JPH0198104A - Information signal recorder - Google Patents

Abstract

PURPOSE:To set an index section with a second rotation detection signal to accurately record an index and a clock signal by generating a first rotation detection signal synchronized with the rotation phase of a rotary magnetic head and generating the second rotation detection signal preceding the first detection signal synchronously with the rotation phase. CONSTITUTION:Rotary magnetic heads 34A and 34B are arranged a prescribed gap apart from a magnetic tape 1 of a recorder and are run at a certain speed and record the information signal from a recording processing circuit 31 and output the reproduced signal to a reproducing processing circuit 37. Pulse generating means 63 and 101 are provided on a revolving shaft 61 of heads 34A and 34B, and first and second pulses PgO and PgN are outputted synchronously with one rotation of heads 34A and 34B so that the pulse PgN slightly precedes the pulse PgO. The whole of the recorder is controlled by a controller 52, and switch circuits 32 and 36 are controlled by the pulse PgO, and the index section is set by detection of the pulse PgN.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information signal recording device, and particularly to a helical scan type information signal recording device.

[Summary of the invention]

In this invention, in a helical scan type information signal recording device in which information signals are sequentially recorded on a magnetic tape as diagonal magnetic tracks, a first rotation detection signal synchronized with the rotational phase of a rotating magnetic head is generated. and means for generating a second rotation detection signal that is synchronized with the rotational phase of the rotating magnetic head and precedes the first rotation detection signal, and the index section is set by the second rotation detection signal. , the signal is recorded in this index section. Therefore, even if the recording device does not have a PCM recording system, it is possible to accurately set the index section at the tip of the magnetic track, and it is possible to record signals within the index section set at the correct position. can.

[Conventional technology]

The track format of 8mm video magnetic tape is
It is determined as shown in FIG.

That is, in the figure, l indicates a magnetic tape, and 2 indicates a magnetic track, and this magnetic track 2 is a tape 1 by two rotating magnetic heads having an angular interval of 180° from each other.
It is formed or scanned obliquely to the object and has a length corresponding to a rotation angle of 221° of the rotary head. Then, from the tip of the magnetic track 2, a section 2S corresponding to a rotation angle of 36° of the rotary head is used for audio signals, and the remaining 185°
A section 2v corresponding to the rotation angle is used for the video signal.

Then, the audio track 2S is distributed in section 2 as shown in the figure.
Section 21 is a scanning start section of the rotating head (head entry section), section 22 is a preamble section where clock run-in is recorded and reproduced, and section 23 is a PCM.
The PCM audio data section in which the audio signal is recorded and reproduced, section 24, is a postamble section for a back margin during after-recording (hereinafter referred to as post-recording), and section 25 is a guard section for tracks 2S and 2V.

In addition, in this case, the PCM audio data in section 23 is a stereo audio signal for one field period that is compressed on the time axis and
The signal is converted into a CM signal, and is also a signal having an error correction code, an ID code, and the like.

The signal in sections 22 to 24 has a frequency of 2.9 MHz when its value is "0", and a frequency of 5.8 MHz when its value is "1".
It is recorded after being converted into a MHz pi-phase mark signal.

Furthermore, the video track 2v follows the guard section 25 with <1
It is divided into a section 28 corresponding to a rotation angle of 80 degrees and a section 29 corresponding to a remaining rotation angle of 5 degrees. Section 28 is a video signal section, in which the FMSS modulated by the luminance signal
One field of a frequency multiplexed signal consisting of a signal, a low frequency converted carrier color signal, an FM signal modulated by a monaural audio signal, and a pilot signal is recorded and reproduced. Also,
Section 29 is a scanning end section of the rotating head (head separation section).

According to such a format, the audio data section 23
Since an ID code is recorded at the same time as the audio signal, various data such as the recording date,
Absolute positions, program numbers, etc. can be recorded, making it extremely convenient for cueing up during playback or editing.

By the way, when the ID code is recorded in the audio data section 23, it is recorded while being dispersed within the section 23 by interleaving together with the PCM audio data.

Therefore, to correctly reproduce the ID code, the rotary head must correctly scan section 23 over a considerable length.

However, during search playback, the magnetic tape 1 runs at, for example, 30 times the speed of recording, so the rotating head moves in section 2.
Therefore, during search reproduction, the ID code may not be correctly reproduced for a considerable period of time.

Therefore, it has been considered to record and reproduce an index signal such as an ID code in the postamble section 24 of the audio track 2S.

