JP2840746B2 - Digital signal recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a digital signal recording / reproducing apparatus for performing electronic editing.

[Summary of the Invention]

According to the present invention, a new composite digital signal is recorded on a recording medium in which a composite digital signal obtained by dividing a digital signal into a plurality of sectors and adding a synchronization signal and an identification signal to each sector is recorded by a helical scan method. In a digital signal recording / reproducing apparatus in which electronic editing recording is performed by a helical scan method, a head position of a sector is detected based on a synchronization signal and an identification signal in a composite digital signal reproduced from a recording medium, and a reproduction sector head position is detected. A reproduction sector head position detection circuit for generating a detection signal, and a reference sector head position window pulse for generating a reference sector head position window pulse indicating a predetermined allowable range of the head position of each sector in the composite digital signal reproduced from the recording medium The generation circuit and the reproduction sector head position detection signal from the reproduction sector head position detection circuit are: An edit enable / disable determination circuit that detects whether or not the reference sector start position window pulse from the quasi-sector start position window pulse generation circuit is within the window and generates a determination signal as to whether or not electronic editing recording is possible. With this configuration, it is possible to easily determine whether or not electronic editing recording is possible according to the degree of positional deviation in the scanning direction of a sector of a composite digital signal recorded on a recording medium. is there.

[Conventional technology]

The format of the digital signal (including digital video signal and digital audio signal) recorded on the magnetic tape by the conventional 4: 2: 2 digital VTR (helical scan digital VTR) on the inclined track is as follows: It is defined as shown in FIG. That is, the digital signal on one inclined track is composed of digital video signals of _two video sectors VS ₁ and VS ₂ separated on both sides, and four audio sectors AS ₀ , AS ₁ , AS ₂ and AS ₃ therebetween. , And an edit gap of a predetermined length is provided between the digital signals of each sector.

Then, as in the NTSC system, the number of scanning lines in one frame is 525.
When recording video signals of the standard television system of
One field of the video signal is composed of ten inclined tracks T
Recorded over

Then, a digital video signal and a digital audio signal are recorded on the inclined track T by the four rotating magnetic heads provided on the tape guiding drum, and are reproduced.

[Problems to be solved by the invention]

Now, when editing and recording in such a digital VTR, elongation of the magnetic tape, tracking error, deviation of the lock phase of the rotation phase detection pulse generated with the rotation of the rotating magnetic head, difference in the digital VTR in recording and reproduction, etc. As a result, the position of each sector of the inclined track T on which the digital video signal and the digital audio signal are recorded on the magnetic tape is shifted from the original position (reference position) in the scanning direction of the rotary magnetic head. At the time of editing recording,
When rewriting the digital video signals of the video sectors VS ₁ and VS ₀ (or the digital audio signals of the audio sectors AS _{0 to} AS ₃ ) with different digital video signals (or digital audio signals), signals of the other sectors, That is, the audio sector
AS _{0 to} AS ₃ digital audio signals (or video sectors VS ₁ , V
There is a fear that erasing the digital video signal) of the S _0.

In view of the above, the present invention provides a new recording medium in which a digital signal is divided into a plurality of sectors and a composite digital signal obtained by adding a synchronization signal and an identification signal to each sector is recorded by a helical scan method. In a digital signal recording / reproducing apparatus in which a complex digital signal is electronically edited and recorded by a helical scan method, electronic editing and recording are performed in accordance with the degree of misalignment of a sector of the composite digital signal recorded on a recording medium in the scanning direction. It is intended to propose a device that can easily determine whether or not the process is possible.

