JP2002329388A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device in which a program can precisely be retrieved even when a calculation error of tape position information is large. SOLUTION: This device is provided with a tape position information detecting means for detecting tape position information indicating the position of a tape periodically based on a rotation period of a reel, a variation detecting means for obtaining the variation of tape position information being a difference between tape position information detected at this time by the tape position information detecting means and the tape position information detected at a previous time, a judging means for judging whether the variation obtained by the variation detecting means is normal or not, a tape position information conjecturing means for conjecturing the tape position information of the next time based on the variation of tape position information when the judging means judges that the variation is normal, and a tape position information compensating means for compensating the tape position information by replacing the tape position information detected at this time by the tape position information detecting means by the tape position information of the next time conjectured by the tape position information conjecturing means when the judging means judges that variation is abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder, and more particularly to a magnetic recording / reproducing apparatus capable of accurately searching for a program recorded on a magnetic tape.

[0002]

2. Description of the Related Art As a method for retrieving a program recorded on a magnetic tape, there is a method of running a tape to a tape position at the beginning of a program while judging a current tape position by detecting position information of the tape. However, during fast-forward (FF) or rewind (REW) of the tape, detection of the remaining tape time, which is positional information of the tape, is performed by running the tape at a constant speed by the capstan. Instead of running the tape, the take-up reel and the supply reel are driven to run the tape, so the tape running speed is not constant depending on the tape winding position.
There is a detection error due to variations in reel rotation detection accuracy and variations in mechanical load, and there is a problem that the beginning of a program to be searched cannot be accurately searched.

As a conventional magnetic recording / reproducing apparatus for retrieving the beginning of a program more accurately, for example, Japanese Patent Application Laid-Open No. 05-0410
No. 68 is disclosed. FIG. 4 is a diagram for explaining a program search method in the conventional magnetic recording and reproducing apparatus described in the above publication.

In this conventional magnetic recording / reproducing apparatus, the tape position information at the beginning of a program is stored in a storage means at the time of recording a program, and the tape position information at the beginning of the program 403 of the searched program is obtained from the storage means at the start of a search. A search target position 4 for searching a position shifted by a fixed amount from the acquired tape position information to the side where the program is recorded, using the tape position information.
02. The tape position information of the search target position 402 is compared with the tape position information of the current tape position 401,
By performing the calculation, if the current tape position 401 is on the start end side of the search target position 402, FF is performed. continue,
While the tape is being wound by FF, search target position 4
02 is compared with the tape position information of the current tape position 401, and the search target position 40 is calculated.
Run the tape position until 2 is reached. Then, a search signal (hereinafter, referred to as a VISS signal) to be recorded at the start of recording is searched in the direction of the beginning 403 of the searched program, and the VISS signal is detected. It is a transition.

In this conventional magnetic recording / reproducing apparatus, as a method for absorbing an error in the positional information of the tape, a position shifted by a fixed amount from the beginning 403 of the searched program to the side where the program is recorded is set as a search target position 402. And VI
Since the movement to the terminal side is realized from the SS signal, a certain amount of shift becomes the amount of absorption of the error of the tape position information. That is, if the position where the tape position information of the current tape position 401 is determined to have reached the search target position 402 is on the end side of the VISS signal and is inside the recording area of the search program, the VISS search searches for the target search program. You can search for the beginning of the program.

[0006]

However, in the conventional method, when the error of the tape position information calculation result is larger than a value shifted by a fixed amount from the recording start position of the search program to the end side, especially when the tape running speed is increased. The error in the result of calculating the tape position information becomes large until the servo pull-in becomes stable when the value changes, and there has been a problem that the beginning of the program cannot be accurately searched.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to provide a magnetic recording / reproducing apparatus which can realize a highly accurate program search even when a calculation error of tape position information is large. And

[0008]

