JPS63113882A - Magnetic reproducing device for information signal - Google Patents

Abstract

PURPOSE:To execute the action of an erasing code without fail by neglecting an erasing code reproduced by the detecting output and an index signal reproduced for a prescribed period before or after the erasing code when the reproduction of the erasing code is detected. CONSTITUTION:At the time of the reproduction of a magnetic tape, the output of a decoder 86 is supplied to a detecting circuit 91, and it is checked whether or not an erasing code IERS is included. When the code IERS is detected, the detecting output is supplied through a control circuit 92 to a checking circuit 87, an index signal CDIX latched in the circuit 87 is cleared and the CRC checking of a prescribed period circuit 87 is prohibited. Consequently, only when the code IERS is not recorded, the signal CDIX is removed from the circuit 87, and when the code IERS is obtained and the signal CDIX is obtained before and after it, they are neglected and not outputted from the circuit 87. Thus, the action of the erasing code can be executed without fail.

Description

[Detailed description of the invention] The explanation will be given in the following order.

A. Industrial application field B. Summary of the invention C Conventional technology D. Problem that the invention aims to solve E. Means to solve the problem (Figure 1) F. Effect G Example Gl first embodiment (Figures 1 to 3) G2 Other examples (Fig. 4, Fig. 5) Effect of H invention A. Industrial application field The present invention relates to a magnetic reproducing device for information signals.

B. Summary of the Invention The present invention provides a magnetic reproducing device for information signals such as 8 mm video, in which an erasure code is recorded as an index signal in the recording track of the information signal separately from the information signal. This erase code is made to work reliably when

C. Prior Art The magnetic tape track format for 8 mm video is determined as shown in FIG.

That is, in the same figure, (1) is a magnetic tape, (2)
indicates a magnetic trunk, this track (2) is formed obliquely to the tape (1) and at a rotation angle of 221° of the rotating heads by two rotating magnetic heads having an angular spacing of 180° from each other. The corresponding length is formed or scanned. Then, from the tip of the track (2), a section (2S) corresponding to a rotation angle of 36° of the rotary head is used for audio signals, and a remaining section (2V) corresponding to a rotation angle of 185°.
is used for video signals.

The audio track (2S) is divided into sections (21) to (25) as shown in the figure, and section (21) is the scanning start section of the rotating head (head entry section), and section (2).
2) is a preamble section where clock run-in is recorded and played back, (23) is an audio data section where a PCM audio signal is recorded and played back, and (24) is a postamble section for back margin during after-recording.
5) is a truck (2S).

This is a guard interval for (2v).

In addition, in this case, the PCM audio data of section (23) is
A stereo audio signal for one field period is time-base compressed and converted into a PCM signal, and is also converted into a signal having an error correction code, an ID code, and the like. And the interval (
The signals 22) to (24) are recorded after being converted into pi-phase mark signals of 2.9 MHz when the value is "01" and 5.8 MHz when the value is "1".

Furthermore, the video track (2v) has a guard section (25)
Subsequently, it is divided into a section (28) corresponding to a rotation angle of 180° and a section (29) corresponding to a remaining rotation angle of 5°,
In the section (28), the l field of the frequency multiplexed signal of the FM signal modulated by the luminance signal, the low frequency converted carrier chrominance signal, the FM signal modulated by the monaural audio signal, and the pilot signal is included. Recorded and played back. Furthermore, the section (29) is the scanning end section of the rotating head (head separation section).

According to such a format, the audio data section (2
3) Since an ID code is recorded at the same time as the audio signal, various data such as recording date, absolute position, program number, etc. can be recorded as this ID code, which is extremely useful for cueing and editing during playback. It's convenient.

However, 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, in order to correctly reproduce the ID code, the section (23
) must be correctly scanned by the rotating head over a considerable length.

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

Therefore, the postamble section of the audio track (2S) (
24) is considered to record and reproduce an index signal such as an ID code.

