KR100240555B1 - Video tape recorder - Google Patents

Abstract

A VTR provided with a rotating drum, wherein the recording medium is wound around the rotary drum in a range of 180 degrees, and the video signal and the PCM audio signal are time-division multiplexed so as to be recorded and reproduced in the head provided in the rotating drum. The video signal is time-base compressed at a predetermined unit period corresponding to a rotation of 180 degrees of the rotating drum, and the PCM audio signal corresponding to the unit period is compressed. Time-base compression is performed so that the time-base compressed PCM audio signal is located in front of the time-base compressed video signal described above so as to perform the time division multiplexing so as to have a length of a margin period generated by time-base compression. And a VTR for recording the time-base-compressed PCM audio signal at the inrush of the furnace.

Description

VTR

1 is a configuration diagram of an example of a VTR according to the present invention.

2a, b, c, d, e is a waveform diagram for explaining the signal.

3a, b, c, d are diagrams for explaining the time base compression.

4 is a diagram showing a relationship between a head and a recording signal.

5 is a configuration of the main part of the VTR.

6 is a diagram for explaining a recording pattern.

7 is a diagram for explaining a recording pattern of another example.

8 is a diagram showing a relationship between a conventional head and a recording signal.

* Explanation of symbols for main parts of the drawings

1: Input terminal 2: A / D conversion circuit

3A, 3B: line memory 4r, 4b: input terminal

5r, 5b: A / D conversion circuit 6r, 6b: line memory

7: input terminal 8: control circuit

9: reference oscillator 10A, 10B: adder

11: frame memory 12A, 12B: D / A converter

13A, 13B: Emphasis and FM Modulation Circuits

14A, 14B: Adder 15A, 15B: Record Amplifier

16: rotary drum 17A, 17B: head

18: tape 19: servo circuit

20: spindle motor of the rotating drum 21: capstan motor

22: Capstan 40R, 40L for tape transfer: Input terminal

41R, 41L: A / D conversion circuit 43: Frame memory

44A, 44B: Coding Circuit for Recording

The present invention relates to a VTR for recording and reproducing an HDTV signal, for example.

According to the present invention, with respect to the VTR, video signals and PCM audio signals are time-base compressed to install these signals within a rotational period of 180 degrees of the rotating drum, and to study the installation positions thereof to enable after-recording with a simple configuration. In addition, the recording and reproduction of a good signal is performed.

Conventionally, in a VTR for recording and reproducing a video signal and a PCM audio signal, for example, the PCM audio signal is frequency multiplexed to a part of the recording signal band or the recording medium is wound over a range of 180 degrees or more of the rotating drum. The method of recording a PCM audio signal in the part over 180 degree | times is implemented.

However, in these methods, it is difficult to perform after-recording, namely, in the method by frequency multiplexing.

In addition, in the method of winding the recording medium to 180 degrees or more as shown in FIG. 8, after-recording is possible, but in the case of after-recording while reproducing a video signal, The PCM audio signal to be recorded is covered, and the reproduction of the video signal is not performed satisfactorily.

It is also considered to reduce the covering by providing a recording amplifier, a reproducing amplifier, a switch, etc. in the rotating drum, but it is difficult to zero the covering, and consequently, the configuration is complicated, thereby reducing the reliability of the apparatus.

This application is made in view of such a point, and after-sales is made possible with a simple structure, and recording and reproduction of a favorable signal are performed.

The first means according to the present invention includes a rotating drum 16, in which a recording medium (tape 18) is wound in a range of 180 degrees around the rotating drum, and a video signal and a PCM audio signal are provided. In the VTR, which is time-division multiplexed and recorded and reproduced by the heads 17A and 17B provided on the rotating drum, time-base compression is performed at predetermined unit periods corresponding to 180-degree rotation of the rotating drum (frame memory 11). In addition, the time-base compression (frame memory 43) is performed such that the PCM audio signal corresponding to the unit period becomes the length of the margin period generated by the time-base compression of the video signal. The time division multiplexing (adders 14A, 14B) are provided so as to be located ahead of the time-base compressed video signal, so that at least the time at the indentation portion of the head into the recording medium. A VTR to be performed by the recording of the compressed PCM audio signal.

