JPS6247802A - Video tape recorder - Google Patents

Abstract

PURPOSE:To ensure the satisfactory reproduction of the PCM signals with use of a common reproduction head and with no use of a head that is used in a reproduction mode only, by providing plural recording tracks for PCM signals in response to the angle division of a recording/reproducing head in a video period. CONSTITUTION:When the PCM signals are recorded and reproduced by a head equivalent to the one that records the periods excluding a video period of video signals, this head is divided into heads 10A-10c equal to three pieces obtained by dividing 360 deg. by 120 deg. (angle formed between heads 32 and 35). At the same time, the level differences are secured so that a magnetic tape shifted in a single field is divided into equal parts by the scanning locus. Thus the heads 10A-10C are available for the reproduction that is carried out by the heads 32 and 35. Thus it is possible to perform the satisfactory reproduction of the PCM signals with use of a common reproduction head for PCM signals and without using the head that is used in a reproduction mode.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a videotape recorder for professionals used in broadcasting stations and the like. [Summary of the Invention] The present invention provides, for example, in a video tape recorder called SMPTIE-C format, when a CM signal is recorded in place of a synchronization signal on a so-called synchronization trunk, a recording track of this PCM example is used. By setting the number of ciM according to the angle of the recording/reproducing head during the video period, it is possible to always achieve good PC regardless of the head used during reproduction.
This is a device that enables playback of video tapes in the so-called SMPTE-C format.
At Florence 1-Evening, there is a 21 on the tram.
A solid head is installed, and one tram per field.
The drum is rotated at 81 rotations, and the magnetic tape is wound obliquely over nearly 360 degrees around the circumferential surface of the drum and is transported at a predetermined speed. The video period of the video signal is recorded on one of the two heads mentioned above, and during the period when this head is separated from the magnetic tape (synchronization period), the signal is recorded on the other head. It is made to be done. Figure 5 shows the recording pattern of the magnetic tape recorded in this manner. In the figure, the ζ magnetic tape is divided into two parts in the width direction, and one of the divided heads is used to record the image period () on the diagonal trunk, and the divided part is divided into two parts. In the narrow part, the signals of the synchronization period are recorded in diagonal tracks by the other head.Between these parts and on both sides of the magnetic tape, there are
A control trunk, first, second and third audio signal tracks are provided, each recorded on a fixed head. By the way, in such a format, if a so-called time base collector is used for the playback signal, even if the synchronization period signal is lost, as long as the video period signal is obtained, the regular video signal can be reproduced without any problem. . Therefore, in the above-mentioned format, it was considered to record a digitized PCM audio signal in place of the synchronization period signal on a diagonal trunk in the narrow portion. That is, in the above-mentioned conventional format, audio signals are recorded in analog form using a fixed head, but such analog recording suffers from significant deterioration, especially when dubbing is repeated. On the other hand, if recording is done digitally, the problem of deterioration during dubbing will be solved. By the way, when recording and reproducing digitally, a time delay occurs in the signal due to AD-DA conversion, error correction, etc. during recording and reproduction. This delay occurs when ■ field-by-field processing is performed, and when recording, 1 field,
During reproduction, the number of fields is one or more for error correction and the like. Therefore, in the above-mentioned recording device, the recording head and the reproduction head are made independent, and the reproduction head is placed in advance by the above-mentioned time delay, so that the timing of the reproduced PCM audio signal matches the recording time. It is made to be. However, in this case, in a so-called SMPTE-C format video tape recorder, in addition to the original head/node for recording and reproducing signals of the video period, a dynamic tracking head for variable speed reproduction etc. is provided. This head is 1
It is installed at a position 20 degrees behind. If playback is performed using a head installed at an angle different from the original head, the tracking of the PCM audio signal recorded on the above-mentioned synchronization track will shift, making it impossible to perform good playback. . On the other hand, it is conceivable to provide another set of PCM audio signal playback heads to match the 120 degree angle, but providing a large number of heads would complicate the structure of the rotating drum.
