JP2737321B2 - Digital information signal reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention detects a jump state when a rotary head jumps a plurality of tracks, and performs first and second jumps in a predetermined period during the jump. The present invention relates to a digital VTR that switches digital audio signals.

[Summary of the Invention]

According to the present invention, the same first digital audio signal and second digital audio signal are duplicatedly recorded on each of two adjacent inclined tracks on the tape, and the digital information signal is recorded from the tape by the rotating head. In a digital information signal reproducing apparatus adapted to reproduce, a head position control means for controlling a scanning position of a rotary head and a track to coincide with each other during variable speed reproduction in which a tape runs at a speed different from that at the time of recording; Detecting means for detecting a jump state when the rotary head jumps a plurality of tracks based on an identification signal in the audio signal; and a first digital signal for a predetermined period during the jump according to the detected jump state. Switching means for switching between an audio signal and a second digital audio signal; By including a, a noise generated between switching period of the first and second digital audio signal with greatly reduced, is obtained so as to smooth the playback state.

[Conventional technology]

For example, as one of the digital VTRs for recording / reproducing a composite digital color video signal and a digital audio signal, there is a digital VTR such as a D1 type digital VTR which double-records a digital audio signal. In such a digital VTR, a reproduced first digital audio signal (referred to as a first copy) and a second digital audio signal (referred to as a second copy) are separately decoded (e.g., erasure corrected) and output. Decryption is performed using both the first copy and the second copy. That is, since the same digital audio signal is doubly recorded as the first copy and the second copy, the error-free data obtained by decoding the inner code is referred to, and the non-error data is copied to the first copy and the second copy. A code block of an outer code is selected from the copy, and the outer code is corrected for this code block. Therefore, the error correction capability can be improved.

In a digital VTR, variable speed reproduction at a tape speed different from that at the time of recording is enabled. During variable speed reproduction, the scanning locus of the rotary head and the inclination of the track do not match. However, normal playback (playback at the same tape speed as when recording)
Even when the tape speed is about several times as high as that at the time, the rotary head is displaced in the height direction by the piezoelectric element, so that the scanning trajectory of the rotary head matches the track. Such a tracking technique is called dynamic tracking.

At the time of variable speed reproduction, for example, double speed reproduction, the rotating head scans a track on which a signal for one field is recorded by dynamic tracking, and jumps a track on which a signal for the next field is recorded. The track on which the signal for the field is recorded is scanned. When this track jump occurs, the contents of the digital audio signals of the first copy and the second copy are not the same. Therefore, when the decoding using the first copy and the second copy is performed according to the error state as in the normal reproduction, an erroneous correction process is performed.

In order to avoid this erroneous correction processing, at the time of variable speed reproduction, only one of the audio signals of the first copy and the second copy is used as a reproduction output. As a result, there is a problem that the error correction capability is reduced as compared with the time of normal reproduction.

Therefore, a digital information signal reproducing apparatus which can prevent the error correction capability from being reduced during variable speed reproduction is disclosed in Japanese Patent Application No. Hei.
-256203 (unknown prior to the filing of the present application).

This is because the same first digital audio signal and second digital audio signal are recorded twice in each of two adjacent tracks on the tape, and the digital information signal is reproduced from the tape by the rotary head. In the digital information signal reproducing apparatus as described above, a head position control means for controlling the scanning position of the rotary head to coincide with the track during variable speed reproduction in which the tape runs at a speed different from the normal time, and a head position control means Detecting means for detecting that the rotary head jumps a plurality of tracks on the basis of a drive signal corresponding to the first and second digital audio signals for a predetermined time during the jump by the detection; Other than the predetermined period, the first
Means for selecting one of the digital audio signal and the second digital audio signal.