That is, this section (24) is 2.06 of the rotating head.
The length is equivalent to 180°, but when converted to the length of time, the rotation angle of 180° is equal to 262.5H (IH is 1 horizontal period), so the time length of section (24) is: Become.

Therefore, for example, as shown in FIG. 7A and B, the section (24
) is the first half of the 1.5H section (241) and the remaining second half of the 1.5H section (241).
5H section (242). And, the same figure B,
As shown in C, section (241) has P of section (23).
All "1" postamble signals for the CM audio data are recorded, and the section (242) starts from 0.
A preamble signal of all "1" is recorded in the 5H section, and a coding index signal C is recorded in the remaining IH section.
DIX is recorded.

Then, the coding index signal CDIX is generated from blocks BLKI to BLKI as shown in the figure.
It is equally divided into BLK6 and a spare block BAUX, and as shown in FIG. E, blocks BLK1 to BLK6 have a 3-bit mark code and an 8-bit ! D code ID
0-ID4 and an 8-bit CRC code for them.

In this case, the block BLKI-BLK6 is the ID code IDO to IDO recorded in the PCM audio data section (23).
Corresponding to modes 1 to 6 to which ID4 belongs, 10 codes summer DO to ID4 are the same as ID codes IDO to ID4 recorded in section (23), and tape (1)
These signals include the absolute position above, the cut number for each cut of the recorded content, the year, month, day, and hour, minute, and second of recording.

Further, when the index signal CDIX is erased or when it is unnecessary, a predetermined bit pattern, for example, an erase code IHR3 of all "1"s, is recorded as the index signal CDIX.

Then, the index signal CD in section (242)
Iχ is O as well as the signal in the audio track (2S)
2.9 MIIz when ``1'', 5.8 when ``1''
It is recorded after being converted into a pi-phase mark signal of MHz.

According to such a recording format of the index signal CDIX, during variable speed playback, the rotating head is placed in the trunk (2).
Although it crosses diagonally, the section (242) is 1.5
Since the horizontal section is short, for example, even during search playback at 30x speed, the rotating head scans almost parallel to section (242), or tracks almost correctly, and the index signal CDIX (ID code) is reliably scanned. Can be played.

Also, the meaning of the ID code differs depending on modes 1 to 6, so when using the ID code recorded together with the PCM audio data in section (23), six trunks must be played. , 6 field periods are required, but according to the above format, all the ID codes of modes 1 to 6 are recorded as the index signal CDIX in one section (242), so the section (242) It is only necessary to reproduce one horizontal section of , and the necessary ID code can be obtained immediately.

Furthermore, after recording the video signal Sc and the audio signals R and R, only the index signal CDIX can be recorded independently, and for example, a chapter number etc. can be attached to the edited tape (1). Or, after editing, if you no longer need the previous index No. 16 corx,
The erasure code can be IER3.

(Literature: Japanese Patent Application Nos. 1984-64554 and Japanese Patent Application Nos. 60-1
No. 61438, etc.) D Problems to be Solved by the Invention However, when the index signal CDIX is recorded in the postamble section (24) as described above, when erasing the index signal CDIX, that is, in the section (242). )'s index signal CDIX as the erase code II! When rewriting to RS, trouble may occur.

In other words, Figure 8A is a reproduction of the vicinity of the beginning of the audio track (2S) and video track (2v) in Figures 6 and 7A, but this is just a standard recording format. . In an actual VTR, when a PCM audio signal is after-recorded,
Due to mechanism errors, signal timing errors, etc., sections (22) to (24) may shift toward the track (28) as a whole, as shown in B in the same figure, or the sections (22) to (24) may shift toward the track (28) as shown in C in the same figure. Conversely, (22) to (24) may shift toward the starting end of track (2). Furthermore, when a PCM audio signal is recorded simultaneously with a video signal, the positions of sections (22) to (24) may shift due to similar errors, as shown in B and C of the figure.

