JPH0644747A - Device for reproducing audio signal - Google Patents

Abstract

PURPOSE:To provide a digital audio reproducing device changing a pitch in voice in proportion to a tape running speed at the time of variable speed reproduction and eliminating fluctuation in an internal and a noise at the time of slow reproduction. CONSTITUTION:By a system control 28, a tape running command is supplied to a servo circuit 11, and speed data is supplied to an audio processing circuit 27. According to that, by a controller 34, frequency data is supplied to a clock generation circuit 35, and after audio data is fetched into the inside from a RAM 32, is outputted to an output interface 33. Further, by a controller 34, an address difference between a write address and a read address is monitored always, and the address difference information is supplied to the system control 28 as memory state data MDATA. By the control 28, tape speed information TSPEED is varied based on the MDATA and sent to the servo circuit 11. Thus, the audio data As' read out at the time of slow reproduction is obtained without fluctuation in an interval and discontinuity in a signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal reproducing apparatus, and more particularly to an audio tape recorder and a player capable of variable speed reproduction.

[0002]

The present invention can be applied to, for example, a digital audio signal reproducing apparatus. It is particularly suitable for digital audio tape recorders and players capable of variable speed reproduction.

As an apparatus capable of recording and reproducing a digital audio signal on a magnetic tape, a dedicated audio apparatus such as an R-DAT (rotary head type digital audio tape recorder) or a digital VTR such as a D-1 format or a D-2 format is used. There is. At present, the mainstream of these digital audio recording systems is a rotary head system, which is relatively easy to record high frequency signals.

An important function of the audio tape recorder and the player is a variable speed reproducing function for reproducing while changing the running speed of the tape. The variable speed reproduction includes a mode in which the tape travels at a constant speed (referred to as a slow reproduction mode here) and a mode in which the tape travels at a speed proportional to the rotation speed of the operation dial (referred to as a jog reproduction mode here). It will be divided into two types. This function is effective when searching for an edit point or a playback start point, and usually finds a target point while listening to the sound during variable speed playback. In the conventional method of recording an analog audio signal on a track in the longitudinal direction of the tape, when the tape traveling speed is changed and reproduced, the pitch of the recorded audio signal changes in proportion to the tape speed and is reproduced. On the other hand, in the rotary head type digital audio variable speed reproduction, since the tracks are recorded discontinuously in the diagonal direction of the tape, when the tape running speed changes, the tilt of the rotary head tracing on the tape and the tilt of the track are different. Differently, the rotary head can only partially trace the track. The reproduced signal at this time is a discontinuous signal that is only partially reproduced. For this reason, there is a problem that an uncomfortable sound including noise is reproduced and it is difficult to find the beginning. Further, in the digital VTR, noiseless variable speed reproduction of the video signal is an important function. In order to achieve this, there is a product that installs a movable head that can change the position of the magnetic head in the direction of the rotary shaft of the rotary head and controls the head so that it can always trace a track even during variable speed reproduction. As a video signal reproduced by this, the same signal continues or is thinned out in a field unit and output. In the existing digital VTR, since the video signal and the audio signal are recorded on the same track by the same magnetic head, the audio signal is also reproduced in the field unit in the same manner as the video signal during the variable speed reproduction. Become. At this time, the audio signal, which was originally a continuous signal, has a discontinuous portion at a field delimiter, which causes noise.

Therefore, as a first prior art example of a reproduction system in which noise is not generated in variable speed reproduction of digital audio, a reproduction signal is temporarily stored in a memory, read out with a clock having a frequency proportional to the tape running speed, and continuously read. A method of outputting an audio signal has been devised, and is described in, for example, Japanese Patent Application Laid-Open No. 3-141079. Furthermore, according to this method, the pitch of the audio signal changes in proportion to the tape running speed and is reproduced in the same manner as the variable speed reproduction of the analog signal recording method, so that the editing operator who is accustomed to the operation of conventional analog machines. It is convenient for the user to operate with a feeling similar to that.

Further, in a commercial digital voice recording / reproducing apparatus, voice data for several seconds is stored in a memory during reproduction, and the data in the memory is responsive to the operation of the operation dial while the tape is not operated. There is a second technical example that can be output. This has an advantage that the reproduction start point and the edit point can be set finely. It is desirable that an audio signal, which is a continuous signal with respect to a field-based video signal, can be edited in the smallest possible unit.

