JPH07121994A - Digital signal processing apparatus and method - Google Patents

Abstract

(57) [Summary] [Object] To provide a digital recording / reproducing apparatus and method capable of recording and reproducing double image data while maintaining upward compatibility with the D1 system. [Structure] In order to maintain the upward compatibility of the digital recording / reproducing apparatus 1 of the present invention and the conventional D1 VTR system, in segments (segment 0 (0) and segment 0 '(0), etc.) on adjacent tracks, The same ID byte is used to prevent the number of ID bytes from increasing. The digital recording / reproducing apparatus 1 uses a code having a signal polarity,
The recording signal is recorded by alternately inverting the signal polarity for each track, and in the case of reproduction, the reproduction signal is read out in accordance with the recording polarity. With such a configuration, even when the reproducing head 42 reads a signal over a plurality of tracks during shuttle reproduction or the like, the digital recording / reproducing apparatus 1 identifies the ID byte between adjacent tracks. It is possible to

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal processing apparatus and method used for recording and reproducing digital image data and the like.

[0002]

2. Description of the Related Art Currently, recording and reproducing of digital image data and the like by the D1 system are generally performed. D1
The method is, for example, Television Image Information Engineering Handbook (November 1990, edited by the Television Society) p526
~ This is a method for recording and reproducing digital image data and the like disclosed in p528. In the D1 system, image data is recorded on both end sides of a track continuously provided in a diagonal direction of the tape, and audio data is recorded in the central portion. These data are recorded in units called segments, and one segment has two image data sectors (video sectors) and four audio data sectors (audio sectors). These sectors are
The head part has a preamble and the tail part has a postamble, and each has a 4-byte identification code (ID byte) used for identifying data. Further, each sector has a plurality of synchronization blocks (sync).
Each sync block has the same identification code as the preamble and the postamble.

The ID word is a 4-bit ID word converted into an 8-bit code by 4-8 mapping, and image data or the like is scrambled and recorded, whereas it is scrambled. It is recorded as it is. The 4-8 mapping protects the contents of the identification code by making the number of the logical values 1 and the logical values 0 of the bits forming the ID word the same so that the code has no DC component (DC-free). It is done for the purpose.
Of the 8-bit codes, there are only 14 types of codes that have no DC component. ID words 0h to Dh are assigned to these 14 types of codes. On the other hand, the ID words Eh and Fh are not used. Further, since the ID words 0h to Dh are all used, the ID byte is a complete code.

There is a demand to record higher density image data while maintaining upward compatibility with the above-mentioned D1 format (D1 format). To meet this demand, the track pitch is set to 1 without changing the recording wavelength of the D1 format.
A method of doubling the number of recording and reproducing heads to double the track density on the magnetic recording tape can be considered. However, if the track density is doubled while maintaining upward compatibility with the D1 format as described above, the ID
The number of words is also doubled. However, 14 types of ID
Since all the words are used, there is a problem that the number of ID words becomes insufficient.

In order to solve the shortage of the number of ID words,
For example, a method of increasing the identification code by 1 byte can be considered. When this method is adopted, the amount of data in the preamble, postamble, and sync block increases by 1 byte, so that there is a problem in that upward compatibility with the D1 format cannot be easily achieved.

In addition, two identical ID bytes are adjacent to each other.
It is also possible to use it for each one track.
According to this method, no problem occurs when all heads are on the same track as in normal data reproduction. However, when the head moves across a plurality of tracks, such as when fast-forwarding, image data of two tracks having the same ID byte cannot be distinguished. Therefore, image data and the like reproduced from two tracks having the same ID byte are mutually
There is a problem that they are mixed in the frame memory of the device.

The present invention has been made in view of the problems that may occur when the above-mentioned requirements are solved. For example, while maintaining upward compatibility with the D1 system, the track width on the magnetic recording tape is 1/2 (track). It is an object of the present invention to provide a digital signal processing device capable of recording and reproducing a large amount of image data and the like by doubling the density) and a method thereof. It is another object of the present invention to provide a digital signal processing device and method capable of using ID bytes having the same value in two adjacent tracks.

