JP2828676B2 - Time information display method of rotary head type digital audio tape recorder - Google Patents

Description

The present invention relates to a rotary head type digital audio tape recorder (hereinafter, referred to as R-DAT), and more particularly to a method for displaying time information.

(B) Conventional technology Hereinafter, absolute time information (information indicating the elapsed time from the beginning of the tape during normal reproduction) in the R-DAT device will be described in detail. The absolute time information is recorded in a subcode area, and one block of the subcode area is configured as shown in FIG.
W _1, W ₂ region of the bit, 8-bit parity area, and a sub-code data area of 256 bits (32 symbols).

The subcode data area is composed of four pack information of 64 bits per pack as shown in FIG. 5, and the pack information is PC1, PC2,... Of one symbol (8 bits).
It consists of PC8, and the upper 4 bits of PC1 contain the contents of the pack information as program time, absolute time, running time, TOC
A pack item indicating whether the information is information or the like, the lower 4 bits of PC1 and a total of 52 bits of PC2 to PC7 indicate pack data, and PC8 is assigned as pack parity of PC1 to PC7. In FIG. 6, the pack item "001" is shown.
It indicates the absolute time of "0".

(C) Problems to be Solved by the Invention However, the tape speed is set to the standard mode (first speed).
The absolute time information recorded on the tape is exactly the same between the case where the recording is performed in the recording mode and the case where the recording is performed in the long time mode (second speed) (0.5 times the standard mode). When a tape recorded in the long time mode is reproduced on the tape, the actual time required until the tape end is 4 hours, but the absolute time information recorded on the tape is "2 hours". Every two seconds, the display of the absolute time changes by only one second, and finally when played back for four hours, "2 hours" will be displayed on the display device.
The actual playback time was not displayed, which was extremely inconvenient for the user.

(D) Means for Solving the Problems The present invention provides a tape running at one of a first speed and a second speed which is a half speed of the first speed, digitally recording an audio signal, and a tape start end. In a rotary head type digital audio tape recorder which records absolute time information corresponding to a first speed in proportion to the distance from the disc, whether the tape speed is the first speed or the second speed at the time of reproduction If the tape speed is determined to be the first speed, the absolute time information is displayed as it is, and if the tape speed is determined to be the second speed, the second absolute time information based on the absolute time information is determined. We propose a method of displaying time information of a rotary head digital audio tape recorder characterized by displaying time information according to speed.

(E) Function According to the above means, the actual elapsed time from the tape start end can be accurately displayed not only at the first speed but also at the second speed.

(F) Embodiment An R-DAT device for realizing the time display method of the present invention will be described with reference to the block diagram of FIG.

In the figure, (1) is an input terminal to which an analog audio signal is input, (2) is a digital signal processing circuit that converts this audio signal into a digital signal subjected to interleaving, time compression, etc. (PCM modulation); 3) is a servo signal generation circuit for generating a servo signal for tracking control (that is, a pilot signal or a sync signal, etc.). A subcode signal generation circuit for generating a subcode signal such as a recording area for information formed on each track of the tape, a tracking area,
A switch circuit which is selectively switched at a predetermined timing to record the digitally converted audio signal, servo signal, and subcode signal in the subcode area, (6) is a recording amplifier, (7) is from a recording amplifier (6). The rotary transformer of the rotary head cylinder that supplies the output of the recorder to two rotary heads (180) 180 ° apart, (9) is a reproduction amplifier, (10) is the output from the reproduction amplifier (9), PLL etc. A digital signal processing circuit converts a digital signal into a digital signal and then converts the digital signal into an analog signal (PCM demodulation). Reference numeral 11 denotes an output terminal from which an original analog audio signal is output. (12) a servo circuit for extracting a servo signal for tracking control from the output of the reproduction amplifier (9) to generate a tracking error signal, and (13) extracting a subcode signal from the output of the reproduction amplifier (9). This is a subcode processing circuit that detects a start ID and reads absolute time information and the like. And (1
4) 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, (17) and (18) are cylinder motors and their motor drive circuits, (19) and (20) are capstan motors. This is the motor drive circuit. And (21) each motor (14) (15) (17) by input of various operation keys and output from subcode processing circuit (13)
The microcomputer is a control circuit for controlling the drive / stop, the rotation speed, the rotation direction, and the like of (19).
(22) is a tape that can be wound 90 degrees around the rotating head cylinder.

