JPH02195555A - Program searching method for dat - Google Patents

Abstract

PURPOSE:To allow program searching at a high speed with reliability by feeding a tape at a middle speed in the same direction as the feed direction of a high speed at a prescribed distance before the precise program searching after searching at a high speed, then performing the precise program searching by confirming that the state ready to reproduce signals is attained. CONSTITUTION:A control circuit 24 controls the respective motors for driving a rotary head 16, a reel 14 and a capstan 18 according to the control signals from a microcomputer 20 and also controls a motor 19 for mechanical driving to move the position of a pinch roller 12, thereby bringing the tape 10 into pressurized contact with the capstan 18 and releasing the contact. A reproducing circuit 22 demodulates the reproduction signal picked up by the rotary head 16 and converts the signal to an audio signal. The tape is fed at the same distance and the middle speed in the same direction after searching at the high speed, by which the tape is prevented from stopping just before the position where the tape is ought to stop by a mechanical cause. The electrical processing of the signal is thereafter surely executed by confirming that the state ready to reproduce signals is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital audio tape recorder (hereinafter referred to as DA).
This invention relates to a method for locating the beginning of each piece of information recorded on a tape.

[Conventional technology]

DAT records signals in digital form, so there is no deterioration in sound quality due to recording.DAT also records and plays secondary digital information in parallel with the digitized audio signal. functions can be realized. As a typical example, a start ID for finding the beginning of a song is recorded at the beginning of each piece of information recorded on a single tape, such as multiple songs, and the tape is played back normally. By searching for this start ID while feeding at a high speed of about 200 times the tape speed, it is possible to find the beginning of information recorded on one tape at high speed.

FIG. 5 is a diagram showing an example of a conventional cueing method. Column (1) conceptually represents the area in which the audio signal is stored. Column (2) conceptually represents the state of the area in which the start ID signal is stored. Usually the start ID
``B'' is written for a length of approximately 9 seconds of playback time from the starting position of each side, and ``0PA'' is written in the other sections. Therefore, searching for the Nth song means moving the reproduction position to the position indicated by SN in the figure.

The third column shows a search method in the forward direction (the same direction as during playback). Approximately 20% of normal playback speed
Send it in the forward direction at the maximum speed of 0 times and stop when it detects the rise of the start ID of the Nth track from O to 1 (step a), then at a medium speed of about 8 times the playback speed in the reverse direction (in the opposite direction from the playback speed) direction), and when the fall of the start ID is detected, the search is completed (step C).
Shift to forward playback operation (step d)
.

The (4)th MA represents a search method in the reverse direction. Send it in the reverse direction at maximum speed and stop when it detects the fall of the Nth track start ID from 1 to 0 (step e), then send it in the forward direction at medium speed and from O to 1
When the rising edge is detected (step [), the flow continues to the processing of steps c and d described above (steps g and h).
.

FIG. 6 is a diagram showing the state of the rotating head type DAT (R-DAT) when the tape is being fed at the maximum speed and medium speed described above. No. (1) 4rA is tape 10
This shows the state when the data is being sent at maximum speed. At this time, the pinch roller 12 and capstan 18 are connected to the tape 1.
0, and the tape IO is driven by being wound on one of the reels 14. The rotation of the rotary head 16 is controlled so that the relative speed between the head 16 and the tape IO is the same as during reproduction or recording. Therefore, while information is read out at the same bit rate as during reproduction, all information tracks are not read out but are read out intermittently.

Column (2) shows the state when the tape is being fed at medium speed. At this time, the pinch roller 12 is moved in the direction of the arrow in the figure, and the tape IO is pressed against the capstan 18 and driven by the rotation of the capstan 18. This state is the same as during recording and reproduction, except that the tape feed speed is fast and therefore the information tracks are read out intermittently, although not as much as when the tape is running at high speed.

[Problems to be Solved by the Invention] As described above, during high-speed running, in order to reduce inertia, the capstan I8 is released from the pressed state and the tape 10 is driven by the rotation of the reel 14.

Therefore, in this state, even if the drive is stopped immediately after detecting the rise or fall of stars 1-10, a slight overrun will occur (see Figure 5), or conversely, backlash in the drive system will cause the tape In some cases, a return of When driving at high speeds, the speed and load just before stopping differ depending on the distance traveled, so the amount of overrun described above is not constant, and combined with the backlash that occurs irregularly, the stopping position varies from front to back. Live.

In addition, when the sudden stop occurs, the servo system that keeps the relative speed between the head 16 and the tape lO constant is disturbed, and as a result, the start
There may be cases where D cannot be reproduced accurately. If this is the cause of the high-speed search in the forward direction (column (3) in Fig. 5), it stops before the SN.
In the next falling detection at medium speed (step C), N
-The start ID of the first song will be detected. Also, in a high-speed search in the reverse direction (Fig. 5 (4)
The same goes for a), and if it stops 1000-before SN, the next step (step f) will start the N+1th song! This means that D will be detected.

If the detection method is changed to a method of detecting at the state of 0 or 1 instead of detecting at the change point of star 1-ID as described above, the above-mentioned problem will disappear, but this time, the problem will be solved at high speed in the forward direction. If the overrun in the search is too large and the start ID exceeds the range of 1, a problem will occur.

Therefore, an object of the present invention is to propose a DAT cueing method that can cue quickly and with high reliability.

[Means to solve the problem]

The DAT cueing method of the present invention to solve the above-mentioned object searches for a start ID while feeding the tape at a high speed faster than the playback speed, and after the search, the start ID is searched for while feeding the tape at a high speed faster than the playback speed. In a DAT cueing method that performs precise cueing while feeding the tape at a slow medium speed, after the search and before the precise cueing, the tape is fed at a medium speed in the same direction as the high speed feed. A DAT characterized by feeding the tape a predetermined amount and then confirming that signal reproduction is possible by, for example, determining whether the servo system is stable, and performing precise cueing. This is a cue method.