[0007]

A problem of the first prior art example is a time delay caused by a process of once storing in memory and then reading. In the digital VTR, if the time difference between the video signal and the audio signal becomes large, the viewer feels uncomfortable. Especially in VTR editing work,
If there is a discrepancy between the video and audio when setting a fine edit point while feeding the tape at low speed, the editor may not be able to edit as desired.

Therefore, it is conceivable to perform control so that the timing of writing and reading the audio data in the memory is minimized so that the audio delay is minimized. However, since the reproduction of the audio data depends on the tape running and the operation of the movable head, the memory data read / write control of the audio data must depend on these operations.
Therefore, in the conventional technique, the speed of reading the audio data from the memory is controlled by the tape speed information set by the user. At this time, the writing and reading addresses in the memory must be close to each other to minimize the audio delay, but the audio data to be read should be read due to the fluctuations in the operation of the tape running or the movable head and the response to the operation command. There may be a case where is not written to the memory. If you do so, no matter how you control the memory, you will not be able to obtain a stable voice output or noise, and you will not be able to get the same operational feeling as an analog machine.

An object of the present invention is to provide an audio signal reproducing apparatus which can obtain a stable audio output with less deviation between video and audio.

As a problem of the second prior art, when setting an edit point in a fine unit, the process of searching for the edit point after performing reproduction in advance and loading the audio data into the memory is troublesome and time-consuming. .

A second object of the present invention is to provide an audio signal reproducing apparatus capable of finely setting edit points while tape running is performed at variable speed reproduction like a conventional analog machine.

[0012]

In order to solve the first problem of the present invention, a reproducing head for outputting a reproducing signal from a magnetic signal on a magnetic tape, a traveling means for traveling the magnetic tape, and the magnetic First receiving means for receiving a tape running command, control means for receiving the running command and giving the running command to a servo circuit, and receiving the running command,
In an audio signal recording / reproducing apparatus having a servo circuit for controlling the traveling means to change the traveling state of the magnetic tape, and a generating means for generating audio data from the reproduced signal, a storage means for storing the audio data. A first reading means for reading the audio data from the storage means in response to the travel command, and a remaining amount of the audio data not yet read out of the audio data stored in the storage means. And has a detection unit that outputs the remaining amount to the control unit,
The control unit corrects the traveling command based on the remaining amount, outputs the corrected traveling command to the servo circuit, and changes the traveling state of the magnetic tape.

In order to solve the second object of the present invention, a reproducing head for outputting a reproducing signal from a magnetic signal on a magnetic tape, a traveling means for traveling the magnetic tape, and a traveling command for the magnetic tape are accepted. First receiving means, second receiving means for receiving a read command relating to the read amount of audio data on the magnetic tape, and receiving the running command, giving the running command to the servo circuit, and receiving the reading command. Then, the control means for outputting the read command to the second read means, the servo circuit for receiving the running command and controlling the running means to change the running state of the magnetic tape, and the audio signal from the reproduced signal. In an audio signal recording / reproducing apparatus having a generating unit for generating data,
Storage means for storing the audio data, second read means for reading the audio data from the storage means in response to the read command, and the audio data stored in the storage means that has not yet been read out. And a detection means for detecting the remaining amount of the audio data which is not present and outputting the remaining amount to the control unit, and the control unit corrects the traveling command based on the remaining amount, and A running command is output to the servo circuit to change the running state of the magnetic tape.

[0014]

In order to solve the first problem of the present invention, the reproducing head outputs the reproducing signal from the magnetic signal on the magnetic tape. The running means runs the magnetic tape. The first receiving means receives the running command of the magnetic tape. The control means receives the traveling instruction and gives the traveling instruction to the servo circuit. The servo circuit receives the traveling command and controls the traveling means to change the traveling state of the magnetic tape. The generation means generates audio data from the reproduction signal. The storage means stores the audio data. The first reading means reads the audio data from the storage means according to the travel command.
The detection means detects the remaining amount of the audio data that has not been read out of the audio data stored in the storage means, and outputs the remaining amount to the control unit. The control unit corrects the traveling command based on the remaining amount, outputs the corrected traveling command to the servo circuit, and changes the traveling state of the magnetic tape.