In the variable speed reproduction operation, when the tape speed is relatively close to that during normal reproduction, track control is performed by, for example, head position control means using a piezoelectric element. Tracks of a plurality of fields are jumped according to the ratio of the tape speed to that at the time of normal reproduction. as a result,
The first copy and the second copy occur in different periods. In this period, a switching process, for example, a cross-fade is performed, and in the period of the other data where the first copy and the second copy are the same, as in the normal reproduction, data without error is changed from the first copy and the second copy. Selected. Therefore, at the time of variable speed reproduction, it is possible to have the same error correction capability as at the time of normal reproduction.

Hereinafter, a specific example of a conventional digital information signal reproducing apparatus will be described with reference to FIGS.

 The present invention is made according to the following order.

a. Recording and reproducing circuit of digital VTR b. Rotating head device and track format c. Variable speed reproducing operation d. Data processing at variable speed reproducing e. Modification a. Digital VTR recording and reproducing circuit FIG. 1 shows an overall configuration of a recording side of a digital VTR. In FIG. 5, (30) is an analog / digital interface, (28) is an input terminal for the analog audio signal, and (29) is an input terminal for the digital audio signal. The buffer memory (31) is connected to the next stage of the interface (30), and the buffer memory (31)
As a result, the time axis of the digital audio signal is compressed and converted into the order of the block structure. (32)
Indicates an outer code encoding connected to the next stage of the buffer memory (31), and (33) indicates a shuffling circuit connected to the next stage. The outer code which is an error correction code is encoded by the outer code encoding (32). The shuffling circuit (33) is configured by a memory, and rearranges the order of data.

(36) is an analog / digital interface,
(34) is the input terminal for the analog video signal, (35)
Is an input terminal for the digital video signal.

An output signal of the interface (36) is supplied to a channel demultiplexer (37), and is converted into a digital audio signal of a two-channel data series. The two-channel digital audio signal is supplied to the outer code encoder (38), and the outer code is encoded.
The output signal of the encoder (38) is supplied to the intra-sector shuffling circuit (39) to rearrange the order of the data in the sector.

The digital audio signal from the shuffling circuit (33), the digital signal from the intra-sector shuffling circuit (39) and the synchronization signal from the ID generation circuit (40)
The ID signal is supplied to the data multiplexer (41).
The output signal of the data multiplexer (41) is supplied to the inner code encoder (42). The inner code encoder (42) performs the process of encoding the inner code. The output signal of the inner code encoder (42) is supplied to the channel encoder (43), and is subjected to Miller square code coding processing. The output signal of the channel encoder (43) is
Output to the output terminal (45) via 4). Output terminal (4
In 5), a rotary head described later is connected. The recording data is recorded on the magnetic tape by the rotating head.

The reproduced signal reproduced from the magnetic tape by the rotating head is supplied from the input terminal (46) in FIG.
7) supplied to. An output signal of the reproduction amplifier (47) is supplied to a channel decoder (48), and a mirror square code is decoded.

The output signal of the channel decode (48) is supplied to a synchronization detection circuit (49), and the synchronization signal is detected. The output signal of the synchronization detection circuit (49) is supplied to the inner code decoder (40), and the inner code is encoded. Inner code decoder (5
The output signal of (0) is supplied to the switch circuit (51), and the digital audio signal and the digital video signal are separated.

The digital audio signal is supplied to the outer code decoder (53) after being deshuffled by the deshuffling circuit (52). The outer code is decoded by the outer code decoder (53) and is written to the memory (54). Decoding of the outer code is, for example, erasure correction with reference to an error flag generated in decoding of the inner code. The memory (54) expands the time axis of the data. The audio data read from the memory (54) is supplied to an error correction circuit (55), and the error data is corrected. An output signal of the error correction circuit (55) is supplied to an analog / audio interface (56), an analog audio signal is obtained at an output terminal (57), and a digital audio signal is obtained at an output terminal (58).

