JPH0233788A - Information retrieving device - Google Patents

Abstract

PURPOSE:To widely shorten the time of retrieval by using a tape traveling time obtained from the number of rotation of a reel, to which a magnetic tape is wound, for the high speed retrieval of arbitrary program information recorded on the magnetic tape. CONSTITUTION:A reel pulse to be generated by the rotation of a winding reel 3 is detected by a detector 18 and the number of rotation is computed by a measuring circuit 19 and supplied to a tape traveling time arithmetic circuit 20. Then, in the circuit 20, the traveling time of a tape 1 is calculated based on a counted value and outputted to a control part 13. In the control part 13, the present position of the magnetic tape 1 is calculated based on the traveling time information and difference to a purpose position is obtained. When the difference goes over a setting value (d), whether the purpose position is in front or back of the present position is compared 11 and super-high speed retrieval is continued. Then, the retrieval is continued until the difference goes into the setting value (d). When the difference goes into the setting value (d), the retrieval of the present position of the tape 1 is obtained by the rotational number of the reel 3 without reading a sub code which is recording to the tape 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an information retrieval device that searches for specified arbitrary program information from among a plurality of program information such as music information recorded on a magnetic tape. It is particularly suitable for application to rotary head type digital audio tape recorders.

[Prior Art] FIG. 5 is a block diagram showing a conventional information retrieval device in a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT).

In the figure, a magnetic tape 1 is wound around a supply reel 2 and a take-up reel 3, and is wound around a rotating drum 6 by a loading mechanism such as a capstan 4 and a pinch roller 5. Two magnetic heads 7a and 7b are attached to the rotating drum 6, facing each other at 180 degrees, and are adapted to read program information and subcode information recorded on the magnetic tape 1, which will be described later.

As shown in the schematic diagram of FIG. 6, the subcode information includes a program number PNO that indicates the recording order of program information such as music information on the magnetic tape 1, and time information (absolute number) that indicates the time from the beginning of the tape. This information is recorded in the subcode area of each track on the magnetic tape 1.

The outputs of the magnetic heads 7a and 7b are amplified to an appropriate level by the Ghent amplifier 8, and program information such as music information is output to an audio system (not shown) and converted into an acoustic signal.
After being separated and regenerated by the PNO regeneration circuit 9, the current PN
The data is stored in the O memory circuit 10.

Comparison circuit 11 compares the program number currently stored in PNO storage circuit 10 and the program number stored in target PNO storage circuit 12, and outputs the comparison result to control section 13, which controls the entire system. Purpose P
The program number of the program information to be searched is stored in the NO storage circuit 12 as the target program number.

The operation section 14 issues commands such as recording, reproduction, and search to the control section 13, and also inputs the program number of the program information to be searched into the target PNO storage circuit 12.

According to such a configuration, as shown in the operation explanatory diagram of FIG. 7, when searching for program information of program number "3", program number Perform a high-speed search to the vicinity of the beginning position where program information "3" is recorded, then detect the beginning position of the program information with a slow search in CUE mode or REV mode, and when the search is completed, switch to playback (PLAY) mode. Switch to play the searched program information.

[Problem to be solved by the invention]

In the conventional example described above, in order to read subcode information recorded on the magnetic tape 1 during a search in a high-speed running mode such as FWD mode or REW mode, the rotation speed of the rotary drum 6 is adjusted according to the running speed of the magnetic tape 1. a magnetic head 7a that traces the magnetic tape 1 and the magnetic tape 1 by changing the
, 7b was required to be controlled so that the relative speed with respect to the two was always constant. For example, when the running speed of the magnetic tape 1 in the FWD and REW modes is 200 times that in the playback mode (or recording mode), the rotation speed of the rotary tram 6 is approximately 300 Orpm in the FWD mode and approximately 1100 Orpm in the REW mode. Then, the relative speed becomes equal to 200 rpm, which is the rotation speed in the reproduction mode (or recording mode).

