JPH035942A - Control id erasing device - Google Patents

Abstract

PURPOSE:To prevent a control ID from being unnecessarily erased or being left erased by fitting preceding heads and following heads to a cylinder so as to obtain frame difference more than the added delay quantity of delay quantity to be generated at the time of reproducing and delay quantity to be generated at the time of recording. CONSTITUTION:Difference between the fitting positions of preceding heads 3 and 4 and following heads 5 and 5 is corresponding to more than a time for which the delay quantity until the discrimination of data on a tape by a discriminating means 15 at the time of reproducing is added with the delay quantity until the recording of the data on the tape by the following heads 5 and 5 after the set of the data to a data setting means 13 at the time of recording. Accordingly, when the control ID is started being erased, the turning ON state of the control ID in the reproducing sub code data of the preceding heads 3 and 4 is discriminated by the discriminating means 15. Afterwards, even when the control ID is started being erased by the following heads 5 and 6, the control ID is started being erased when the following heads 5 and 6 are on the frame before the record starting frame of the control ID which is a purpose. Thus, the control ID can start being erased without being left erased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the erasure of control IDs in digital audio-tape recorders (hereinafter referred to as DATs).

BACKGROUND OF THE INVENTION FIG. 7 shows the types of signals recorded in a DAT track. 59 is a PCM area, in which modulated music signals and the like are recorded. Reference numeral 60 denotes an ATF area, in which servo control signals and the like for the head to correctly trace tracks on the tape are recorded. 61 is a subcode area, where the control ID
, program number, time code, etc. are recorded. The control ID includes the start ID that indicates the beginning of the song, and the next start ID when detected during playback.
There is a skip ID that prompts you to fast forward to D, a priority ID that indicates the validity of the program number, etc.

With DAT, in addition to simple playback and recording, it is also possible to rewrite only the subcode area on an already recorded tape. This is called subcode dubbing.

FIG. 5 shows a block diagram of a conventional general AT. The cylinder 33 has an A head 35. To B, two heads of the rod 36 are attached at 180 degrees apart, and the tape is wound around the cylinder 33 by about 90 degrees by the guide post 34.

When performing reproduction, the signal processing circuit 40 which sets the signal processing circuit 40 to the reproduction mode drives the switch 37 and selects the reproduction amplifier 38. The signal processing circuit 40 demodulates the reproduced signal and corrects errors, and the subcode is stored in a memory inside the signal processing circuit 40. The data reading means 42 accesses the signal processing circuit 40 and reads the subcode.

The determining means 44 determines the state of the control ID of the subcode. The control circuit 46 is constituted by a microcomputer, and performs control as shown in step 51 in FIG. 6 based on the determination result of the determination means 44.

When recording, when the signal processing circuit 40 is set to the recording mode, the signal processing circuit 40 drives the switch 37 and selects the recording amplifier 39. At this time, if the data setting means 43 sets the subcode to be recorded in the signal processing circuit 40, the desired subcode will be recorded. The mode setting of the signal processing circuit 40 is performed by the control circuit 46.

When the signal processing circuit 40 is set to subcode dubbing mode, the A head 35. When the B head 36 is tracing the subcode area, recording is performed, and at other times, reproduction is performed.

The frame recognition signal generator 41 has a period of 30 m5ec, which is equal to the period of one frame when the DAT is running at normal speed.

Outputs a periodic square wave. Counter 45 counts rising edges of the frame recognition signal. The memory 47 stores the count value of the counter 45 after the discrimination by the discrimination means 44. The comparison means 48 compares the counted value of the counter 45 and the memory 47.
The count value of the counter 45 stored in the 45 is compared. The control circuit 46 performs control as shown in step 55 in FIG. 6 in response to the output from the comparison means 48.

Please refer to the figure I! when deleting the start ID in a DAT with such a configuration. (This will be explained while referring to L.) Fig. 4 is a diagram showing a tape on which the start ID is recorded, and 32 indicates the part where the start ID is recorded. 30 is the recording start position of the star ID. , 31
is the recording end position of the star ID. 29 indicates a frame several frames before the recording start position 30 of the start ID 32.

Now A head 35. It is assumed that the B head 36 is on the frame indicated by 29.