The digital video signal separated by the switch circuit (51) is written to the buffer memory (59). The digital audio signal read from the buffer memory (59) is supplied to the outer code decoder (61) via the intra-sector deshuffling circuit (60). The error-corrected digital video signal from the outer code decoder (61) is supplied to a channel multiplexer (62), and the two-channel digital video signal is converted into a one-channel digital video signal. The output signal of the channel multiplexer (62) is supplied to an error correction circuit (63), and error data is corrected. An output signal of the error correction circuit (63) is supplied to an analog / digital interface (64). An analog video signal is obtained at the output terminal (65),
A digital video signal is obtained at the output terminal (66).

b. Rotary head device and track format An example of a digital VTR rotary head device will be described with reference to FIG. Drum rotating in the direction of arrow h (6
7), four head chips HA to HD are mounted. The head chips HA and HB are close to each other, the head chips HC and HD are close to each other, the head chips HA and HC have a 180 ° facing distance, and the head chips HB and HD have a 180 ° facing distance. A magnetic tape (68) is obliquely wound around the peripheral surface of the drum (67) at a winding angle slightly wider than 180 °, and travels in the direction of arrow t. Magnetic tape (6
8) The combination of head chips HA and HB and head chip H
The set of C and HD slides alternately. The angle of the gap between the head chips HA and HB is made different, and similarly, the angle of the gap between the head chips HC and HD is made different, so that azimuth recording is performed. A reproduction signal in which the reproduction signals of the head chips HA and HC having the same azimuth angle are time-division multiplexed is formed. Similarly, a reproduction signal in which the reproduction signals of the head chips HB and HD are time-division multiplexed is formed.

The head chips HA and HB are plate-like 2
The head chips HC and HD are provided at one end of a support plate formed of a single piezoelectric element, and the head chips HC and HD are provided at one end of the same support plate. The support plate displaces the head chip in the height direction by an amount corresponding to the drive voltage. For example, (−1 to +3) ｛code is
The driving direction of the magnetic tape (68), +1 means the tape speed during normal reproduction. When reproducing at the tape speed set in the range of the tape speed of 駆 動, the driving voltage for the piezoelectric element according to the tape speed. Is generated by a microcomputer or the like. As a result, the head chips HA to HD correctly scan the tracks formed on the magnetic tape (68).

In the case of a video signal having a field frequency of 60 Hz as in the NTSC system, one field is divided into three segments, and one segment is recorded as two tracks. That is,
A video signal for one field is recorded on a magnetic tape (68) as three segments and six tracks.

FIG. 8A shows a track pattern viewed from the magnetic surface side of the magnetic tape (68), and FIG. 8B shows one track in the order of head scanning. A0, A1, A2, A3 are
Each represents an audio sector, and these audio sectors A0 to A3 are arranged at track ends. For A0-A3,
Digital audio signals of the first, second, third and fourth channels are recorded. The same content of the digital audio signal is recorded twice at different ends of two tracks. In other words, digital audio signals having the same contents are recorded at the head separation side end of the previous track and the head entry side end of the current track, respectively. The first digital audio signal recorded on the end on the head separation side is called a first copy, and the second digital audio signal recorded on the head entry side is called a second copy. The video sector is located in the center of the track.
T0 and T1 are track numbers, and S0 is a segment number.

As shown in FIG. 8B, an editing gap is provided between the audio sectors and between the audio sector and the video sector. Audio sectors A0 to A3 are 6
The video sector is composed of 204 sync blocks. In FIG. 8B, T is
E indicates a track gap preamble, E indicates an edit gap preamble, and P indicates a post preamble.

As shown in FIG. 9, each sync block has a length of 190 bytes, and a 2-byte synchronization pattern is added at the beginning. Next, a 2-byte ID pattern is added,
The ID code and the 85-byte data are encoded with an inner code to form an 8-byte check code. Also, an 8-byte check code is added to the other 85-byte data to form an inner code block.

The inner code is common to digital audio signals and digital video signals. A Reed-Solomon code is used as the inner code and the outer code. The number of samples of the digital audio signal recorded in each audio sector is 266 samples or 267 samples. Tenth
The figure shows a block configuration included in one audio sector.