Therefore, for track 2) where sections (22) to (24) are currently being recorded with deviations as shown in FIG. After-recording the PCM audio signal using a VTR that performs recording with a lag like this, and erasing code IE
I? When S is recorded, the recording result is as shown in the same figure. That is, new sections (22) to (24) are formed by after-recording, but at this time,
A section (242) having the erasure code IRES remains between the new section (24) and the video track (28).

When the rotary head scans such a track (2), the new section (242) erases the erase code l1l.
iR3 is obtained, and then an old index signal CDIX is obtained in the old section (242), which causes trouble when various controls are performed using the index signal CDIX.

Furthermore, track (2) recorded as shown in C of the same figure
In contrast, a VTR records with a shift as shown in Figure B.
When only the erase code IER3 is recorded independently using
Old interval with X (241).

(242) may be followed by new sections (241) and (242) having erasure codes IERS.

In this case as well, since the erasure code IER3 is obtained from the new section (242) and the index signal CDIX is obtained from the old section (242), trouble also occurs during reproduction.

This invention attempts to solve these problems.

E. Means for Solving the Problems Therefore, in the present invention, a predetermined function is added to the erasure code IER5 recorded in the section (242).

F During playback, the old index signal CDIX is ignored by the erase code IERS.

G Example G1 First Example In FIG. 1, (34A) and (34B) indicate rotating magnetic heads, and these heads (34A),
(34B) have an angular spacing 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 approximately 221° with respect to its rotating circumferential surface. is run diagonally at a constant speed over an angular range of . And in this case,
Although not shown, the heads (34A) and (34B
) is servo-controlled so as to synchronize with the recorded video signal during recording and to correctly scan track (2) during playback.

Therefore, as shown in FIG. 2A and FIG. 6, in every other field period 7'a, the head (34^) scans the section (2B) of the track (2), and at the same time scans the section (2B) of the track (2). In the previous 115 field period, the head (34A) scans the section (2S) before the section (28), and in the remaining every other field period Tb, the head (34B) scans the section (2S) before the section (28).
scans the section (28) of the track (2), and the head (34B) scans the section (28) of the track (2), and the head (34B)
will scan the section (2S) before the section (28).

At the time of recording, the color video signal Sc and the monaural audio signal Sm are supplied to the recording processing circuit (31), and the above-mentioned FM luminance signal and the low frequency-converted carrier color signal are processed.
A frequency multiplexed signal Sf of the FM audio signal and the pilot signal is continuously extracted as shown in FIG. 2B, and this signal Sf is supplied to the switch circuit 1tPf (32).

Further, for example, a pulse generating means (63) is provided on the rotating shaft (61).
are provided and one of the heads (34A) and (34B)
A pulse Pg having a frame period indicating the rotational phase of the heads (34A) and (34B) is extracted for each rotation, and this pulse Pg is supplied to the signal forming circuit (65) through the shaping amplifier (64) as shown in FIG. Like period T
A rectangular wave signal Sw that is inverted every a and Tb is extracted,
This signal Sw is switch times &! 3 (32) as its control signal, and the switch circuit (32) is switched between the state shown in the figure and the state opposite to that shown in the figure during periods Ta and Tb. Therefore, as shown in the figure, signals Sf and Sf are alternately taken out from the switch circuit (32) every period Ta and Tb.

Then, these signals sr, sr are sent to the recording amplifier (338).
(33B), furthermore, the switch circuit (67A)
, (67B) through the recording side contact R of Herad (
34^), (34B). Therefore, the ninth
As shown in the figure, tape (1) has a period Ta.

Signals sr and sr are video signal sections (28) for each Tb.

(28) are sequentially recorded.

Furthermore, the stereo audio signal R is a recording processing circuit (41
), and the ID code (index signal CDIX) is supplied to the controller (52) that manages the ID code (index signal CDIX).
is supplied to the processing circuit (41).

Further, the signal Sw is supplied to the forming circuit (66), and as shown in FIG. 2, the head (
34A ) and (34B ) are the intervals (22) and (
23), a pulse Ps of "H" level is formed, and this pulse P3 is supplied to the processing circuit (41) to generate a signal for one field period, as shown in FIG. Then, the R and ID codes are compressed on the time axis during the period of Ps="H" and converted into PCM signals, and the R and ID codes are
) is added, and then converted into a pi-phase mark signal Sp and extracted.

