KR100210547B1 - Vtr - Google Patents

Abstract

According to the present invention, a plurality of heads are provided on the rotating drum with at least a predetermined stratification in the head scanning direction, and video and PCM audio signals are time-division multiplexed and distributed to a plurality of channels to record and reproduce as the plurality of heads. In the VTR, the PCM sets the angle between the best row and the last row in the plurality of heads on the rotating drum as θ, and the recording angle on the rotating drum of the video signal as θ _V. and the recording angle above the rotating drum of the audio signal to θ _a, and the angle of the guard above the rotating drum between the said video signal and said PCM audio signal to the _AV θ, θ _V + θ _{a +} θ _AV The time axis of the video signal and the PCM audio signal are compressed to be 180 [deg.]-Θ.

Description

VTR

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

2A to 2E are waveform diagrams for explaining signals.

3 is a configuration diagram of main parts of the VTR.

4 is a configuration diagram of an example of a recording pattern.

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

6 is a diagram for explaining a recording pattern.

7A and 7B are timing chart diagrams of signals.

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

9 and 10 are diagrams for explaining a conventional recording pattern.

11a, 11b, and 11c are diagrams of a conventional Tommy signal.

* Explanation of symbols for main parts of the drawings

2,5r, 5b, 41R, 41L: A / D conversion circuit 3A, 3B, 6r, 6b: line memory

8: control circuit 9: reference oscillator

19: servo circuit

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

According to the present invention, when the recording and reproduction using a plurality of heads is performed, the time axis is compressed so that the recording angles of the video signal and the PCM audio signal on the rotating drum are equal to or less than a predetermined angle. This is done.

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.

In these methods, however, in the method by frequency multiplexing, it is difficult to perform after-recording, so to speak.

As shown in Fig. 8, in the method of winding the recording medium to 180 degrees or more, after-recording can be performed. However, when after-recording is performed while reproducing a video signal, The recorded PCM audio signal was damaged, and the reproduction of the video signal could not be satisfactorily performed. It is also possible to reduce the damage by installing a recording amplifier, a reproduction amplifier, a switch, etc. in the rotating drum, but it is difficult to reduce the damage to zero, and the configuration thereof is complicated, and the reliability of the apparatus is also lost.

On the other hand, it is considered that the time axis of the signal is compressed so that the recording angle on the rotating drum between the video signal and the PCM audio signal is 180 degrees or less to solve the damage of the PCM audio signal to the reproduction signal of the video signal during the after recording. It is becoming.

However, for example, in a high-vision VTR, it has been proposed to distribute signals to a plurality of channels and record and reproduce them in multiple tracks by using a plurality of heads. In this case, in the above-described recording / reproducing method, the recording pattern is formed as shown in FIG. 9 by the angle θ formed by the preceding head and the following head on the rotating drum, and is correlated in the range shown by a in the figure. Since no signal is adjacent, interference is likely to occur.

Thereby, for the purpose of solving such interference problems, it is considered to supply only the time τ of the quotient corresponding to the angle θ formed by the head detailing the signal recorded by the trailing head. As a result, the recording pattern is formed as shown in FIG. 10, and matching between adjacent tracks can be achieved, and generation of interference is eliminated.

In this method, however, signal concurrency is lost. That is, in this case, the timing chart of the signal at the time of recording becomes as shown in FIGS. 11A to 11C. Here, for the original signal as shown in FIG. 11A, recording is performed in the preceding head at the same timing as shown in FIG. 11B. On the contrary, in the trailing head, recording is performed at the? Delayed timing as shown in Fig. 11C. At the time of reproduction, as shown in Figs. 11B and 11C described above, the reproduction signal is drawn out, and the signal is synchronized while delaying the signal from the preceding head.