In this way, in R-DAT, the rotating drum servo is turned off so that the relative speed is constant during the search, so the rotational speed of the rotating drum 6 is high in the FWD mode and low in the REW mode. As shown in FIG. 8, this rotation speed is proportional to the running speed of the magnetic tape 1, so for example,
When the search speed in the REW mode becomes about 400 times that of playback, the number of rotations of the rotary drum 60 becomes zero, making it impossible to read subcode information and to search for program information. Also, in FWD moto, 4
When performing a 00 times speed search, the rotational speed of the rotating drum 6 must be set to approximately 400 rpm, which also poses a problem in terms of reliability of the drum motor of the rotating drum 6.

Furthermore, in the operation of reading subcode information from the magnetic tape 1, multiple matching checks are generally performed on the read data in order to improve the reliability of the read data, but especially in the REW mode, the rotation speed of the rotary drum 6 is extremely low. As a result, the frequency of reading subcode information decreases, and there is a problem in that multiple matching checks become impossible.

For these reasons, the information retrieval speed of the conventional R-DAT has been limited to about 200 times the speed.

However, the R-DAT formant is designed to have no problems even at magnetic tape running speeds exceeding 200 times the speed, and the advantages of this format have not been fully utilized in conventional search operations.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information retrieval device that can perform ultra-high-speed retrieval operations exceeding 200 times speed using simple means.

[Means to solve the problem]

The present invention provides an information retrieval device that searches at high speed for arbitrary program information specified from among a plurality of program information recorded on a magnetic tape. a first memory means for storing the position information read from the magnetic tape as the current position information; and a second memory means for storing the position information read from the magnetic tape as the current position information, and the program number and the recording position on the magnetic tape of the plurality of program information. a third memory means for storing the information in association with each other; a running position detecting means for detecting the rotational speed of a reel around which the magnetic tape is wound to obtain running position information of the magnetic tape; and the program information to be retrieved. and a comparison means for comparing the program number of the program information and the current program number, the program number and recording position of the program information to be searched are stored in the third memory means, and the program number and the recording position of the program information to be searched are stored in the third memory means, and If the difference exceeds a predetermined value, a high-speed search is performed based on the traveling position information as a first high-speed search mode, and the program number and recording position of the program information to be searched are stored in the third memory means. If it is not stored or if the difference between the recorded position and the traveling position is within a predetermined value, a second high-speed search mode slower than the first high-speed search mode is set based on the current program number. It was configured to perform a high-speed search.

[For production]

When arbitrary program information is designated from among a plurality of program information and a search operation is commanded, first, it is determined whether the program number and recording position of the program information to be searched are stored in the third memory means, and the storage is performed. If so, the difference between the stored position and the running position is further determined, and if the difference exceeds a predetermined value, an ultra-high speed search operation is performed in the first high speed search mode. In this mode, the subcode information recorded on the magnetic tape is not read.
The running position of the magnetic tape is determined by a running position detection means that detects the running position of the magnetic tape by detecting the number of revolutions of a reel around which the magnetic tape is wound, and the running position of the magnetic tape is determined until the running position of the magnetic tape reaches a predetermined value.

If the program number and recording position of the program information to be searched are not stored in the third memory means, or even if they are recorded, the difference between the storage position and the current position is within a predetermined value, the second high-speed search is performed. mode, and performs a search operation slower than the first high-speed search mode. In this mode, the current program number read from the magnetic tape and the program number of the program information to be searched are compared until the two program numbers match. When a match is detected, the search operation is terminated and the searched program information is reproduced.

〔Example〕

The first part is a block diagram showing an embodiment of an information retrieval device according to the present invention, and parts corresponding to those in FIG. 5 are given the same reference numerals and explained.

In this embodiment, the current time information ATM is separated and reproduced from the subcode information amplified by the head amplifier 8.
Every time a program number PNO is read out from the TM reproducing circuit 15, the current ATM storage circuit 16 that stores this current time information ATM, and the PNO reproducing circuit 9, the program number PNO and the current time information ATM at that time are associated with each other to generate table of contents information. A table of contents information storage circuit 17 for storing information as a table of contents, a detector 18 for detecting reel pulses generated as the take-up reel 3 rotates, and a rotation period of the take-up reel 3 by counting the reel pulses from this detector 18. The fifth reel rotation period measuring circuit 19 has a reel rotation period measuring circuit 19, and a tape running time calculating circuit 20, which calculates the running time from the starting end of the magnetic tape 1 based on the output from the measuring circuit 19.
It has the same configuration as the figure.