Further, when starting in the reverse direction, it is preferable that the high-speed search is terminated upon detection of the rising edge of start (2) D, and then the predetermined amount of feed is performed.

[For production]

By feeding the tape a predetermined amount at medium speed in the same direction after searching at high speed, it is possible to prevent the tape from stopping short of the desired stop position due to mechanical causes, and to ensure that signal playback is possible after that. By checking, the electrical processing of the signal can be performed reliably.

In addition, when starting in the reverse direction, high-speed feed is stopped when the start ID rises instead of falling, and then the feed is continued by a predetermined amount in the same direction at medium speed, thereby preventing excessive feed in the reverse direction. It is possible to reduce the loss of time.

〔Example〕

FIG. 1 shows an example of a device to which the method of the present invention is applied.
Rotating head digital audio tape (R-DAT)
FIG. 2 is a block diagram showing a playback device.

Components that are the same as in FIG. 6 are given the same reference numerals. The control circuit 24 controls each motor (not shown) for driving the rotary head 16, reel 14, and capstan 18 according to control signals from the microcomputer 20, and servo-controls their rotation states.

In addition, the mechanical drive motor 19 is controlled to control the pinch roller 12.
By moving the position of the tape 10, the tape 10 is brought into pressure contact with the capstan 18, and the pressure contact is released. The reproduction circuit 22 demodulates the reproduction signal picked up by the rotary head 16 and converts it into an audio signal. The microcomputer 20 sends control signals to the playback circuit 22 and the control circuit 24 to realize normal R-DAT playback device operations, such as playback of records, information search, tape rewinding, tape loading/unloading, etc. Similar to the -11Q microcomputer, it has a CPU, ROM, and
It consists of RAM, input/output interface, etc. The display/operation unit 26 displays the operating state and operating mode of the device based on output signals from the microcomputer 20, and also transmits manual operating commands to the microcomputer 20 by setting a manually operable switch.

FIG. 2 is a main flowchart of the operation of the microcomputer 20 shown in FIG. The "system control" in step a is a process for realizing operations other than the search operation among the operations of the R-DAT reproducing apparatus described above.

Next, it is determined whether the mode is forward search mode (step b), and if so, forward search processing (
Perform step d). If not, then it is determined whether the mode is reverse search mode (step c), and if so, reverse search processing (step e) is performed.

FIG. 3 is a flowchart showing details of the forward search process in FIG. 2. First, the mechanical drive motor 19 is controlled to release the pressure contact between the pinch roller 12 and the capstan 18, and as shown in FIG. Feed the tape 10 in the forward direction at a maximum speed of 200 times (step a)
, the fast forwarding is continued until the rising edge of the start ID (S-10) of the target image is detected (step b). Next, the mechanical drive motor 19 is controlled to press the pinch roller 12 and the capstan 18 against the tape 10 (state shown in FIG. 6 (2)), and the capstan 18 is driven by the drive motor to approximately the normal playback speed. The tape is fed forward for a predetermined time at a medium speed of about 8 times (steps c, d) until the playback condition becomes good (step e).
Steps c and d are repeated until the servo mechanism that performs control to keep the relative velocity constant is in a stable state. Thereafter, the falling edge of the star ID is detected (step g), and until it is confirmed (step h), the data is sent in the reverse direction at a medium speed (step f) to complete the process.

FIG. 4 is a flowchart showing details of the reverse search process of FIG. 2. First, if the song to be cued is not currently being played (step a), it is first set to the state shown in FIG. Figure 6 (2)
feed in the same direction at medium speed for a predetermined time (step e).

f), repeat steps e and f until the servo mechanism is stabilized (step g). At this time, the start ID value is 1.
If not (step h), it is assumed that the start ID has crossed the area of 1, so it is sent in the forward direction at medium speed (step i), and the rise of star 1-ID (step j) is confirmed. (step k). Next, feed in the reverse direction at medium speed (stepping,
Start [Wait for the falling edge of D (step m) and its confirmation (step n).

If the song to be cued in step a is currently being played, it is first determined whether the current start ID value is 1 (step b), and if not, step C is performed. If so, the process is omitted and the process is continued in step 2. Start with step h ■Step even if D is 1! merges into processing.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a DAT cueing method that can cue at high speed and with high reliability.

[Brief explanation of the drawing]

FIG. 1 shows an R-DA which is an example of a device to which the present invention is applied.
A block diagram of the T playback device, FIG. 2 is a flowchart of the processing of the microcomputer 20 in FIG. 1, FIG. 3 is a flowchart showing details of the forward search processing in FIG. 2, and FIG. 4 is in FIG. FIG. 5 is a flowchart showing details of the reverse search process; FIG. 5 is a diagram showing a conventional cueing method; FIG. 6 is a diagram showing the state of the device during high-speed and medium-speed running. In the figure, IO...Tape, 12...Pinch roller, 14...Reel, 16...Rotating throat, 18...Capstan. Figure 3

Claims (1)

[Claims] 1. Searching for the start ID while feeding the tape at a high speed faster than the playback speed, and after the search, feeding the tape at a medium speed faster than the playback speed and slower than the high speed. In a DAT cueing method that performs precise cueing, after the search and before the precise cueing, the tape is fed a predetermined amount at the medium speed in the same direction as the high-speed feeding, and then the signal is played back. A DAT cueing method characterized in that the precise cueing is performed after confirming that the DAT is in a possible state. 2. The method according to claim 1, wherein when starting in the rewinding direction, the high-speed search ends upon detection of a rising edge of a start ID, and then the predetermined amount of forwarding is performed.