JPS60247867A - Rotary head type pcm recorder - Google Patents

Abstract

PURPOSE:To stabilize the operation of a synchronizing signal detecting circuit to improve the effect of synchronizing signal extraction, by making the width of recording area on a track integer multiple of the cycle of the synchronizing signal. CONSTITUTION:When a case where the gap is set four times wider than the cycle of a synchronizing signal is considered as an example in the figure, the signal (h) is a reproduce signal and the block No.n is the last block of the previous area, and then, the block No.1 is the first block of the next area. The signal (i) is a gate signal and the (D) is a gate pulse produced by the previous synchronizing signal and the (E), (F), (G), (H), and (I) are gate pulses produced by the (K) of the signal (j). That is to say, gate pulses whose cycles are equal to the cycle of the synchronizing signal are repeatedly produced by using the timing of (K) as a reference. The (L) is obtained by extracting the synchronizing signal extracted from the block No.1 from the (I) of the gate signals. In the same way, synchronizing signals are continuously extracted when synchronizing signals (N), (O), (P), and (Q) are recorded during the gap period of the reproduced signal (k).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary head type digital audio tape recorder, and more particularly to a rotary head type PCM recorder suitable for a signal format in which the recording area is divided.

As the demand for higher quality audio equipment has increased, the technology for recording and reproducing information on magnetic tape or rotating disk media using the PCM system has progressed, and products are now being supplied.

Furthermore, due to the diversity of recent informatization, high quality audio information,
There is an increasing demand for recording and reproducing information on the same medium with associated high-quality image information.

However, in the past, no product media or technology existed to meet this demand. A closely related system is the VTR, which records audio signals using PCM8.
wm Video system, which is not necessarily suitable as a conventional example, but I will explain it a little for comparison (
.

FIG. 1 shows the tape format for 8 m Video. 1-1 and 1-2 respectively indicate the edges of the magnetic tape, and the tracks are structured as 1-3. This 1 track contains 1-4 audio PCM signals.
, the image information is in the area 1-5, and the audio PC is in the area 1-5.
Clock line signals for M signals 1-4 are recorded in areas 1-6. In this case, image information 1-5 is FM modulated and recorded. The angles in the figure indicate values for NTSC7 format expressed in cylinder angles.

Here, image information 1-5 is recorded as an analog signal of one field per track, and is recorded in an area of 180°.

The audio PCM signal is recorded as a digital signal which is sampled at twice the frequency of the horizontal periodic signal and compressed from 10 bits to 8 bits by performing a predetermined noise reduction process.

Furthermore, when the recording area is divided, in order to correctly extract signals for each area, it is necessary to correctly detect a synchronization signal and generate a data clock. However, it is not possible to determine whether the first synchronization signal in each area is correct or not. For this reason, each area required an area for recording a signal for pulling in a synchronization signal.

This will be explained from the synchronization signal detection method.

The synchronization signal detection method will be explained with reference to FIG. The synchronization signal is a specific pattern, and this pattern is first detected. However, the signals detected from this pattern include those having the same pattern as the synchronization signal in the signal pattern or the same pattern as the synchronization signal generated due to dropout, etc., and are not necessarily synchronization signals. In order to detect this erroneously detected synchronization signal pattern, we use the fact that the synchronization signal period is constant, measure the interval of signals detected from the pattern, and synchronize only when it is equal to the synchronization signal period. There is a way to use it as a signal.

For example, when a signal as shown in b) in the same figure comes, only the signal separated by Tsyn from the first signal is extracted.

That is, only the signal that has passed through the gate signal b) is confirmed as a synchronization signal.

However, in this case, as shown in d) in the same figure, a signal starting with the synchronization signal of the no.tsuchi part is input, and the pattern shown in e) -
When a scattered power is generated, the synchronization signal (a) of the first block cannot be determined because there is no reference pulse in the signal f).

