JPH05159461A - Digital audio signal reproducing device - Google Patents

Abstract

PURPOSE:To improve a signal processing system at the time of reproducing at high speed, to obtain a reproduced sound similar as much as possible to an original sound and with high quality and to rapidly allow to comprehend a recording content. CONSTITUTION:The absorption of jitters, the deshuffling of a sound sample and time axis expansion are performed at the time of reproducing by a regenerative field memory 14. The regenerative field memory 14 is controlled by a regenerative memory controller 15 as follows. The write address of the regenerative field memory 14 is generated by an ID decoder 22 based on a field pulse signal and a head switch signal at the time of reproducing in a shuttle mode and further, a block error number is counted by a counter 23 in sector and stored in a status register 26. The read address is supplied from a read address counter 29 in accordance with the content of the status register 26 and the high speed reproduce sound with high quality is obtained front the regenerative field memory 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary voice recording system for reproducing a digital audio signal.

[0002]

2. Description of the Related Art In recent years, as LSI technology has advanced, digital processing of audio and video signals has rapidly progressed, and audio and video equipment capable of recording and reproducing in a digitally encoded form has begun to permeate. A digital VTR, which has a characteristic that performance is not theoretically deteriorated even when video and audio are digitally encoded and recorded and copied, is about to reach full-scale spread from commercial use to consumer use. In these digital recording devices, the error detection code and the error correction code added to the recording signal data work against the occurrence of errors due to the dropouts distributed on the recording medium, and the same level as the original input recording signal. The mechanism is such that a quality reproduction output signal can be obtained.

In the above digital VTR, in order to faithfully restore the original signal, it is necessary to perform sampling at a sampling frequency which is at least twice the original analog signal band and to take as many quantization bits as possible. Therefore, as compared with the conventional rotary head type analog VTR, the frequency band required for recording becomes extremely wide, and it is essential to realize high density recording.

In order to realize high-density recording, it is of course necessary to shorten the recording wavelength and narrow the recording track width, but in order to realize these technologies, it is necessary to accumulate advanced elemental technologies. This is a prerequisite, and high-density recording that is several times higher than in the past cannot be easily realized. Therefore, a technique generally used for realizing a digital VTR is multi-channel recording in which a plurality of heads share a recording signal, and the rotary drum is rotated at a high speed to perform divided recording in a plurality of segmented areas. , So-called segment recording technology.

On the other hand, regarding the above-mentioned commercial VTR,
In addition to the improvement in performance, at least in terms of functionality, it is required that the functions that were possible with a conventional analog recording VTR be fully realized. Among them, the realization of the special playback function is a major issue. However, the high-speed queuing function for searching the edit point and the reproduction start point, which was easy in the conventional analog fixed head recording, has a complicated signal processing in the case of the digital recording by the rotary head method, which results in technical and cost reduction. Difficulties. That is, in each mode of jog / val / shuttle,
In order to realize variable speed special playback at tape speed according to the dial rotation angular velocity, high quality playback sound can be obtained only by using a considerable amount of memory and complicated digital signal processing technology. Normally, in high-speed reproduction of ± 1 speed or more, speeds of multiples of 2, such as ± 2 times, 4 times, ..., 32 times, ..., Are generally used, but of course, values in between are also effective. Also, in order to enable special playback such as slow playback while maintaining a good playback screen, auto tracking that moves the position in the height direction of the head mounted on the carrier of voltage distortion element such as piezo element A mechanism (hereinafter referred to as AT) is mounted, and for example, in the jog / val mode in the range of + 3 × speed to −1 × speed, the recording track can be accurately traced and reproduced.

However, the reproducing operation in the case of using the high speed shuttle mode in which tracking by the AT mechanism is not possible or the rotary head fixedly mounted is described below. Generally, in the case of a video signal, even if the video signals stored in the field memory etc. which belong to different fields temporally behind each other are displayed as the same field signal as they are, from the viewpoint of the content identification of the video due to the effect of the accumulation of eyes. Does not cause a feeling of strangeness, but in the case of an audio signal detected by hearing, if the same process is performed, an inappropriate reproduced sound is produced. In the case of audio that uses multiple segments as processing units, the audio signal that is detected and played back is only the playback signal obtained by scanning a portion of the recording track, and it is part of the entire field of data in inverse proportion to the tape speed. Since it can only be detected in a sampled form, the detected time-series voice signals are stored in the field memory as they are in the same process as at normal speed, and even if they are read, the temporal order is changed, which makes sense. No reproduced sound is output, and even the identification of the recorded content is disturbed.