That is, this section 24 has a length corresponding to 2.06° of the rotating magnetic head, but when converted into a length of time, 180° of rotation angle is 262.5H (LH is one horizontal period ), so the time length of section 24 becomes.

Therefore, as shown in FIGS. 7A and 7B, for example, the section 24 is divided into a 1.5H section 241 in the first half and a 1.5H section 242 in the remaining half. As shown in FIGS. B and C, section 241 is a postamble section of all "1"s for the PCM audio data of section 23, and
42 is an index section. This index section 242 is entirely "0°5H" from the tip.
A clock run signal SCL of 1'' is recorded, and an index signal CDIX is recorded in the remaining IH section.

Then, the index signal CDIX is
As shown in the figure, the blocks BLKI to BLK6 are equally divided into blocks BLKI to BLK6 and end marks, and as shown in the figure, each block BLKI to BLK6 has a 3-bit header and an 8-bit ID code IDO to ID4. and an 8-bit CRC code for them.

In this case, blocks BLKI to BLK6 have ID codes IDO to ID4 recorded in the PCM audio data section 23.
corresponds to mode 1 to mode 6 to which the ID code ID
O~ID4 is the ID code ID0 recorded in section 23
- It is the same as ID4, and is a signal such as the absolute position on the magnetic tape 1, the cut number for each cut of the recorded content, the year, month, day, hour, minute, and second of recording.

Furthermore, the index signal CDIX in the index section 242 is similar to the signal in the audio track 2S,
The signal is converted into a pie-phase mark signal of 2.9 MHz when it is "0" and 5.8 MHz when it is "l" and then recorded.

According to such a recording format of the index signal CDIX, the rotating magnetic head diagonally crosses the magnetic track 2 during variable speed reproduction;
42 is as short as 1.5 horizontal intervals, so even during search playback at 30x speed, the rotary magnetic head will almost accurately track and operate the index interval 242, ensuring the index signal CDIX (ID code). can be played.

Furthermore, since the meaning of the ID code differs depending on modes 1 to 6, when using the ID code recorded together with the PCM audio data in section 23, six tracks must be played, and six tracks must be played. However, according to the above format, all the ID codes of modes 1 to 6 are recorded as the index signal CDIX in one index section 242, so one horizontal section of the section 242 is All you need to do is play it.
You can get the D code immediately.

Further, after recording the video signal and the audio signal, only the index signal CDIX can be recorded independently, and for example, a chapter signal or the like can be added to the edited magnetic tape 1.

[Problem that the invention seeks to solve]

In the recording format shown in Figures 6 and 7, P
A CM audio signal, a clock run signal ScL, an index signal CDIK, a video signal, etc. are recorded on the same magnetic track 2. - This is possible because the PCM recording system of the recording device is equipped with a recording/reproducing function for the index signal CDrX.

By the way, camera-integrated VTRs that do not record PCM audio signals, so-called camcorders [CAM], have become popular in recent years.
With Coder), it was not possible to record not only the PCM audio signal but also the clock run signal S CL + index signal CDIX, and only video signals and frequency-multiplexed audio signals could be recorded.

However, even with such a camcorder, if a control signal is obtained from a pulse output in synchronization with the rotational phase of the rotating magnetic head, and this control signal is delayed by about one field period of the video signal, this can be achieved. It is not impossible to set the index interval 242 based on the control signal.

However, when the index section 242 is set by delaying the control signal as described above, variations in the delay time tend to occur, and therefore variations and fluctuations occur in the set position of the index section 242. As a result,
There is a problem in that it is difficult to accurately set the index section 242 and record/reproduce signals in the index section, and an improvement has been desired.

Therefore, an object of the present invention is to record a control signal without delaying the control signal as described above even when there is no PCM recording function.
An object of the present invention is to provide an information signal recording device that can accurately set an index interval and accurately record an index signal and a clock run signal within the index interval.

[Means for solving problems]

In this invention, a magnetic tape is run diagonally at a constant speed over a predetermined angular range with respect to the rotating peripheral surface of an 11-rotation magnetic head, and information signals are supplied to the rotary magnetic head for predetermined periods of time to cause the magnetic tape to run diagonally across a predetermined angular range. In a helical scan type information signal recording device that is sequentially recorded as a magnetic track, there is provided a means for generating a first rotation detection signal synchronized with the rotational phase of a rotating magnetic head; , and means for generating a second rotation detection signal preceding the first rotation detection signal, the index section is set by the second rotation detection signal, and the signal is recorded in this index section. .