In order to solve the second problem of the present invention, the reproducing head outputs the reproducing signal from the magnetic signal on the magnetic tape. The first receiving means is a traveling means for traveling the magnetic tape. Receives the running command of the magnetic tape. The second accepting means accepts a read command regarding the read amount of the audio data on the magnetic tape. The control means receives the travel command, gives the travel command to the servo circuit, receives the read command, and outputs the read command to the second read means. The servo circuit receives the traveling command and controls the traveling means to change the traveling state of the magnetic tape. The generation means generates audio data from the reproduction signal. The storage means stores the audio data. The second reading means reads the audio data from the storage means in response to the read command. The detection means detects the remaining amount of the audio data that has not been read out of the audio data stored in the storage means, and outputs the remaining amount to the control unit. The control unit corrects the traveling command based on the remaining amount, outputs the corrected traveling command to the servo circuit, and changes the traveling state of the magnetic tape.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, in order to obtain a stable reproduced sound, the tape running speed is controlled so that the address difference between writing and reading in the memory is within a certain range as follows. is there.

For example, in the slow reproduction mode of the VTR, the V circuit is controlled by the servo circuit for controlling the tape running operation.
The tape speed is controlled based on the tape speed command generated from the system control which controls the overall operation of the TR system. The audio data is read from the memory based on a clock having a frequency proportional to the tape speed command. However, since there is a slight difference between the tape speed command and the actual tape speed, if the memory is controlled in this state, the data to be read may not have been written yet, or the read timing may be too late. Occurs.

Therefore, in order to prevent these from occurring, there are two methods of finely adjusting the read speed of the memory and controlling the reproduction timing of the audio data written in the memory by changing the tape speed. The former method is disadvantageous in terms of the quality of reproduced voice because the pitch of the memory varies because the read speed of the memory is changed. Therefore, the latter method is adopted to constantly detect the address difference between writing and reading in the memory, and control the tape speed so that the address difference is within a certain range. Since the reproduction output by the movable head in the VTR is generated for each field, the data of the same field is repeatedly reproduced in the low speed variable speed reproduction. At this time, since it is not necessary to write the same data to the memory, it is the same as that after writing the first reproduced data to the memory, the data is not reproduced until the data of the next field is reproduced. Therefore, the reproduction timing of the next field data may fluctuate on a field-by-field basis due to the influence of fluctuations in the tape running state. If the memory absorbs fluctuations in the input data speed that are difficult to predict, it is effective to increase the capacity of the buffer by ensuring a large address difference between writing and reading in the memory for stable reading. is there.

However, a problem at this time is the delay of the reproduction signal. In the case of VTR, signals output to the outside include video output and time code output in addition to audio output. Since the audio output is delayed with respect to these signals, it is conceivable to delay signals other than the audio output signal in order to adjust the timing relatively. These video output delays are given only when setting edit points and finding the target point in variable speed playback, so by canceling the delay in output of video signals during normal playback and editing, the system No inconvenience arises.

Further, in order to set the edit point and find the cue in small units while running the tape and outputting the audio signal, the rotation amount of the operation dial is detected in the jog reproduction mode and the rotation amount is detected according to the rotation amount. Advance the read address of memory. When the read / write address difference is out of the fixed range, the tape is run to reproduce the data in the next field, the data is written in the memory, and the fixed displacement amount of the address is held. At this time as well, if it is a VTR, the output audio signal and the video signal are deviated from each other, so that the video signal is delayed to match the timing. This is performed by outputting the video signal of the field corresponding to the currently output audio data.

As described above, digital reproduction is possible in which slow reproduction for reproducing a continuous audio signal in which the pitch does not fluctuate and the pitch changes with respect to the speed command, and jog reproduction for setting edit points or cueing in fine units by the operation dial. An audio playback device can be realized.

The present embodiment will be described in detail below. Figure 2
A digital V which is a video signal recording / reproducing apparatus according to the present invention.
It is a figure showing an example of composition of a tape running system of TR.
P0, P1, P2, and P3 are reproduction heads for outputting reproduction signals from magnetic signals on the magnetic tape, 1 is a drum, 2 is a magnetic tape, 3 is a guide, 4 is a drum motor, and 5 is a running for running the magnetic tape. Means is a capstan motor, 6 is a capstan, 7 is a pinch roller, 8 is a drum pulse generator, 9 is a capstan frequency generator, 10 is a control signal head, 11 is a servo circuit, 12a and 12b are displacement elements, and DD is Drum rotation direction, TD is tape running direction, CTL is control signal, TSPEED is tape speed information that is running speed command, HCONT is displacement control signal, DPG is drum pulse signal, DCONT is drum control signal, and CFG is capstan frequency signal. , CCONT are capstan control signals, S0 and S1 are playback It is an issue.