[Means for solving the problem]

According to the present invention, a new composite digital signal is recorded on a recording medium in which a composite digital signal obtained by dividing a digital signal into a plurality of sectors and adding a synchronization signal and an identification signal to each sector is recorded by a helical scan method. In a digital signal recording / reproducing apparatus in which electronic editing recording is performed by a helical scan method, a head position of a sector is detected based on a synchronization signal and an identification signal in a composite digital signal reproduced from a recording medium, and a reproduction sector head position is detected. A reproduction sector head position detection circuit for generating a detection signal, and a reference sector head position window pulse for generating a reference sector head position window pulse indicating a predetermined allowable range of the head position of each sector in the composite digital signal reproduced from the recording medium The generation circuit and the reproduction sector head position detection signal from the reproduction sector head position detection circuit are: An edit enable / disable determination circuit that detects whether or not the reference sector start position window pulse from the quasi-sector start position window pulse generation circuit is within the window and generates a determination signal as to whether or not electronic editing recording is possible. Digital signal recording and reproducing apparatus.

[Action]

According to the present invention, the editing permission / inhibition determination circuit
The electric sector recording is detected by detecting whether or not the reproduction sector head position detection signal from the reproduction sector head position detection circuit is within the window of the reference sector head position window pulse from the reference sector head position window pulse generation circuit. A determination signal is generated as to whether or not it is possible.

〔Example〕

In the following, referring to FIG. 1, the present invention is applied to a 4: 2: 2 digital V
An embodiment applied to a TR (a VTR that enables recording, reproduction and electronic editing recording) will be described in detail. A counter (3) is a clock signal from the input terminal (2) (9.837 MHz, which is the frequency of the system clock signal of the digital VTR).
1/3 times the frequency, ie, 3.279MHz clock signal) CK
And is reset by a reset pulse RS (see FIG. 2A) from the input terminal (1). The reset pulse RS is a pulse related to a rotation phase pulse generated once per rotation of the rotary magnetic head, and has a phase corresponding to the vicinity of the head position of the inclined track T in FIG.
After being reset by the above-mentioned reset pulse RS, the counter (3) counts the above-mentioned clock signal CK and sets its radix to generate a carry signal at a timing corresponding to the vicinity of the end of the inclined track. Is done. FIG. 2B shows a change in the count output CO of the counter (3).
The length of one inclined track T corresponds to the rotation angle of the rotary magnetic head of 257 °.

(4) is an address decoder, which receives a count output (parallel multi-bit digital signal) CO from the counter (3) and decodes the count value (address). The decoded output is supplied to a recording absolute position output circuit (5).

The absolute position output circuit (5), based on the Dekoto output address decoding (4), as shown in FIG. 3, the original head of the fourth diagram of an audio sector AS ₀ ~AS ₃ and video sectors VS ₀ A set pulse SP having a start timing of a position allowable range and reset pulses RP ₀ , RP ₁ , RP ₂ , RP ₃ , RP ₄ having an end timing thereof are generated, and these pulses are used in an editability determination circuit (6). Supplied to In the decision circuit (6), rising at the timing of the set pulse SP, falls window signal at the timing of the reset pulse RP ₀ to Rp ₄ is made.

On the other hand, a reproduced signal from the rotating magnetic head (a composite digital signal composed of a digital video signal and a digital audio signal divided for each sector and each signal described later)
Is supplied to an input terminal (9), a reproduced signal thereof is supplied to a synchronization detection circuit (10), and a block synchronization signal of a plurality of blocks constituting each sector is detected, and a discrimination (ID) address is provided. The signal is supplied to the decoder (11), and the discrimination address (identification address) signal (consisting of a field number, a segment number, a sector number, and a block number signal) of a plurality of blocks constituting each sector is decoded. Then, the sector head position detection circuit (12), and determine the address signal from the block synchronization signal and determine the address decoder from the synchronization detection circuit (10) (11) is supplied, the audio sector AS ₀ ~AS ₃ and video sector Timing signal ID composed of sector head position timing pulse based on reading of discrimination address signal of first block of VS ₀
P ₁ , IDP _2, and IDP ₃ are output and supplied to the above-described editability determination circuit (6).

