JP2622158B2 - Information retrieval device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an information retrieval apparatus for retrieving specified program information from a plurality of pieces of program information such as music information recorded on a magnetic tape. In particular, the present invention is suitably applied to a rotary head type digital audio tape recorder or the like.

[Conventional technology]

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

In FIG. 1, 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 mounted on the rotating drum 6 so as to face each other by 180 °, and read program information recorded on the magnetic tape 1 and subcode information described later.

As shown in the schematic diagram of FIG. 6, the subcode information includes a program number PNO indicating the recording order of program information such as music information on the magnetic tape 1 and time information (absolute / 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 a head amplifier 8, and program information such as music information is output to an audio system (not shown) and converted into an audio signal.
After being separated and reproduced by the reproduction circuit 9, the current PNO storage circuit 10
Is stored.

The comparison circuit 11 compares the program number currently stored in the PNO storage circuit 10 with the program number stored in the target PNO storage circuit 12, and outputs the result of the comparison to the control unit 13 which controls the entire system. Purpose PNO storage circuit 1
2 stores the program number of the program information to be searched as the target program number.

The operation unit 14 issues commands such as recording, reproduction, and search to the control unit 13 and 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 the program information of the program number "3" is searched, the program number is changed from the current position p1 or p1 'in the FWD mode or the REW mode. A high-speed search is performed up to the vicinity of the head position where the program information of "3" is recorded. After that, the head position of the program information is detected by a low-speed search in the CUE mode or the REV mode. The switched program information is reproduced.

[Problems to be solved by the invention]

In the above-described conventional example, the subcode information recorded on the magnetic tape 1 at the time of retrieval is read in a high-speed running mode such as an FWD mode or a REW mode. And it is necessary to control so that the relative speed between the magnetic tape 1 and the magnetic heads 7a and 7b on the magnetic tape 1 to be traced is always constant. For example, when the running speed of the magnetic tape 1 in the FWD and REW modes is set to 200 times that in the reproduction mode (or the recording mode), the rotation speed of the rotating drum 6 is about 3000 rpm in the FWD mode and about 1000 rpm in the REW mode. Then the relative speed is the number of revolutions in playback mode (or recording mode) 20
It is equal to 00rpm.

As described above, in the R-DAT, the rotation speed of the rotary drum 6 is high in the FWD mode and low in the REW mode because the rotary drum servo is applied so that the relative speed becomes constant during the search. Since this rotation speed is proportional to the running speed of the magnetic tape 1 as shown in FIG. 8, for example, when the search speed in the REW mode becomes about 400 times that during reproduction, the rotation speed of the rotating drum 6 becomes zero. As a result, it becomes impossible to read the subcode information, and it becomes impossible to search for the program information. Further, when performing a 400-times speed search in the FWD mode, the rotation speed of the rotary drum 6 must be set to about 4000 rpm, which also has a problem in terms of the reliability of the drum motor of the rotary drum 6.

Further, in the operation of reading the subcode information from the magnetic tape 1, a multiple match check of the read data is generally performed in order to improve the reliability of the read data. The lower the frequency, the lower the frequency of reading the subcode information, which makes it impossible to perform a multiple match check.

For this reason, the information search speed of the conventional R-DAT is limited to about 200 times speed. However, the format of the R-DAT is considered so as not to cause any trouble even at a magnetic tape running speed exceeding 200 times speed, and the superiority of this format has not been fully utilized in the conventional search operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information search device capable of performing an ultra-high-speed search operation exceeding 200 times speed with simple means.

[Means for solving the problem]

The present invention relates to an information retrieval apparatus for retrieving specified program information at high speed from a plurality of program information recorded on a magnetic tape, wherein a number of each of the program information read from the magnetic tape is A first memory unit for storing as a program number; a second memory unit for storing position information read from the magnetic tape as a current position information; a program number of the plurality of program information and a recording position on the magnetic tape Third memory means for associating and storing the magnetic tape; running position detecting means for detecting a rotation speed of a reel around which the magnetic tape is wound to obtain running position information of the magnetic tape; Comparing means for comparing the current program number with the current program number, and The program number and the recording position of the ram information are stored in the third memory means, and when the difference between the recording position and the traveling position exceeds a predetermined value, the traveling position is set as a first high-speed search mode. A high-speed search based on the information is performed, and if the program number and the recording position of the program information to be searched are not stored in the third memory means, or even if they are stored, the difference between the recording position and the traveling position is predetermined. When the value is within the value, a high-speed search based on the current program number is performed as a second high-speed search mode lower than the first high-speed search mode.