[0007]

In order to achieve the above object, a digital signal processing device of the present invention is a digital signal processing device for digitally recording a video signal by a code having a signal polarity, and the digital signal processing device is arranged on adjacent tracks. A signal processing means for alternately reversing the signal polarity is provided. Further, it is characterized in that it has a reading means for reading out a signal recorded by alternately inverting the signal polarity for each track by a code having a signal polarity as a reproduction signal with a signal polarity matched with the signal polarity at the time of recording. To do. Also preferably, the signal is a video signal, and
Used for identifying the video signal, including at least an identifier that can have the same value in adjacent tracks, the video signal and the identifier are identified from the read reproduction signal, the signal polarity, and It is characterized by further comprising identification means for identifying the corresponding video signal based on the value of the identifier. Further, preferably, the video signal is recorded by the digital signal processing device described above, and the video signal is reproduced by the digital signal processing device described above.

The digital signal processing method of the present invention is a digital signal processing method for digitally recording a video signal with a code having a signal polarity, and is characterized in that the signal polarities are alternately reversed in adjacent tracks. Further, it is characterized in that a signal recorded by alternately inverting the signal polarity for each track by a code having a signal polarity is read out as a reproduction signal with a signal polarity matched with the signal polarity at the time of recording. Also preferably, the signal includes at least a video signal and an identifier used to identify the video signal and having the same value in adjacent tracks, and the video is read from the read reproduction signal. A signal and the identifier are identified, and the corresponding video signal is further identified based on the signal polarity and the value of the identifier. Further preferably, the value of the identification code is composed of the same number of logical values 1 and 0. Further preferably, the signal is recorded in a format compatible with the D1 format in an upward compatible manner.

[0009]

In two adjacent tracks, for example, the ID byte of the D1 format having the same value is used. When data is a code with signal polarity, that is, when the signal waveform is reversed,
Recording is performed by alternately inverting the signal polarity for each track on the recording medium using a code having a value different from that before the reversal. In addition, in accordance with the signal polarity at the time of recording for each track, the signal polarity is alternately inverted for each track on the recording medium to read the recorded data,
The normally identifiable ID word is determined as the corresponding data.

[0010]

Embodiments of the digital signal processing apparatus and method of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a digital recording / reproducing apparatus 1 of the present invention. The digital recording / reproducing apparatus 1 is, for example, a digital V
This is a TR device in which the track pitch and the recording density are doubled by halving the track pitch of the D1 recording format. Digital recording / reproducing apparatus 1
Is digitally encoded into an image signal input by the recording device 20 and recorded on the magnetic recording tape 12 as digital image data.
The digital image data recorded in 2 is reproduced and output. The control unit 10 controls the entire operation of the digital recording / reproducing apparatus 1 and processes the ID byte.

The recording device 20 includes an analog / digital conversion circuit (A / D) 22, a multiplexing circuit (MUX) 24, an encoder (ENC) 26, which are connected as shown in FIG.
It is composed of a polarity reversing circuit 28, a driving circuit 30, and a recording head 32. The image signal input to the recording device 20 is converted into digital format image data by the analog / digital conversion circuit 22 and input to the multiplexing circuit 24. The multiplexing circuit 24 multiplexes the image data input from the analog / digital conversion circuit 22 and the ID byte input from the control unit 10 into a format described later and inputs the multiplexed data to the encoder 26. The encoder 26 encodes the multiplexed image data input from the multiplexing circuit 24 and inputs the encoded image data to the polarity inverting circuit 28 as a recording signal. The polarity reversing circuit 28 converts the recording signal from the encoder 26, changes the polarity, and inputs it to the drive circuit 30.

The drive circuit 30 is, for example, a balanced input / output type amplifier circuit, which amplifies the recording signal input from the polarity inverting circuit 28 and inputs it to the recording head 32. The recording head 32 converts an electric recording signal input from the drive circuit 30 into a magnetic signal and writes it on the magnetic recording tape 12.

The reproducing device 40 includes a reproducing head 42, a reproducing amplifier 44, and a polarity inverting circuit 4 which are connected as shown in FIG.
6, equalizer (EQ) 48, identification circuit (DET) 5
0, a decoding circuit (DEC) 52, and a frame memory (FM) 54. The reproduction head 42 converts the magnetic signal recorded on the magnetic recording tape 12 into an electric reproduction signal, reads the electric signal, and inputs the electric reproduction signal to the reproduction amplifier 44. The reproduction amplifier 44 is, for example, a balanced input / output type amplification circuit, which amplifies the reproduction signal input from the reproduction head 42 and inputs the amplified reproduction signal to the polarity inversion circuit 46. The polarity inverting circuit 46 changes the polarity of the reproduction signal input from the reproduction amplifier 44 according to the polarity control signal from the control unit 10 and inputs the reproduction signal to the equalizer 48.