In the second means, in the first means, the PCM audio signal is provided with a plurality of recording channels of at least two channels, and the time division multiplexing is performed so that these systems are in independent positions. VTR.

The third means is a VTR in which the position of each system of the PCM audio signal is provided at least one system share before and after the time-base compressed video signal in the second means.

The fourth means comprises, in the first, second, or third means, an image in which the shortest recording wavelength (emphasis and FM modulation circuits 13A, 13B) of the time-base-compressed PCM audio signal is obtained. The VTR is set to be longer than the shortest recording wavelength of the signal (coding arcs 44A and 44B for recording).

According to this, the video signal and the PCM audio signal are time-base compressed so that these signals are installed within the rotational period of 180 degrees of the rotating drum, the installation position and the like are studied, and after-sales recording is possible with a simple configuration. A good signal can be recorded and reproduced.

However, as a VTR for recording and reproducing an HDTV signal, for example, a high-vision signal, especially for a consumer device, the chroma signal is first-sequentially expanded, the time axis is stretched and time-division multiplexed with the luminance signal, that is, the TCI signal. In this regard, recording and reproduction by dividing into a plurality of channels using a multichannel head has been considered.

(See Japanese Patent Laid-Open Showa Publication 63-194494, etc.).

That is, FIG. 1 shows an example of an apparatus in the case where it is applied to such a system. In this figure, reference numeral 1 denotes, for example, an input terminal of a luminance signal Y that is demodulated HDTV signal. The signal from 1) is supplied to the line memories 3A and 3B via the A / D conversion circuit 2. Further, 4r and 4b are input terminals of a chroma signal (color difference signal RY: C _R , BY: C _B ) demodulating the HDTV signal, and the signals from these terminals 4r and 4b are respectively A / D conversion circuits ( It is supplied to the line memories 6r and 6b via 5r and 5b.

Again 7 is an input terminal of the synchronization signal Syne separated from the HDTV signal, and a signal from this terminal 7 is supplied to the control circuit 8. Therefore, in this control circuit 8, various control signals and clock signals described later are formed in accordance with the reference clock signal supplied from the predetermined reference oscillator 9 and the synchronization signal described above.

Accordingly, the signal drawn out from the memory 3A and the signal drawn out from the memory 6r are combined with the adder 10A and supplied to the frame memory 11, and the signal drawn out from the memory 3B and the memory 6b. The signal to be extracted from is synthesized in the adder 10B and supplied to the frame memory 11. Thus, the signal extracted from the memory 11 is supplied to the emphasis and FM modulation circuits 13A and 13B via the D / A converters 12A and 12B, so that the emphasis and FM modulated signals are added to the adder 14A, 14B).

Further, 40R and 40L are, for example, input terminals for stereo left and right audio signals, and signals from these terminals 40R and 40L pass through the A / D conversion circuits 41R and 41L to write processing circuits for the audio signals. Supplied to 42, conversion to a PCM audio signal such as addition of a predetermined error correction code is performed. The signal from this processing circuit 42 is supplied to the frame memory 43. Thus, the signal extracted from the memory 43 is supplied to the adders 14A and 14B via the coding circuits 44A and 44B for recording.

Thus, the signals from the adders 14A and 14B are supplied to the heads 17A and 17B on the head drum 16 via the recording amplifiers 15A and 15B and recorded on the tape 18. Here, the heads 17A and 17B are integrated in each axis as described later, and a magnetic gap corresponding to each head is formed in one magnetic head device.

The reference signal from the control circuit 8 is supplied to the servo circuit 19 again, and the spindle motor 20 of the head drum is driven as a signal from the servo circuit 19. In addition, a signal from the servo circuit 19 is supplied to the capstan motor 21, and the motor capstan 22 for feeding the tape 18 is driven by the motor 21.

