JP2641225B2 - Playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for digital audio signals (PCM audio signals) and the like, and more particularly to a method for selecting an absolute address in the reverse direction of the reproducing apparatus.

[Prior Art] Digital audio tape recorders (DATs) include a fixed head system (S-DAT) and a rotating head system (R-DAT).
There is. S-DAT is a method of recording PCM audio signals on a number of tracks parallel to the longitudinal direction of a magnetic tape using a multi-track fixed head.
Is a method of recording PCM audio signals on tracks oblique to the longitudinal direction of a magnetic tape by helical scanning using a rotating head.

When recording audio signals or other information (video signals, etc.) as a program in DAT, along with PCM-converted audio signals or other information, position information such as program numbers (track numbers), time codes, and other necessary information A subcode signal including auxiliary data is recorded. Based on this subcode signal, the position of the magnetic tape can be known at the time of reproduction, and the head of the magnetic tape can be located in the search mode.

For example, a data configuration when an audio signal is recorded by R-DAT will be described with reference to FIGS. 6, 7, and 8. FIG. FIG. 6, FIG. 7, and FIG. 8 are data configuration diagrams showing a track format, a block format, and a bit configuration of an ID code and a block address.

As shown in FIG. 6, one track is composed of 196 blocks, and is centered on a PCM period of 128 blocks in which a PCM audio signal is recorded. There is an ATF period, and outside these, there is a sub-code period of 8 blocks each in which a sub-code signal is recorded, and outside these, a margin period of 11 blocks is provided.

At the beginning of the PCM period and the subcode period, a PLL period for each two blocks for synchronization is provided, and between the PCM period and the ATF period and between the ATF period and the subcode period, three PLL periods are provided. A gap period is provided for each block, and a postamble period is provided for each block immediately after the subcode period. The PCM audio signal or the subcode The signal can be recorded independently.

As shown in FIG. 7 (a), one block is composed of 288 bits, each having 8 bits of synchronization, an identification code (ID code), a block address, a parity, and 256 bits of data (PCM data + parity). ) Is provided. As shown in FIGS. 7 (b) and (c), the MSB (B7) of the block address is set to "0" in the PCM audio signal block and "1" in the subcode signal block. The ID code in the PCM period indicates use of voice, emphasis characteristics, quantization characteristics, sampling frequency, number of channels, and the like.

As shown in FIG. 8, the data structure of the ID code and the block address in the subcode period is different between the even block shown in FIG. 8A and the odd block shown in FIG. In the even block, the upper 4 bits (B7 to B4) of the ID code are provided with the control ID, the lower 4 bits (B3 to B0) are provided with the data ID, and the upper 3 bits (B6 to B4) of the block address are provided with the pack ID. I have. In the odd block, the upper 4 bits and lower 4 bits of the ID code
The lower three bits, the middle bit, and the uppermost bit of the program number of the BCD code are provided in the upper three bits of the bit and the block address, respectively.
Note that addresses are provided for the lower 4 bits (B3 to B0) of the block addresses of the even block and the odd block. The above-described subcode period is composed of eight blocks in the order of even number (0), odd number (1),..., Odd number (7).

A start signal indicating the beginning of the recorded audio signal (song) is assigned to the control ID B6 and is represented by "1". At the beginning of each song, a start signal and a program number are recorded for 9 seconds.

FIG. 3 is a block diagram showing a conventional reproducing apparatus. In FIG. 3, (1) shows a magnetic tape attached to a rotating drum (not shown), and (2) and (3) show magnetic tapes (1). Wound reels, (4) and (5) are rotary heads provided on the rotary drum, (6) and (7) are amplifiers respectively connected to rotary heads (4) and (5), and (8) ) Is a switch circuit connected to the amplifiers (6) and (7),
(9) is a timing signal generation circuit connected to the switch circuit (8), (10) is an equalizer connected to the switch circuit (8), (11) is a comparator connected to the equalizer (10), (12) is connected to this comparator (11)
A PLL circuit (13) is an error correction circuit connected to the PLL circuit (12). (14) is a digital / analog converter connected to the error correction circuit (13), (15) is a low-pass filter connected to the digital / analog converter (14), and (16) is a low-pass filter (15). ), An output terminal connected to the output side, (17) a terminal connected to the output side of the error correction circuit (13), (18) a system controller connected to the error correction circuit (13), (19) Is a display unit connected to the system controller (18), (20) is a drum servo circuit connected to the system controller (18),
(21) is a drum motor connected to the drum servo circuit (20) and connected to the rotating drum, (22) is a reel drive circuit connected to the system controller (18),
(23) and (24) are connected to the reel drive circuit (22), the reel motors connected to the axes of the reels (2) and (3), and (25) is the cap motor connected to the system controller (18). (26) is the capstan motor connected to this capstan servo circuit (25), (2)
7) is a capstan connected to this capstan motor (26) and an RS connected to the system controller (18).
Is the key. Although not shown, a pinch roller is provided at a position facing the capstan (27), and a plunger circuit connected to the pinch roller is also provided.