The equalizer 48 equalizes the reproduction signal whose polarity is changed by the polarity inverting circuit 46. The identification circuit 50
The reproduction signal equalized by the equalizer 48 is identified and input to the frame memory 54 as image data. The frame memory 54 stores the image data identified by the equalizer 48, for example, for each frame. The frame memory 54 separates the image data from the D1 format and outputs it, and also separates the ID byte and the like and inputs it to the control unit 10.

FIG. 2 is a diagram showing the structure of tracks on the magnetic recording tape 12 in the digital signal processing apparatus and method according to the present invention. In FIG. 2, T _{1 to} T ₁₁ indicate tracks on the magnetic recording tape 12, and 0 (0) to 4 ′.
(0) indicates a segment, and the magnetic recording tape 12
The movements of the magnetic recording tape 12 and the reproducing head 42 and the movement of the tape with respect to the arrow mark are as shown by arrows f and g, respectively. Image data is recorded in the ranges a and c shown in FIG. 2, and audio data is recorded in the range shown in FIG. 2b. It should be noted that analog audio tracks and the like on the magnetic recording tape 12 parallel to the tape traveling direction are omitted in FIG. The recording signal is recorded on the magnetic recording tape 1 as shown in FIG.
2 Recording is performed on the track in the direction oblique to the tape traveling direction.

When writing a recording signal to the tracks T ₁ , T ₃ , ..., T ₁₁ , the control unit 10 controls the polarity reversing circuit 28 to non-invert the recording signal to the non-inversion input a of the drive circuit 30, for example. The signal is recorded on the magnetic recording tape 12 by inputting an inversion signal of the recording signal to the inversion input b. Track T _1, T _3, ..., when reading the reproduced data from the T _11, the control unit 10 controls the polarity inversion circuit 46, for example, non-inverting output a playback amplifier 44 'of the signal and the inverted output b' of The signal is input to the circuits under the equalizer 48 without replacing the signal to reproduce the image data.

When writing a recording signal to the tracks T ₂ , T ₄ , ..., T ₁₀ , the control unit 10 controls the polarity reversing circuit 28 so that, for example, an inversion signal of the recording signal is input to the non-inverting input a of the drive circuit 30. The non-inverted signal of the recording signal is input to the inverting input b and recorded on the magnetic recording tape 12. When reading the reproduction data from the tracks T ₂ , T ₄ , ..., T ₁₀ , the control unit 10 controls the polarity reversing circuit 46 to, for example, the signal of the non-inversion output a ′ and the inversion output b ′ of the reproduction amplifier 44. The signals are replaced and input to a circuit below the equalizer 48 to reproduce the image data.

That is, when reproducing the recording signal written on the magnetic recording tape 12 by inputting the recording signal to the drive circuit 30 without inverting the polarity of the recording signal, the polarity of the reproducing amplifier 44 is not inverted. Play. On the contrary, drive circuit 3
When reversing the polarity of the recording signal to 0 and reproducing the recording signal written on the magnetic recording tape 12, the polarity of the reproducing amplifier 44 is reversed to reproduce the image data.

As described above, the control unit 10 controls the polarity inversion circuit 2
8 and the regenerative amplifier 44 to control a code having a signal polarity, that is, S-NRZ (Scrambled N).
When data is decoded based on a waveform such as RZ) having a polarity opposite to that at the time of recording, a code (a polarity-free code) that causes the recorded data and the reproduced data to have different values is used. The data recorded on the recording tape 12 can be correctly reproduced. In order to maintain the upward compatibility between the digital recording / reproducing apparatus 1 of the present invention and the conventional D1 VTR system, segment 0 (0) and segment 0 '(0), segment 1 (0) and segment 1'
(0), ..., Segment 1 (0) and Segment 1 '
(0) uses the same ID byte. Even if the same ID byte is used in the adjacent tracks, the recording signals of the adjacent tracks are written in the magnetic recording tape 12 with the opposite polarities, and therefore, when the digital recording / reproducing apparatus 1 performs the shuttle reproduction, etc. The image data can be identified even when the signal is read by the head across tracks.