Recording is performed by the above. In addition, at the time of reproduction, the above operation is performed in reverse, for example, an HDTV signal and a stereo left and right audio signal are reproduced.

Therefore, in this apparatus, for example, when recording a high-vision signal, first, the luminance signal Y and the chroma signal RY: C _R , BY: C _B as shown in Figs. 2a, b, and c are first shown. Are sampled with clock signals of the frequencies f _A and f _B from the control circuit 8, A / D converted, and written into the memories 3A, 3B, 6r, and 6b.

Here, the frequency f _A is selected to be, for example, a simple integer ratio of 74.25 MHz, which is the basic clock of the high vision, and an integer multiple of the horizontal frequency (f _HA = 33.75 MHz) of the high vision, for example,

It becomes F _B is also chosen to be 1/4 of f _A.

That is, the reference oscillator 9 having a frequency of 44.55 MHz is provided so that the clock signal from the oscillator 9 is supplied to the control circuit 8, so that the clock signal of the frequency f _A is directly outputted. Together, the clock signal of frequency f _B can cause the supplied signal to be divided into quarters and output.

As a result, the luminance signal Y and the chroma signals C _R and C _B are respectively sampled in 1320 and 330 samples, as shown in the above-described drawings, to the memory 3A, 3B, 6r, and 6b. Is written.

In addition, writing is performed as a start signal for each horizontal synchronizing signal, and the memory 3A and 3B are alternately written to each of the horizontal periods.

Again, the written signal is read out as a clock signal of frequency fc, and the time axis is stretched and synthesized by the adders 10A and 10B, for example, as shown in D and E in the above-described drawings. In other words, a TCI signal is formed.

Here, the clock frequency fc of this TCI signal, the horizontal scan line L per frame, and the sample number S per one horizontal scan line are selected as follows. In other words, when the TCI signal is formed from the above-described high-vision signal, the above-described apparatus performs two-channel simultaneous recording.

In this case, the values of L and S are selected by the characteristics of the VTR and the like, and for example, when the recording format is L = 1332 and S = 1500,

It becomes

Therefore, a clock signal of this frequency fc is supplied to the memories 3A, 3B, 6r, and 6b, and for example, the chroma signals C _R and C written in the line memories 6r and 6b after 50 clocks of the horizontal synchronizing signal, for example. 280 samples of the effective screen period of _B ) are read out, and then 1120 samples of the effective screen period of the luminance signal Y written in the line memories 3A, 3B and 100 samples of the synchronous period are read out.

As a result, a TCI signal of two (A, B) channels as shown in the above-described drawing is formed. Further, reading is performed by one jump, and a horizontal synchronizing signal is performed as a start signal, and a signal formed by an alternate horizontal scanning line signal is simultaneously drawn out for each channel.

In this case, since the frequency fc is larger than 1/2 f _A , the length of one horizontal period of the actual TCI signal is somewhat shorter than twice the high vision signal.

The TCI signal thus formed is sequentially written to the frame memory 11.

Thus, the signal written in the frame memory 11 is read out as a clock signal of frequency fc. In the frame memory 11, the signal of the horizontal period is generated by jumping from the first (first segment) to the tape 18 of the heads 17A and 17B and one of the states written in the memory 11 in the hospitality travel period. It reads out in turn by the clock signal of frequency fc, and it reads out so that the signal of a horizontal period may be taken out one by one in the 2nd (second segment) hospitality driving period. At the same time, this readout is performed in succession for each horizontal period, and while the length of one horizontal period of the TCI signal is slightly shorter than twice the high-vision signal as described above, the readout is performed in the frame memory 11. The total length of the signal to be shortened is shorter than the length of each hospitality traveling period with respect to the tape 18 of the heads 17A and 17B.

The read signal is subjected to D / A conversion, emphasis and FM modulation, and supplied to the adders 14A and 14B.