Therefore, in order to obtain a reproduced sound in the shuttle mode, basically, signal processing by a method different from the normal speed is required.

[0008]

However, the rotary head type DAT (Digital Audio Tape recorder) has been heretofore used.
rder: Digital audio tape recorder) corresponds to one recording track, and even if scanning is performed diagonally, playback signals detected from different tracks are sequentially written into the memory of the signal processing unit, Except when a read sound is sampled in the same order and a reproduced sound sampled is obtained, it is recorded by being divided into a plurality of segments by the rotary head recording method, and the unit of signal processing spans a plurality of segments. In a digital VTR that is shuffled, the signal processing is complicated, so that there is no example that has been performed, and in the shuttle mode, no playback sound is produced until now.

In view of the above problems, it is an object of the present invention to provide a digital audio signal reproducing device capable of reproducing a good digital audio signal even at high speed reproduction.

[0010]

In order to achieve this object, a digital audio signal reproducing apparatus of the present invention forms a tilted track on a tape by a rotary head and is divided into a plurality of fixed unit periods, and a plurality of divided tracks are formed. A digital audio signal reproducing device for reproducing a digital audio signal recorded in a divided area, wherein when reproducing the recorded tape at a high speed, the reproduction signal from the rotary head is regenerated every fixed unit period. A memory means for storing the reproduced signal, allocating a storage area to the memory means, which is different from the allocation in the case other than high speed reproduction, based on the head switch signal of the rotary head and the constant unit period signal, Write means for generating a write address to the memory means in block units from an address signal added for each block; When writing the reproduction signal to the means, when counting the error flag signal added to the reproduction signal in the unit of the block and holding it, and when reading the audio signal from the memory means, , A unit for reading a time-series audio signal with reference to the counting result of the error flag and the identification result of the constant unit period.

[0011]

According to the present invention, with the above-described structure, during high-speed reproduction, the reproduction signal obtained by scanning the recording track obliquely and partially obtained for each constant unit period is divided into blocks.
The data is sequentially written into a memory having a capacity of a certain unit period, and at the same time, the order of the certain unit period in which the count result of the error flag accompanying the reproduction signal and the reproduction signal are included is held. At the time of reading from the memory, the audio data is read out preferentially from the group of blocks having a small number of errors and in accordance with the held detection order of the constant unit period to obtain a time-series audio signal.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a digital audio signal reproducing apparatus according to an embodiment of the present invention.

In the figure, 1 is a search dial for controlling the tape speed in the shuttle mode, 2 is a dial speed detecting section for detecting the angular speed of the search dial 1, and 3 is a search dial.
Is a tape speed command unit that determines the tape speed according to the movement of the search dial 1, 4 is a capstan motor drive unit that drives the tape to travel, 5 is a capstan motor, 6 is a magnetic tape as a recording medium, and 7 is a cap. An FG detection circuit that detects the rotation speed of the stun motor 5, and 8 is an AT control unit that drives and controls an AT mechanism that moves a position in the height direction of a reproducing head mounted on a carrier of a voltage distortion element such as a piezo element. Reference numeral 9 is a reproduction head having an AT mechanism, 10 is a reproduction detection circuit for detecting a reproduction signal from the magnetic tape 6, 11 is a demodulation circuit for restoring a reproduction signal subjected to digital modulation to original information data, and 12 is signal processing. A sync detection and protection circuit for detecting and protecting a sync signal added to each block, which is a unit of, and 13 is for detecting and correcting an error due to a dropout in a reproduced signal. Is an error detection / correction circuit for performing processing by an inner code having a block as a processing unit, and 14 stores a reproduced signal in a unit of one field, and TBC (time A reproduction field memory having a base-collector function, for example, having a three-page configuration, a reproduction memory controller 15 for supplying write and read addresses to the reproduction field memory 14,
Reference numeral 16 is an error detection / correction circuit that performs detection and correction of an error due to dropout in a reproduced signal by an outer code that extends between blocks, and 17 is a sample of preceding and succeeding samples when an error that exceeds the limit of correction capability occurs. An interpolation circuit that performs correction by calculating an average value, 18 is a DA conversion circuit that converts a digitized audio signal into an analog audio signal, and 19 is an analog audio signal output terminal.

