JPH0218738A - High speed searching method for rotary head type digital audio tape recorder - Google Patents

Abstract

PURPOSE:To improve the reliability of high speed search operation by reproducing program time information (P-time) for the recording period of start identification information (start ID). CONSTITUTION:When the high speed search of the start ID, which is recorded to a sub code area on a magnetic tape 22, is executed and a recorded main signal is reproduced near the starting edge of the start ID, the P-time in the termination of the start ID is reproduced. Only when the P-time at such a time is coincident with the recording period of the regular start ID to be already determined, the tape 22 is rewound up to the starting edge of the recording period for the start ID and after that, the main signal is reproduced. Accordingly, when the high speed search to use the start ID is executed in the tape 22, to which the start ID of the short recording period, is recorded, the lacked start ID is prevented from being judged as the regular start ID. Thus, the reliability of the high speed search is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a high-speed search method for a rotary head digital audio tape recorder (hereinafter referred to as R-DAT), and particularly relates to a high-speed search method for a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT). The present invention relates to a high-speed search method using start identification information (hereinafter referred to as start ID) recorded in a subcode area corresponding to the start position of a program to be executed.

(b) Prior art The system configuration of a general R-DAT is shown in FIG. 6 and will be explained. In the figure, (1) is an input terminal into which an analog audio signal is input, and (2) is an input terminal that converts this audio signal into a digital signal that has undergone interleaving, time compression, etc.
(3) is a servo signal generation circuit that generates servo signals (i.e., pilot signals, sync signals, etc.) for tracking control; (4)
(5) is a subcode signal generation circuit that generates subcode signals such as a start ID, track number, and performance time information (hereinafter referred to as P time) for high-speed search, and (5) is formed for each track of the tape. A switch circuit that is selectively switched at a predetermined timing to record digitally converted audio signals, servo signals, and subfood signals in the information recording area, tracking area, and subcode area (61 is a recording amplifier, (7) is a The output from the recording amplifier (6) is 1
A rotary transformer of a rotary head cylinder that supplies two recording and reproducing rotary heads (8) 80 mm apart, (9) is a playback amplifier, and (10) is a P
A digital signal processing circuit 01) that generates a clock from data using LL, etc., converts it into a digital signal, and then converts it into an analog signal (PCM demodulation) is an output terminal to which the original analog audio signal is output. The decoy is a servo circuit that extracts a servo signal for tracking control from the output of the reproduction amplifier (9) and generates a tracking error signal. u3) extracts a subcode signal from the output of the reproduction amplifier (9) and generates a start ID. This is a subcode processing circuit that performs detection and reading of P time and the like. 09 is a take-up reel motor that directly drives the take-up reel shaft; 09 is a supply reel motor that directly drives the supply reel shaft; 06)
is its motor drive circuit, (1& is the cylinder motor and its motor drive circuit, and OJ■ is the capstan motor and its motor drive circuit.

The company operates each motor 041 (15) (1η
It is a control circuit that controls the drive/stop, rotation speed, rotation direction, etc., and is composed of a microcomputer.

■ is a tape that can be wrapped 90 times around the rotating head cylinder.

Therefore, during recording, the audio signal input to the input terminal (1) is first converted into a digital signal by the digital signal processing circuit (2), and then the servo signal (pilot signal or sync signal) is output from the servo signal generation circuit (3). etc.) and the subcode signal (start ID, track number, P time) generated by the subcode generation circuit (4) and the recording amplifier (
6). The output of this recording amplifier (6) is then transferred to the rotary transformer (7) of the rotating head cylinder.
The recorded data is sent to the recording/reproducing rotary head (8) and recorded on the tape. At this time, the fifth
A track pattern as shown in the figure is formed, with an information recording area (D) in the center of each track, and a tracking area (Ts) (Te) and subcode areas (Ss) (Se) on both sides. They will be formed respectively.

Next, during playback, various signals recorded on the tape are read by a recording/playback rotary head (8) and sent from a rotary transformer (7) of a rotary cylinder to a playback amplifier (9). And this playback amplifier (9)
The output of is converted into a digital signal by creating a clock from data using a PLL etc. in a digital signal processing circuit α0), which is then converted into an analog signal, and then output as the original audio signal from the output terminal tll). Become.

Furthermore, the output of this reproducing amplifier (9) is sent to the servo circuit 0z, where a servo signal for tracking control is extracted to generate a tracking error signal, which is sent to the motor drive circuit. The capstan motor controls the plate. In addition, the output of the playback amplifier (9) is also sent to the subcode processing circuit 0J, which extracts the subcode signal and reads the track number, time information, etc., and the control circuit (
21) to the display unit to display the song number and time.

High-speed search of start ID in R-DAT with the above configuration [
Regarding this, Sanyo Technical Review Vol. 19
2 (published in August 1987), and its contents will be explained with reference to Figures 5 (a), (b) (CI (d)). are the programs (+1), (n+1), (n+2) recorded in the PCM area.
) The sub-food area corresponding to the beginning position of )... is schematically shown in which the start ID is recorded for only nine seconds.

In the search operation in the fast forward direction, when the rising edge of the start ID is detected in the first step as shown in Fig. 5 (ψ), tape running is stopped, and in the second step the pinch roller 01J is moved to the capstan as shown in Fig. 6. (19a), and the capstan motor runs the tape in the opposite direction at 8 times the tape speed during normal playback until the falling edge of the start ID is detected. When detected, the tape running is switched to the normal playback state with the pinch roller G11 pressed against the capstan (198), and the cueing operation is completed.