However, the signals (b), e→, etc. from the second block onward are gated by the gate signal f) to generate the output zr).

Therefore, there is a drawback that the first block cannot always be input. In other words, when recording is performed by dividing into areas, data of the first block of the same area cannot be obtained.

The above operation will be explained in more detail with reference to FIG. 2C.

First, the region ψa is a region such as a gap, and ψS is a signal region.

This signal a is a reproduced signal to which a synchronization signal pattern SYN of a predetermined length, e.g., 8 bits, is added, with each block having a predetermined length, e.g., 160 bits. This is the signal pattern in which an error occurred.

b shows the synchronization signal detected from a.

This is an example in which the synchronization signal of the fourth block is missing.

C is a detection gate pulse, and if a synchronization signal is lost, it will remain open until the next synchronization signal arrives (this is an example of a method. In other words, there is no synchronization signal in the region of ψa, so it will continue to open and close. .Next, gate C1 is set based on the timing of
generate. Gate C! , and so on. Since no synchronizing signal is detected at gate C4, the next gate C3 continues to open until a periodic signal is detected, and closes at synchronizing signal b-4.

The synchronization signals detected by the above operation are dl and d,
The other signals in the dashed line indicate signals to be supplemented because they cannot be detected or confirmed.

That is, the circuit output includes the confirmed detection signal and the supplementary signal. Here, the broken line portion of the ψa region indicates an arbitrary signal or a supplementary signal from the previous region.

In this way, the first detection signal b1 of the ψS area cannot be confirmed and is therefore not output, and furthermore, the supplementary signal from ψa or the previous area does not necessarily match.

The purpose of the present invention is to solve the problems of the prior art described above.
An object of the present invention is to provide a method for improving the ability to detect synchronization signals in signals recorded on a recording medium by dividing into areas in a rotary head type PCM recorder that records and reproduces image information and audio signals in high quality.

The present invention facilitates signal synchronization in a system in which recording areas are divided and recorded.

The present invention will be explained below using specific examples.

Here, as an example, the previous 8■Video 7#
- Explained by Matt.

The area 1-6 in FIG. 1 is the area of the PLL signal, ie, the clock line, and has a 3H period length in the case of NTSC.

A synchronizing signal pattern is recorded in this clock line area 1-6 at synchronizing signal intervals as shown in FIG. That is, Figure 3a
) has a conventional signal configuration, and simply clock line signals are recorded in areas 1-6. On the other hand, Figure b) shows the signal configuration of the present invention, in which in addition to the clock line signal in areas 1-6, a synchronization signal pattern is added at the synchronization signal period in areas 1-4. By doing this, the detection of the synchronization signal is performed by first detecting the synchronization signal in the clock line region 1-6 before detecting the synchronization signal in the signal in the region 1-4, and then detecting the synchronization signal in the signal. Therefore, highly accurate extraction is possible from the first synchronization signal in region 1-4. Here, Figure 3b
) are the synchronization signal regions, and the intervals are also set in regions 1-6 so as to be equal to the synchronization signal period T of the PCM signal in regions 1-4, respectively.

FIG. 3C) is an enlarged view of a part of FIG.

FIG. 3-4 shows a clock line signal. Here area 1
If −6 is not an integer multiple of the period T, the synchronization signal regions of the region 1-6 are arranged sequentially at the period T starting from the synchronization signal of the signal region 1-4.

The present invention will be explained below using other specific examples. As an example, a PCM recorder using a rotating head type two-head helical scan type tape recorder will be described.

An embodiment of the present invention will be explained with reference to FIG. 4a).

4-8 represents the magnetic tape, 4-9 represents the track, θ represents the track angle, A represents the tape width, W represents the effective tape width, L represents the track length, vt represents the tape feed speed, and vh represents the relative speed. .