FIG. 3 is a diagram showing the structure of the segment shown in FIG. In FIG. 3, (A) shows video sector 1
, (B) shows the configuration of audio sectors 0 and 1, (C) shows the configuration of audio sectors 2 and 3, and (D) shows the configuration of video sector 0. 3 to 5
The signal format of the digital recording / reproducing apparatus 1 of the present invention shown in FIG. 1 maintains the upward compatibility of the D1 system. As shown in FIG. 3, the segment is composed of two video sectors and four audio sectors.

Video sectors 1 and 0 shown in FIGS. 3A and 3D have a preamble (P) at the beginning and a postamble (T) at the end, respectively, and are composed of 160 synchronization blocks (sync block). Has been done. Figure 3
Each of audio sectors 0 to 3 shown in (B) and (C) has a preamble at the beginning and a postamble at the end, and is composed of 5 synchronization blocks.
Further, edit gaps (EG0 to EG4) are placed at both ends of each audio sector and between them. ID
The bytes are placed in the preamble and postamble above.

FIG. 4 is a diagram showing the configuration of the preamble, postamble, synchronization block, and sector shown in FIG. In FIG. 4, (A) shows a preamble structure, (B) shows a postamble structure,
(C) shows the structure of the synchronization block, and (D) shows the structure of the sector. Each sector shown in FIG. 3 is the same as the sector shown in FIG. As shown in FIG. 4A, the preamble has a 20-byte run-up, a 2-byte synchronization pattern, a 4-byte ID byte (ID), and a 4-byte F.
It is composed of each information of ILL. As shown in FIG. 4B, the postamble has a 2-byte synchronization pattern, 4
Byte ID is composed of bytes (ID). Figure 4
As shown in (C), the sync block is composed of a 2-byte sync pattern, 4-byte ID byte, 60-byte data 0, 4-byte error code 0, 60-byte data 1 and 4-byte error code 1. Has been done.

The ID byte is a 4-bit ID word converted into 8 bits (1 byte) by 4-8 mapping. The reason why 4-8 mapping is performed is to make the number of logical values 0 and 1 in one byte the same (4 bits of 0 and 4 bits of 1) to obtain a code without a DC component. And the resulting ID
This is to protect the byte contents. The conversion by 4-8 mapping is shown in the table below. As shown in the table below, there are 14 types of ID words. Also, the recorded image data is
The S-NRZ scrambled by the M series is recorded on the magnetic recording tape 12, but the ID bytes are recorded on the magnetic recording tape 12 without being scrambled.

[0024]

[Table 1] (Input value: 4 bits) (Output value: 8 bits) 0 1B 1 2E 2 35 3 3 47 4 5C 5 69 6 6 72 7 8D 8 96 9 A3 A B8 B CA C D1 D E4 E (use) No) F (Not used)

FIG. 5 is a diagram showing an example of the waveform of the NRZ code used for recording on the magnetic recording tape 12. In FIG. 5, (A) shows a code whose polarity is not inverted,
(B) shows a sign whose polarity is inverted. As can be seen from FIG. 5, when the polarity of the NRZ code is inverted, the value of the code before the inversion and the value of the code after the inversion become completely different. Therefore, even if the digital recording / reproducing apparatus 1 performs shuttle reproduction and the head simultaneously reads out ID bytes from a plurality of tracks, the image data can be identified by determining the values of the ID bytes from tracks having different signal polarities. is there. Therefore, it is possible to prevent a situation in which image data from different tracks are mixed.

