JPH0397183A - Residual amount time display method for rotary head type digital audio tape recorder - Google Patents

Abstract

PURPOSE:To display the residual amount time in the any search mode such as CUE or REVIEW when the total tape length time is once obtained by subtracting an absolute time from a total tape length time so as to always display the residual amount time. CONSTITUTION:A period T is represented by a pulse number N generated one revolution of a reel base of a magnetic sensor 23 detecting the rotation of the reel base and the residual amount time S is obtained when the period T is clarified. On the other hand, since the absolute time information recorded in the standard mode is recorded on a subcode sector on a tape, the absolute time information is detected and the total length time of the tape is recognized by adding the absolute time and the residual amount time and the result is stored in a memory in a control circuit 21. Then the absolute time at search is reproduced and the absolute time is subtracted from the total tape length time, then the residual amount time is simply calculated and the residual amount time display is attained by a display device 24. Thus, when the total tape length time is once obtained, the residual time is accurately displayed in any search mode such as CUE or REVIEW.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a method for displaying remaining time of a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT), particularly in a search mode where the tape speed is not constant. However, the present invention relates to a method for displaying the remaining amount time of an R-DAT that can display the remaining amount time.

(b) Conventional technology The subcode signal of R-DAT includes four control IDs (star ID, shortening ID, priority ID, TOC-TD) and absolute time information (A
-TIME), program time information (P-TIME), and calendar information.

The start ID is recorded in the first 300 frames of the program, and P-TIME is also recorded in the 300 frames.

Note that there is a method of calculating the remaining tape time from the tape thickness, the number of tape turns, the tape speed, and the hub radius.To explain this with reference to FIG. 2, tape y'I. t, the number of tape turns n, the tape speed V, and the hub radius r, the remaining tape time S is π (◆n・t ) 1−r・r″ S=
(1) V-t According to the above equation (1), when the tape thickness t is constant and the tape speed V is constant within the measurement period, a hub that can indirectly calculate the number of tape turns n or the number of tape turns n The remaining tape time S can be determined from the rotation period of .

(c) Problems to be Solved by the Invention In the method for detecting remaining amount time described above, since a certain measurement time is required to determine the number of tape turns or the hub rotation period for calculating the number of tape turns, the remaining amount is continuously measured. It is impossible to measure and display time. Therefore, the remaining amount of tape is once determined, and then only when the tape speed is constant, a control signal corresponding to real time is used to display the remaining amount of tape. However, if this method is adopted, it is good during playback or recording when the tape speed is constant, but in search modes such as cue review, it is impossible to calculate or display the tape speed because it is not constant.

Also, during playback and recording, especially in the case of DAT, the transition time when switching from stop mode to playback mode is long, so if a control signal corresponding to real time is used, there is a possibility that errors will become large. Yes, it is necessary to calculate the remaining amount again during playback to eliminate errors. In addition, when the mode is switched midway through a tape with a mixture of standard mode and long-time mode, a transition period occurs because the control signal and tape speed corresponding to real time also switch.
A big error had occurred.

(2) Means for Solving the Problems The present invention is intended to solve the above problems, and provides sub-codes such as absolute time information indicating the elapsed time from the beginning of the tape, in addition to digital signals such as voice A1. In a rotary head type digital audio tape recorder that can record signals,
A rotating device characterized by being able to always display the remaining time by calculating the total tape length during operation at a constant tape speed, reproducing the absolute time information, and subtracting the absolute time from the total tape length. This paper proposes a method for displaying the remaining time of a head-type digital audio tape recorder.

(E) Effect According to the above means, once the total tape length is determined, the remaining time can be displayed in any search mode including cue and review, and furthermore, the recording in standard mode and long mode is possible. Even if mixed tapes are used or the mode is repeatedly switched from stop to play, the remaining time can be displayed without error.

(f) Example R-DAT for realizing the remaining amount time display method of the present invention
The device will be explained below. In the figure, (+) is an input terminal into which an analog sweating voice signal is input, and (2) is a digital signal that converts this voice signal into a digital signal (PCM modulation) that is subjected to interleaving, time compression, etc. A processing circuit (3) is a servo signal generation circuit that generates servo signals (i.e., pilot signals, sync signals, etc.) for tracking control, and (4) is a servo signal generation circuit that generates servo signals (i.e., pilot signals, sync signals, etc.) for tracking control. A subcode signal generation circuit that generates subcode signals such as time information, (5) is a voice that is digitally converted into a recording area, a tracking area, and a subcode area for information that is formatted on each track of the tape. A switch circuit that is selectively switched at a predetermined timing to record signals, servo signals, and subcode signals, (6) is a recording amplifier, and (7) is a switch circuit that switches the output from the recording amplifier (6) to 1.
A rotary transformer of a rotary head cylinder that supplies two recording/reproducing rotary heads (8) 80 degrees apart, (9) is a playback amplifier, and (10) is a PLI. A digital signal processing circuit that creates black and white data from data, converts it into a digital signal, and then converts it into an analog signal (PCM demodulation), (1)
is an output terminal to which the original analog audio signal is output. (12) is a servo circuit that extracts a servo signal for tracking control from the output of the regenerative amplifier (9) and generates a tracking error signal; (13) is the regenerative amplifier (9)
This is a subcode processing circuit that extracts a subcode signal from the output of the subcode and detects the star ID and reads absolute time information.