FIG. 4b) shows a rotating head cylinder (hereinafter referred to as cylinder) 4-1 and a wrap angle 4-7,
Cylinder 4-1, magnetic head 4-2.4-3. tape 4
-4. Guide posts 4-5, 4-6 and N represent the number of revolutions of the cylinder 4-1, and the number of rotations of the fourth cylinder is determined by each head.
A recording track as shown in Figure a) is created.

FIG. 5 is a track area layout diagram expressed in cylinder angles when the diameter φ of the cylinder 4-1 in FIG. 4b) is set to a predetermined value.

In Fig. 5, 5-1 and 5-2 are margin zones for the start and end of signal writing, respectively, and 5, 3.4, and 5 are clock lines for subcodes 5-6 and 7 and PCM signal 5-8. Signal bands 5-11, 12 and 16 are after-recording margin bands to prevent old data from being left unerased in the event that a timing error occurs during after-recording and the recording area is shifted.
-9 and 10 are tracking signal bands, 5-14.1
5.16 and 17 are gap bands between each area, and each signal is divided into areas and recorded.

Here, the recording pattern on the track is divided into areas as shown in FIG. 5, and unlike the case where each piece of information is multiplex recorded, the same recording method, ie modulation method, recording density, etc. can be used.

This embodiment relates to signal formats for interval differences in margin areas, clock line areas, block gap areas, etc. for these fine signals.

FIG. 6 is an enlarged view of a part of the track area and layout shown in FIG. for example? a/ is the PCM signal area or subcode area, ψa' is the PCM signal or subcode clock line signal area, and ψp' is the margin area, block gap area, etc., which are expressed in angles. be.

Here, pa'block is equal to ps'block, set to an integral multiple of ψa'block, and ψp'b
Set equal to lock.

By taking it in this way, it matches the synchronization signal period, so 9
When entering the ψS area from the p area via the ψa area, the synchronization signal can be extracted immediately.

Furthermore, by recording at least a synchronization signal pattern in the region of ψa with the same period, the synchronization signal is 95% from the region of ψp.
It is possible to continuously extract up to the area of .

That is, the synchronization signal is extracted from the synchronization signal pattern, but the same pattern may exist in the signal or the same pattern may be generated by mistake. For this reason, a correct synchronization signal is extracted by extracting a synchronization signal pattern, measuring the interval between each other synchronization signal pattern, and comparing whether the same interval is an integral multiple of the period of the synchronization signal. Therefore, since the interval of the first synchronization signal cannot be measured, there is a possibility that it may not be possible to determine whether or not it is a correct synchronization signal. Therefore, it is necessary to provide a synchronization signal in advance. In the present invention, the first synchronization signal can be extracted by setting the interval to be an integral multiple of the synchronization signal of the previous area. Furthermore, the effect can be further increased by recording a synchronizing signal pattern in the region of ψa' at the synchronizing signal period.

Explain the operation of the synchronization signal detection circuit based on the method of the present invention!
A. This will be explained below with reference to FIG.

First, in the case of A in the figure, for ease of explanation, the gap is set to four times the synchronization signal period.

Signal h) is a reproduction signal, block number n is the previous area,
This is the last block of the area, and the same number 1 is the first block of the next area.

Signal i) is a gate signal, 2 is generated by the previous synchronization signal, and E, H, G, J and S are generated from L of signal j). That is, a gate pulse whose period is equal to the synchronization signal period is repeatedly generated with reference to the timing of the signal.

The synchronization signal extracted from block number 1 is extracted from the gate signal to obtain O.

Similarly, if the synchronizing signal strength, Y, Y, and Y are recorded in the gap period of each B (reproduced signal k), the synchronizing signals are extracted continuously.

FIG. 8 shows an example in which the signal area is divided and other signals are placed in the area ψX.

a) is a recording pattern, and the areas on both sides of area qx are signal areas. Here, the block interval of the signal is ψb l
ock, and b) indicates the timing of the synchronization signal in the signal. As shown in the figure, the synchronization signal is missing in the fX region.