FIG. 2 is a detailed block diagram of the reproduction field memory 14 and the reproduction memory controller 15 shown in FIG.

In the figure, 14a, 14b, and 14c are field memories each having a capacity of 1 field, and constitute a reproduction field memory 14 having a total of 3 pages. Reference numerals 20a, 20b, 20c are multiplexers (MUXs) for switching respective addresses supplied to the reproduction field memories 14a, 14b, 14c, and 21 is an ID decoder used in a case other than the shuttle mode. The ID code added prior to the audio signal data together with the synchronization signal added to
The content of this ID code is composed of a field number, a segment number, a block number and the like. 22 is an ID decoder valid only in the shuttle mode, 23 is an error flag counter for counting error flags added to residual errors after error correction by the inner code, and 24 is a write upper address of the reproduction field memories 14a, 14b, 14c. A multiplexer (MUX) to be selected, 25 is a write address counter which similarly generates a write lower address, and 26 is based on the number of error blocks for each audio channel and for each sector which is a recording area divided into a plurality of blocks. A status register for storing the allocation result of the storage area of the reproducing field memory, which is set for each sector, 27 is an error correction address counter for supplying an address for error correction by an outer code,
28 is a read address counter for supplying a read address of voice data except in the shuttle mode, 2
Reference numeral 9 is a read address counter for supplying a read address in the shuttle mode, and 30 is a multiplexer (MUX) for selecting the read address.

FIG. 3 shows an example of an audio recording signal format. For example, NTSC which records 800 or 801 audio samples per field sampled at a frequency of 48 KHz into three 2-pair track segments. An array of audio sample data and outer check code for one field period for one audio channel in the case of the system is shown. In the figure, the "D" symbols with subscripts 0 to 800 are time-series audio sample data, and the "AUX" symbols are various information associated with audio by using slots with excess data. The recordable and reproducible auxiliary (AUX) code data and the symbol "P" indicate outer check code data generated from the data and the AUX code. These data are 8 × 2 in the vertical direction as shown in FIG.
It is arranged in slots of 34 samples in rows and 3 columns in the horizontal direction. Further, one block is composed of 34 sample data in the horizontal direction, and one sector is composed of a total of eight blocks # 1 to # 8. The outer check code is generated by generating an 8-byte check code arranged below the 8-byte data in the vertical direction in FIG. A sector having a pair configuration of one audio channel is formed from a total of 16 blocks, each block including eight data blocks and eight outer check codes which are hatched of the same type. Although not directly related to the present invention, when the format of FIG. 3 is applied to the PAL system, the segment recording system consisting of four pair tracks is appropriate.

FIG. 4 shows a state in which the rotary head is used in the shuttle mode in which the AT head cannot follow during high-speed reproduction.
FIG. 3 is a track pattern diagram showing a scanning state of tracks recorded in the format shown in FIG. 3, showing a case where the tape speed is +3 times the normal speed.

FIG. 5 is also a track pattern diagram showing the scanning state of the recording tracks of the format shown in FIG. 3 in the shuttle mode, and shows the case of the tape speed +4 times the normal speed.

In FIGS. 4 and 5, the rotary heads facing each other by 180 degrees are used to form one field section of the format shown in FIG. 3 using three paired tracks, but the drawing is simplified. For the sake of realization, the pair track is shown as one track. That is, in the case of the NTSC system, one field is segmented into three pair tracks, and one track consists of a video signal recording sector and four audio recording sectors. Further, the central portion of the inclined track is a video signal recording track sector, the areas at both ends of the track are audio signal recording track sectors, and A1 to A4 are recording sectors for each of audio channels 1 to 4.
Therefore, although not shown in the drawing, in the pair track, sectors of the same audio channel are arranged adjacent to each other. Further, in reality, the video signal recording sector is sufficiently longer than the audio signal recording sector, but in the present invention, this portion is shortened and simplified for the purpose of focusing on the description of the audio recording sector, so that it is originally a straight line. The scanning trace on the track is displayed as a polygonal line. That is, the scanning locus of the reproducing head is shown by a wide arrow line, of which the solid line portion shows the scanning locus of the audio signal recording sector portion, and the broken line portion shows the scanning locus of the video signal recording sector portion.