In FIG. 10, numerals 0 to 266 indicate audio sample numbers, PV0 to PV3 indicate outer code check codes, and AUX0 to AUX3 indicate auxiliary words. These digital audio signals, check codes, and auxiliary words are shuffled. In FIG. 10, the illustration of the check code of the inner code is omitted. Although the bit length of one sample of the digital audio signal is 20 bits, the encoding of the inner code uses one byte as one symbol. A plurality of bytes aligned in the vertical direction of the array shown in FIG. 10 constitute a block of an outer code. Therefore, one sector is
It consists of 85 outer code blocks.

c. Variable speed reproduction operation The variable speed reproduction operation will be described with reference to FIG. The above track format is shown in FIG. 11A.
In FIG. 11A, reference numerals A to D denote tracks to be scanned by the head chips HA to HD. At the time of variable-speed playback, for example, at 2 × speed playback, three segments (six tracks) in which the field F1 is recorded by the dynamic tracking control are similar to the head chips HA to HD as in normal playback.
Reproduced by. When playback of field F1 ends,
Six tracks on which the signal of the next field F2 is recorded are skipped, and the track on which the signal of the next field F3 is recorded is reproduced. Therefore, as shown in FIG. 11B, at the time of double speed reproduction, the field F1 is followed by the field F1.
F3 playback data is obtained. In FIG. 11B, S0, S1, and S2 are:
The first, second, and third segments of each field are shown.

Focusing on before and after the track jump, as shown in FIG. 11A, the first copy DA1 is recorded at the end of the track in the field F1 on the head separation side, and the first copy DA1 is recorded on the end of the track in the next field F2 on the head entry side. Two copies DA1 'are recorded. The first copy DA1 and the second copy DA1 'are the same audio data. However, field F2
Is not reproduced, the second copy DA2 of the field F2 skipped as the second copy paired with the first copy DA1 is reproduced as shown in FIG. 11C. Naturally, the second copy DA2 is different data from the first copy DA1.

Therefore, a cross-fade process is performed at a joint between fields in which the first copy and the second copy have different data, and during the same data period of the first copy and the second copy, the same decoding process as during normal reproduction is performed. Is made.

d. Data Processing During Variable Speed Playback FIG. 12 shows a digital audio signal processing circuit applicable during variable speed playback. (1) and (2)
Indicates a deshuffling circuit. One of the deshuffling circuits (1) is supplied with reproduction data in which reproduction outputs of the head chips HA and HC are alternately arranged, and the other deshuffling circuit (2) is supplied with the head chips HB and HD.
Are output alternately.
These signals are supplied to an outer code decoder (4) via output signal selectors (3) of the deshuffling circuits (1) and (2). The output signals of the deshuffling circuits (1) and (2) are supplied to outer code decoders (7) and (10), respectively.

The selector (3) refers to the error flag generated by the inner-code decoder, selects the non-error data of the first copy and the second copy, and forms a code block of the outer code. The outer code decoder (4) includes a selector (3)
Decrypts the output data of The decoded output of the outer code decoder (4) is supplied to the selector (19) via the memory (5) and the output signal of the error correction circuit (6).

The data decoded by the decoders (7) and (10) are stored in the memories (8) and (11) and the error correction circuits (9) and (1), respectively.
It is supplied to the crossfader (23) via 2). The output signal of the crossfader (23) is supplied to the selector (19). The signal selected by the selector (19) is supplied to an analog / digital interface (56) (see FIG. 6). A control signal is supplied from the control signal generation circuit (27) to the selector (19) and the crossfader (23). The detection signal Pd is supplied to the control signal generation circuit (27) from the detection circuit (26).