FIG. 6 shows an algorithm of the control circuit 46 when erasing the start ID 32 under the above conditions.

First, in step 49, the signal processing circuit 40 is set to playback mode, and playback is started. Next step 50
Then, the signal processing circuit 4 is read by the data reading means 42.
The reproduced subcode data of 0 is read, and then the process proceeds to step 51, where the determining means 44 determines the state of the start ID of the subcode data read in step 50. Star) I
If D is off, return to step 50, if on, go to step 5
Proceed to step 2. Both heads are 35°3 when proceeding to step 52.
6 has passed through the recording start position 30 of the start ID 32. In step 52, the data setting means 43 sets subcode data with the start ID turned off in the signal processing circuit 40. Next, proceeding to step 53, the signal processing circuit 40 is set to the subcode dubbing mode, and erasing of the star ID 32 is started.

According to the DAT format, it is desirable to record the start ID for about 9 seconds. Even with DATs that are actually commercially available, the start ID is recorded for about 9 seconds. Therefore, if you continue to erase the start ID for more than 9 seconds, most of the star 1-IDs will be erased. The subsequent steps are for determining 9 seconds as 'A-1'. In step 54, the count value of the counter 45 is stored in the memory 47. Next, proceeding to step 55, the comparison means 48 compares the counted value of the counter 45 with the counted value of the counter 45 stored in the memory 47 in step 54. If the difference between the two is less than 300 grooves, step 55 is repeated. If it is 300 or more, proceed to step 56. The count value of counter 45 is 30m5
Since it is added every ec, when the process proceeds to step 56, the erasure of 32 has continued for 9 seconds since the start.

In step 56, the signal processing circuit 40 is set to the reproduction mode, and erasing of the star ID 32 is completed.

Problems to be Solved by the Invention Let us consider the positions of both heads 35 and 36 at the time when the process advances to step 51 and the timing at which erasing of the start ID is started. For example, assume that this is the moment when the A head 35 finishes tracing the first half of the subcode area. If erasing of the star ID is started at this point, at least the start ID recorded in the first half subcode area that has been traced will be erased and left.

Furthermore, since it is undesirable for different subcodes to exist within the same frame, subcodes are generally recorded in units of frames. If you follow that general rule, you can start erasing start ID 32 at the earliest.
- One frame after the recording start position 30 of ID 32, and when the start ID is erased using the algorithm shown in FIG. 6, there is a problem that more than one frame of the start ID remains unerased.

Start ID again? Regarding the timing of the end of li leave,
It is sufficient to finish erasing the start ID when both heads 35 and 36 pass the recording end position 31 of the start ID 32, but with conventional DATs, it is impossible to read subcode data during subcode dubbing. Therefore, it is difficult to recognize that both heads 35 and 38 have passed the recording end position 31 of the start ID 32. Therefore, in the conventional example, start ID 32 is erased uniformly for 9 seconds, but in this case, if start ID 32 is recorded for only 4 seconds, 5 seconds are wasted and erased, and conversely, for 9 seconds or more There was a problem in that while it was being recorded, it could not be completely erased.

The present invention has been made in view of the problems of conventional DATs, and it is an object of the present invention to provide a device that can efficiently erase control IDs.

Means for Solving the Problems The control ID erasing device of the present invention is a control ID erasing device for a digital audio tape recorder, and comprises a cylinder having a recording/reproducing magnetic head including two leading heads and two trailing heads. , a first one connected to a leading head and a trailing head of the cylinder, respectively.
a second signal processing circuit; a data reading means for reading reproduction subcode data reproduced from the first signal processing circuit; and a determining means for determining the state of a control ID among the reproduction subcode data by the data reading means. a counter for counting a reference signal corresponding to the playback speed of the tape recorder; a memory for storing the counted value of the counter; and a control ID by the determining means.
subcode data with the control ID to be erased turned off is set, and the data setting means provides the data to the second signal processing circuit, and the determining means sets the control ID of the subcode data in the off state. and a comparison means for comparing the counted value of the counter with the counted value of the counter stored in the memory in order to measure the time from the time when the following head is determined to the frame corresponding to the writing of the trailing head. However, the difference in the mounting position of the preceding head and the following head is determined by the amount of delay until the data on the tape is determined by the determining means during playback and the amount of delay until the data on the tape is determined by the determining means during recording, and the amount of delay between the following head after data is set in the data setting means during recording. The difference is equivalent to more than the time added to the amount of delay until actually recorded on the tape.