The reproducing heads P0 and P1 have displacement elements 12a,
The reproducing heads P2 and P3 are installed at the tip of the displacement element 12b, and the ends thereof are fixed to the drum 1. Therefore, the reproducing heads P0, P1, P2 and P3 are connected to the servo circuit 1
Displacement control signal HCON from 1 to displacement elements 12a, 12b
By applying T, the drum 1 can be displaced in the rotation axis direction. The reproducing heads P0 and P2 have the same azimuth angle (for example, +15 degrees). The reproducing heads P1 and P3 are also provided with the same azimuth angle (for example, −15 degrees), which is different from the reproducing heads P0 and P2.

The magnetic tape 2 is guided by the guide 3 to the drum 1
Wrapped around. The drum 1 rotates in the drum rotation direction DD, and the magnetic tape 2 runs in the tape running direction TD for normal reproduction. The rotation of the drum 1 is performed by the drum motor 4. The magnetic tape 2 runs on the capstan 6
With the pinch roller 7 sandwiching the magnetic tape 2,
The capstan motor 5 rotates by rotating the capstan 6 which is the axis. The servo circuit 11 drives the drum motor 4 and the capstan motor 5.

The servo circuit 11 is used to perform these controls.
Now we are referring to some signals. The drum pulse generator 8 generates a pulse signal once with a constant rotation phase while the drum motor 4 makes one rotation. Based on this, the servo circuit 11 determines that the rotation phase of the drum motor 4 is a reference signal ( In the case of a VTR, a video signal inputted from the outside is generally selected), and the drum control signal DCONT given to the drum motor 4 is controlled so as to be locked. The capstan frequency generator 9 generates a capstan frequency signal CFG which is a signal having a frequency proportional to the rotation frequency of the capstan motor 5. The servo circuit 11 refers to this to detect the speed of tape running and controls the capstan motor 5.

Further, the control signal CTL reproduced from the control signal head 10 is referred to by the servo circuit 11. Here, the control signal CTL causes one pulse signal to be reproduced from the control signal head 10 each time the drum 1 makes a half rotation and each set of two helical tracks is reproduced by the reproducing heads P0 and P1 or the reproducing heads P2 and P3. Shall be. The servo circuit 11 controls the rotation phase of the capstan motor 5 so that the reproduced control signal CTL is locked in a predetermined phase relationship with the reference signal.

Further, the servo circuit 11 is a displacement element so that the reproducing head always scans the track of the tape in order to obtain a noiseless image not only in normal reproduction but also in low-speed variable speed reproduction (for example, -1 to +3 times speed). 12a and 1
The voltage of the displacement control signal HCONT is controlled to 2b. This is the drum pulse signal DPG, the control signal CT
L, reference to capstan frequency signal CFG. Further, although not shown in the figure, microcomputer with detection of output levels of reproduction signals S0 and S1 and detection of reproduction data attributes (information such as field number and track number). It can be realized by control. Further, the servo circuit 11 changes the tape running speed in accordance with the command of the tape speed information TSPEED given from the system control 28 which controls the entire system.

In this embodiment, it is assumed that the magnetic tape 2 has a digital video signal and a 4-channel digital audio signal recorded thereon. FIG. 3 is a diagram showing an example of a recording pattern of the magnetic tape 2. T0 and T1 are helical tracks, 19 is a control signal track, V is a video recording area, A0 is an audio channel 0 recording area,
A1 is an audio channel 1 recording area, A2 is an audio channel 2 recording area, and A3 is an audio channel 3 recording area.

The video signal of one field is recorded on the six helical tracks shown in the figure. For this reason, the servo circuit 11 must control the displacement of the reproducing head so that reproduction can be performed in units of low speed variable speed reproduction. The helical tracks T0 and T1 are moved in the drum rotation direction DD by the reproducing heads P0 and P1 or P2 and P3.
And the tape running direction TD, two tracks are simultaneously scanned from the lower end to the upper end of the magnetic tape 2 from left to right.

The video signal is recorded at the center of the helical track. The audio signal is recorded in eight recording areas continuously at the upper end and the lower end of the tape. These are for writing the same 4-channel audio signal twice to improve the reliability of the reproduction data. The audio recording areas A0 to A3 at the upper end and the audio recording areas A0 to A3 at the lower end are continuously reproduced. The same audio data as is recorded.