So in this case, for example, considering the after-recording of the PCM audio signal, the trailing heads facing at time t ₀ when the preceding head starts recording the PCM audio signal are also playing the video signal, and the video signal therebetween. The PCM audio signal recorded in the playback signal is damaged, and the playback video signal is lost. On the contrary, at the end time t ₁ of recording of the PCM audio signal of the trailing head, the playback of the video signal of the preceding head starts while the recording is not finished, and the reproduced video signal is lost.

This application is made in view of such a point, and after-sales recording is 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, and a plurality of heads 17A and 17B are provided on the rotating drum with at least a predetermined laminar difference in the head scanning direction, and a video signal and a PCM are provided. In the VTR in which the audio signal is time-division multiplexed (adders 14A and 14B) and distributed to a plurality of channels (frame memories 11 and 43) for recording and reproduction in the plurality of heads, The recording angle on the rotating drum of the PCM audio signal is θ _A , with the angle between the best and the last line in the head of θ being θ, the recording angle on the rotating drum of the video signal being θ _V. A guard angle on the rotating drum between the video signal and the PCM audio signal is θ _AV .

And a time axis of the video signal and the PCM audio signal (frame memories 11 and 43).

The second means, in the first means, measures the values of the angles θ _AV and θ.

It is a VTR characterized by the above-mentioned.

According to this, when recording and reproducing using a plurality of heads, the time axis is compressed so that the recording angles of the video signal and the PCM audio signal on the rotating drum are equal to or less than a predetermined angle, so that after-recording can be performed with a simple configuration. At the same time, it is possible to perform recording and reproduction of a good signal.

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 serialized, the time axis is stretched and time-division multiplexed with the luminance signal, that is, a TCI signal. The use of a multi-channel head for dividing into a plurality of channels for recording and reproducing has been considered (see Japanese Patent Laid-Open No. 63-194494, etc.).

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

Again 7 is an input terminal of the synchronization signal Sync 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.

Thereby, the signal withdrawn from the memory 3A and the signal withdrawn from the memory 6r are synthesized by the adder 10A and supplied to the frame memory 11, and the signal and memory 6b withdrawn from the memory 3B. 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 through the D / A converters 12A and 12B, and the emphasis and FM modulated signals are added to the adder 14A, 14B).

40R and 40L are, for example, input terminals for stereo left and right audio signals, and signals from these terminals 40R and 40L are passed through the A / D conversion circuits 41R and 41L to write processing circuits for the audio signals. Supplied to 42, conversion into a PCM audio signal such as a predetermined error correction code and addition 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 on each side as will be described later, and the magnetic gap corresponding to each head is formed by one magnetic head device.

The reference signal from the control circuit 3 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 to drive the capstan 22 for conveying the tape 18 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, the HDTV signal and the left and right audio signals of stereo are reproduced.

Therefore, in this apparatus, for example, when recording a high-vision signal, the luminance signal Y and the chroma signals RY _R : C _R and BY: C as shown in FIGS. 2A to 2C are first shown. _B ) is 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.

The frequency f _A is here chosen to be as simple as possible, for example, a high integer base clock of 74.25 MHz, and to be an integer multiple of the high vision horizontal frequency (f _H1 = 33.75 KHz), 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. At the same time, a signal supplied with a clock signal of frequency f _B can be divided into 1/4 and outputted.

As a result, the luminance signal Y and the chroma signals C _R and C _B are respectively sampled with 1320 and 330 samples, as shown in the above-described drawings, and are stored in the memory 3A, 3B, 6r, and 6b. Is written. In addition, writing is performed using each horizontal synchronizing signal as a start signal, and writing is alternately written into the memories 3A and 3B every horizontal period.

Again, the written signal is read out as a clock signal of frequency f _C , and the time axis is stretched, and these signals are synthesized by the adders 10A and 10B, for example, as shown in FIGS. 2D and 2E described above. As such, the TCI signal is formed.

Here, the clock frequency f _C of the TCI signal, the horizontal scan line L per frame, and the sample number S per horizontal scan line are selected as follows. That is, when the TCI signal is formed from the above-described high-vision signal, the above-described apparatus records two channels simultaneously.