FIG. 6 is a timing chart showing the relationship between each reference timing signal and the audio reproduction signal sector during reproduction, which corresponds to the case of the # 1 field shown in FIG.

FIG. 7 is a diagram schematically showing address allocation per audio channel when the reproduced signal of the format shown in FIG. 3 is written into the reproduced field memory 14 block by block.

Next, the operation of the present embodiment shown in FIG. 1 will be described. In the figure, when the jog / val mode or the shuttle mode is operated by operating the search dial 1, a rotary encoder (not shown) connected to the search dial 1 generates a pulse corresponding to the rotational angular velocity. The dial speed detecting section 2 counts the number of pulses input for a fixed time, and inputs this value to the tape speed command section 3 as dial speed information. The tape speed command unit 3 converts the dial speed information into tape speed information according to the current mode state and outputs it to the capstan motor drive unit 4 as a speed command. The capstan motor 5 is driven by the capstan motor drive unit 4 generating drive power according to the tape speed command, and an FG pulse corresponding to the rotation speed of the capstan motor 5 is output from the FG detection circuit 7 to the capstan motor drive unit 4. Is fed back to and the speed is controlled so that the capstan motor 5 rotates at a constant rotation speed. Although not shown in the figure, during reproduction, a control signal pulse recorded on the magnetic tape 6 is detected, and feedback is performed to compare the phase with a reference signal to perform more precise phase control corresponding to tape slip and expansion / contraction. Call. Although not shown in the drawing, a reproduction operation at an arbitrary tape speed can be performed by a button operation for mode selection and the above dial operation.

In the case of reproduction using the AT mechanism in a mode other than the shuttle mode, a reproduction operation at a normal tape speed will be described first. In response to a command from the AT control unit 8, the height position of the reproducing head 9 is moved so that the recording track can be traced accurately, and the reproducing signal detected by the reproducing head 9 is amplified by the reproduction detecting circuit 10 and the waveform is reproduced. It is converted into a digital signal by digitizing and pulse shaping. Further, the envelope signal of the reproduction signal is fed back to the AT control unit 8 and controlled so that the reproduction signal amplitude obtained is constant and maximum. Next, the demodulation circuit 11 performs clock recovery and demodulation to the original data, and the synchronization detection protection circuit 12 detects the block synchronization signal for establishing bit synchronization at the beginning of the block, dropout, etc. Protection against omissions and false positives is provided. With respect to the occurrence of error data due to dropout included in the reproduced signal, the error detection and correction circuit 13 including the voice data and the ID code performs error detection and correction by the inner code added in block units.
When an uncorrectable error remains in the inner error correction stage, an error flag is added in block units and the result is passed to the next outer error correction process stage. The reproduction memory controller 15 separates and detects an ID code indicating a memory address in block units from the audio data block, and accesses the reproduction field memory 14 as an upper address in block units of the write address of the reproduction field memory 14. As described above, the data of the signal format shown in FIG. 3 is arranged on the recording track in sector units as shown in FIGS. 4 and 5. For example, in A1 of the first segment of the # 1 field. The sector shown is composed of 8 blocks of data hatched with diagonally downward-sloping lines in the format of FIG. 3, data of an outer check code of 8 blocks, and a block sync signal, D code signal, and inner check code (not shown). A block signal of a total of 16 blocks, which is made up of blocks, is divided and recorded on two tracks alternately by 8 blocks. Similarly, for the voice of the first channel, a block with halftone dots is assigned to the second segment from the left, and a plain portion is assigned to the third segment. The reproduction field memory 14 is composed of three pages of field memories A, B, and C, and the reproduced digital audio signals are sequentially written into the memories A, B, and C for each field. The write timing at this time is based on the timing of the block sync signal detected by the sync detection protection circuit 12. Although the address assignment of the reproduction field memory 14 is shown only for one channel, the format shown in FIG. 3 is reflected as it is in FIG. 7, and the audio data blocks are sequentially assigned to A, B and C and the outer one in each segment. The data block consisting of the check code is A ', B',
It is accumulated in the area indicated by C '. The function of the reproduction memory 14 is to decode the reproduction signal, which is compressed on the time axis based on the recording signal format and whose data array is rearranged, to expand and restore the reproduction signal to the original time series of the audio, and jitter due to tape running. It has a TBC function of re-reading a reproduction signal containing a component from a crystal oscillator with a frequency-divided clock to remove fluctuations in the time axis, and a temporary storage function for error correction. Addresses and timing signals of the reproduction field memory 14 necessary for these processes are all supplied from the reproduction memory controller 15.