The determination circuit (6) rises at the timing of the set pulse SP and reset pulses RP _{0 to} R
It is determined whether or not the head position timing pulse of each of the timing signals IDP ₁ , IDP ₂ and IDP _{3 is included in} the window pulse falling at the timing of P ₄ .
Then, the output of the determination result is supplied to a system controller (7) of the digital VTR and subjected to signal processing, and one or more of the head position timing pulses of each sector of the timing signals IDP ₁ , IDP ₂ and IDP ₃ are output. If it is out of the window signal, a non-editable signal is generated from the system controller (7), and the display (8) displays a non-editable state in which the audio sector and the video sector are distinguished. Generates an editable signal, and the display (8) displays an editable state.

Incidentally, when editing records, a digital video signal of the video sector VS _0, VS _1, and when rewriting in other digital video signals, and when rewriting the digital audio signal of the audio sector AS ₀ ~AS ₃ in another digital audio signal In both cases, the editing and recording are performed in one or a plurality of units for one field of the digital video signal, that is, in units of ten tracks.

According to the digital VTR described above, it is determined whether or not the head position of any sector of the inclined track on the magnetic tape is shifted from the original sector position by a predetermined value or more. In this case, the editing recording is stopped, and if less than the predetermined value, the editing recording is performed. Therefore, the possibility of erasing the recording signal of another sector that should not be edited and recorded on the inclined track is avoided.

〔The invention's effect〕

According to the present invention described above, a new digital signal is divided into a plurality of sectors, and a synchronizing signal and an identification signal are added to each sector. In a digital signal recording / reproducing apparatus in which a composite digital signal is electronically edited and recorded by a helical scan method, a head position is detected based on a synchronization signal and an identification signal in a composite digital signal reproduced from a recording medium, and a reproduction sector is detected. A reproduction sector head position detection circuit for generating a head position detection signal, and a reference sector head position for generating a reference sector head position window pulse indicating a predetermined allowable range of the head position of each sector in the composite digital signal reproduced from the recording medium A window pulse generation circuit and a read sector head position detection signal from a read sector head position detection circuit. Is a reference sector head position window pulse from the reference sector head position window pulse generation circuit. Digital signal recording / reproducing which can easily determine whether or not electronic editing recording is possible according to the degree of positional deviation of the composite digital signal recorded on the recording medium in the scanning direction. A device can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 3 are timing charts for explaining the embodiment, and FIG. 4 is a track on a magnetic tape of a 4: 2: 2 digital VTR. It is a diagram showing a format. (3) is a counter, (4) is an address decoder, (5)
Is a recording absolute position output circuit, (6) is an editability determination circuit, (7) is a system controller, (8) is a display,
(10) is a synchronization detection circuit, (11) is a discrimination address decoder, and (12) is a sector head position output circuit.

Continuation of the front page (56) References JP-A-1-94566 (JP, A) JP-A-61-292268 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 27 / 036

Claims (1)

(57) [Claims] A new composite digital signal is recorded on a recording medium in which a digital signal is divided into a plurality of sectors and a composite digital signal obtained by adding a synchronization signal and an identification signal to each sector is recorded in a helical scan system. In a digital signal recording / reproducing apparatus which electronically records the data in a helical scan system, a head position of a sector is detected based on a synchronization signal and an identification signal in a composite digital signal reproduced from a recording medium.
A reproduction sector head position detection circuit for generating a reproduction sector head position detection signal, and a reference sector for generating a reference sector head position window pulse indicating a predetermined allowable range of the head position of each sector in the composite digital signal reproduced from the recording medium. A head position window pulse generation circuit, and whether or not the reproduction sector head position detection signal from the reproduction sector head position detection circuit is within the window of the reference sector head position window pulse from the reference sector head position window pulse generation circuit. A digital signal recording / reproducing apparatus, comprising: an editing permission / inhibition determination circuit for detecting whether the electronic editing recording is possible or not and generating a determination signal as to whether or not electronic editing recording is possible.