FIG. 4 shows a structure of a reproducing circuit in a digital VTR which is a video signal recording / reproducing apparatus according to the present invention. 21a and 21b are reproduction preamplifiers, 22
Reference numerals a and 22b are reproduction equalizers, 23a and 23b are data strobe circuits, 24a and 24b are demodulation circuits, 25a and 25b are synchronization signal detection circuits, and 26 is an error correction circuit. VS is video data, AS is audio data, I
D is an ID signal, ACLK is an audio reference clock, 2
Reference numeral 7 is an audio signal processing circuit, 28 is a system control which is a control means for receiving the travel command and giving the travel command to the servo circuit, 29 is an operation panel, 30 is an operation dial, AS ″ is converted audio data, SDATA.
Is speed data, MDATA is memory status data, MOD
E is a mode signal. Playback preamplifiers 21a, 21
b, the reproduction equalizers 22a and 22b, the data strobe circuits 23a and 23b, the demodulation circuits 24a and 24b, the synchronization signal detection circuits 25a and 25b, and the error correction circuit 26 are generation means and video generation means for generating audio data from the reproduction signal. is there.

The reproduction signal S0 reproduced from the reproduction heads P0 and P2 is supplied to the reproduction preamplifier 21a, and the reproduction signal S1 reproduced from the reproduction heads P1 and P3 is reproduced to the reproduction preamplifier 21.
amplified by b. Playback equalizers 22a and 22b
Corrects the frequency characteristic of the signal deteriorated by the tape head system, and the data strobe circuits 23a and 23b generate a reproduction clock by the PLL from the timing information at which the level transition of the signal is performed, and use this as a strobe signal to set the logic level of the signal. It is something to detect.

Since the transmission path for recording / reproducing the tape by the rotary head through the rotary transformer as in this reproducing apparatus does not pass the DC component, the data to be recorded is converted into a signal having a small DC component based on a certain rule. It will be recorded later. The demodulation circuits 24a and 24b perform inverse conversion of the conversion performed at the time of recording.

Further, in recording a digital signal, an error correction for correcting when an error occurs not only in these signals but also in a reproduced signal so that a video signal and an audio signal can be correctly reproduced at the time of reproduction. A code, a sync signal indicating a delimiter of a block of data for which error correction signal processing is performed (hereinafter referred to as a sync block), and an ID indicating an attribute of data belonging to the sync block
Data necessary for signal processing of the system such as signals are recorded together. The sync signal detection circuits 25a and 25b detect a sync signal having a constant pattern that appears periodically, and subsequent reproduction signal processing is performed based on this timing information. The error correction circuit 26 performs error correction processing and the like by referring to the ID signal and inner error correction code added at the time of recording in units of data included in the sync block divided by the sync signal.

After the error correction processing, the signal processing is divided into video and audio, and the error correction circuit 26 outputs video data VS and audio data AS. The video data VS is an 8-bit parallel signal, and the audio data AS is a 4-bit multiplexed 20-bit parallel signal. The sampling frequency of the audio signal is Fs
Then, the data rate of the audio data AS is Fs.
4 times the

The audio signal processing circuit 27 controls the writing and reading of the audio data AS by the memory, and changes the pitch of the audio signal to be output according to the tape running speed. Audio signal processing circuit 27
In addition to the audio data AS, the signals required for the processing include the ID signal ID, the audio reference clock ACLK, and the speed data SDATA. The ID signal ID indicates the attribute of the data included in the sync block, and includes information such as the field to which the data belongs, the track, and the sync block number. Audio reference clock ACLK
Is a clock synchronized with the audio data AS and has a frequency four times that of Fs. For tape running, a mode signal MODE having information such as tape running mode and tape running speed is sent from the operation panel 29 to the system control 28, and the system control 28 sends the tape speed information TSPEED.
To the servo circuit 11 and the servo circuit 11
Is for tape running control. However, in the present invention, the tape speed information TSPEED sent to the servo circuit 11 depends not only on the mode signal MODE but also on the memory status data MDATA. The information of the speed data SDATA is used to generate a timing signal for reading the audio data from the memory. The relationship between these signals will be explained in the section where the memory control method is described again.