Therefore, at the time of recording, first, after the audio signal input to the input terminal (1) is converted into a digital signal by the digital signal processing circuit (2), the servo signal (pilot signal or sync signal) from the servo signal generation circuit (3) is output. ) And the subcode signal (start ID, music number, absolute time information) generated by the subcode generation circuit (4) are transmitted to the recording amplifier (6) in a time division manner. And this recording amplifier (6)
Is output to the rotary transformer (7) of the rotary head cylinder and is recorded on the tape by the recording / reproducing rotary head (8). It should be noted that the third on the tape
A track pattern as shown in the figure is formed, an information recording area (D) is provided at the center of each track, and a tracking area (Ts) (Te) and a subcode area (S) are provided on both sides thereof.
s) (Se) will be formed respectively.

Next, at the time of reproduction, various signals recorded on the tape (22) are read by the recording / reproducing rotary head (8) and sent out to the reproduction amplifier (9) from the rotary transformer (7) of the rotary head cylinder. The output of the reproduction amplifier (9) is clocked from data by a digital signal processing circuit (10) by a PLL or the like, converted into a digital signal by this, converted into an analog signal, and output as an original audio signal. It will be output from terminal (11). Further, the output of the reproduction amplifier (9) is sent to a servo circuit (12), where a servo signal for tracking control is extracted to generate a tracking error signal.
This is sent to the motor drive circuit (20) to control the capstan motor (19). The output of the reproduction amplifier (9) is also sent to a sub-code processing circuit (13), where the sub-code signal is extracted to read the song number and time information, etc., and is displayed through a control circuit (21). ) To display the song number and time.

Next, a method of displaying absolute time information according to the present invention will be described with reference to the flowchart of FIG. First, it is determined in step 1 whether the mode is the standard mode or the long time mode. If the mode is the long time mode, the absolute time reproduced from the tape is doubled in step 2. In step 3, it is determined whether or not the frame number of PC7 in the pack information shown in FIG. 6 is 17 or more. If it is 17 or more, 1 is added to the value obtained by doubling the absolute time in step 2 (step 4). ), Display on a display device such as a fluorescent display tube (step 5), and if it is less than 17, display as it is without step 4 (step 5).
Then, the operations of the above steps 1 to 5 are repeated until the reproduction is stopped.

If it is determined in step 1 that the mode is the standard mode, the absolute time information reproduced from the tape is displayed as it is (step 5). All of the above operations are performed by the control circuit (21). The reason for determining whether the frame number is equal to or greater than 17 or less than 17 in steps 4 and 5 is as follows.
Since about 33 frames are traced per second in the standard mode,
In the long time mode, since about 33 frames are traced in 2 seconds, it is determined whether or not 1 is added to a value obtained by doubling the absolute time with reference to 17 frames which is about half of the 33 frames.

(G) Effect of the Invention As described above, according to the present invention, the actual elapsed time from the tape start end is calculated based on the absolute time information recorded from the tape start end not only at the first speed but also at the second speed. Since it can be displayed, it is extremely useful for the user during operations such as recording and reproduction.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a time information display method of the present invention, FIG. 2 is a block diagram of an R-DAT device for realizing the time information display method, and FIG. 3 is a track format of the R-DAT device. FIG. 4 is a diagram showing a subcode format in the R-DAT device, FIG. 5 is a diagram schematically showing pack information in the subcode, and FIG. 6 is a diagram showing the contents of the pack information in absolute time. It is a schematic diagram in the case. (13) Sub-code processing circuit, (21) Control circuit, (23) Display unit.

Claims (2)

(57) [Claims] The tape is run at one of a first speed and a second speed which is half of the first speed to digitally record an audio signal or the like, and the tape is moved in proportion to the distance from the tape start end. In a rotary head digital audio tape recorder that records absolute time information corresponding to one speed, it is determined whether the tape speed is a first speed or a second speed during reproduction, and the tape speed is determined to be a second speed. When it is determined that the tape speed is one speed, the absolute time information is displayed as it is, and when it is determined that the tape speed is the second speed, time information corresponding to the second speed based on the absolute time information is displayed. A time information display method for a rotary head type digital audio tape recorder. 2. The rotary head digital audio tape recorder according to claim 1, wherein the time information corresponding to the second speed is calculated by obtaining absolute time information and frame number information. Time information display method.