There was also a risk that the signal processing system would become complicated. [Problems to be Solved by the Invention] As mentioned above, in the conventional technology, there was a problem in that if the signal of the video period was reproduced by another head, the PCM signal could not be reproduced satisfactorily. . [Means for Solving the Problems] The present invention provides a rotating drum provided with a first head for recording and reproducing a video period of a video signal and a second head for recording and reproducing a period other than the video period. The first head performs recording and reproduction, and the second head performs recording and reproducing on each portion of the magnetic tape that is transferred diagonally along the circumferential surface of the rotating drum. In a video tape recorder which is provided with a third head for reproducing the signal of the video period and recording and reproducing the PCM signal with the head corresponding to the second head, , the number of spatulas I corresponding to the second head is set to 360 degrees ÷ (angle formed by the first and third heads - 120 degrees) (3 pieces), and the scanning gL trace is set in one field period. The magnetic tape (11) to be transferred is provided with steps 4J so as to be equally divided, and when played by the first and third heads (32) (35), a spatula corresponding to the second head is installed. l” (IO
A) (10B) (IOC) is a video tape recorder that can be used in common. [Operation] According to this, a plurality of PCM signal recording tracks are provided according to the angle division of the recording/reproducing head during the video period, so that a common PCM signal can be recorded during reproduction regardless of the head used.
Good PCM signal reproduction can be performed using the signal reproduction head. [Example] In the block diagram of Fig. 1, an analog audio signal supplied to the input terminal (11) is supplied to the AD conversion circuit (3) through the 10 circuit (2) and converted into digital data. 4) via the data bus. The data on this data bus (4) is supplied to the memory (5) and stored therein. Furthermore, the data stored in the memory (5) is transferred to the data bus (
6) to the encoder (7), where the encoder (7) performs encoding such as addition of a predetermined error correction code and rearrangement. The data from the memory (5) is sent to the modulation circuit (8).
A PCM audio signal based on the modulated data is supplied to the recording head (10) through the recording amplifier (9), and the synchronization of the magnetic tape (11) is performed. - It is recorded on the diagonal trunk in the narrow part corresponding to the tsuku. The configuration of the rotating drum on which the recording head (10) is provided is shown in FIG. In the figure, the drum is rotated clockwise and twelve heads are provided around its periphery at angular intervals of 30 degrees. The PCM audio signals are recorded and played back by heads 311I11, respectively, and the audio signal recording heads (10^) (1013) (
LOG), video signal erasing head (31), video signal recording/reproducing spatula F' (32), audio (d) playback head for recording confirmation (34A) (3411) (3
4C), dynamic tracking head for video signals (35), playback head for audio signals (36Δ) (36
B) (37C) is provided. Also, each head (108) ~ (IOC) (348) ~ (34C)
(368) to (36G) are respectively 1”A
, B, C scanning! ! The IL traces are provided in steps so as to divide the magnetic tape (11) transferred in one field period into three equal parts. Therefore, the recording pattern of the magnetic tape (11) by this rotating drum is as shown in FIG.
) 1 including up to 1/2 of each of the front and rear guard bands
PCM that divides the track pitch range Ut+ into three equal parts (;' trunk (428) (4211) (42C
) is formed. In addition, the illustrated video track (41) and P
The fields of CM (word track (428) to (42C)) do not match. Furthermore, during playback, the playback head (1
2) C (348) (34B)
(34C) (368) (36B) (36
C) The signal reproduced in ) is supplied to the demodulation circuit (14) through the reproduction amplifier (13), and the recorded digital data is demodulated. This demodulated data is supplied to the data bus (15) (16), and this data bus (1
5) The data in (16) is supplied to the memo January 5), and the data in (16) is supplied to the first and second decoders (17) (
1B). Further, the address of the data detected by the demodulation circuit (14) is supplied to the memo via the address bus (19). Then, the data that has been decoded such as predetermined sorting and error correction is transferred from the data bus (January 5) to the data bus (4).
). The data on this data bus (4) is DA
The signal is supplied to the conversion circuit (20) and converted into an analog audio signal, and this signal is passed through the 10 circuit (2) to the output product 1 (21).
) is taken out. Further, the signal from the digital signal input terminal (22) is supplied to the 'ζ data bus (4) through the digital 10 circuit (23), and the signal from the data bus (4) is supplied to the digital signal through the 10 circuit (23). is taken out to the output terminal (24) of. In addition, variable speed playback, etc.
(35), the control signal is transmitted to the terminal (2).
5) to the control circuit (26), and this circuit (
Control signals from 26) are supplied to the memory (5) via an auxiliary bus (27). Furthermore, FIG. 4 shows a time chart of recording and reproducing operations of this apparatus. Vertical lines in the figure are field boundaries. In this figure, A is a recording operation, for example, a field

The signal AD-converted during the period [0] is encoded in the first half of the next field [1], compressed in the time axis and read out in the second half of this field [1], and sent to the recording head (IOA) (1013). (IOC). On the other hand, B is a normal reproduction operation, and for example, the signal reproduced by the reproduction head (368) (361() (36C: ) in the first half of field [-2] is
From the second half of this field [-2] to the next field (-
1], and then the next field is decoded.