FIG. 1 shows an audio signal processing circuit 2 of the present invention.
7 shows an example of the configuration of No. 7. Reference numeral 31 is an input data interface, 32 is a RAM that is a storage unit that stores the audio data, 33 is an output data interface, and 34 is a first reading unit that reads the audio data from the storage unit according to the travel command. (This is also a second reading means, and a detecting means for detecting the remaining amount of the audio data not yet read out of the audio data stored in the storage means and outputting the remaining amount to the control section. There is a controller, 3
5 is a clock generation circuit, DB is a data bus, AD is an address signal, MCONT is a microcomputer control signal, and FDATA.
Is frequency data, RCLK is a read clock, A
S'is read audio data. The audio data AS is introduced to the data bus DB via the input interface 31. The input audio data is temporarily stored in the RAM 32 by the controller 34 including a microcomputer or a digital signal processor. Further, the read clock RCLK output from the clock recovery circuit 35 based on the frequency data FDATA.
The audio data is read from the RAM 32 at the timing of, and the read audio data AS ′ is output via the output interface 33. Next, an operation of writing and reading audio data in the RAM 32 will be described. FIG. 5 shows a method of controlling the address of the RAM 32. WRAD is a write address, RD
AD is a read address, and RWDIR is an address advancing direction. What is shown as a ring in the figure shows the entire address space of the RAM 32 for storing audio data. Addresses for writing and reading the memory are advanced so as to circulate in a limited address space. The write address WRAD is always advanced before the read address RDAD. Fig. 6 shows R in 1/3 speed reproduction
Audio data AS and RAM 32 to be written in AM 32
It shows the relationship of the read audio data AS 'read from the. One division shown in the figure shows audio data for one field, and the numeral in the division shows the field number. In the variable speed reproduction in the VTR using the movable head, the signal is reproduced in the unit of field, so that the signal in the same field is continuously reproduced at the 1/3 speed. Therefore, in the audio data AS of FIG. 6, three signals of field number 1 are continuously reproduced. At this time, of the audio data AS, it is not necessary to write a signal of the same field many times, so only the field data whose field number has changed first is RA.
Write to M32. Since the change of the field number can be seen from the ID signal ID, the controller 34 monitors this and controls the writing of the RAM 32. FIG. 7 shows the relationship between the timing signals of each signal. Writing control by the controller 34 of the RAM 32 will be described. The controller 34 is interrupted by the audio reference clock ACLK synchronized with the audio data AS, and the audio data AS input to the input interface 31 is introduced to the data bus DB by the microcomputer control signal MCONT and taken into the controller 34. Further write address WRA
D is incremented by 1 and writing to the RAM 32 is performed. The interrupt at this time is applied with a cycle of a frequency four times as high as the sampling frequency. However, by providing a buffer for four channels in the input interface 31 and setting the interrupt frequency to 1/4, the load on the controller is reduced. Can be reduced.

When the variable speed reproduction speed is ⅓ times, the audio data is read from the RAM 32 at a speed ⅓ times the data rate of the input audio data AS. Reproduction at 1/3 speed is performed by setting the mode signal MODE to "1/3 speed reproduction" by operating the operation panel 29 in FIG. Mode signal MO
Upon receiving DE, the system control 28 gives a tape running speed command as the tape speed information TSPEED to the servo circuit 11 for the servo circuit 11 to actually run, and the speed data SDATA is processed as an audio signal by the audio data read speed from the memory. It is given to the circuit 27. At this time, the speed data SDATA is set to "1/3 speed reproduction", and accordingly, the controller 34 causes the clock generation circuit 35 to set the frequency of the read clock RCLK to the audio reference clock ACL.
The frequency data FDATA is given so as to be 1/3 of K. The controller 34 advances the read address RDAD by one each time an interrupt is generated by the read clock RCLK, fetches the audio data from the RAM 32 inside, and then outputs the audio data to the output interface 33.