Next, the operation of this embodiment will be explained.

First, the operation of storing the program number PNO and the corresponding current time information ATM in association with each other in the table of contents information storage circuit 17 will be described with reference to flowcharts 1 to 1 of FIG.

PLAY, FWD, REW, CUE from the operation unit 14
, REV, etc., the control unit 13 controls the entire system so that the specified operation mode is achieved. Then, it is determined whether the running direction is the forward direction or the reverse direction (step S1), and if the running direction is the forward direction, when the program number PNO is detected (step S2), the time of the detection occurrence point and the start point of the program information concerned is determined. The information ATM is stored in the table of contents information storage circuit 17 together with the program number PNO (step S3). When the running direction is in the opposite direction, when the program number PNO is detected (step S4), the time information ATV of the detected vanishing point, that is, the starting point of the program information, is stored in the table of contents information storage circuit 17 together with the program number PNO. Step S3). This operation continues until a stop command is issued from the operation unit 14 or until the tape 1
until the end or start of is detected and a stop command is issued (
Step S5) Continue.

Next, the operation when a command to search for specific program information is issued from the operation unit 14 will be described with reference to the flowchart shown in FIG.

First, it is determined whether the program number of the specified program information and the time information of its starting point are stored in the target information storage circuit 17 (step 5IO). If not, the comparison circuit 11 determines whether the current PNO and purpose P
If they match, a precise cue operation is performed (step 512) to detect the starting point of the designated program information and end the search operation.

If they do not match, it is determined whether the target PNO is in front or behind the current PNO (step 513). If the target PNO is in front or behind the current PNO, the FWD mode is set at 200 times the speed, and if the target PNO is in the rear, the FWD mode is set at 200 times the same speed.
Perform a high-speed search in double-speed REW mode (step 14,
Continue until the current PNO read from the 15L magnetic tape 1 and the target PNO match (steps 16 and 17).
If they match, the process moves to a precise cueing operation (step 512). During this time, if the end or start of tape 1 is detected (step 18.19), the search operation is interrupted and the system is stopped (step 520).

If the program number of the designated program information and the time information of its starting point are stored in the target information storage circuit 17, the time information of the starting point and the arithmetic circuit 2
The difference between the destination position and the current position, that is, the distance, is detected from the traveling time information of 0, and it is determined whether the difference is within the set value d (step 521). If it is within the set value d, the processes of steps Sll to S20 described above are performed.

If the value exceeds the set value d, it is determined whether the target position is in front or behind the current position (step 522). If the target position is in front of the current position, the speed is set in FWD mode, and if the target position is in the rear direction, the speed is set to 300 times faster in R or EW mode. Step S to start a super fast search for
23, 24), and continues until the value is within the set value d (steps S25 and 26).

When the speed is within the set value d, change the speed to 200x (
Steps S27, 28), the aforementioned step S12. S
The process moves to steps 14 to S20.

During ultra-high-speed retrieval at 300x speed, (the current position of the tape 1 is detected by detecting the number of revolutions of the reel 3, and the sub code information recorded on the magnetic tape 1 is not read out. The detector 18 detects the rilbars generated by the rotation of the take-up reel 3, and the number of rotations is counted by the measuring circuit 19 and supplied to the tape running time calculation circuit 20. The calculation circuit 20 calculates the number of rotations based on the counted value. Calculate the running time of tape 1 and get 1ltll.
The control unit 13 calculates the current position of the magnetic tape 1 based on this travel time information, and calculates the difference from the target position. Therefore, in this mode, the servo that keeps the relative speed of the rotating drum constant is released and the rotating drum is rotated at a constant speed of, for example, about 200 rpm. It can be prevented.

