block diagram showing an example of the configuration of the synchronization addition / two-channel conversion circuit 7. As shown in FIG. FIG. 4 shows a timing chart thereof. From the synchronization signal generating circuit 38 in which data such as the negative synchronization signal is stored, data such as the negative synchronization signal is output at the timing shown in FIG.
It is output intermittently at a sampling frequency of 8.636 MHz, and is connected to one terminal of the switch 39. The synchronizing signal generating circuit 38 can also generate a time code which is a frame address as described later.
On the other hand, the data temporarily stored in the C frame memory 6 and the Y frame memory 4 are also 28.6 at the timing shown in FIG.
It is output intermittently at a sampling frequency of 36 MHz,
Each is connected to the switch 40. Switch 39
And the switch 40 switches the input data as appropriate so that the output data becomes like the TCI data shown in FIG.
The TCI data is input to the one-line memories 41 and 42. The one-line memories 41 and 42 alternately fetch the input TCI data at a sampling frequency of 28.636 MHz as shown in FIG.
By reading at a sampling frequency of Hz, the time axis is doubled so that continuous data is obtained.
Thereafter, only the data of channel 2 is input to the 3-6 line memory 43, where the 3-6 line data is delayed and output. The reason why only the data of the channel 2 is delayed is that the data of the two channels of the channels 1 and 2 are simultaneously recorded on the magnetic tape 18 by the magnetic heads 16 and 17 respectively. It is physically impossible to arrange the magnetic heads 17 at the same position, and recording is performed simultaneously. Therefore, if two heads are arranged too close to each other, the magnetic head 17 is affected by crosstalk. Further, if the two heads are arranged too far apart, the gap between the tape and the head does not contact well, causing a problem that the head contact becomes poor. Therefore, usually, the distance between the gaps of the two heads is set to 3
Approximately 6 lines apart. In the present invention, the magnetic head 17 for recording the signal of channel 2 is arranged such that the magnetic head 17 for recording the signal of channel 2 comes into contact with the magnetic tape with a delay from the rotation direction of the drum. Accordingly, only data of channel 2 is delayed by 3 to 6 lines.

FIG. 5 shows a first example of the configuration of one line of a recording signal according to the present invention. As shown in the figure, 1H of the recording signal includes a negative synchronization signal, a C signal of 192 samples, and a Y signal of 640 samples. From the synchronization signal generating circuit 38, two samples are used as the front porch portion of the negative synchronization signal, two samples are used as the falling portion of the negative synchronization signal, 68 samples are used as the bottom of the negative synchronization signal, and the rising portion of the negative synchronization signal is used. Two samples, two samples as a back porch portion of the negative polarity synchronization signal, and a total of 78 samples of data between the C signal and the Y signal are output. The effective sample number of one line of the luminance signal Y of the HDTV studio standard is 1920. In the present invention, since the sampling frequency is 1/3 of the HDTV studio standard, the sample number is 1/3 of 640. The number of effective samples of one line of the color difference signals P _B and P _{R according to} the HDTV standard is 960, and the sampling frequency is 1/5.

FIG. 6 shows the arrangement of heads on a drum according to the present invention and a tape pattern when recorded on a magnetic tape. FIG. 3A shows the arrangement of the heads on the drum. Magnetic head 16
Is composed of a magnetic head 16A and a magnetic head 16B which are arranged 180 ° opposite to each other. And the magnetic head 1
A magnetic head 17A is arranged close to the magnetic head 16B, and a magnetic head 17B is arranged close to the magnetic head 16B at a position 180 ° opposite to the magnetic head 16A. That is, similarly to the magnetic head 16, the magnetic head 17 has a magnetic head 17A and a magnetic head 17B.
It is composed of Magnetic head 16A and magnetic head 1
6B have the same azimuth angle.
A and the magnetic head 17B have the same azimuth angle different from that of the magnetic head 16. FIG. 7B shows a tape pattern when recording is performed on a magnetic tape using the drum having such a configuration. At this time, the running speed of the magnetic tape is 33.35 m, which is the same as the standard mode of the VHS-VTR.
m / s, and the track pitch is 19 μm, which is the same as in the triple mode of the VHS-VTR. In this manner, the recorded tape pattern has a space for one track every two tracks, but is similar to the tape pattern in the triple mode of the VHS-VTR. A high-quality audio signal or the like may be recorded in tracks vacated every two tracks.