For an error which cannot be corrected by the inner code due to an error caused by a scratch or dust on the tape contained in the reproduction signal, an error detection and correction process by the outer code extending between blocks is performed. That is, the data once written in the reproduction field memory 14 is read out in the generation sequence of the outer code extending between the blocks, input to the error detection / correction circuit 16, and executed by a predetermined arithmetic processing. Further, when the error correction by the outer code is impossible, the interpolation circuit 17 performs the interpolation processing by the average value calculation of the preceding and following samples on the time series audio samples read from the reproduction field memory 14, and the DA conversion circuit 18
After being converted into an analog audio signal by, the reproduced sound is finally obtained from the output terminal 19.

Although the above is the reproduction operation at the normal speed, the shuttle mode reproduction operation which is the subject of the present invention will be described in detail with reference to FIGS.

First, in the shuttle mode, a description will be given by taking the normal triple speed as an example. As shown in FIG. 4, even in the shuttle mode, one field is formed by a total of three scans as in the normal speed. Focusing on the audio channel 1, data of 1 sector × 2 is obtained for each scanning.
However, the sector block signals obtained in sequence are signals belonging to different fields, and 1 of each field
It is possible to obtain audio data in the form of sampling every / 3. If this is used as it is and a writing method to the reproduction field memory 14 similar to the normal speed is adopted, there may be a case where data obtained later is overwritten on already obtained data, or the reading order according to time series is performed. In some cases, the correct write address corresponding to can not be obtained. That is, the write operation is to determine the write area in block units by combining the field number, the segment number, and the block number, which are the ID data added to each block, so that the write operation is performed for the # 1 field shown in FIG. A1 of the first sector from the bottom of the first segment from the left is written in the areas A and A'shown in FIG.
A1 of the segment and the third sector is C and C ', and A1 of the # 3 field, the first segment and the second sector is A and A'.
Is the writing area when processing is performed at the normal speed, and if it is left as it is, overwriting occurs in the areas A and A ′.
The audio data detected by the reproducing head 9 is not effectively utilized. Decompression reading in normal speed reproduction of voice follows the time series as the suffix of D shown in FIG. 3, and A → B → C → A → B → ・ on the memory area shown in FIG. 7 for each voice sample.
・ Switch in the order of. When the above-mentioned method is used for the data when the writing method at the normal speed described above is adopted, A → B → C → A → B → ...
Even if they are read in the order of, the order of reading in time series is # 3 → # 2 → # in the order of the fields shown in FIG.
3 → # 2 → ... It is clear that it is meaningless as a voice.

With respect to this point, in the present invention, first, segment identification in the shuttle reproduction mode is performed with reference to the head switch signal shown in FIG. 6B, and the segment number of the ID code is shuffled in sector units. Used only for channel identification. That is, in the case of FIG. 4, # 1
The data of A1 of the field, the first segment, and the first sector are stored in the area A of FIG. 7, and similarly, A2 of the # 2 field, the third segment, and the third sector are stored in B, and the # 3 field, the first segment, A1 of the second sector is written in the area C. Regarding the recording sectors of other audio channels, A, B, C are sequentially recorded in sector units on the basis of the head switch signal.
Write in the area. In the case of +3 times speed in FIG. 6, (c)-
In the relationship between the reproduction signal sector and the write address allocation shown in (e), channels 1 and 2 happen to have the same allocations as the normal speed reproduction and the shuttle reproduction, but in the present invention, the shuttle switch reproduction is based on the head switch signal. Write sequentially. That is, in the case of using the signal format in which the field to which the present invention is applied is used as a structural unit, in the case where reproduced signals belonging to different fields come in succession, the head switch signal is used as a reference in the order in which they arrive in the sector unit. When writing to and reading from areas A, B, and C shown in FIG. 3, since the audio data belongs to different fields, the shuffling relationship can be ignored, and the sector area corresponding to A in FIG. Switching from # 2 to # 3 to # 4 on a sample-by-sample basis and then reading B and C in the same manner gives a time-series voice in which the whole is sample-compressed to 1/3.