According to another aspect of the present invention, there is provided a magnetic recording / reproducing apparatus having a recording / reproducing function of recording and reproducing information on a magnetic tape. Tape position information detecting means for periodically detecting tape position information indicating the position of the tape based on the rotation cycle of the reel on which the tape runs, and the tape position information detected this time by the tape position information detecting means and the tape position information detected last time A change amount detecting means for obtaining a change amount of the tape position information which is a difference between the tape position information, a judging means for judging whether or not the change amount of the tape position information obtained by the change amount detecting means is normal; Tape position information estimating means for estimating the next tape position information based on the change amount of the tape position information when the change amount of the position information is determined to be normal; When the judging means judges that the change amount of the tape position information is not normal, the tape position information detected by the tape position information detecting means is replaced by the next tape position information estimated by the tape position information estimating means, and the tape position is changed. Tape position information correcting means for correcting information.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

In the drawing, a cassette 109 is connected to a hub 11.
The magnetic tape 108 wound around 0,111 is stored, and a take-up reel (hereinafter, referred to as T reel) 112 for winding the magnetic tape 108 and a supply-side reel (hereinafter, referred to as S reel) 113 for sending out the magnetic tape 108 are provided. Will be loaded.

The peripheral portions of the T reel 112 and the S reel 113 are alternately provided with a shielded portion and a non-shielded portion, and are provided inside and outside the peripheral portion, such as a photo interrupter. Light emitting / receiving section 114,
115 are provided. Microcomputer 101
A period detecting unit 102 for detecting rotation of the reel in response to signals from the light emitting / receiving units 114 and 115; a tape position information detecting unit 103 for detecting tape position information based on the output of the period detecting unit 102; A tape position information correction unit 104 for correcting tape position information, and a reel drive control unit 105 for driving a reel via a motor 106 and a transmission mechanism 107 are included.

The operation of the magnetic recording / reproducing apparatus configured as described above will be described in detail below. FIG. 2 is a flowchart for explaining a program search method in the magnetic recording and reproducing apparatus according to the present embodiment. In the magnetic recording / reproducing apparatus according to the present embodiment, for example, R
The tape position information at the beginning of the program is stored in a recording medium such as an AM. When the program search processing routine 200 starts, first, in step 201, the microcomputer 101 acquires tape position information of the beginning of the program to be searched from the storage medium, and in step 202, the microcomputer 101 obtains the tape position information of the beginning of the program to be searched from the program recording side. (Terminal side)
Is set as a search target position.
This is the same as one method of increasing the accuracy of searching for a search program shown in the conventional example.
The distance from the end of the SS signal to the start end from the recording end position of the program, for example, if the program search can be performed by recording for 5 minutes or more, the position at the end of 2 minutes and 30 seconds from the recording start position Is set as the search target position.

In step 203, by comparing the search target position with the current tape position information, if the current tape position is on the start end side of the search target position, step 204
To start searching with FF. If the current tape position is on the end side of the search target, the search is started by REW in step 205.

After the start of the search, in step 206, while the magnetic tape 108 is being wound, the light emitting / receiving parts 114, 1
From the signal of No. 15, the T reel 112 and the S
The rotation cycle of the reel 113 is detected, and the tape position information detector 103 calculates tape position information. A method for detecting tape position information is known. For example, Japanese Patent Application Laid-Open No. 05-041068 described in the related art also describes a method for calculating information on a remaining tape time as having the same meaning as tape position information. In step 207, the tape position information correction unit 104
The detection error of the tape position information obtained in step 3 is corrected.

Here, a method of correcting the detection error of the tape position information will be described in detail with reference to FIG. When the tape position information error correction routine 300 starts, first, in step 301, the tape position information detection unit 10
The difference between the previous tape position information calculated in step 3 and the current tape position information is calculated as the tape position change amount.

In step 302, step 301
The tape position change amount obtained in step (1) is observed, and if the tape position change amount is within one minute, it is determined that the tape position information calculated this time is normal. Determine as position information.

Subsequently, in step 304, the tape position change amount when it is determined that the tape position is normal is stored, and in step 305, the latest tape position change amount including the present tape position change amount is calculated. A value obtained by averaging the batches is stored as a correction value when the tape position detection information is abnormal.

In step 302, the tape position change amount obtained in step 301 is observed. If the tape position change amount is greater than one minute, it is determined that the tape position information calculated this time is abnormal. In 306, the tape position information is added by adding the correction value created at the time of normality to the previous tape position information during the search in the REW direction, and by subtracting it from the previous tape position information during the search in the FF direction. to correct.