FIG. 7 shows a first example of a recording tape pattern according to claim 2 of the present invention. The effective lines of the HDTV baseband signal are 41 to 557 in the first field.
527 lines in the second field.
120 528 lines. When this effective line is divided into an odd line into channel 1 and an even line into channel 2 as shown in the figure, the effective line is 528 only in the track for recording the even line in the first field, and 529 in other tracks. Will be there. At this time, the head switching margin is three lines from the end of the second field of the channel 2 to the beginning of the first field, and a sufficient area for a head switching margin can be secured.

FIG. 8 shows a second example of the recording tape pattern according to the second aspect of the present invention and an example of a recording tape pattern according to the third aspect of the present invention. In FIG. 8, one line immediately before the beginning of the effective line of the video signal of each track is used as an area for recording a frame address (so-called time code) (TC in FIG. 8).
Area). If the time code can be recorded, there is an advantage that editing and cueing can be easily performed. In this case, the head switching margin is two lines where the head switching margin is the smallest. However, the present inventor has confirmed through experiments that the head switching margin is sufficient if one line before and after the head switching point is sufficient. It doesn't matter. At this time, time code data is generated from the synchronization signal generation circuit 38. The recording method of the time code is VITC (Vertical Interval Time Cod)
A method well known under the name of e) may be used.

FIG. 9 is a diagram showing a configuration of one line of a recording signal according to claim 4 of the present invention. The configuration of one line of the recording signal is a second example. At this time, 68 samples are used as the negative synchronizing signal, 10 samples are used as the burst signal, and the C signal and the Y signal similarly constitute one line with 192 samples and 640 samples. At this time, the sampling frequency of the recording signal is 14.318 MHz.
Therefore, the pulse width of the negative polarity synchronization signal is 4.75 μsec, which is almost the same as the pulse width of the negative polarity synchronization signal of the NTSC signal. Also, since there are 10 samples as the burst signal, it is possible to form four burst signals having a frequency half of the sampling frequency. If this burst signal is used as a phase reference signal for the clock of the time base collector, a highly accurate time signal can be obtained. Axis correction processing can be performed.

While the present invention has been described in detail with regard to the presently preferred embodiments, it will be apparent to one skilled in the art that various modifications may be made within the scope of the present invention. Therefore, it is to be understood that the scope of this invention is limited only by the claims.

[0033]

As described above, in the magnetic recording / reproducing apparatus according to the present invention , the sampling frequency for A / D conversion of the luminance signal Y of the Hi-Vision baseband signal is equal to the sampling frequency of the luminance signal Y of the Hi-Vision studio standard. 24.75M which is 1/3 of 74.25MHz which is
Hz, the band of the luminance signal Y is 12.375 MH
The effective number of samples for z and 1H is 640. Also, the color difference signals PB and PR of the HDTV baseband signal are A / D
The sampling frequency to be converted is 37.12 which is the sampling frequency of the color difference signal of the HDTV standard.
Since it is 7.425 MHz, which is 1/5 of 5 MHz,
The band of the color difference signals PB and PR is 3.7125 MHz, and the number of effective samples for 1H is 192. If the color difference signal is line-sequentially multiplexed with the luminance signal on the time axis, the number of samples becomes 640 + 192 = 832 samples. If a recording signal is obtained by adding 78 samples as data such as a negative polarity synchronization signal to the recording signal, the number of 1H samples of the recording signal is 832+
78 = 910. At this time, when the sampling clock of the recording signal is 14.318 MHz (238,875 times the field frequency of 59.94 Hz of the NTSC signal), the recording signal can be made similar to the NTSC signal. .

As described above, the magnetic recording / reproducing apparatus according to the present invention divides the time base multiplexed Hi-Vision baseband signal into two channels and sets the number of recording lines per track to 262.5H. The tape pattern recorded on the magnetic tape can be made similar to the tape pattern of the VHS-VTR.