In the conventional example having the above-described configuration, digital signals recorded on the magnetic tape (1) are reproduced by the rotary heads (4) and (5) and supplied to the amplifiers (6) and (7). . By these amplifiers (6) and (7),
The digital signal is amplified and supplied to the switch circuit (8). In response to a switching signal of 33.3 Hz from the timing signal generation circuit (9), the switch circuit (8) causes the switch circuit (8) to perform a half rotation period including the magnetic tape contact period of the rotary head (4) and a magnetic tape contact period of the rotary head (5). And a half-rotation period including And a switch circuit (8)
The digital signal switched by the above constitutes an electromagnetic conversion system. After passing through an equalizer (10), a comparator (11), and a PLL circuit (12), an error correction circuit (1
3) supplied to. With this error correction circuit (13),
The error is corrected and supplied to the digital / analog converter (14). The digital / analog converter (14) converts a digital signal into an analog signal, passes through a low-pass filter (15), and outputs the analog signal to an output terminal (16). When it is desired to directly extract a digital signal, the digital signal can be derived from a terminal (17) on the output side of the error correction circuit (13).

The system controller (18) controls the drum motor (21) via the drum servo circuit (20), the reel motors (23) and (24) via the reel drive circuit (22), and the capstan servo circuit (25). The rotation of the capstan motor (26) is controlled via this.

Further, a subcode signal including a start signal and a program number is extracted (detected) by the system controller (18) serving as an interface, and the program number and the like are displayed on the display unit ( 19) is displayed.

Next, regarding the operation of song cueing (absolute address selection),
This will be described with reference to FIGS. 4 and 5. FIG. 4 and FIG. 5 are explanatory diagrams of absolute address selection.

As shown in FIG. 4, for example, during reproduction of a program, pressing the RS key (28) which is the reverse direction cue key once during reproduction of the magnetic tape (1) in the reverse direction as shown in FIG. This is done by rewinding to the fall of the start signal of the program and reproducing from there. Also,
For example, if the RS key (28) is pressed twice during reproduction of the program number "3", the program number "2" is searched. In this way, the number of programs to be searched for decreases according to the number of times the RS key (28) is pressed.

However, as shown in FIG. 5, for example, during the reproduction of the program number "3" on the B side, even if the RS key (28) is pressed four or more times, the program number for cueing does not fall below "1". Searches for the program number "1" on the side. This is the same even if the RS key (28) is pressed twice or more while the program number "1" on the B side is being reproduced, and the beginning of the program number "1" on the B side is performed.

[Problems to be Solved by the Invention] In the conventional reproducing apparatus as described above, for example, a magnetic tape on which two or more program numbers "1" are recorded is reproduced, and the absolute address selection program in the reverse direction is located. If you press the RS key (28) many times, the first program number “1” will be searched, and the program before the first program number “1” cannot be searched. there were.

To find the beginning of the program before the first program number “1”, use the rewind key (not shown).
There has been an operational problem that the music must be selected by the RS key (28) after the magnetic tape is once positioned before the first program number "1".

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a playback apparatus that can easily find a program before a program number "1" in an absolute address selection in a reverse direction. I do.

[Means for Solving the Problems] A reproducing apparatus according to the present invention provides a reproducing apparatus for reproducing a PCM audio signal recorded on a track oblique to the longitudinal direction of a magnetic tape by helical scanning using a rotary head. In the apparatus, a program number is extracted from a reverse direction cue key of the magnetic tape and a subcode signal in a reproduction signal from the rotary head, and when the program number is 1, the reverse direction cue key is at least. When pressed twice, set to the rewind mode and run the magnetic tape in the reverse direction,
The start signal is extracted from the subcode signal in the reproduction signal in the reverse direction from the rotary head, and when the start signal falls for the second time, the reproduction mode is set so that the program before the reproduction of the program number 1 is set. And a system controller for searching for a program of a different series.