A drive signal Sd for dynamic tracking is supplied from the controller (25) to the support plate (24) of the head. The detection circuit (26) detects a track jump from the drive signal Sd. FIG. 13 shows a track jump detection operation. At the time of 2 × speed reproduction shown in FIG. 11,
A sawtooth drive signal Sd is supplied to the support plates of the head chips HA and HC. The field F1 is reproduced, and then a track jump occurs to shift to the reproduction of the field F3. At the time of this track jump, the drive signal Sd
Is rapidly changed, and the detection pulse Pd is formed from this change. In order to accurately detect a track jump, the detection pulse Pd is generated only when the change in the drive signal Sd is equal to or higher than a predetermined level. The start timing of the crossfader is determined from the detection pulse Pd.
A control signal for the selector (19) is formed.

As shown in FIG. 14, the error correction circuits (9) and (1)
From 2), a first copy and a second copy of the reproduced digital audio signal are obtained. FIG. 14 is the first for simplicity.
Only the digital audio signal of the channel (decoded output of the audio selector A0) is shown, a0, a1, and a2 represent the reproduced data of each segment of the field F1, b0, b1, and b2 represent the reproduced data of each segment of the field F2, c0, c1 , c2 means reproduction data of each segment of the field F3, and d0, d1, d2 means reproduction data of each segment of the field F4.

At the time of double speed reproduction, the field F1 is reproduced by dynamic tracking, then the track of the field F2 is jumped, and the field F3 is reproduced. Field F1
The digital audio signal a2 of the segment S2 of the
Obtained as a copy. However, due to the track jump, the second copy is the digital audio signal b2 of the segment S2 of the field F2. Field F3 to F5
Also when a track jump is made, the digital audio signal of the segment S2 of the field F3 becomes the signal d2 of the field F4.

The crossfader (23) operates during different segments of the first copy and the second copy of the digital audio signal, and multiplies each sample of the first copy of the digital audio signal by a gradually decreasing coefficient; Each sample of the second copy of the digital audio signal is multiplied by a gradually increasing coefficient.

The selector (19) selects the output of the error correction circuit (6) during a period when the digital audio signals of the first copy and the second copy are the same, and when the digital audio signals of the first copy and the second copy are different from each other,
During the operation of the crossfader (23), the crossfader (2
Select the output of 3).

The switching process of the period in which the track jump occurs is not limited to crossfade, and may include a process of generating an average value of the digital audio signals of the first copy and the second copy, a process of muting the digital audio signal of the second copy, and the like. Can be used. However, the cross-fade processing has an advantage that the sound is smoothly connected at the switching point of the field.

[Problems to be solved by the invention]

Incidentally, such a conventional digital VTR has a controller (see FIG. 12) as described with reference to FIG.
The detection circuit (26) detects a sudden change in the level of the drive signal Sd for dynamic tracking from (25), generates a detection pulse Pd, and controls the digital audio signal by the detection pulse Pd. Was. Therefore, it is not always possible to accurately detect whether or not the rotating head is jumping the track, and it is not possible to process the playback state between the first and second digital audio signals according to the jump state of the rotating head with respect to the track. As a result, the reproduction state between the first and second digital audio signals is not smooth or noise.

In view of the above, the present invention accurately detects whether or not the rotating magnetic head is jumping a track, and performs processing of a reproduction state between the first and second digital audio signals in accordance with the detection mode. It is an object of the present invention to propose a digital information signal reproducing apparatus capable of greatly reducing noise generated during a switching period of the first and second digital audio signals and smoothing a reproduction state thereof.

[Means for solving the problem]

According to the present invention, the same first digital audio signal and second digital audio signal are duplicatedly recorded on each of two inclined tracks adjacent to each other on a tape, and a digital information signal is recorded from the tape by a rotating head. In a digital information signal reproducing apparatus adapted to reproduce, a head position control means for controlling a scanning position of a rotary head and a track to coincide with each other during variable speed reproduction in which a tape runs at a speed different from that at the time of recording; Detecting means (13) and (14) for detecting a jump state when the rotary head jumps a plurality of tracks based on an identification signal in the audio signal; Switching processing between the first digital audio signal and the second digital audio signal is performed for a predetermined period. Switching means (15), (16),
(17) and (18).