As described above, by using a code such as S-NRZ having a signal polarity for the recording signal, the signal polarity is alternately inverted in the adjacent tracks, and recording is performed on the magnetic recording tape 12 and recorded. By reading the reproduction signal from the magnetic recording tape 12 in accordance with the signal polarity at the time, the same ID can be used in adjacent tracks. In addition, by using the same ID, I
Equivalently, it is possible to identify double the image data without increasing the number of D bytes, and the digital recording / reproducing apparatus 1 of the present invention realizes the upward compatibility with the conventional D1 system VTR. . Needless to say, during normal reproduction, the signal polarity at the time of recording matches the signal polarity at the time of reproduction, so normal reproduction is possible. The above-described digital signal processing apparatus and method of the present invention are not limited to VTR apparatuses, but can be applied to recording various data, for example, audio signals, in an apparatus in which data may be mixed between tracks. It is possible. The conversion of the identification code is not limited to 4-8 mapping, and 8-10 conversion or the like can be used. The code is not limited to S-NRZ,
It is possible to use a code having a signal polarity, for example, an NRZ code without scrambling.

[0027]

As described above, according to the digital signal processing apparatus and the method thereof of the present invention, it is possible to record and reproduce double the amount of image data while maintaining the upward compatibility with the D1 system, for example. it can. Also, the ID byte having the same value can be used in two adjacent tracks. In addition, even when the heads straddle a plurality of tracks during shuttle reproduction or the like, it is possible to normally record and reproduce image data or the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a digital recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a configuration of tracks on a magnetic recording tape in a digital signal processing device and method of the present invention.

3A and 3B are diagrams showing the configurations of the segments shown in FIG. 2, in which FIG. 3A shows the configuration of video sector 1, FIG. 3B shows the configuration of audio sectors 0 and 1, and FIG. The structure of sectors 2 and 3 is shown, and (D) is video sector 0.
Shows the configuration of.

FIG. 4 is a preamble, a postamble shown in FIG.
It is a figure which shows the structure of a synchronous block and a sector, (A) shows the structure of a preamble, (B) shows the structure of a postamble, (C) shows the structure of a synchronous block, (D). Indicates a sector configuration.

FIG. 5 is a diagram showing an example of a waveform of an NRZ code used for recording on a magnetic recording tape, (A) shows a code whose polarity is not inverted, and (B) shows a code whose polarity is inverted. Show.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Digital recording / reproducing apparatus, 10 ... Control part, 12 ... Magnetic recording tape, 20 ... Recording device, 22 ... Analog / digital conversion circuit, 24 ... Multiplexing circuit, 26 ... Encoder, 28 ... Polarity inversion circuit, 30 ... Drive Circuits, 32 ... Recording head, 40 ... Reproducing device, 42 ... Reproducing head, 44 ... Reproducing amplifier, 46 ... Polarity inverting circuit, 48 ... Equalizer, 5
0 ... Identification circuit, 52 ... Decoding circuit, 54 ... Frame memory

Claims (9)

[Claims] 1. A digital signal processing device for digitally recording a video signal with a code having a signal polarity, characterized in that signal processing means for alternately reversing the signal polarity in adjacent tracks is provided. Processing equipment. 2. A signal recorded by alternately inverting the signal polarity for each track by a code having a signal polarity,
A digital signal processing device having a reading means for reading out as a reproduction signal with a signal polarity matched with a signal polarity at the time of recording. 3. The video signal includes at least a video signal and an identifier used to identify the video signal and having the same value in adjacent tracks, the video being read from the reproduced signal. 3. The digital signal processing apparatus according to claim 2, further comprising an identification unit that identifies a signal and the identifier and identifies the corresponding video signal based on the signal polarity and the value of the identifier. . 4. A digital signal processing device comprising the digital signal processing device according to claim 1 and the digital signal processing device according to claim 2 or 3. 5. A digital signal processing method for digitally recording a video signal with a code having a signal polarity, wherein the signal polarities are alternately reversed in adjacent tracks. 6. A signal recorded by alternately inverting the signal polarity for each track by a code having a signal polarity,
A digital signal processing method characterized by reading out as a reproduction signal with a signal polarity that matches the signal polarity at the time of recording. 7. The video signal includes at least a video signal and an identifier used to identify the video signal and having the same value in adjacent tracks, and the video is read from the read playback signal. 7. The digital signal processing method according to claim 6, further comprising identifying a signal and the identifier, and further identifying the corresponding video signal based on the signal polarity and the value of the identifier. 8. The value of the identification code is the same number of logical values 1,
8. The digital signal processing method according to claim 7, wherein the digital signal processing method comprises a logical value of 0. 9. The digital signal processing method according to claim 7, wherein the signal is recorded in a format compatible with the D1 format.