[Effect]

Every time the rotating magnetic head makes one revolution, a first rotation detection signal synchronized with the rotational phase of the rotating magnetic head is generated and output.

Further, a second rotation detection signal synchronized with the rotational phase of the rotating magnetic head is generated and output at a predetermined timing slightly preceding the time point at which the first rotation detection signal is generated and output. .

When the second rotation detection signal is output, a corresponding preceding switching pulse is formed, and a clock run signal and an index signal are supplied to the rotating magnetic head. The clock run signal is precisely set in response to the second rotation detection signal.

Index signals are recorded accurately.

Next, a switching pulse corresponding to the first rotation detection signal described above is formed with a delay of a predetermined timing, and the video signal is thereby supplied to the rotating magnetic head, so that the video signal is recorded after the index period p.

As a result, the index section is set prior to the video signal section, and the clock run signal and index signal are recorded.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an information signal recording apparatus as shown in FIGS. 1 to 5.

FIG. 1 shows the circuit configuration of a VTR as an information signal recording device. This VTR is a camera-integrated VTR that does not record PCM audio signals.

In FIG. 1, reference numeral 55 indicates a system controller (hereinafter referred to as system controller) that controls the operation of the VTR. When a mode switch 56 such as a recording switch or a playback switch connected to this controller is operated, the VTR is activated by the system controller 55. The operation mode is controlled to correspond to the operated mode switch 56.

Further, 34^ and 34B indicate rotating magnetic heads (hereinafter simply referred to as heads), and these heads 34A and 34B are
They have an angular interval of 180° from each other, are rotated at a frame frequency by a motor 62 through a rotating shaft 61, and the magnetic tape 1 is rotated at an angle of about 180°+1 with respect to the rotational circumferential surface.
It is run diagonally at a constant speed over an angular range of 0°. In this case, although not shown, the rotational phases of the heads 34A and 34B are servo-controlled so as to synchronize with the recorded video signal during recording and to correctly scan the magnetic track 2 during reproduction.

Therefore, as shown in FIG. 2A, in every other field period Ta, the head 34A scans the index section 100 at the beginning of the period Ta, and then scans the section 28 of the magnetic track 2. . Further, in every other field period Tb, the head 34B scans the index section 100 at the beginning of the period Tb, and then scans the section 28 of the magnetic track 2.

During recording, the color video signal Sc and monaural audio signal Sm are supplied to the recording processing circuit 31. Then, the FM luminance signal, the low frequency converted carrier color signal, and the FM
Frequency multiplexed signal Sf of audio signal and pilot signal
are successively taken out as shown in FIG. 2B, and this signal Sf is supplied to the switch circuit 32.

Incidentally, the rotating shaft 61 is provided with a pulse generating means 101, which synchronizes with the rotational phase of the heads 34A, 34B and generates a pulse P, which will be described later, every rotation of the heads 34A, 34B. A pulse PgH (second rotation detection signal) with a frame period output slightly in advance of the rotation detection signal is extracted as shown in FIG. 3. This pulse PgH is supplied to the signal forming circuit 103 through the shaping amplifier 102. Third
As shown in FIG. F, when the rectangular wave signal SWN formed in response to the pulse Pgs is extracted and this signal SwH is applied to the forming circuit 66, the pulse Ps immediately rises.

The pulse Ps is set at the H'' level for three horizontal periods during which the heads 34A and 34B operate the index section 100 with reference to the rising point of the pulse Ps formed in the forming circuit 66.

Note that the index signal CDIK is sent from the controller 52 that manages the index signal CDIK to the heads 34A and 34B in the section 10.
It is supplied to the recording processing circuit 51 in advance during a period when 0 is not being scanned.

When the pulse Ps is supplied to the recording processing circuit 51, FIG.
, F, during the Ps-“H” period, the clock run signal Set and the index signal CDIX are sequentially converted into the pie-phase mark signal Ss and sent to the recording processing circuit 5.
1.

Then, this signal Ss is transmitted during the field period Ta to [
Recording processing circuit 51 → switch circuit 32 → recording amplifier 33
B → is supplied to the head 34B through the signal line of the contact R of the switch circuit 67B, and during the field period Tb,
[Recording processing circuit 51 → switch circuit 32 → recording amplifier 3
3A→through the signal line of the contact R of the switch circuit 67A] is supplied to the feed 34A. Therefore, as shown in FIG. 3C and D, the clock run signal 5 is placed on the magnetic track 2 within the index section 100 prior to recording the signal Sf.
eL (2H) and index signal CDIX (IH) are recorded.