[Action]

According to the present invention described above, at the time of variable speed reproduction in which the tape runs at a speed different from that at the time of recording, the head position control means controls so that the scanning position of the rotary head matches the track, and the detection means (13) , (14) detect a jump state when the rotary head jumps a plurality of tracks based on the identification signal in the reproduced digital audio signal, and switch means (15), (16), (17), (18) ) According to the detected jump state, a predetermined period during the jump,
A switching process between the first digital audio signal and the second digital audio signal is performed.

〔Example〕

Hereinafter, an embodiment according to the present invention will be described in detail with reference to FIGS. 1 to 4.
Parts corresponding to the conventional digital VTR described with reference to FIG. 12 and FIG. 12 are denoted by the same reference numerals, and redundant imaging is omitted.

FIG. 1 shows a configuration on the reproduction side at the time of variable-speed reproduction of a digital VTR. (13) is an ID separation circuit which separates the ID signal from the digital audio signal from the deshuffling circuits (1) and (2) and supplies it to the track jump detection circuit (14). The track jump detection circuit (14) determines whether or not the ID signals of the first and second copies of the digital audio signal from the ID separation circuit (13) match, and determines whether the first copy of the digital audio signal is the first copy of the digital audio signal. Detects whether the ID signal of the audio signal immediately before the digital audio signal coincides with the digital audio signal, supplies a flag control signal to the error correction circuits (9) and (12) according to the mode, and When a jump is detected, a select signal is supplied to selectors (3) and (19).

An audio I / O circuit (15) supplies the digital audio signals of the first and second copies from the error correction circuits (9) and (12) to a bus consisting of a data bus, an address bus and a control bus, respectively. The flag signal of the digital audio signal of the first and second copies is supplied to the coefficient signal generating circuit (16). The coefficient signal generation circuit (16) generates a coefficient signal according to the flag signal from the audio I / O circuit (15), and supplies the generated coefficient signal to the multiplexer (17). The multiplexer (17) multiplies the digital audio signal of the first or second copy from the audio I / O circuit (15) by the coefficient signal from the coefficient signal generation circuit (16).
The multiplied first or second digital audio signal is supplied to an analog / digital interface (20) through a selector (19).

Next, the format of the digital audio signal will be described with reference to FIGS. FIG. 2A shows
FIG. 2B shows a 48 kHz sampling clock SCLK.
Shows a bit clock 1/128 SCLK having a period of 1/128 of the sampling clock, and FIG. 2C shows a digital audio signal. A0 to A3 of the digital audio signal shown in FIG. 2C indicate the four audio sectors A0 to A3 of FIGS. 8A and 8C described with reference to the conventional example, that is, one sample of each of the four channels of the digital audio signal. .

One sample of the digital audio signal of each of the audio sectors A0 to A3 has 32 bits of data.
FIGS. 3A, 3B, and 3C are diagrams in which the time axis of FIGS. 2A, 2B, and 2C is expanded, and FIG. 3C is a digital audio signal of one of the audio sectors A0 to A3. This is for one sample. SY is a sync mark used for synchronization with other devices. MU is a mute (silence) flag, which is set to, for example, "1" in each of error correction circuits (9) and (12) by a flag control signal from the track jump detection circuit (14). CR is a cross-fade flag, which is set to, for example, "1" in each of the error correction circuits (9) and (12) by a flag control signal from the track jump detection circuit (14). The CO is set to, for example, "1" by the outer code decoders (4), (7) and (10) when it is necessary to correct the concealed flags, that is, the error correcting circuits (6), (9) and (12). Is done. B0 to B3 are pre-emphasis, U1 to U4 are user's bits, and D0 to D19 are audio data.