(14) is a take-up reel motor that directly drives the take-up reel shaft; (15) is a supply reel motor that directly drives the supply reel shaft; (16) is its motor drive circuit;
7) (18) is a cylinder motor and its motor drive circuit, (19) and (20) are a capstan motor and its motor drive circuit, and (19a) is a capsun.

(2l) is operated by each motor (14) (15) by the various operation key manual inputs and the output from the subcode processing circuit (13).
) (17) (19) The control circuit controls the drive/stop, rotation speed, rotation direction, etc., and is controlled by a microcomputer. (22) is 90 on the rotating head cylinder.
゜It is a tape that can be wrapped around. (23) is a rotation sensor (magnetic sensor) that detects the number of rotations of the reel stand rotated by the reel motor (14), and (24) is a display device that displays various time information.

Next, the method of calculating the remaining amount time according to the present invention will be explained below with reference to FIG.

As explained in the prior art section, the tape remaining time S can be determined using the following equation.

r(r+nt)"-rS S= (1)Vt Also, a magnetic sensor (23) that detects the rotation of the reel stand
For example, 2.1 or 48 pulses are generated in one rotation of the reel base (hub). So 1
When the number of rotation pulses is y, the time it takes for one pulse to appear, that is, the period T, can be expressed by the following equation.

2z(r◆n・t) T=
(2) V-N Therefore, from equations (1) and (2), π V-N fS = -(
− )・Tl− −・r′ −−(3)V−
t 2t VT. Therefore, if the period T is known, the remaining amount time S can be obtained. That is, the remaining time can be calculated by measuring the interval between pulses generated from the reel base (hub) during constant speed playback, recording, etc.

On the other hand, the subcode area on the tape contains long-term mode,
Regardless of the standard mode, since absolute time information is recorded continuously from the beginning of the tape as the elapsed time recorded in the standard mode, it is possible to detect the absolute time information at the time of calculating the remaining amount time described above. Therefore, by adding the absolute time at the time when the remaining amount time is calculated and the remaining amount time, the total length of the tape can be determined. The total tape length thus determined is stored in a memo in the control circuit (2l).

Next, during a search, the tape speed changes moment by moment, so it is impossible to obtain the number of tape turns or the rotation period of the reel stand (hub) in a short time, but as mentioned above, the total tape length can be memorized. Therefore, by reproducing the absolute time during a search and subtracting the absolute time from the total length of the tape, the remaining amount of time can be easily calculated and the remaining amount of time can be displayed.

Next, the operation will be explained with reference to the flowchart shown in FIG. First, a tape is loaded into the R-DAT, and playback or recording at a constant tape speed is specified (step 1).
Then, in step 2, the reel pulse is detected, in step 3, the remaining amount time Si is calculated, and at the same time, in step 4, the absolute time Ai at that tape position is reproduced, and in step 5, the remaining amount time Si and the absolute time Ai are calculated. Add the total tape length L
Calculate and store.

Therefore, when entering the search mode, the absolute time A is played back in step 6, and the remaining time S is calculated by subtracting the absolute time A from the total tape length L in 7 steps.
Display in step 8.

Note that the remaining time S can be displayed until the tape is removed from the R-DAT.

(G) Effects of the Invention According to the present invention, once the total tape length is determined, the cue,
It is possible to accurately display the remaining time in any search mode including review, and it is also possible to display the remaining time on tapes that record in both standard mode and long-time mode.
Even if the mode is repeatedly switched from stop to play, it is possible to display the remaining amount of time without error, which is very useful. Another advantage is that when the end search is performed to find the end of the recording section on the tape, the remaining time is displayed instantly, allowing you to record the song you want to record without cutting off the beginning.

[Brief explanation of drawings]

FIG. 1 shows R for realizing the remaining amount time display method of the present invention.
- A block diagram of the DAT device, FIG. 2 is a schematic diagram for explaining the formula for calculating the remaining tape time. FIG. 3 is a flowchart for explaining the remaining amount time display method of the present invention. (23)...Magnetic sensor, (24)...Display device.

Claims (2)

[Claims] (1) In a rotary head type digital audio tape recorder that can record subcode signals such as absolute time information indicating the elapsed time from the beginning of the tape in addition to digital signals such as audio signals, when the tape speed is constant, A rotating head type digital audio tape recorder characterized in that the remaining time can always be displayed by calculating the total tape length, reproducing absolute time information, and subtracting the absolute time from the total tape length. Quantity time display method. (2) The total tape length is the remaining tape length calculated from the tape speed, hub radius, tape thickness, and number of tape turns at the same time as the absolute time information at a certain tape position is played back when the tape speed is constant. A method for displaying remaining time in a rotary head type digital audio tape recorder according to claim (1), characterized in that the remaining time is determined by adding the following.