Next is the search operation in the rewinding direction.As shown in Figure 5 (Φ), as the first step, the cylinder servo system is set to search mode until the falling edge of start ■D is detected. The tape is driven by the reel motor so as to run in the reverse direction at the same speed.When the fall of the start ID is detected, the capstan motor switches to forward 8x tape running, and then the rise of the start ID is detected. Then, the tape runs in the reverse direction at 8x speed.

The subsequent operation is the same as the fast forward direction search operation.

Using the algorithm described above, it was possible to find the beginning of any song through a high-speed search.

(C) Problems to be Solved by the Invention However, when the user performs overwriting or splicing on various subcode dubbing or recorded parts,
Only the end portion of the recording period C of the start ID recorded in the subcode area of the tape (for example, 9 seconds in normal playback mode) is missing, and only the leading portion of the start ID recording period remains. A tape is produced. When performing a high-speed search for R-DAT as described above using such a tape, the rising edge of the start ID as described above is detected and the playback mode is entered, causing a problem in the reliability of the high-speed search using the start ID. Ta.

B) Means for Solving the Problems When performing a high-speed search for a start ID recorded in one subcode area on a magnetic tape and reproducing a main signal recorded near the beginning of the start ID, the start ID The P time at the end l is played back, and only when the P time at this time matches the recording period of the regular start ID that has already been determined, the tape is rewound to the beginning of the recording period of the start ID, and then the main signal is R to play
-Propose a high-speed search method for DAT.

(e) Effect: If a high-speed search using a start ID is performed on a tape in which the end portion of the recording period of the start ID is missing, that is, a start ID with a short recording period is recorded, such a missing start ID will be searched. It is no longer judged as a normal start ■D.

(C) Example The system configuration of the present invention is the same as the conventional one, so its explanation will be omitted. For the search operation of the present invention, refer to the flowchart in FIG. 1 and the time charts in FIGS. 2 and 3. I will explain as I go along.

First, when a high-speed search operation of the start ID is specified ζ step 1), the control circuit +211 performs a high-speed search operation (step 2) at a tape feed speed nearly 200 times, and the signal processing circuit (1311) starts the recording period of the start ID. (For example, 300 frames) When the leading edge (rising edge) is detected (step 3), the magnetic tape is switched to the stop mode (step 4) in which the magnetic tape is stopped. End of period (
It overruns and stops. After that, 8
A low-speed search (step 5) in the reverse direction of about twice the speed is performed, and the end (rising edge) of the recording period of the start ID is detected (
Step 6) Then, the P time at the end is played back (Step 7) and at the same time, the tape enters a stop mode (Step 8) in which the tape is stopped.

Therefore, the recording period of the played P time and start ID (
(usually 9 seconds in playback mode), and when the two values are almost equal (when the P time is 9 seconds), it is determined that the start ID is correct, and when the P time is less than 9 seconds, it is determined that the start ID is incorrect. It is determined to be the start ID (step 9).

After that, if it is determined that the start ID is correct, the low-speed search operation in the opposite direction (step 10) is started again.
When the start (rise) of the recording period of the star hID is detected (step 11), the stop mode (step 2) is switched by one, and immediately after that, the normal playback mode (step 16) is entered from the beginning of the program (Figure 2). (a) (b) (see φ).

In addition, if it is determined that the start ID is incorrect in step 9, this is fed back to the high-speed search operation in step 2, and a high-speed search for the next start ID is started (see Fig. 6 (a) and (b) (φ)). .

(G) Effects of the Invention According to the high-speed search operation of the present invention, by reproducing the P time of the recording period of the start ID, star +, I
Since the length of the recording period of D can be detected, the start ID
This method is extremely useful because it can improve the reliability of high-speed search operations using the .

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the high-speed search operation of the present invention, FIGS. 2 and 6 are time charts showing the high-speed search operation of the present invention, and FIG. 4 is a flowchart showing the high-speed search operation of the present invention. 5 is a diagram showing the tape format of R-DAT, FIG. 6 is a time chart showing the conventional high-speed search operation, and FIG. 7 is a diagram showing the tape drive system of R-DAT. FIG. (D)...Information recording area (PCM area), (Ts)
(Te)-) racking area, (SS) (Se)...
Subcode area, (branch)...tape.

Claims (1)

[Claims] (1) A tracking area and a subcode area are formed together with the PCM area on each track of the tape that is helically scanned by a rotating head, and when recording, the digitally converted main signal is recorded in the PCM area, and the tracking area is The tracking control signal is also stored in the subcode area at least as start identification information (hereinafter referred to as start ID) indicating the start position of the program recorded in the PCM area and program time information (hereinafter referred to as P time) indicating the playing time of the program. A rotary head digital audio tape recorder for recording a start I recorded in a subcode area on said tape.
When performing a high-speed search for D and reproducing the main signal recorded near the start point of the start ID, after detecting the start ID, the P time at the end of the start ID is reproduced, and if the P time at this time is already A high-speed rotary head type digital audio tape recorder characterized in that the tape is rewound to the beginning of the recording time of a start ID only when the recording time of a predetermined regular start ID matches, and then the main signal is played back. Search method.