The track locus shown in FIG. 4 is an example in which the central portion in the track width direction is scanned. However, when the tape speed further increases, the inclination of the scanning locus becomes steeper with respect to the inclination of the recording track. However, if the audio channel determination based on the ID code can be surely performed, the reproduction field memory 1 may be detected.
No problem occurs when the writing of No. 4 is performed by the above method.

Next, in the case of the quadruple speed shown in FIG. 5, when the same head switch signal contains sector block signals of the same audio channel belonging to different fields,
Alternatively, in another expression, sector data belonging to the same field is included twice. According to the present invention, the data indicated by A1 in the first segment and the first sector of the # 1 field in the figure is the data block indicated by A1 in the first segment and the fourth sector of the # 2 field in the area shown in A of FIG. Signal is written in the area indicated by A'in FIG.
Thereafter, A1 of # 2 field, second segment and first sector is B, A1 of # 3 field, second segment and fourth sector is B ', and A1 of # 3 field, third segment and first sector is A1. Is written in C, and A1 of the # 4 field, the third segment, and the fourth sector is written in the area of C '. That is, when the sector block of the same audio channel belonging to the same field is included twice, in the present invention, the signal of the latter half sector block is written in the storage area of the outer check code at the normal speed reproduction and is detected. The reproduced signal thus obtained is taken into the reproduced field memory 14 to the maximum extent. The scanning shown in FIG. 5 shows the case where only the audio channels 1 and 2 are obtained and the channels 3 and 4 happen to be not obtained. However, in actuality, such a situation does not continue steadily. Since the center locus deviates from the center of the track width, it can be considered that the probability that each audio channel is detected is almost the same in a long period.

Based on the above concept, the reproduction field memory 14
The reading of the audio data signal written above is described below. Corresponding to the data written in the reproduction field memory 14, a residual error flag for error correction by an inner code is also written in block units. In the shuttle reproduction mode, since data belonging to different fields are stored in the memory in the form shown in FIGS. 3 and 7, these are meaningless as an error correction process as an outer code extending between blocks in field units. Therefore, the error correction by the outer code is not performed, and the appropriate processing method is to refer to the error flag added at the stage of the inner code and finally output only the highly reliable data without the flag. is there.
In the example shown in FIG. 4, the total number of errors in the areas A and A ′ is compared by counting, and one sample from each block is sequentially arranged from the head data of the head block of the area A in FIG. # 1 → # 2 → # 3 → # 4 →
.. are read in time series while changing the blocks, and when the area of A or A'is completed, then the area of B or B ',
Finally, the area C or C'is read out, and as a whole 3
A reproduced sound in the form of extracting one sample for every sample is obtained.

As described above, in the present invention, the number of inner error flags added to each block is counted in advance in units of sectors at the same time as writing, and at the time of reading, A to C and A'to based on the counting result. In each sector area of C ', sectors with a small number of error blocks are preferentially read in chronological order, a valid data block is selected as much as possible, a data block with an error flag and low reliability is discarded, and reproduction is performed. It enhances the quality of the sound. If the sector block to be read is determined by the count result of the error flag, this is temporarily stored and held until the time of reading.

The above-described one embodiment of the present invention is summarized as follows in the writing and reading processes to and from the reproduction field memory 14 during the shuttle mode reproduction.

When the reproduced voice data signal is written in the reproduced field memory 14, the memory is stored in the memory in the form of (1) one head switch signal period corresponding to one segment period with reference to the field pulse and the head switch signal. Divide the area. (2) When a sector block signal of the same audio channel is detected more than once in the same field period, it is first written in the data storage area during normal speed reproduction and then in the outer check code area based on the order of detection. .. (3) The number of error flags associated with a data block at the time of writing is counted in units of audio channels and units of sectors and held. At the time of reading from the reproduction field memory 14, (1) reading is performed in the order of the received field numbers. (2) If there are a plurality of sectors of data blocks belonging to the same field in the same audio channel, the sector with the smallest number of error blocks is read out first.

The writing and reading operations to and from the reproducing field memory 14 described above will be described based on the circuit having the configuration of FIG.