(Operation)

When an arbitrary program information is designated from a plurality of pieces of program information and a search operation is commanded, first, it is determined whether or not the program number and the recording position of the program information to be searched are stored in the third memory means. If so, the difference between the storage position and the traveling position is further obtained, 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 sub-code information recorded on the magnetic tape is not read, and the running position of the magnetic tape is detected by running position detecting means for detecting the rotation speed of the reel around which the magnetic tape is wound and detecting the running position of the magnetic tape. The position is obtained and the operation is performed until the magnetic tape reaches a predetermined value.

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

〔Example〕

FIG. 1 is a block diagram showing an embodiment of an information retrieval apparatus according to the present invention, and portions corresponding to those in FIG.

In the present embodiment, the ATM for separating and reproducing the current time information ATM from the subcode information amplified by the head amplifier 8
Each time the program number PNO is read from the reproduction circuit 15, the current ATM storage circuit 16 for storing the current time information ATM, and the PNO reproduction circuit 9, the program number PNO is associated with the current time information ATM at that time as the table of contents information. A table of contents information storage circuit 17 to be stored, a detector 18 for detecting a reel pulse generated as the take-up reel 3 rotates, and counting the reel pulses from the detector 18 to measure the rotation cycle of the take-up reel 3 Reel rotation cycle measurement circuit 19, this measurement circuit
It has the same configuration as that of FIG. 5 except that it has a tape running time calculation circuit 20 for calculating the running time from the beginning of the magnetic tape 1 based on the output from 19.

 Next, the operation of this embodiment will be described.

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

When operation commands such as PLAY, FWD, REW, CUE, REV, etc. are issued from the operation unit 14, the control unit 13 controls the entire system so as to be in the specified operation mode. Then, it is determined whether the traveling direction is the forward direction or the reverse direction (step S1). If the traveling direction is the forward direction, the program number PNO is detected (step S2). ATM with program number PNO Table of contents information storage circuit 17
(Step S3). If the traveling direction is the reverse direction, the program number PNO is detected (step S4).
The detection disappearance point, that is, the time information ATM of the start 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 is performed using the operation unit 14.
Until a stop command is issued, or until the end or start of tape 1 is detected and a stop command is issued (step
S5) Continued.

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 designated program information and the time information of the start point thereof are stored in the target information storage circuit 17 (step S10). The PNO and the target PNO are compared (step S11), and if they match, a precise cueing operation is performed (step S12), the start point of the designated program information is detected, and the search operation ends.

If they do not match, it is determined whether the target PNO is ahead or behind the current PNO (step S13). If the target PNO is ahead, a 200 × FWD mode is used. The process is continued (steps 14 and 15) until the current PNO read from the magnetic tape 1 and the target PNO match (steps 16 and 17), and if they match, the process proceeds to the precise cueing operation (step S12). If the end or start of the tape 1 is detected during this time (steps 18 and 19), the search operation is interrupted and the system is stopped (step S20).

If the program number of the designated program information and the time information of its start point are stored in the target information storage circuit 17, the time information of the start point and the arithmetic circuit 20
Then, the difference between the target position and the current position, that is, the distance is detected from the travel time information, and it is determined whether or not the difference is within the set value d (step S21). If the value is within the set value d, the above-described steps S11 to S20 are performed.

If the value exceeds the set value d, it is determined whether the target position is ahead or behind the current position (step S22). If it is ahead, it is in FWD mode, and if it is behind, it is in REW mode.
An ultra-high-speed search at 300 times speed is started (steps S23, S24), and is continued until it is within the set value d (step S25, S26). When the speed falls within the set value d, the speed is switched to 200 times speed (steps S27 and S28), and the process proceeds to the above-described steps S12 and S14 to S20.