Where the values of L and S are selected according to the characteristics of the VTR and the like, for example, in the case of a recording format of L = 1322 and S = 1500,

It becomes

Therefore, a clock signal of this frequency f _C is supplied to the memories 3A, 3B, 6r, and 6b and, for example, the chroma signal C _R , which is written to the line memories 6r and 6b after 50 clocks of the horizontal synchronizing signal, for example. 280 samples of the effective screen period of C _B ) are read, and then 1120 samples of the effective screen period of the luminance signal Y written in the line memories 3A and 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. In addition, reading is performed as a start signal using one or more horizontal synchronizing signals, and signals formed by alternating horizontal scanning lines are simultaneously drawn out for each channel. In this case, since the frequency f _C is larger than 1/2 f _A , the length of one horizontal period of the actual TCI signal is shorter than twice the high vision signal.

The TCI signals thus formed are sequentially written to the frame memory 11.

Thus, the signal written in this frame memory 11 is read out as a clock signal of frequency f _C. Moreover, in the frame memory 11, the signal of the horizontal period of one space | interval with the state written in the memory 11 in the 1st (first segment) hospitality driving period with respect to the tape 18 of the head 17A, 17B. Is sequentially drawn out as a clock signal of frequency f _C , and reading is performed so that the signals of the horizontal period of the remaining one interval are sequentially drawn out in the second running period (second segment). At the same time, this readout is performed successively for each horizontal period, and again, the length of one horizontal period of the TCI signal is slightly shorter than twice the high-vision signal as described above, so that the readout is performed in the frame memory 11. The total length of the signal to be made is shorter than the length of each hospitality travel period with respect to the tape 18 of the head 17A, 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 adding a predetermined error correction code to a signal sampled at, for example, 48 KHz or 32 KHz by the A / D conversion circuits 41R and 41L, respectively, has a predetermined frequency. It is written to the clock signal of f _D. Thus, the clock signal of the predetermined frequency f _E is supplied to the frame memory 43 again, so that in the frame memory 43, the total length of the signal read out from the above-described frame memory 11 is equal to the head 17A, In a period shorter than the length corresponding to a quotient that is shorter than the length of each scan period for the tape 18 of 17B), the readout is performed such that a PCM voice signal corresponding to each scan period of the heads 17A and 17B is formed. Is done.

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. Thus, the signals from these 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 at a period of frequency f _F , and a predetermined track pitch therebetween. The conveyance of the tape 18 is performed so that is obtained.

Again in this apparatus, the heads 17A and 17B are each formed of two heads, while their heads are installed 180 degrees apart from each other on the rotating drum 16, and on one side thereof, the heads 17A The configuration of, 17B is, for example, as shown in FIG. 3, and for example, the magnetic gap 17a of the azimas angle and the other corresponding to the head 17B correspond to the head 17A. The magnetic gap 17b of the convenience Azimas angle is integrally provided with the track pitch P of the track pattern formed when the tape is conveyed at a standard speed and the increase h, so that one magnetic head device 71 is formed. . Therefore, in this magnetic head apparatus 71, two inclined tracks are formed at once, four inclined tracks are formed in one rotation of the rotating drum 16, and the azimas angles of the recordings of these inclined tracks are alternately different. It is.

Thereby, on the tape 18, as shown in FIG. 4, for example, as shown in FIG. 4, 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 PCM audio signal or the like is recorded in a 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 portion ahead of the recording range of the video signal in the head scanning direction as shown in the figure. Here, each track corresponds to a 166.5 horizontal period of 180 degrees of winding, and becomes a recording range of the audio signal in 23 horizontal periods (24.86 degrees) at a second speed. Thus, about 1.2 degrees of the front end becomes margin, the next 2.0 degrees becomes the preamble part, and the PCM audio signals of the third and fourth channels are recorded in the subsequent 8.0 degrees. The next 1.2 degrees becomes a post amble portion, and the subsequent 1.2 degrees becomes a guard portion between audio signals. Next, the next 2.0 degrees becomes a preamble portion, and the following PCM audio signals of the first and second channels are recorded in the subsequent 8.0 degrees, and the subsequent 1.26 degrees become a post amble portion.