Next, the sector ID signal will be described with reference to FIG.

As described with reference to FIG. 9, the ID signal is 2 bytes. Of the two bytes, one byte is assigned to a sync block number, and the remaining one byte is a sector ID shown in FIG. The first bit of this sector AD, that is, the V / A bit, is used for the video sync block and the audio sync.
The second bit, that is, the T bit, indicates the track number of one of the two tracks to be recorded. The third and fourth bits, ie, the S0 and S1 bits, indicate the segment, and the fifth, sixth, and seventh bits, ie, the F0, F1, and F2 bits, indicate the field.

Whether the sector ID signal described above, that is, the ID signal of the digital audio signal of the first copy matches the ID signal of the digital audio signal of the second copy, and the ID signal of the digital audio signal of the first copy, The track jump detection circuit (14) detects whether or not the ID signal of the first or second copy digital audio signal reproduced immediately before the first copy digital audio signal is continuous. Then, an error correction circuit (9) is provided by a flag control signal corresponding to the mode of the detected result.
The flags (mute flag MU and crossfade flag CR) of the digital audio signals of the first and second copies in (12) are set to, for example, “1”.

Next, a detection mode of the track jump detection circuit (14) and a process according to the mode will be described. First, first
And when both the digital audio signal of the second copy and the digital audio signal of the second copy are reproduced, the ID signals of the digital audio signal of the first copy and the digital audio signal of the second copy match each other, and the digital audio signal of the first copy When the ID signal of the digital audio signal of the first or second copy reproduced immediately before the ID signal of the first copy or the digital audio signal of the first copy thereof is continuous, it is determined that there is no track jump of the DT head. Then, a control signal is supplied to the selector (19), and the second copy digital audio signal from the error correction circuit (6) is supplied to the analog / digital interface (20).

Next, when both the ID signals of the first and second copies of the digital audio signal are reproduced, the ID signals of the first and second copies of the digital audio signal match each other, and Audio signal ID
If the signal and the ID signal of the digital audio signal of the first or second copy reproduced immediately before the digital audio signal of the first copy are discontinuous, it is determined that a track jump has been performed. Then, a flag control signal is supplied to the error correction circuit (12), and the mute flag MU of the second digital audio signal is set to "1".

Next, the ID signals of the first and second copies of the digital audio signal reproduced immediately before the first copy of the digital audio signal and the ID signals of the first and second copy of the digital audio signal do not match each other. Are consecutive, it is considered that a track jump has been performed.
Then, a flag control signal is supplied to the error correction circuit (12), and the crossfade flag CR of the second digital audio signal is set to "1".

Next, the ID signals of the digital audio signals of the first and second copies do not match each other, and immediately before the ID signal of the digital audio signal of the first copy and the digital audio signal of the first copy are reproduced. Regenerated first
Alternatively, when the ID signal of the digital audio signal of the second copy is continuous, it is determined that a track jump has been performed. Then, a flag control signal is supplied to the error correction circuit (12), and the mute flag MU of the digital audio signal of the second copy is set to "1".

Next, the ID signal of one of the digital audio signal ID signals of the first and second copies is output.
When only the signal is obtained, the ID signal of the obtained first or second copy digital audio signal and the obtained first or second copy digital audio signal of the obtained ID signal are reproduced immediately before reproduction. When the ID signal of the reproduced first or second copy digital audio signal is continuous, it is determined that the track jump has not been performed.
Then, a select signal is supplied to the selector (19),
A second copy of the digital audio signal from the modifying circuit (6) is supplied to the analog / digital interface (20).

Next, the ID signal of one of the digital audio signal ID signals of the first and second copies is output.
When only the signal is obtained, the ID signal of the obtained first or second copy of the digital audio signal and the obtained first or second copy of the digital audio signal of the obtained ID signal are reproduced immediately before the reproduction. When the ID signal of the reproduced digital audio signal of the first or second copy is continuous, it is determined that a track jump has been performed. Then, a flag control signal is supplied to the error correction circuit (9) or (12), and the mute flag MU of the first or second copy digital audio signal is set to "1".