FIG. 4 is a schematic diagram showing an example of the search operation of this embodiment.
The vertical axis shows the double speed number, the horizontal axis shows the position of the magnetic tape, and an example is shown in which program information of program number "11" is searched. Further, in this example, it is assumed that the target information storage circuit 17 has already stored the program number "11" and time information indicating its recording position.

When a search operation is started from position P1 on program information "1", the search mode immediately enters a 300x ultra-high speed search mode, and progresses while detecting the running position from the rotation speed of the reel 3.

20 when reaching position p3, which is a distance d away from target position p2.
The speed is switched to 0x, and a high-speed search mode is entered in which the current program number PNO as subcode information is read from the magnetic tape 1. When the target current program number "11" is read from the magnetic tape 1, the process switches to a precision cueing operation, detects the leading position p2 of the program information "11", and ends the process.

In the above embodiment, if the program number of the program information to be searched and the time information indicating its recording position are not stored in the target information storage circuit 17, the search is unconditionally performed in the 200x search mode. However, if the number and recording position of program information in the vicinity of the program information to be searched are stored in the storage circuit 17, the program is run in an ultra-high speed search mode of 300 times speed to the vicinity of the known program information. Thereafter, the search speed may be improved by switching to a 200x search mode.

Further, in the above embodiment, the program number and the time information indicating the recording position thereof are gradually stored in the purpose information storage circuit 17 by the user performing operations such as PLAY and FWD. It is also possible to automatically perform operations such as FWD and REW when the magnetic tape is loaded, and to store all program information data all at once.

[Effects of the Invention] According to the information retrieval device of the present invention, the tape running time determined from the rotational speed of the reel around which the magnetic tape is wound can be used for high-speed retrieval of arbitrary program information recorded on a magnetic tape. Since this information is used, it is not necessary to read the subcode information recorded on the magnetic tape during a search, making it possible to dramatically shorten the search time. Further, in this case, the constant relative speed servo of the rotating drum can be canceled, making it possible to prevent the rotational speed of the rotating drum from abnormally increasing or decreasing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the information search device according to the present invention, FIGS. 2 and 3 are flowcharts for explaining the first operation, and FIG. 4 is an operation showing an example of the search operation. 5 is a block diagram showing an example of a conventional information retrieval device, FIG. 6 is a schematic diagram showing the recording status of subcode information, and FIG. 7 is an operation explanatory diagram showing an example of the search operation of FIG. 5. , FIG. 8 is a relationship diagram showing the relationship between drum rotation speed and search speed. 1... Magnetic tape, 2, 3... Reel, 10...
TlfPNO storage circuit, 11... Comparison circuit, 16...
・Current ATM storage circuit, 17... Purpose information storage circuit,
18...Detector, 19...Reel rotation period measuring circuit, 20...Tape running time calculation circuit.

Claims (2)

[Claims] (1) In an information retrieval device that searches at high speed for arbitrary program information specified from among a plurality of program information recorded on a magnetic tape, the number of each program information read from the magnetic tape is set in the current program. a first memory means for storing the position information read from the magnetic tape as a current position information; and a second memory means for storing the position information read from the magnetic tape as the current position information; a third memory means for storing information in association with each other; a running position detecting means for detecting the number of revolutions of a reel around which the magnetic tape is wound to obtain running position information of the magnetic tape; and a running position detecting means for obtaining running position information of the magnetic tape; a comparison means for comparing a program number and the current program number, wherein the program number and recording position of the program information to be searched are stored in the third memory means, and between the recording position and the running position; If the difference exceeds a predetermined value, a high-speed search is performed based on the traveling position information as a first high-speed search mode, and the program number and recording position of the program information to be searched are stored in the third memory means. If it is not stored or if the difference between the recorded position and the traveling position is within a predetermined value, a second high-speed search mode slower than the first high-speed search mode is set based on the current program number. An information retrieval device characterized by high-speed retrieval. (2) The information retrieval device according to claim 1, wherein each of the positional information is time information from the beginning of the magnetic tape at the time of recording or reproduction.