In the present invention, by setting the area ψa to an integer multiple of ψblock, the synchronization signal at timing 8 in b) of the same figure can be changed to
It is possible to determine whether or not the signal is a synchronous signal by setting a timing that is five times the synchronous period from the synchronous signal at the timing of .

Furthermore, by superimposing and recording a synchronizing signal in the area ψX, the operation of the aforementioned synchronizing signal detection circuit can be stabilized.

In the above embodiments of the present invention, the gap between the still image (or image) signal area and the audio signal area is mainly explained when the two areas are divided, but the gap area between the still image (or image) signal area and the audio signal area is also explained. When a recording area on a track is divided and recorded using another control signal or the like, a similar effect can be obtained by making the width of the area an integral multiple of the synchronization signal period.

Further, when the signal block lengths of the two-headed regions are different, the effect of synchronization signal extraction can be improved by setting the gap interval to an integral multiple of the signal block length of the subsequent region.

According to the present invention, in the synchronization signal detection replenishment circuit, the synchronization signal can be detected quickly even if it enters the next area because the backward a line period, etc. is an integral multiple of the synchronization signal period or the synchronization signal is included in the synchronization signal. 3

[Brief explanation of drawings]

Fig. 1 is a tape format diagram of B and Video, Fig. 2 A, Fig. 2 B, and Fig. 2 C are timing chart diagrams showing a synchronization signal detection method, Fig. 3 (al is a conventional signal configuration, Figure 3 (bl is a signal configuration diagram of the present invention, Figure 3 (
C1 is a partially enlarged view of FIG. 3(b), FIG. 4(a) is a tape format diagram, FIG. 4(b) is a diagram showing the rotating head and tape winding, and FIG. 5 is a diagram of the book. FIG. 6 is an enlarged view of the track area arrangement, FIG. 7 is a time chart showing the synchronization signal detection operation, and FIG. 8 is a diagram of the general track area arrangement. This is an enlarged view. 1-1.2...Edge of magnetic tape, 1-6.
...Track, 2-1...Magnetic tape,
6-1... Rotating head cylinder, 5-2.5.
...Magnetic head, 4-3...Unrecorded band. 12 countries to Umugi 214 β No. Yuro C Kaki + m 1! J31Σ b) Procedural amendment (formality) Indication of the case 1982 Patent Application No. 245862 Title of the invention
Iku with 11 cases of rotary head type PCM recorder correction Patent applicant name! 510'li, Type 4 manufactured by Hitachi
Contents of the personal amendment In accordance with the notes in the procedural amendment order sent on May 28, 1985, the typed stamp of the specification with the declaration and the explanation in Figure 3(C) added as attached. I'll submit it.

Claims (1)

[Claims] 1. PCM converts a plurality of analog signals, divides the converted signals into a predetermined number of signals, and encodes these divided signals into a predetermined error detection and correction code. A signal processing circuit is provided which divides these encoded signals into a predetermined number of blocks and generates blocks to which predetermined control signals and synchronization signals are added, and a circuit which generates control/display signals. When a predetermined modulation process is performed on both of these signals and the signals are recorded on a recording medium, an area on the recording medium for recording the PCM-converted signal and an area for recording the control/display signal is provided. In addition to the area to record the tracking signal and the above signals, there is also an area to record the tracking signal, an area to record the clock line signal for generating the clock pulse of the above signal, and an area to record the clock line signal for generating the clock pulse of the above signal, and when some of the above signals are rewritten. R A single head type PCM recorder, characterized in that the interval between the various areas or a plurality of areas is set to an integral multiple of the synchronization signal interval of the signal converted to the PCM or the control/display signal. PCM recorder. 2. A rotary head type PCM recorder as set forth in claim 1, characterized in that the interval between each region is set to an even multiple of the synchronization signal interval. 5. Percentage of Claims The rotary head type PCM recorder according to claim 1, characterized in that a synchronizing signal pattern is recorded in a clock line signal area and an unerased signal area.