Then, this signal Sp is transmitted from OR circuit (42) to switch circuit (32) to amplifier (33) during field period Ta.
B) → is supplied to the head (34B) through the signal line of contact R of the switch circuit (67B), and during period Tb, OR circuit (42) → switch circuit (32) → amplifier (33
^)→It is supplied to the head (34A) through the signal line of contact R of the switch circuit (67^). therefore,
The track (2) has a signal Sf in the video signal section (28).
Prior to recording the signal Sp, that is, the preamble signal and the PCM audio data, are recorded in sections (22) and (23).

Also, the index signal CD from the controller (52)
IX (T Day-de) is supplied to the recording processing circuit (51), and at the same time, the pulse P is supplied to the forming circuit (66).
The heads (34A) and (34B) move in the section (34A) and (34B) based on the rising point of s (or the changing point of the signal Sw).
During the 1st and 5th horizontal periods during which 242) is being scanned, a pulse Pi that goes to the "H'" level is formed, and this pulse Pi is supplied to the processing circuit (51), and as shown in H in the same figure, the pulse Pi becomes pt-
During the "H" period, the preamble signal and index signal C are converted into a pie-phase mark signal Si and taken out.

Then, during the field period Ta, this signal Si changes from the OR circuit (42) to the switch circuit (32) to the amplifier (33).
B) - is supplied to the head (34B) through the signal line of contact R of the switch circuit (67B), and the field period T
In b, OR circuit 14 (42) - switch circuit (32) →
The amplifier (33A) is supplied to the head (34A) through the signal line of contact R of the switch circuit (67^). Therefore, in track (2), the signal Sp is recorded in the PCM audio data section (23), and then the signal Sp is recorded in the section (24).
2), the signal St, that is, the preamble signal and index signal CDIX is recorded.

Therefore, each signal is recorded on track (2) in the format shown in FIG.

On the other hand, during playback, the heads (34A) and (34
The signals Sp, SL and Sr are alternately reproduced from the track (2) by the switch circuit (67
It is supplied to the switch circuit (36) through the reproduction side contact P of , the signal Sf is continuously taken out from the switch circuit (36), and the signals Sp and St are taken out for each field period.

Then, the signal S 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 signals sp and s+ from the switch circuit (36) are supplied to the reproduction processing circuit (43), and the pulse Ps
is the processing port II! 3 (43) as a window signal, and the original stereo audio signal R is extracted from the signal sp.

Furthermore, a signal Sp from the switch circuit (36).

St is supplied to a reproduction processing circuit (53), and an index signal CDIX is extracted from the signal S1. However, in this case, the processing circuit (53) detects whether or not the reproduced index signal CDIX is the erasure code IER3, as will be described in detail later, and the erasure code II!
When it is not R5, its index signal CDIX
is supplied to the controller (52) and erase code IER
3, this code II! corresponds to the state of DSE in FIG. The signals of R3 itself and several horizontal periods before and after are ignored.

In the controller (52), the processing circuit (
When the index signal CDIX is obtained from 53), processing such as cue 7, absolute position, cut number, etc. is performed using this index signal CDIX.

FIG. 3 shows an example of the processing circuits (51) and (53), in which the portion indicated by the chain line is implemented as a single-chip IC.

That is, in the same figure, (45) indicates a clock forming circuit, and the clock formed by this is transmitted to the processing circuit (45).
1) and (43) as well as processing circuits (51) and (53). Also, (55
) indicates a control signal forming circuit, in which various control signals are formed at predetermined timings based on the pulse P1, and these control signals and the forming circuit (
45) is supplied to each circuit.