On the other hand, in the frame memory 43, a PCM audio signal formed by the A / D conversion circuits 41R and 41L, for example, a sample sampled at 48 KHz or 32 KHz with the addition of a predetermined error correction code, respectively, has a predetermined frequency f. _It is written by the clock signal of _D. Therefore, the clock signal of the predetermined frequency f _E is supplied to the frame memory 43 again, and from this frame memory 43, the total length of the signal read out from the frame memory 11 described above is determined by the head 17A, Readout is performed such that a PCM audio signal corresponding to each scanning period of the heads 17A and 17B is formed in a period shorter than the length corresponding to the share shorter than the length between the syringes of the tape 18 of 17B). All.

The read signal is converted into a predetermined recording signal by the encoding circuits 44A and 44B and supplied to the adders 14A and 14B.

That is, in the above-described apparatus, in the case where there are a video signal and a PCM audio signal as shown in Figs. 3A and 3B, the video signal of each of the hospitality travel periods with respect to the tape 18 of the heads 17A and 17B. As shown in the same figure c, the period share corresponding to the length is time-base compressed, and the share corresponding to the same period of the PCM audio signal is time-time-compressed as shown in FIG. . At the time of compression, the video signal is provided at the rear side of each hospitality traveling period, and is provided so that the PCM audio signal is located at the front side.

Thus, these signals are added by the adders 14A and 14B to perform time division multiplexing, and the signals from the adders 14A and 14B are supplied to the heads 17A and 17B and recorded on the tape 18.

At this time, the reference signal of the frequency f _F = 60 Hz from the control circuit 8 is supplied to the servo circuit 19 so that the heads 17A and 17B are rotated around the frequency f _F and a predetermined track therebetween. The transfer of the tape 18 is performed so that a pitch is obtained.

Therefore, in this apparatus, the heads 17A and 17B perform recording and reproduction of the video signal and the PCM audio signal during the 180-degree hospitality driving period as shown in FIG. By setting the range to 180 degrees, it is possible to record and reproduce a good signal without damaging the signal even during after-recording.

In addition, since the multiplexing is performed so that the PCM audio signal is located at the front side of the video signal, for example, the recording of the PCM audio signal is performed at the indentation of the heads 17A and 17B to the tape 18. As a result, a good signal can be recorded and reproduced. In other words, the spacing loss is large because the air film is thick at this rush, and it is inadequate for recording analog video signals. As described above, since the PCM audio signal is recorded at this portion, the influence of the spacing loss can be reduced, and the recording and reproduction of a good signal as a whole can be performed.

In this way, for example, recording of a high-vision signal can be performed. However, according to the above-described apparatus, the video signal and the PCM audio signal are time-base compressed so that these signals are provided within a rotational period of 180 degrees of the rotating drum. Since the installation position and the like are studied, after-recording can be performed with a simple configuration, and recording and reproduction of a good signal can be performed.

Again, in this apparatus, the heads 17A and 17B are each formed of two heads, and their heads are installed 180 degrees apart from each other on the rotating drum 16, and on one side thereof, the head ( 17A and 17B are configured as shown in FIG. 5, for example, corresponding to the head 17A and corresponding to the magnetic gap 17a and the head 17B of the azimas angle, for example. The magnetic gap 17b of the other azimas angle is integrally provided with the layer difference h equal to the track pitch P of the track pattern formed when the tape is transferred at a standard speed, so that one magnetic head device 71 is formed. have. Thus, two magnetic inclination tracks are formed in this magnetic head device 71 at once, and the four rotation tracks are formed in one rotation of the rotating drum 16, and the azimas angles of the recordings of these inclination tracks are alternately different. It is supposed to be.

As a result, on the tape 18, for example, as shown in FIG. 6, a video signal is recorded in a recording pattern in which one frame is made of two channels of four segments (8 tracks) by two rotations of the rotating drum 70. As described above, the recording of the PCM audio signal or the like is performed in the range generated by compressing the time axis of the video signal.