The time axis is extended during the period [0], DA conversion is performed, and the data is extracted. Therefore, in the device described above, the same field

[0] (
To take out No. 6, use the playback head (36A) (36B)
(36G) is the recording head <108) (10B) (
It is necessary to provide at least three fields in advance of the IOC). And in the case of the device described above, the exogenous head (3
6A)<368) (36C rotary tram)
The second mounting position is the recording head (108) (IOB) (
Since it is 90 degrees ahead of IOc), the actual amount ahead is 3-fields. Furthermore, C is a dynamic tracking (DT) head (
35) is used for reproduction. In this case, D
Since the T head (35) is positioned 120 degrees behind the original playback head (32), when the video period is played back with this head (35), the magnetic tape (11) is It will be transported 1/3 track pitch ahead of the position. However, in that case, since the trunks (42A) (42B) (42C) of the PCM signal are arranged every 1/3 track pitch as described above, even if they are transferred in advance by 1/3 track pitch, , trunk (428) (42B) (4
2C) is the head (368) (36B) (36C)
It can be reproduced equally well. However, in this case,
Since the PCM signal is preceded by 1/3 track pitch, the PCM signal that is played back at the same timing as normal will be, for example, track (42B>(42G)) and track (428) of the next field. For example, the signal of the track (42A) played in field C-2] is stored until the next field, and is decoded together with the signal of track (42B) (42C) played in the next field [-1]. That is, the control signal from the control circuit (26) is supplied to the memo (January 5) so that the memo 5) is controlled in this way. According to the above-mentioned device, the same playback head can also be used when using the dynamic 1-ranking head.
CM No. 475 can be reproduced, and PCM signals can be recorded and reproduced with a simple configuration. Note that the capacity of the memo January 5) is required to be one field larger when reproducing the dynamic tracking head. Furthermore, the arrangement of the heads on the rotating drum is not limited to the above example. [Effects of the Invention] According to the present invention, since a plurality of PCM (ti) recording trunks are provided according to the angle division of the recording/reproducing head in the video period, a common recording trunk is provided during reproduction regardless of the head used. It has become possible to perform good PCM signal reproduction with a PCM signal reproduction head.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an example of the present invention, FIGS. 2 to 4 are diagrams for explaining the same, and FIG. 5 is a diagram for explaining a conventional technique. (1) is the input terminal, (2) is the 10 circuit, (3) is the AD conversion circuit, (41 (61 (15), (16) is the data bus, (5) is the memory, (7) is the encoder, ( 8) is a modulation circuit, (9) is a recording amplifier, (10) is a recording head,
(11) is a magnetic tape, (12) is a playback head, (13)
) is the reproduction amplifier, (14) is the demodulation circuit, (17) (
1B) is a decoder, (19) is an address bus, (20)
is a DA conversion circuit, (21) is an output terminal, (22) is a digital input terminal, (23) is a digital 10 circuit, (24)
is a digital output terminal, (25) is a terminal, (26) is a control circuit, and (27) is an auxiliary bus. Book F ＼ Same Hidemori Matsukuma <, %:', ・Pa・, °(゛Example imaginary lock pattern Figure 1, de Figure 5

Claims (1)

[Scope of Claims] A rotating drum is provided with a first head for recording and reproducing a video period of a video signal and a second head for recording and reproducing a period other than the video period. Recording and reproduction are performed by the first head and recording and reproduction by the second head, respectively, on each portion of the magnetic tape that is divided into two in the width direction on the magnetic tape that is transferred diagonally along the circumferential surface. In a video tape recorder provided with a third head for reproducing the signal of the video period, when recording and reproducing a PCM signal with the head corresponding to the second head, the head corresponding to the second head corresponds to the second head. The number of heads to be used is 360 degrees ÷ (the angle formed by the first and third heads), and
Steps are provided so that the scanning locus equally divides the magnetic tape transferred in one field period, and when the first and third heads perform reproduction, the second head
A videotape recorder in which a head equivalent to that of the above head can be used in common.