Further, a pulse generating means 63 is provided on the rotating shaft 61, and the pulse generating means 63 is arranged to generate a pulse generating means 63 for each rotation of the heads 34A, 34B.
A pulse P with a frame period synchronized with the rotational phase of 4B
g0 [first rotation detection signal] is taken out as shown in FIG. 3A. This pulse Pgo has a phase slightly delayed from the aforementioned pulse PgH, and is supplied to the signal forming circuit 65 through the shaping amplifier 64. Then, as shown in FIG. 2C and FIG. 3B, there is a period Ta.

The square wave signal Swo is inverted every Tb and is taken out as a switching pulse corresponding to the pulse Pga. This signal SW0 is formed later than the signal Sw by a time equal to the time that the pulse Pgo lags the pulse PgN. Moreover, since this signal Sw is supplied to the switch circuit 32 as its control signal, the switch circuit 32
is switched to a state opposite to that shown in the figure during periods Ta and Tb. Therefore, the signals Sf and Sf are alternately taken out from the switch circuit 32 during each period Ta and Tb, as shown in the second diagram.

These signals Sf and Sf are sent to the recording amplifier 33A.

33B, further switch circuits 67A, 67B
It is supplied to the heads 34A and 34B through the recording side contact R of the head.

Therefore, as shown in FIG.
8.28, which are sequentially recorded after the index section 100.

On the other hand, during reproduction, signals Ss and Sf are alternately reproduced from the magnetic track 2 by heads 34A and 34B as shown in FIG. 2G, and these reproduced signals Ss and Sf are reproduced by switch circuits 67A and 67B. The signal is supplied to the switch circuit 36 through the side contact P and further through the reproducing amplifiers 35A and 35B. Since the signal Swo is supplied to the switch circuit 36 as its control signal, the signal Sr is continuously taken out from the switch circuit 36, and the signal Ss is taken out every field period.

Then, the signal Sf from the switch circuit 36 is supplied to the reproduction processing circuit 37, and the original color video signal SC and monaural audio signal Sm are extracted.

Further, the signal Ss from the switch circuit 36 is supplied to the reproduction processing circuit 53, and the index signal CDI is converted from the signal Ss.
X is taken out, and this index signal CDIX is supplied to the controller 52 and used for cueing, etc.

FIG. 4 shows the recording processing circuit 51. This shows an example of the reproduction processing circuit 53, in which the portion indicated by the chain line is formed into a single-chip IC.

That is, in the figure, 45 indicates a clock forming circuit,
The clock generated thereby is used by the recording processing circuit 41. In addition to being supplied to the reproduction processing circuit 43, the recording processing circuit 51
．． The signal is supplied to the reproduction processing circuit 53. Further, 90 indicates a control signal forming circuit, in which various control signals are formed at predetermined timings with reference to the pulse Ps, and these control signals and the clock of the clock forming circuit 45 are used for each circuit. is supplied to

During recording, an index signal CDIX is output from the controller 52 during a period when the heads 34A and 34B are not scanning the index section 100, and this index signal CDIX is supplied to the buffer RAM 71 through the switch circuit 72. The address signal is supplied from the address forming circuit 73 to the RAM 71 through the switch circuit 74, and therefore the index signal CDIχ to be recorded is stored in the RAM 71.

Then, the heads 34A and 34B are in the index section 1.
When reaching the start edge 104 of 00 (see FIG. 5), the pulse Ps becomes "H" level, so the clock run signal ScL is output from the preamble forming circuit 81 for two horizontal periods, and this clock run signal ScL is supplied to the encoder 85 and the pie phase mark signal Ss
This signal Ss is output to the switch circuit 32.

Next, just before the heads 34A, 34B pass through two horizontal periods of the clock run signal section 105, an address signal is supplied from the address forming circuit 73 to the RAM 71 via the switch circuit 74, and the index signal CDIX is read out. This index signal CDIX is then supplied to the register 83 through the switch circuit 72 and converted from a parallel signal to a serial signal, and this serialized index signal CDIX is sent to the CRCC forming circuit 83.
The index signal CDIX to which the CRC code has been added is then supplied to the encoder 85 following the aforementioned clock run signal ScL and is converted into a pi-phase mark signal Ss.
s is output to the switch circuit 32.