At the time of the ultra high speed search at 300 times speed, the current position of the magnetic tape 1 is detected by detecting the number of revolutions of the reel 3, and the reading of the subcode information recorded on the magnetic tape 1 is not performed. That is, a reel pulse generated by the rotation of the take-up reel 3 is detected by a detector 18, the number of rotations is counted by a measuring circuit 19 and supplied to a tape running time calculating circuit 20. , And calculates the running time of the tape 1 and outputs it to the control unit 13.
The control unit 13 calculates the current position of the magnetic tape 1 based on the traveling time information, and obtains a difference from the target position. Therefore, in this mode, the servo of the rotating drum at a constant relative speed is released and, for example, at a constant speed of about 2000 rpm, an abnormal increase or decrease of the rotating speed of the rotating drum in the ultra high speed search mode is prevented. be able to.

FIG. 4 is a schematic diagram showing an example of the search operation of the present embodiment, in which the vertical axis represents the double speed number, the horizontal axis represents the position of the magnetic tape, and an example of searching for program information of program number "11" is shown. I have. In this example, it is assumed that the program number “11” and the time information indicating the recording position are already stored in the target information storage circuit 17.

When the search operation is started from the position p1 on the program information "1", it immediately becomes the ultra-high-speed search mode of 300 times speed,
It proceeds while detecting the running position from the rotation speed of the reel 3. When the position p3, which is a distance d away from the target position p2, is reached, the speed is switched to 200 times speed, and a high-speed search mode for reading the current program number PNO as subcode information from the magnetic tape 1 is set. When the target current program number "11" is read from the magnetic tape 1, the operation is switched to the precise cueing operation, and the head position p2 of the program information "11" is detected and the operation is terminated.

In the above-described embodiment, if the program number of the program information to be searched and the time information indicating the recording position are not stored in the target information storage circuit 17, the program number is unconditionally set.
The search is performed in the 200 × speed search mode. However, when the number of the program information and its recording position in the vicinity of the program information to be searched are stored in the storage circuit 17, the search is performed up to the vicinity of the known program information. The vehicle may be driven in the double speed ultra-high speed search mode and then switched to the 200 times speed search mode to improve the search speed.

In the above-described embodiment, the user gradually stores the program number and the time information indicating the recording position in the target information storage circuit 17 by performing operations such as PLAY and FWD. FWD,
Operations such as REW may be performed, and data of all program information may be stored collectively.

〔The invention's effect〕

According to the information search device of the present invention, the tape running time information obtained from the rotation speed of the reel around which the magnetic tape is wound is used for high-speed search for any program information recorded on the magnetic tape. Therefore, it is not always necessary to read the subcode information recorded on the magnetic tape at the time of the search, and the search time can be drastically reduced. Further, at this time, since the relative speed constant servo of the rotary drum can be released, abnormal increase or decrease of the rotational speed of the rotary drum can be prevented.

[Brief description of the drawings]

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

Claims (2)

(57) [Claims] An information retrieval apparatus for retrieving specified program information at high speed from a plurality of program information recorded on a magnetic tape, wherein a number of each of the program information read from the magnetic tape is determined. First memory means for storing a current program number; second memory means for storing position information read from the magnetic tape as current position information; recording of the plurality of program information on a program number and a magnetic tape A third memory unit for storing the positions in association with each other; a traveling position detecting unit for detecting a rotation speed of a reel around which the magnetic tape is wound to obtain traveling position information of the magnetic tape; Comparing means for comparing the program number of the information with the current program number; The program number and the recording position of the gram information are stored in the third memory means, and if the difference between the recording position and the traveling position exceeds a predetermined value, the traveling position is set as a first high-speed search mode. A high-speed search based on the information is performed, and if the program number and the recording position of the program information to be searched are not stored in the third memory means, or even if they are stored, the difference between the recording position and the traveling position is predetermined. An information search device wherein a high-speed search based on the current program number is performed as a second high-speed search mode lower than the first high-speed search mode when the value is within the value. 2. The information retrieval apparatus according to claim 1, wherein the position information is time information from the start of the magnetic tape during recording or reproduction.