During recording, an index signal C old is output from the controller (52) during a period when the heads (34^) and (34B) are not scanning the section (242), and this index signal CDIX is sent to the switch circuit (72). ) is supplied to the buffer RAM (71), and an address signal is also supplied from the controller (73) to the RAM (71) through the switch circuit (74), so that the index to be recorded is supplied to the RAM (71). Signal C port IX is stored.

Then, the head (34^) and (34B) are the section (
242), the pulse Pi becomes H.
”, a preamble signal is output from the preamble forming circuit (81) over a 0.5 horizontal period, and this preamble signal is supplied to the encoder (85) and encoded into the pi-phase mark signal St. Sl is output to the OR circuit (42).

Next, when the head (34A), <34B) passes through the 0.5 horizontal section of the section (242), the RA is transmitted from the address forming circuit (73) through the switch circuit (74).
The address signal is supplied to M (71), the index signal CDIX is read out, and this index signal CDI
X is supplied to the register (83) through the switch circuit (72) and converted from a parallel signal to a serial signal,
This serialized index signal C[lIX is C
The index signal CDIX to which the CRC code is added is supplied to the RCC forming circuit (84) and is supplied to the encoder (85) to form the signal Si.
This signal St is output to the OR circuit (42). Further, when index signal CDIX is to be used as erasure code IER5, the erasure code fERs is supplied from the formation circuit (82) to the encoder (85) and converted into signal Si, and this signal Si is used as index signal C
An OR circuit (42) is output instead of the signal Si from DIX.

Therefore, the preamble signal and index signal CDIX are recorded in section (242).

On the other hand, during playback, the signal S from the switch circuit (36)
p, Si are supplied to a decoder (85) to decode the index signal CDIX, and this index signal C
DIX is supplied to the CRCC check circuit (87) and C
An error check is performed on the index signal CDIX using the RC code, and the index signal CDIX subjected to the error check is scanned over several horizontal periods, that is, when the heads (34A) and (34B) scan at least the guard interval (25). It is held or latched by the check circuit (87) for a certain period of time.

At the same time, the output of the decoder (86) is supplied to the detection circuit (91) and the heads (34A) and (34B)
) is scanning sections (24) and (25),
It is checked whether the output of the decoder (86) contains the erasure code IEIIS, and the erasure code IER is checked.
3 is detected (this is the case of D1E in FIG. 8), the detection output is supplied to the check circuit (87) through the control circuit (92) and the check circuit (87)
The index signal C, which is latched in the old index signal, is cleared (this is to deal with the state shown in E in the same figure), and since the head (34^) and (34B) are detected, the head (34^) and (34B) are in the interval (24
) and (25), the CRC check of the check circuit (86) is prohibited (this is to deal with the situation shown in the figure).

Therefore, from the check circuit (87), the interval (24
2), the index signal CDIX is taken out only when the erasure code IERS is not recorded, and the erasure code IERS is extracted.
When ER5 is obtained, even if index signal CD[X is obtained before or after it, this is ignored and is not output from the check circuit (87).

Then, the index signal CDfX from the check circuit (87) is supplied to the register (88) and converted from a serial signal to a parallel signal, and this parallelized index signal CDTX is sent to the RAM (71) through the switch circuit (72). written. In addition, at this time, the RA is connected from the formation circuit (73) through the switch circuit (74).
The address signal is supplied to M (71).

When writing of the index signal is completed, an address signal is supplied from the controller (52) to the RAM (71) through the switch circuit (74), and the index signal CDIX is read out. is taken into the controller (52) through the switch circuit (72), and thereafter, processing corresponding to the index signal, such as cueing, is performed.

Thus, according to the present invention, during reproduction, the erasure code I
When ER5 is played, the index signals C before and after it
Since DIX is ignored, as shown in Figure 8, E, even if the newly recorded erase code [R5 has not completely erased the old index signal CDIX, the index signal CDIχ has been erased. Therefore, the effect of the erasure code I uR3 is ensured.