Again, following the recording range of this audio signal, a guard section between the audio signal and the video signal of two horizontal periods is provided, and the reference level and clamp of the vertical synchronization signals V ₁ , V ₂ and AGC in the subsequent 11 or 11.5 horizontal periods. An information signal such as a level is provided, and then TCI signals of 130 horizontal periods each are 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.

Thus, in this apparatus, as shown in FIG. 5, the angle at which the plurality of heads 17A and 17B are formed on the rotating drum 16 is θ, and the recording angle of the video signal is θ _V. The recording angle of the signal is θ _A , the guard angle between the video signal and the PCM audio signal is θ _AV ,

The time axis of the video signal and the PCM audio signal are compressed so that.

Again

The guard length between the video signal and the PCM audio signal is determined.

In addition, since the signal recorded at the trailing head 17A is supplied by delaying by the time τ of the quotient corresponding to the forming angle θ of the head, the resulting recording pattern is formed between adjacent tracks as shown in FIG. It is assumed that the unity is achieved.

Therefore, in this apparatus, the timing chart of the signal at the time of reproduction is as shown in Figs. 7a and 7b, and is reproduced from the preceding head as shown in Fig. 7a, and from the trailing head to Fig. 7b. As shown in the figure, reproduction is performed at a delayed time? Of the quotient corresponding to the angle θ. At the time of reproduction, the signal is synchronized by delaying the signal from the preceding head.

So in this case, for example, considering the after-recording of the PCM audio signal, the trailing heads facing at the time t ₀ when the preceding head starts recording the PCM audio signal are already satisfied, satisfying the above expression (1). The reproduction of the video signal is finished, and the PCM audio signal recorded in the playback signal of the video signal is not damaged, and the playback video signal is not lost. Conversely, at the end time t ₁ of recording of the PCM audio signal of the trailing head, the preceding head is still guarded between the video signal and the PCM audio signal, and the reproduction video signal is lost in the same manner as the above expression (2) is satisfied. It doesn't happen.

In this way, according to the above-described apparatus, when recording and reproducing using a plurality of heads, the time axis is compressed so that the recording angle of the video signal and the PCM audio signal on the rotating drum is equal to or less than a predetermined angle, so that the after-sales is simple. In addition to recording, recording and reproduction of a good signal can be performed.

In the above-described apparatus, when the number of heads is three or more heads, the above-described conditions can be implemented in the same manner, with the angle formed by the best row and the last row in those heads.

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

According to the present invention, when recording and reproducing using a plurality of heads, after-recording can be performed with a simple configuration by compressing the time axis such that the recording angle of the video signal and the PCM audio signal on the rotating drum is equal to or less than a predetermined angle. At the same time, it is possible to record and reproduce a good signal.

Claims (2)

The rotary drum includes a plurality of heads having a predetermined stratification difference in at least the head scanning direction on the rotary drum, and PCM audio signals of video signals are time-division multiplexed and distributed to a plurality of channels for recording and reproducing as the plurality of heads. In such a VTR, the angle formed between the best row and the last row in the plurality of heads on the rotating drum is θ, and the recording angle of the video signal on the rotating drum is θ _V , and the PCM The recording angle on the rotating drum of the audio signal is θ _A , and the guard angle on the rotating drum between the video signal and the PCM audio signal is θ _AV , θ _V + θ _{A +} θ _AV And a time axis of the video signal and the PCM audio signal so as to be 180 [deg.]-[Theta]. The method of claim 1, wherein the values of the angles θ _AV and θ are θ _AV. VTR characterized in that it is set to (theta).