That is, in this figure, the recording range of the PCM audio signal is provided in the part of the front side in the head scanning direction from the recording range of the video signal.

Here, each track corresponds to a 166.5 horizontal period at 180 degrees of winding, where the horizontal period (24.86 degrees) is the recording range of the audio signal. Thus, about 1.2 degrees at the front end becomes a margin, the next 2.0 degrees becomes a preamble portion, and the PCM audio signals of the third and fourth channels are recorded in the subsequent 8.0 degrees. The next one or two degrees becomes a postamble portion, and the subsequent one or two degrees become a guard portion between audio signals. Next, the next 2.0 degrees becomes a preamble section, followed by recording of PCM audio signals of the first and second channels in 8.0 degrees, and subsequent 1.26 degrees into a postamble section.

Again, following the recording range of this audio signal, a guard section between the audio signal and the video signal in two horizontal periods is provided, and in the subsequent 11 or 11.5 horizontal periods, the reference level clamps of the vertical registration signals V ₁ , V ₂ , and AGC An information signal such as a level is provided, and then TCI signals of 130 horizontal periods are respectively recorded as shown in accordance with the above-described distribution. In addition, the numbers in the figure show the numbers of the horizontal periods, and R and B show chroma signals to be multiplexed. After the recording range of this TCI signal, a margin of 0.5 or 1 horizontal period is provided.

Therefore, according to this apparatus, since the PCM audio signal is provided with two systems (first, second, third, and fourth channels) of two channels each, and these two signals are recorded independently, These signals can be after-recorded independently, and in this case, there is no fear of damage to the video signal during the after-recording described above.

In addition, when recording two or more PCM audio signals in this manner, as shown in FIG. 7, at least one system is provided before and after the video signal, so that the heads 17A and 17B enter the tape 18. FIG. In addition to the negative portion, the influence on the analog video signal due to the instability of the tape 18 can be eliminated in the detachment portion.

In the apparatus described above, the shortest recording wavelength of the recording signal of the PCM audio signal converted by the coding circuits 44A and 44B is the shortest of the video signal FM-modulated by the emphasis and the FM modulation circuits 13A and 13B. By being configured to be longer than the recording wavelength, it is possible to reduce the influence of the spacing gross and to record and reproduce a better signal as a whole.

The present application is not limited to the high-vision VTR but also applies to the case of recording and reproducing other HDTV signals or ordinary video signals.

According to the present invention, after the video signal and the PCM audio signal are time-base compressed, these signals are installed within a rotational period of 180 degrees of the rotating drum, and the installation position and the like are studied, so that after-recording can be performed with a simple configuration. Therefore, recording and reproduction of a good signal can be performed.

Claims (4)

A VTR having a rotating drum, wherein a recording medium is wound and attached in a range of 180 degrees around the rotating drum, and at the same time, the video signal and the PCM audio signal are time-division multiplexed so as to be recorded and reproduced in a head installed in the rotating drum. Compressing the time axis every predetermined unit period corresponding to 180-degree rotation of the rotary drum, and simultaneously making the PCM audio signal corresponding to the unit period the length of the margin period generated by the time-base compression of the video signal. Time-base-compressed, and the time-base-compressed PCM audio signal is positioned at the front side by the time-base-compressed video signal to perform the time division multiplexing, thereby at least the time-base-compressed PCM voice at the inrush to the recording medium of the head. VTR, characterized in that signal recording is performed. The VTR according to claim 1, wherein the PCM audio signal is provided with a plurality of recording systems of at least two channels, and the time-division multiplexing is arranged such that these systems are in independent positions. The VTR according to claim 2, wherein the position of each system of the PCM audio signal is arranged at least one system before and after the time-base compressed video signal. 4. The VTR according to any one of claims 1, 2, or 3, wherein the shortest recording wavelength of the time-base compressed PCM audio signal is longer than the shortest recording wavelength of the time-base compressed video signal.