G2 Other Embodiments FIG. 4 shows another example of the index signal. That is,
Format) A is the above-mentioned signal formant, and for format B, in the section (292), a preamble signal of all "L" is recorded in the section 0.5H from its tip, and the remaining lH All "01s" are recorded as the cue index signal C11IX in the interval, and in the case of format C, all "1"s are recorded as the cue index signal C[IIX in format B.

Furthermore, in the case of formats D and E, the interval (291
) is made equal to the interval (292) of formats B and C, and the interval (292) is made equal to the interval (292) to the format (
292).

The above format is used in any of the types I to II shown in FIG. 5, depending on the grade of the VTR.

That is, as shown to my countrymen, it is assumed that the recording on tape (1) is divided into a plurality of cuts (the term "cut" here includes the concept of chapters, etc.). Then, in the case of type (2), the index signal is recorded in format A regardless of each cut, as shown in the mortar in the figure. Therefore, this type (■) uses the index signal CDlX17) I in higher models (high-end models)
Information such as absolute position can be obtained by checking D codes IDO to ID5.

Furthermore, in the case of type H, the index signal is recorded in format B for, for example, 10 seconds from the beginning of each cut, and the index signal is recorded in format C for the remaining period, as shown in FIG. Therefore, this type ■ is "01." in lower model (low cost model).
This can be used to locate the beginning of each cut by determining 1".

In the case of type ■, as shown in the same figure, index signals are recorded alternately for each track (2) in formats A and B for, for example, 10 seconds from the beginning of each cut, and for the remaining period, index signals are recorded in format A. and C to track (2
), index signals are recorded alternately. Therefore, according to this type (2), lower models can locate the beginning of each cut by determining "0" and "1" of the index signal CUIX, and higher models can use the ID codes IDO to ID5 of the index signal CDIX. Information such as absolute position can be obtained by checking. In other words, it is compatible with lower models and higher models.

Furthermore, in the case of type ■, as shown in the same figure, the index signal is recorded in format D for, for example, 10 seconds from the beginning of each cut, and the index signal is recorded in format E for the remaining period.
The index signal is recorded. Therefore, according to this type (2), in the lower model, the index signal CUIX is 0'.

By determining “1”, you can locate the beginning of each cut.
For higher-end models, ID code I of index signal CDIX
Information such as absolute addresses can be obtained by checking DO to ID5, and it is also compatible with lower and higher model models.

Note that the above is for 8mm video, but
The present invention can also be applied to a multi-track machine that divides the video signal section (28) into a plurality of sections and records or reproduces information signals such as PCM audio signals and still image video signals in the divided sections. Furthermore, in formats A to C, the section (241') can be made into a no-signal section, and other index signals can be recorded and reproduced. Also, in the formation circuit (82), the erasure code 1εl? s, and the detection circuit (91) and control circuit V& (92) generate the erase code II! Instead of prohibiting the processing of old index signals according to R3, the old index signals may be ignored in the controller (52),
The start code ISTC and the end code IBNC can also be generated by the controller (52). Furthermore, it can also be used when recording and reproducing index signals in sections (21), (22), and (29).

Effects of the Invention According to this invention, when the erase code I[2R5 is reproduced during playback, the index signals CDIX before and after it are ignored. Even if the code I ER5 has not completely erased the old index signal CDIX, the index signal CDIX has been erased, thus ensuring the effect of the erase code I ER3.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an example of the present invention, and FIGS. 2 to 8 are diagrams for explaining the same. (31), (41), and (51) are recording processing circuits; (37); (43) and (53) are reproduction processing circuits.

Claims (1)

[Scope of Claims] Information signals are sequentially recorded on one diagonal magnetic track for each predetermined period, and the magnetic track has an index section at a position where the information signal is not recorded. In a helical scan type magnetic reproducing device that reproduces the information signal using a rotating magnetic head from a magnetic tape on which an index signal is recorded in the index section, an erasure code of a predetermined bit pattern is reproduced as the index signal from the index section. When the reproduction of this erasure code is detected, the reproduction code is used to ignore the reproduced erasure code and the index signal reproduced during a predetermined period before or after this erasure code. A magnetic reproducing device for information signals.