Therefore, as shown in FIG. 5, an index section 100 is accurately set between the starting end of the magnetic track 2 and the video signal section 2. In a period of 2H from the start end 104 of this index section 100, the clock run signal SeL and then the IH index signal CDIX are recorded. Note that a clock run signal section 105 is formed in the first half of the clock run signal SCL, and the clock run signal section 105 is
The latter 0.5H period of CL and the index signal C of IH
DIX forms an index signal section 106 of 1.5 H. This clock run signal ScL has a total of 2
Since there is an H period, the followability of the clock formed by the PLL to the reproduced data can be greatly improved, and data reading errors can be prevented.

On the other hand, during reproduction, the signal Ss from the switch circuit 36 is supplied to the decoder 86 to decode the index signal CDIX.
The index signal CDIX is supplied to a C check circuit 87, and an error check of the index signal CDIX is performed using the CRC code.

Then, the index signal CD from the check circuit 87
IX is supplied to the register 88 and converted from a serial signal to a parallel signal, and this parallelized index signal CDIX is sent to the RAM 71 through the switch circuit 72.
will be written to. Note that at this time, the address forming circuit 7
3, the address signal is supplied to the RAM 71 through a switch circuit 74.

When the writing of the index signal CDIX is completed, the address signal is supplied from the controller 52 to the RAM 71 through the switch circuit 74, the index signal CDIX is read out, and the read index signal CDIX is sent to the controller 52 through the switch circuit 72. After that, processing corresponding to the index signal, such as cueing, can be performed.

〔Effect of the invention〕

In this invention, a switching pulse is formed by generating and outputting a first rotation detection signal that is synchronized with the rotational phase of the rotating magnetic head, and a first rotation detection signal that is synchronized with the rotational phase of the rotary magnetic head and is smaller than the first rotation detection signal. also generates and outputs a preceding second rotation detection signal to form a rectangular wave signal Sw, sets an index section based on this rectangular wave signal SWN, and records a signal in this index section. .

Therefore, according to the present invention, even if there is no PCM recording system, the position of the index section can be set accurately without delaying the control signal as described above, and the index signal and clock run can be accurately set within the index section. This has the effect that signals can be recorded.

Further, according to the embodiment, within the index interval,
Since the clock run signal is recorded over a period of 2H, the followability of the clock formed by the PLL to the reproduced data can be greatly improved and the phases of the clock and the reproduced data can be synchronized more accurately. This embodiment also has the effect of preventing data reading errors and allowing various data to be read accurately.

Furthermore, since the index signal can be recorded at an appropriate position, operations such as cueing and editing can be easily performed, and the recorded video signal can be fully utilized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the entire circuit showing one embodiment of the present invention, FIGS. 2 and 3 are timing charts of the circuit shown in FIG. 1, and FIG. 4 is a recording and playback diagram shown in FIG. 1. A block diagram of some circuits showing an example of a processing circuit, FIG. 5 is an explanatory diagram showing that an index section is set on a magnetic track, FIG. 6 is a route map showing a conventional track format, and FIG. 7 is a diagram showing a conventional track format. FIG. 7 is a partially enlarged explanatory diagram of a recording format showing the configuration of the postamble section in FIG. 6; Explanation of main symbols in the drawings 1: Magnetic tape, 2: Magnetic track, 100, 242
: Index section, 28: Video signal section, 34A
, 34B: Rotating magnetic head, 63, 101: Pulse generating means, 105: Clock run signal section, 10
6: Index signal section, 104: Starting end, 5et=
Clock run signal, CDIX: index signal,
Pg. , pgH:/Ma, Reyu, S W a, S w
H: Square wave signal. Agent Patent Attorney Tadashi Sugiura Chi-on β/) lko Seki Figure 4

Claims (1)

[Claims] A magnetic tape is run obliquely at a constant speed over a predetermined angular range with respect to the rotating peripheral surface of a rotating magnetic head, and information signals are supplied to the rotating magnetic head for a predetermined period of time to In a helical scan type information signal recording device that is sequentially recorded on a tape as diagonal magnetic tracks, means for generating a first rotation detection signal synchronized with the rotational phase of the rotating magnetic head; synchronized with the rotational phase of the first
means for generating a second rotation detection signal that precedes the rotation detection signal of the second rotation detection signal, an index section is set by the second rotation detection signal, and a signal is recorded in this index section. Signal recording device.