Finally, in step 307, when it is determined that the tape position information is normal, the actually measured value of the tape position information determined in step 303 is used, and when it is determined that the tape position information is abnormal, the tape position information corrected in step 306 is used. Is stored as previous tape position information.

In step 208, the tape position information corrected as described above is compared with the tape position information of the search target position to determine whether or not the search target point has been reached. The tape is run by FF / REW while repeating steps 206 and 207 until the tape reaches the search target position.

After running the tape to the search target position, in step 209, the processing shifts to the REW direction (start end side) to search for the VISS signal at the beginning of the search program. After detecting the VISS signal in step 210, step 211
By stopping or reproducing at, the beginning of a desired recorded program can be searched.

As described above, in the magnetic recording / reproducing apparatus according to the present embodiment, the error correction routine 300 for the tape position information is performed.
The tape position information change amount is observed and the corrected tape position information is used as the tape position information calculation value when it is judged that the change amount is not normal, so the actual tape position and tape position information calculation An error with the value can be minimized, and the beginning of the target program can be reliably searched.

In this embodiment, the threshold value of the tape position change amount used for determining whether the calculated tape position information is normal or abnormal is set to the maximum value obtained by actual measurement during normal operation. Although the tape change amount is set to one minute by giving a margin, any threshold value may be used as long as the threshold value is suitable for the actual apparatus.

Also, the correction value when the tape position detection information is abnormal is a value obtained by averaging the latest four times of the past tape position change amount including the present tape position change amount. It may be.

[0025]

As described above, according to the magnetic recording / reproducing apparatus of the present invention, the tape position information for periodically detecting the tape position information indicating the tape position based on the rotation cycle of the reel on which the magnetic tape runs. Detecting means, a change amount detecting means for obtaining a change amount of the tape position information which is a difference between the tape position information currently detected by the tape position information detecting means and the tape position information detected last time, and a tape obtained by the change amount detecting means. Determining means for determining whether or not the amount of change in the position information is normal; and the next tape position based on the amount of change in the tape position information when the determining means determines that the amount of change in the tape position information is normal. When the tape position information estimating means for estimating the information and the judging means judges that the change amount of the tape position information is not normal, the tape position information detecting means which has detected this time is used. Tape position information correcting means for correcting the tape position information by replacing the tape position information with the next tape position information estimated by the tape position information estimating means. Since the error correction is performed when it is determined that the calculation result is abnormal, there is an effect that a highly accurate program search can be realized even when the calculation error of the tape position information is large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart of a program search in the magnetic recording and reproducing apparatus according to the embodiment of the present invention;

FIG. 3 is a flowchart of error correction of tape position information in the magnetic recording / reproducing apparatus according to the embodiment of the present invention;

FIG. 4 is a schematic diagram showing an example of a running operation of a tape during a conventional program search;

[Explanation of symbols]

 Reference Signs List 101 Microcomputer 102 Cycle detector 103 Tape position information detector 104 Tape position information corrector 105 Reel drive controller 106 Motor 107 Transmission mechanism 108 Magnetic tape 109 Cassette 110 T reel side hub 111 S reel side hub 112 T reel 113 S reel 114 T reel side light emitting / receiving part 115 S reel side light emitting / receiving part 200 Program search processing routine 300 Error correction routine of tape position information 401 Current tape position 402 Search target position 403 Beginning of program of search program

Claims (1)

[Claims] 1. A magnetic recording / reproducing apparatus having a recording / reproducing function for recording / reproducing information on / from a magnetic tape, wherein tape position information indicating a tape position is periodically displayed based on a rotation cycle of a reel on which the magnetic tape runs. A tape position information detecting means for detecting, a change amount detecting means for calculating a change amount of the tape position information which is a difference between the tape position information detected this time and the tape position information detected last time, and the change amount Determining means for determining whether the amount of change in the tape position information obtained by the detecting means is normal; and changing the tape position information when the determining means determines that the amount of change in the tape position information is normal. Tape position information estimating means for estimating the next tape position information based on the amount, and the judging means judges that the change amount of the tape position information is not normal Tape position information correcting means for correcting the tape position information by replacing the tape position information detected by the tape position information detecting means at this time with the next tape position information estimated by the tape position information estimating means. A magnetic recording / reproducing apparatus characterized by the above-mentioned.