JP2714045B2 - High-speed search method of rotary head type digital tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention records a PCM signal in a PCM area, and records subcode information such as time information in an independent subcode area on a track. And a rotary head type magnetic recording / reproducing apparatus for reproducing subcode information.

(B) Conventional technology Conventionally, in a rotary head digital audio tape recorder (hereinafter, referred to as R-DAT), each track recorded by the rotary head has a PCM area for recording a PCM signal, An ATF area for recording a signal and a subcode area for recording subcode information are divided and formed, and can be independently recorded and reproduced. The subcode area includes a cue signal (start ID), a track number (P-No), and an absolute time (A-time) from the beginning of the tape.
Such information is recorded, and it is possible to perform a search using each piece of information. For example, as for a high-speed search using sub-code information, there is a search described by JP-A-62-188084 (G11B27 / 10) as a search by P-No.

(C) Problems to be Solved by the Invention In the above R-DAT, when a target position is searched for using information (A-Time or the like) that continuously changes from the beginning of the tape,
The search is performed according to a fixed procedure regardless of the magnitude of the distance from the current position to the target position. For example, a target A-Time is detected in a fast forward high-speed search at 200 times speed, and an overrun occurs.
Time was detected again and the search for the target position was performed.
Since overrun occurs, a search is performed to absorb the overrun, so that there is a problem in that the time required for the search becomes longer.

(D) Means for Solving the Problems In order to solve the above-mentioned problems, in the present invention, when performing a search, first, the head is rotated without moving the tape to read the address value at the current position. By comparing with the address value at the target position,
At the same time as determining the moving direction of the tape, the tape moving means and the target tape speed at the beginning of the search are determined according to the difference between the two address values.

(E) Operation According to the above means, overrun does not occur at the time of high-speed search, so that the time required for search can be shortened and the tape can be stopped at the target position.

(F) Embodiment An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, (1) is a tape drive mechanism, (2) is a magnetic head (3), (3) 'is a rotary head cylinder provided with 180 ° separation, (4) is a capstan,
(5) is a pinch roller, (6) is a supply side reel, (7)
Is the take-up reel, (8), (9), (10), (11)
Is a tape guide post, and (12), (13), and (14) are FG detectors that detect the rotation of the cylinder (2), capstan (4), supply-side and take-up side reels (6), (7), respectively. (15) is a magnetic tape, (16) is a loading drive for winding the magnetic tape (15) around the cylinder (2), and has a role of pressing and releasing the pinch roller from the capstan. (17) is an input terminal for information signals such as audio signals, (18) is a circuit that samples and holds an input analog signal, (19) is an A / D converter, and (20) is a digital signal interleave and error. Digital signal processing circuit for adding correction code, time axis compression, etc., (21) is a recording amplifier, (22) is a recording / reproduction switching circuit, (23) is a reproduction amplifier, and (24) is a reproduction signal waveform. Equalizer for shaping, (25) D / A conversion circuit, (2
6) is a low pass filter, (27) is an output terminal, (28) is a serve system for controlling the cylinder, capstan and both reels, and (29) is a microcomputer for controlling the system.

Further, in the R-DAT having the above configuration, each track recorded on the tape has a PCM area (P) for recording an input signal and a subcode area (Ss) for recording subcode information as shown in FIG. (Se), an ATF area (Ts) (Te) for recording a signal for tracking is formed by area division. In this subcode area, subcode information such as a signal for cueing (S-ID), a track number (P-No), and an absolute time (A-time) from the beginning of the tape can be entered. Can be read even during high-speed search.

Next, an operation when the target search position is given by information that continuously changes from the tape start end recorded in the subcode area, for example, an absolute time (A-time) from the tape start end, that is, an address will be described. I do.

First, when the microcomputer (29) controlling the system receives an instruction to search for a target position (address value As) (step 30), it performs an operation of reading the address value Ap at the current position (step 31). That is, the cylinder (2) is rotated (step 32), and the reels (6) and (7) are controlled to rotate in directions opposite to each other in the direction in which the tape (15) is stretched (step 33). After the slack is removed so that the tape (15) hits the heads (3) and (3) ', the address value Ap at the current position is read (step 34). The tape moving direction (step 37) or (step 38) is determined by comparing the magnitude of the current position address Ap thus read with the given search position address As (step 36) (step 35). ). Next, the absolute value of the difference between the address values Ap and As | Ap−As |
Is calculated (step 39). Depending on the magnitude of this value, the tape moving means reels (6) and (7) at the beginning of the search
Alternatively, the capstan (4) feed and the target tape speed (± 200 × speed, ± 100 × speed, ± 10 × speed, ± 3 × speed) are determined (steps 40 and 45). Compare the value of | Ap−As | with a2 (step 41). If | Ap−As |> a2, select the high-speed search by reel feed (step 42) as the moving means, | Ap−As | ≦
If it is a2, a low speed search by capstan feed (step 43) is selected as the moving means. If the high-speed search by reel feed (step 42) is selected, then | Ap-A
The magnitude of s | and a3 are compared, and if | Ap-As |> a3, the target tape speed is 200 times that of normal reproduction (step 47), and | Ap-As |
If .ltoreq.a3, the target tape speed is set to 100 times (step 48), and tape movement is started (step 52). on the other hand,
If the low-speed search by capstan feed is selected (step 43), the pinch roller (5) is pressed against the capstan (4) by the loading drive unit (16) (step 43).
44) Then, compare the magnitude of | Ap-As | and a1 and | Ap-As |> a1
If so, set the target tape speed to 10 times, and if | Ap−As | ≦ a1, set the target tape speed to 3 times (steps 50 and 5).
1), tape movement is started (step 52).

Incidentally, the values a1, used for the comparison used in steps 46, 41, 49,
The relationship between a2 and a3 is a3>a2>a1> 0. FIG. 2 shows the target tape speed and the tape moving means at the distance between the current position (Ap) and the target position. For example, when searching for the position indicated by the arrow X, the search is started from reel feeding at -100 times speed. It is.

(G) Effect of the Invention In the present invention, when a search is performed using information that changes continuously from the beginning of the tape, the tape moving means and the target tape speed at the beginning of the search can be selected according to the moving distance. The time required can be greatly reduced, which is extremely advantageous.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a rotary head type digital tape recorder of the present invention, and FIGS. 2 and 3 are schematic diagrams of a tape for explaining an embodiment of the present invention, and FIGS. FIG. 4 is a diagram showing an R-DAT tape format. (P): PCM area, (Ts) (Te): ATF area, (Ss)
(Se): Subcode area, (15): Tape, (4)
...... Capstan (tape moving means), (6), (7)
... Reel (tape moving means).

Claims (1)

(57) [Claims] 1. A PCM area in which digital information is recorded on each track of a tape helically scanned by a rotary head, a tracking area in which information for performing tracking control is recorded, and a subcode in which subcode information is recorded. When a high-speed search is performed using address information that continuously changes from the beginning of the tape recorded in the subcode area in a rotary head digital tape recorder that forms Is compared with the address value of the specified search position to determine the tape moving direction, and the tape moving means at the beginning of the search and the tape speed by the means are determined according to the difference between the two address values. A high-speed search method for a rotary head type digital tape recorder characterized by the following.