Here, it is assumed that "1/3 speed reproduction" is set in both the tape speed information TSPEED and the speed data SDATA. At this time, considering a system in which the tape speed does not fluctuate and the operation of the movable head ideally operates in accordance with the tape speed, the address positional relationship between the write address WRAD and the read address RDAD in the RAM 32 makes the appearance of the audio data to be written discontinuous. Therefore, fluctuations will occur, but a constant relationship will be maintained. However, in an actual system, such a state does not occur, and the read address RDAD coincides with the write address WRAD and there is no audio data to read, or conversely, the read signal RDAD is too far away and the output signal is too late, or the write address is delayed by one cycle. However, there is a problem that the signal read out is discontinuous. In order to solve this, as shown in FIG. 5, the address shift allowable minimum amount RWMIN and the address shift allowable maximum amount RWMAX are set.
Is set, and the controller 34 constantly monitors the address difference between the write address WRAD and the read address RDAD. If this address difference is smaller than the address shift allowable minimum amount RWMIN, the tape running speed is increased, and if it is larger than the address shift allowable maximum amount RWMAX, the tape running speed is slowed down. Therefore, the controller 34 sends this address difference information to the memory status data M
The data is given to the system control 28 as DATA, and the system control 28 further receives the memory status data MDA.
The tape speed information TSPEED is changed based on TA and sent to the servo circuit 11. As a result, the read audio data AS ′ in the slow reproduction can be stably obtained without the pitch variation and the signal discontinuity.

Further, as shown in FIG. 7, the data rate of the read audio data AS 'is 1 of the audio data AS.
Since it is / 3, it is necessary to restore the original data rate when outputting to the outside. Therefore, the sampling frequency converter 36 generates converted audio data AS ″. The conversion method in the sampling frequency converter 36 is performed by data interpolation or processing by a digital filter. At this time, the data rate of the read audio data AS ′ is equal to the tape speed. Therefore, it is necessary to change the processing method according to this, and a DSP (digital signal processor) that can easily change the signal processing method by software is applied as means for performing these processing. Conceivable.

Variable speed reproduction includes jog reproduction in addition to slow reproduction. According to the present invention, the head of an edit point can be specified in fine units while running a tape. Jog reproduction is performed by rotating the operation dial 30 provided on the operation panel 29. At this time, the tape running speed changes according to the speed of rotation of the operation dial 30. In normal jog playback mode, operation dial 30
The rotation speed is constantly detected by the operation panel 29, and speed information such as "1/3 speed reproduction" which changes every moment is sent to the system control 28 as a mode signal MODE.

That is, the difference from the slow reproduction is that the speed command changes every moment, and there is no difference in the way of processing according to the mode. Conventionally, the beginning of a voice can be specified only in units of fields, but according to the present invention, it is possible to specify in smaller units within fields. Further, by making the amount of rotation of the operation dial 30 correspond to the amount of audio data read from the memory, it becomes easier to find the head in smaller units. To do this, as the mode signal MODE output from the operation panel 29 to the system control 28, the speed information and the rotation amount information of the operation dial 30 may be output in increments.

When this signal processing is performed, the converted audio data AS ″ that is finally output has a delay with respect to the audio data AS. A problem occurs when only audio-related equipment or a VTR performs only audio-related editing. However, there is a case where the deviation of the image or time code signal with respect to the sound is a problem.To deal with this problem, the image or time code may be delayed by the delay of the sound.

FIG. 8 shows a means for delaying the video data VS, and FIG. 9 shows the timing relationship of each signal. Reference numeral 41 is a buffer memory which is a video storage means, 31
Is a controller which is a video reading means, VS 'is delayed video data, and SEL is a field selection signal. The buffer memory 41 is a memory that can store video data for several fields, and writes the video data VS once and reads it as the delayed video data VS ′. The reading of the delayed video data VS ′ is controlled by the field selection signal SEL from the controller 31.

The control method will be described with reference to FIG. The relationship between the reproduced video data VS and the audio data AS is output in field units without delay. A delay occurs in the read audio data AS 'due to the memory writing and reading of the audio data AS. Since the controller 31 controls the memory of the audio data AS, it can detect the change of the field of the read audio data AS '. Therefore, if this change is detected, the field selection signal SEL output from the controller 31 causes
A signal of the same field as the field of the read audio data AS 'is output at the field boundary synchronized with the video data VS as the delayed video data VS'. As a result, it is possible to configure a system in which the difference between the audio and the video is small. Further, the time code signal can be realized by the same idea.

According to the present invention, in the digital audio signal reproducing system in which the pitch of the reproduced audio signal changes according to the tape running speed during the variable speed reproduction by the memory control, the deviation amount between the write address and the read address of the memory is detected. , If it deviates from the set allowable deviation amount range, the tape speed is changed so that it falls within the allowable deviation range, so that a continuous audio signal whose pitch changes with respect to the tape speed command is reproduced without pitch fluctuation. It enables slow playback, and jog playback that sets edit points and finds the beginning of a file while operating the tape with the operation dial.