Operation The control ID erasing device of the present invention is configured as described above, and when starting erasing the control ID, the determination means recognizes the ON state of the control ID in the reproduced subcode data of the preceding head, and then Even if the row head starts erasing the control ID, since there is a difference between the preceding head and the following head that is greater than the information transmission delay between each circuit, erasing the control ID will start at the succeeding head. From the point in time when the head is on a frame before the recording start frame of the target control ID,
Control ID without erasing control ID
You can start erasing. The amount of delay in information transmission between each circuit here refers to the amount of delay until the data on the tape is determined by the determining means during playback, and the amount of delay until the data on the tape is determined by the determining means during playback, and the amount of delay until the data on the tape is actually recorded on the tape by the trailing head after data is set in the data setting means during recording. This is the sum of the above and the amount of delay until recording.

Furthermore, while erasing the control ID, by keeping the first signal processing circuit on the preceding head in the reproduction state, the subcode data on the tape can always be obtained.
After the determination means recognizes the OFF state of the control ID, erasure of the control ID is completed after the trailing head passes through the OFF state portion of the control ID.

Embodiment A control ID erasing device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a control ID erasing device which is an embodiment of the present invention. Cylinder 1 has a leading A head 3. Leading B head 4. Trailing A head 5. A trailing B head 6 is attached.

FIG. 3 is a diagram showing the difference in the mounting positions of the leading A head 3 and the trailing A head 5 to the cylinder 1.

The difference between both heads is 4 frames. The tape is wrapped around the cylinder 1 by about 90 degrees by the guide post 2.

The first signal processing circuit θ and the second signal processing circuit 10 have the same function as the signal processing circuit 40 described in the conventional example section, but here the first signal processing circuit 9 is connected to the preceding head. A second signal processing circuit 10 connected to 3.4 and used exclusively for reproduction.
are connected to the trailing heads 5 and 6 and used exclusively for subcode dubbing.

The control circuit 16 is composed of a microcomputer,
The algorithm for erasing the start ID 32 is shown in FIG.

Each block of the control circuit 16 is the same as that described in the section of the conventional example, so a description thereof will be omitted here.

During reproduction, the amount of delay until the subcode data on the tape reproduced by the preceding spatulas P3, 4 is determined by the discriminating means 15 is one frame, and during recording, the data setting means 1
3 sets the subcode data in the signal processing circuit 10 and the delay amount until it is recorded on the tape by the trailing heads 5 and 6 is also one frame.

The case of erasing the start TD 32 in FIG. 4 will be described below with reference to the drawings. FIG. 2 shows a control ID erasing device according to an embodiment of the present invention.) 103
2 shows the algorithm of the control circuit 16 when erasing 2.

It is assumed that the preceding head 3.4 is located at 29 and playback is started from there.

First, in step 19, the first signal processing circuit 9 is set to a reproduction mode, and reproduction is started. Next step 20
Then, the reproduction subcode data of the first signal processing circuit 9 is read by the data reading means 12. Next step 21
Then, the determining means 15 determines the state of the start ID of the subcode data read in step 20. If the start ID is off, the process returns to step 20. If the start mode is on, the process advances to step 22.

At the time of proceeding to step 22, since the delay amount during playback is one frame, the leading heads 3 and 4 are positioned one frame after the recording start position 30 of star 1-ID 32, and the trailing heads 5 and 8 are positioned in the leading position. Since there is a delay of 4 frames with respect to heads 3 and 4, the recording start position 30 of START II) 32 is positioned three frames before. The delay amount during recording is also one frame, so if the second signal processing circuit 10 is set to subcode dubbing mode at this point, subcode dubbing will start two frames before the recording start position 30 of ID 32. It will be done.

In step 22, the data setting means 13 sets the second
Subcode data with the ID part turned off is set in the signal processing circuit 10 of . Next, the process proceeds to step 23, and the second signal processing circuit 10 is set to subcode dubbing mode. One frame after this point, trailing head 5.
8 starts erasing the start ID 32, and at that time the trailing head 5.6 moves to the recording start position 3 of the start ID 32.
Since it is located two frames before 0, there is no unerased star) ID at the recording start portion as in the conventional example.