Next, if neither the ID signal of the digital audio signal of the first copy nor the ID signal of the digital audio signal of the second copy can be obtained, a flag control signal is supplied to the error correction circuit (12), and the mute flag MU of the digital audio signal of the second copy is reproduced. And the crossfade flag CR is set to “1”.

The first or second supplied to the audio I / O circuit (15)
Mute flag MU of copy digital audio signal
Alternatively, when the crossfade flag CR is detected, for example, the mute flag MU is 1 and the crossfade flag is 0 or 1
In this case, the digital audio signal for one sample shown in FIG. 3C is muted. When the mute flag MU is "0" and the crossfade flag CR is 1, the digital audio signal of the first copy is muted. , Are multiplied by a gradually decreasing coefficient, and the second copy of the digital audio signal is multiplied by a gradually increasing coefficient and cross-fade.

Then, the mute flag MU and the crossfade flag
When both CRs are "1", the audio signals A0 to A3 for one segment described with reference to FIG. 2 are muted. When both the mute flag MU and the crossfate flag CR are "0", the digital audio signal is Not supplied to the bus Bus.

〔The invention's effect〕

According to the present invention described above, at the time of variable speed reproduction in which the tape runs at a speed different from that at the time of recording, the head position control means controls so that the scanning position of the rotary head matches the track, and the detection means (13) , (14) detect a jump state when the rotary head jumps a plurality of tracks based on the identification signal in the reproduced digital audio signal, and switch means (15), (16), (17), (18) ) According to the detected jump state, a predetermined period during the jump,
Since the switching processing between the first digital audio signal and the second digital audio signal is performed, noise generated during the switching period between the first and second digital audio signals is greatly reduced, and the reproduction state of the noise is reduced. Can be smoothed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing four-channel audio data, FIG. 3 is a diagram showing one-channel audio data, and FIG. 4 is a sector ID. FIG. 5, FIG. 5 is a block diagram showing a configuration of a recording side of a conventional digital VTR, FIG. 6 is a diagram showing a configuration of a reproducing side of the conventional digital VTR, FIG. 8 shows a format on a tape, FIG. 9 shows a sync block format, FIG. 10 shows an arrangement of audio data blocks, FIG. 11 shows a variable speed reproduction operation, and FIG. FIG. 13 is a diagram showing a part of a conventional digital VTR, FIG. 13 is a diagram showing detection of a track jump of a DT head, and FIG. 14 is a timing chart showing a relationship between a first copy and a second copy. (1) and (2) are deshuffling circuits, (3) and (19) are selectors, (4), (7) and (10) are outer code decoders, (5), (8) and (11) Is memory,
(6), (9) and (12) are error correction circuits, and (13) is
ID separation circuit, (14) track jump detection circuit, (1
5) is an audio I / O circuit, (16) is a coefficient signal generation circuit,
(17) is a multiplexer, (18) is a computer, (2
0) is an analog / digital interface, and (21) and (22) are output terminals.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 20/18 572 G11B 20/18 572G

Claims (1)

(57) [Claims] An identical first digital audio signal and a second digital audio signal are recorded on each of two adjacent inclined tracks on a tape, and a digital information signal is rotated from the tape. In a digital information signal reproducing apparatus adapted to be reproduced by a head, a head position control for controlling the operation position of the rotary head and the track to coincide with each other during variable speed reproduction in which the tape runs at a different speed from the time of recording. Means for detecting a jump state when the rotary head jumps the plurality of tracks based on an identification signal in the reproduced digital audio signal; and detecting the jump state in accordance with the detected jump state. The first digital audio signal and the second digital audio signal for a predetermined period of time. Digital information signal reproducing apparatus characterized by comprising a switching means for switching processing of the O signal.