According to the present invention, in the digital audio signal reproducing system in which the pitch of the reproduced audio signal changes according to the tape running speed during the variable speed reproduction by the memory control, the deviation amount between the write address and the read address of the memory is detected. , If it deviates from the set allowable deviation amount range, the tape speed is changed so that it falls within the allowable deviation range, so that a continuous audio signal whose pitch changes with respect to the tape speed command is reproduced without pitch fluctuation. It enables slow playback, and jog playback that sets edit points and finds the beginning of a file while operating the tape with the operation dial.

[0048]

According to the present invention, it is possible to provide an audio signal reproducing apparatus which can obtain a stable audio output with less deviation between video and audio.

Further, it is possible to provide an audio signal reproducing apparatus capable of finely setting edit points while running a tape at variable speed reproduction like a conventional analog machine.

[Brief description of drawings]

FIG. 1 is a block diagram of audio signal processing.

FIG. 2 is a block diagram of a tape running system.

FIG. 3 is an explanatory diagram of a tape recording pattern.

FIG. 4 is a block diagram of a reproduction signal processing system.

FIG. 5 is an explanatory diagram of a configuration of a RAM for audio data.

FIG. 6 is an explanatory diagram of a timing of writing and reading audio data to and from a RAM.

FIG. 7 is an explanatory diagram of timing of each signal in the signal processing circuit.

FIG. 8 is a block diagram of a video data delay circuit.

FIG. 9 is an explanatory diagram of timing of each signal in video data delay.

[Explanation of symbols]

1. Drum, 2. Magnetic tape, 6. Capstan, 7.
Pinch roller, 12. Displacement element, 29. Operation panel, 3
0. Operation dial.

Claims (5)

[Claims] 1. A reproducing head for outputting a reproducing signal from a magnetic signal on a magnetic tape, a traveling means for traveling the magnetic tape, a first receiving means for receiving a traveling command of the magnetic tape, and the traveling command. Receiving and giving a running command to the servo circuit, a servo circuit for receiving the running command and controlling the running device to change the running state of the magnetic tape, and audio data generated from the reproduction signal. An audio signal recording / reproducing apparatus having a generating unit for storing the audio data, a first reading unit for reading the audio data from the storing unit in response to the travel command, and the storing unit. Detects the remaining amount of the above audio data that has not been read out of the above audio data stored in The control unit corrects the traveling command based on the remaining amount, outputs the corrected traveling command to the servo circuit, and outputs the corrected magnetic tape to the servo circuit. An audio signal reproducing device characterized by changing a running state. 2. The audio signal recording / reproducing apparatus according to claim 1, wherein the detecting means determines a write address for writing the remaining amount of the audio data in the storing means and a read address for reading the audio data. An audio signal reproducing device characterized by detecting as a difference in read address. 3. A reproducing head for outputting a reproducing signal from a magnetic signal on a magnetic tape, a traveling means for traveling the magnetic tape, a first receiving means for receiving a traveling command of the magnetic tape, and the above-mentioned magnetic tape. Second receiving means for receiving a read command relating to the read amount of the audio data, and the run command for the servo circuit, the run command for the servo circuit, and the read command for the second read means. An audio signal having a control means for outputting the running command, a servo circuit for receiving the running command and controlling the running means to change the running state of the magnetic tape, and a creating means for creating audio data from the reproduced signal. A recording / reproducing apparatus, comprising: storage means for storing the audio data; and the audio data from the storage means in response to the read command. Second reading means for reading, and detecting means for detecting the remaining amount of the audio data which has not been read out of the audio data stored in the storage means and outputting the remaining amount to the control section. The control unit corrects the running command based on the remaining amount, outputs the modified running command to the servo circuit, and changes the running state of the magnetic tape. Audio signal reproduction device. 4. The audio signal recording / reproducing apparatus according to claim 3, wherein the running command is a running speed command of a magnetic tape, and an operation dial having functions of the first and second receiving means is provided. The audio signal reproducing device, wherein the operation dial outputs the rotation speed of the operation dial as a traveling speed command and the rotation amount of the operation dial as a read command to the control unit. 5. A video signal recording / reproducing apparatus having the audio signal recording / reproducing apparatus according to claim 1, 2, 3 or 4, wherein: video generating means for generating video data from the reproduced signal; and storing the video data. A video signal recording / reproducing apparatus comprising: a video storage means and a video reading means for reading the video data from the video storage means in synchronization with the reading of the audio data.