Further, as described above, the magnetic recording / reproducing apparatus according to the present invention includes the frame address generating means and can record the frame address at the head of the recording track. And editing can be easily performed.

Further, as described above, the magnetic recording / reproducing apparatus according to the present invention is provided with the synchronizing signal adding means for adding the negative synchronizing signal and the burst signal, and the frequency of the burst signal is D / D. Since the frequency becomes a half of the sampling clock of the recording signal to be A-converted, the burst signal can be used as a phase reference signal of the clock of the time base collector at the time of reproduction. This has the effect of being possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a block diagram showing a configuration of a vertical filter / line sequentialization circuit of the magnetic recording / reproducing apparatus of the present invention.

FIG. 3 is a block diagram showing a configuration of a synchronous addition / two-channel conversion circuit of the magnetic recording / reproducing apparatus of the present invention.

FIG. 4 is a timing chart showing a synchronous addition / two-channel circuit of the magnetic recording / reproducing apparatus of the present invention.

FIG. 5 shows recording signals 1 by the magnetic recording / reproducing apparatus of the present invention.
FIG. 3 is a diagram illustrating a first example illustrating a line configuration.

FIG. 6 is a diagram showing a head arrangement on a drum and a recording pattern on a tape of the magnetic recording and reproducing apparatus of the present invention.

FIG. 7 is a diagram showing a first example of a recording tape pattern by the magnetic recording / reproducing apparatus of the present invention.

FIG. 8 is a diagram showing a second example of a recording tape pattern by the magnetic recording / reproducing apparatus of the present invention.

FIG. 9 shows recording signals 1 by the magnetic recording / reproducing apparatus of the present invention.
FIG. 9 is a diagram illustrating a second example illustrating a line configuration.

[Explanation of symbols]

 1, 2, 3 A / D converter 4 Y frame memory 5 Vertical filter / line-sequencing circuit 6 C frame memory 7 Synchronous addition / two-channel conversion circuit 8, 9 D / A converter 10, 11 Emphasis circuit 12, 13 FM modulator 14,15 Recording amplifier 16,16A Magnetic head 17,17A, 17B Magnetic head 18 Magnetic tape 21,22 Reproduction amplifier 23,24 De-emphasis circuit 25,26 A / D converter 27,28 Time base collector 29 1 Channeling / Y / C separation circuit 30 Y frame memory 31 C frame memory 32 Interpolation filter 33,34,35 D / A converter 36,37 Vertical filter 38,39,40 Switch 41,42 1 line memory 43 3-6 Line memory

Claims (1)

(57) [Claims] At least a high definition baseband signal
That can store video for one field
Means for recording and reproducing a high definition baseband signal,
2 closely arranged with different azimuth angles
Rotate two magnetic head pairs consisting of two magnetic heads
A rotating silicide arranged approximately 180 ° opposite on the drum
And the luminance signal Y of the HDTV baseband signal is 24.7.
A / D conversion with 5MHz sampling clock
A / D converter and the color difference signals PB and PR are respectively 7.4
A / D conversion with 25 MHz sampling clock
2. The third A / D converter and the field frequency (23)
8,875 × N) times (N is a natural number) sampling clock
First and second D / A converters for performing D / A conversion by
And Bei, the second, third A / D converter in A / D converted PB
, And PR are converted to line-sequential data, and the first A
And time of the luminance signal Y converted by the A / D converter
Time axis multiplexed, and the time axis multiplexed signal alternately line by line.
Dividing into first and second channels, the first and second channels
The signal obtained by D / A conversion by the D / A converter is the above magnetic head
Simultaneously record two tracks in pairs, one on the rotating drum
Hi-Vision base using 4 tracks by rotation
It is configured to record and reproduce one frame of the band signal.
A magnetic recording and reproducing apparatus, wherein a negative synchronization signal and a burst signal are added to a recording signal,
A synchronizing signal adding means for adding a synchronizing signal to the recording signal;
The frequency of the burst signal is 238,87 of the field frequency.
Magnetic recording characterized in that the frequency is five times as high as 1/2
Playback device.