When the shuttle reproduction mode is selected, FIG.
The shuttle mode signal shown in (1) becomes active, the inside of the reproduction memory controller 15 is switched to the shuttle mode operation, and the MUX 24 and MUX 30 are selected for the shuttle mode processing. The ID decoder 22 dedicated to the shuttle mode identifies the audio channel from the field number and segment number of the ID code, and based on the field pulse signal and the head switch signal shown in FIG. 6, different from the normal speed reproduction shown in FIG. Allocation of write areas in sector units shown in A to C'is performed. In each recording area of each sector, according to the block number of the ID code, # 1 → # 2 → # 3 → # 4 → shown in FIG.
・ ・ Writing is performed in the specified order. Further, the error flag in block units added to the audio data is taken into the error flag counter 23 from the data bus, the number of error blocks in each sector is counted, and the result is stored in the status register 26. The upper write address of the block unit generated by the ID decoder 22 is MUX2.
4, the block sync signal is started, and a lower write address (not shown) generated by counting the reproduction signal clock is added to the reproduction field memories 14a to 14c through the MUXs 20a to 20c while sequentially switching for each field. , Writing in one field equivalent period in the shuttle reproduction mode is continued.

When the writing of one field unit to the reproduction field memories 14a to 14c is completed, the error correction by the outer code is not performed in the shuttle reproduction mode as described above.
Disable 7

Finally, the reproduction field memories 14a to 1
The decompression read from 4c is performed by the read address supplied from the read address counter 29 dedicated to the shuttle reproduction mode via the MUX 30. At this time,
As mentioned above, the order of read access is
The operation is performed by sequentially selecting A or A ', B or B', and finally C or C'in sector units. In the status register 26, the number of errors in sector units is compared for each of the stored same audio channels, and the sector to be finally read is selected.

By the above-mentioned processing, it is possible to realize efficient processing of taking in the detected and reproduced voice data signal as little as possible and returning it to the time-series voice in the correct order.

Note that the example shown in FIG. 3 as a signal format used in the embodiment of the present invention is merely an example, and can be applied to the case of using other signal formats, and does not limit the present invention. Absent.

In the description of the embodiment of the present invention, the case where the digital audio signal is configured in the field unit of the video signal has been described. However, even in the case of the longer frame unit, the field is further subdivided. Even when the above-mentioned unit is used as a constituent unit, the size of the field memory and the like only change, and this also does not limit the present invention.

[0042]

As described above, according to the present invention, when no reproduced sound is obtained in the muting state during high-speed reproduction, a sampled reproduced sound at a level that does not hinder the confirmation of the recorded contents is obtained. The editing point search setting and the program start point can be quickly obtained, and the operational merit in the digital VTR or the like is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a digital signal reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a reproduction field memory 14 and a reproduction memory controller 15 in the embodiment.

FIG. 3 is a schematic diagram showing a configuration of a voice recording signal format used in the embodiment.

FIG. 4 is a track pattern diagram showing scanning trajectories during high-speed reproduction at 3 × speed.

FIG. 5 is a track pattern diagram showing a scanning locus during high-speed reproduction at 4 × speed.

FIG. 6 is a timing diagram of a reproduction reference timing signal and an audio reproduction signal sector.

FIG. 7 is an explanatory diagram showing write address allocation of the reproduction field memory 14.

[Explanation of symbols]

 14 playback field memory 15 playback memory controller 16 error detection / correction circuit 21,22 ID decoder 23 error flag counter 25 write address counter 26 status register 27 error correction address counter 28,29 read address counter

Claims (2)

[Claims] 1. A digital audio signal reproducing device for reproducing a digital audio signal recorded in a plurality of divided areas by forming a slanted track on a tape by a rotary head, and dividing the tape into fixed unit periods. A memory means for storing a reproduction signal from the rotary head for each fixed unit period when the recorded tape is reproduced at a high speed; and a head switch signal of the rotary head and the fixed unit for the reproduction signal. The storage area is allocated to the memory means different from the allocation in the case other than the high speed reproduction on the basis of the period signal, and the write address to the memory means in block units is given from the address signal added for each block. When writing a reproduction signal to the writing means for generating and the memory means, it is added to the reproduction signal in block units. And a counting means for counting and holding the error flag signal and a voice signal read from the memory means, referring to the counting result of the error flag and the identification result of the certain unit period, A digital audio signal reproducing device, comprising: a reading means for reading a series audio signal. 2. The digital audio signal reproducing apparatus according to claim 1, wherein the fixed unit period is a video signal field period.