The following steps relate to the timing of completion of start ID deletion.

In step 24, the data reading means 12 reads the reproduction subcode data of the first signal processing circuit 9. Next, the process proceeds to step 25, and the determination means 15 determines the result of step 24.
The start ID of the subcode data read is determined.

If it is on, return to step 24, if off, go to step 2θ
Proceed to.

At the time of proceeding to step 2θ, the transmission delay amount during reproduction is l frames, so the preceding head 3.4 is a star) ID3
It is located one frame after the recording end position 31 of 2.
Since the trailing heads 5 and 6 are delayed by 4 frames from the leading heads 2 and 3, they are positioned before the acquisition. Therefore, if erasing of the star ID is completed three frames after this point, the start ID 32 will be completely erased.

The following is a process for counting three frames.

In step 26, the count value of the counter 14 is stored in the memory 1.
Memorize to 7. Next, in step 27, the comparison means 18 compares the count value of the counter 14 with the memory 17 in step 26.
The counted value of the counter 14 stored in If the difference is 3 or more, proceed to step 28; if the difference is less than 3, proceed to step 27.
repeat.

At the time of proceeding to step 28, the trailing heads 5 and 6 are located above the recording end position 31 of the start ID 32. When the second signal processing circuit 10 is set to the playback mode in step 28, since the transmission delay amount during recording is one frame, the trailing head 5.6 reaches one frame after the recording end position 31 of the star) ID32. star at the moment)
The erasure of the ID is complete and is completely erased regardless of the length of the start ID 32.

In this way, the control ID erasing device according to one embodiment of the present invention can completely and efficiently erase the start ID.

For other control IDs, skip ID.

There are Priority ID and )Tsuku ID, but these are all recorded in the subcode area as one bit data at a time, similar to the star) ID, and the discriminating means 15 determines the bit of interest when discriminating the reproduced subcode data. By changing the position, all control IDs can be determined. Therefore, the control ID erasing device according to one embodiment of the present invention can completely and efficiently erase other control IDs as well as star IDs.

Effects of the Invention The control ID erasing device of the present invention has two independent recording and reproducing systems, and the leading head and the trailing head are capable of handling frames larger than the sum of the amount of delay occurring during reproduction and the amount of delay occurring during recording. It is attached to the cylinder with a difference, and the control ID in the reproduction subcode data by the leading head is used to determine the control ID by the trailing head.
Controls the start and end of erasing. Start erasing the control ID while anticipating the subcode data to be played.
It is possible to control the end of the process, prevent unnecessary erasure of control IDs, and prevent deletion of control IDs, which is extremely advantageous in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control ID erasing device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a control ID erasing device according to an embodiment of the present invention. amplifier, 9...first signal processing circuit, 10...second
a signal processing circuit; 12... data reading means;
13...Data setting means, 14...Counter, 15...Discrimination means, 16...Control circuit, 17...Memory, 18...Comparison means.

Claims (1)

[Claims] Control ID of digital audio tape recorder
The erasing device comprises a cylinder having a recording/reproducing magnetic head including two leading heads and two trailing heads, and first and second magnetic heads connected to the leading heads and trailing heads of the cylinder, respectively.
a signal processing circuit; a data reading means for reading reproduction subcode data reproduced from the first signal processing circuit; and a determining means for determining a state of a control ID among the reproduction subcode data by the data reading means; a counter that counts a reference signal corresponding to the playback speed of the tape recorder; a memory that stores the counted value of the counter; and subcode data that turns off the control ID to be erased when the determination means determines the control ID. set,
a data setting means for supplying the data to the second signal processing circuit; and a time from when the off state of the control ID of the subcode data is determined by the determination means to the frame corresponding to the writing of the trailing head; and a comparison means for comparing the counted value of the counter with the counted value of the counter stored in the memory, and the difference in the mounting positions of the preceding head and the following head is determined by:
Adding the amount of delay until the data on the tape is determined by the determining means during playback and the amount of delay from when data is set to the data setting means during recording until it is actually recorded on the tape by the trailing head. A control ID erasing device characterized in that the difference is equal to or more than the time taken by the user.