[Operation] In the present invention, the system controller extracts a program number from the subcode signal in the reproduction signal from the rotary head, and when this program number is 1, the reverse direction cue key is at least two.
When the magnetic tape is pressed twice, the magnetic tape is set to the rewind mode, the magnetic tape is caused to travel in the reverse direction, and the start signal is wiped from the subcode signal in the reproduction signal in the reverse direction from the rotary head, and the start signal is transmitted. When the fall of the second time is the second time, the reproduction mode is set, thereby searching for a different series program located before the program of the program number 1 being reproduced.

Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention. (1) to (17), (19) to (28), and a rotating drum, a pinch roller, a plunger circuit and the like (not shown) Is exactly the same as that of the above-mentioned conventional device. (18A) is the error correction circuit (13), display unit (19), drum servo circuit (2
0), a reel drive circuit (22), a capstan servo circuit (25), and a system controller connected to an RS key (28) and configured by a microcomputer or the like.

First, the basic operation of the above embodiment will be described with reference to FIG. For example, if the RS key (28) is pressed once during the reproduction of the program number "3" on the B side, the beginning of the program number "3" currently being reproduced is located. Similarly, when the RS key (28) is pressed twice or three times, the program numbers to be searched are reduced, and the program numbers "2" and "1" on the B side are respectively searched. Even if the RS key (28) is pressed four or more times, the program number "1" on the B side is searched. When the RS key (28) is pressed once during the reproduction of the program number "1" on the B side, the beginning of the program number "1" currently being reproduced is located. When the RS key (28) is pressed twice or more times, the program before the program number "1" on the B side (the program number "2" on the A side) is searched. In this way, the program on the A side preceding the program number "1" on the B side is searched for in the absolute address selection.

Next, the detailed operation of the above-described embodiment will be described with reference to FIG. Figure 2 shows the system controller (18
FIG. 4 is a flowchart diagram showing a program incorporated in A) for performing absolute address selection in the reverse direction. Note that the operation of reproducing the audio signal is the same as that of the conventional example, and a description thereof will be omitted.

In FIG. 2, steps (31) to (33) correspond to 1
The part for determining the condition for performing the cueing of the previous program, and the steps (34) to (36) are the parts for performing the cueing operation of the immediately preceding program.

For example, when the system controller (18A) is set to the absolute address selection and the RS key (28) is operated, the operation of the absolute address selection in the reverse direction is started in step (30) in FIG.

Next, in step (31), it is determined whether the program number is "1". That is, the program number is extracted from the ID code and block address of the odd-numbered block of the reproduced subcode signal.

If the program number is “1” (YES), go to step (3
In 2), it is determined whether the RS key (28) is pressed.

If the RS key (28) has been pressed (YES), it is determined in step (33) whether the RS key (28) has been pressed twice or more after the condition of step (31) is satisfied. .

If the RS key (28) is pressed more than once (YES),
In step (34), set to rewind mode,
The magnetic tape (1) runs in the reverse direction.

Next, in step (35), it is determined whether the falling of the start signal is the second time. That is, one bit of the control ID B6 in the even-numbered block of the reproduced subcode signal is extracted. The first fall of B6 from "1" to "0" is the beginning of the program currently being played, and the second fall from "1" to "0" is 1
This is the beginning of the previous program.

If the start signal falls for the second time (YES),
Set to playback mode. Next, in step (37), the operation ends.

If the program number is not "1" in step (31) (NO), if the RS key (28) is not pressed in step (32) (NO), and if the RS key (28) is 2 in step (33) If it has not been pressed more than once (NO), step (31)
Return to If the fall of the start signal is not the second time in step (35) (NO), the delay operation is repeated until the second time is detected.

In the above embodiment, the program number and the start signal are detected. However, when the program number is not recorded on the magnetic tape (1), the program number is generated by counting the start signal. This program number "1" can be used for magnetic tape (1)
It is needless to say that the intended purpose can be achieved by the same operation as in the above-mentioned embodiment even in the middle of the process.

By the way, in the above description, a case where the present invention is used for a reproducing apparatus has been described, but it goes without saying that the present invention can also be used for a reproducing section of another recording / reproducing apparatus.

[Effects of the Invention] As described above, the present invention relates to a reproducing apparatus for reproducing a PCM audio signal recorded on a track oblique to the longitudinal direction of a magnetic tape by helical scanning using a rotating head. A program number is extracted from a reverse tape cueing key of the magnetic tape and a subcode signal in a reproduction signal from the rotary head. When this program number is 1, the reverse cueing key is pressed at least twice. In this case, the magnetic tape is set to the rewind mode, the magnetic tape is caused to travel in the reverse direction, a start signal is extracted from the subcode signal in the reproduction signal in the reverse direction from the rotary head, and the start signal falls for the second time. In the case of, the program of program number 1 being reproduced is set by setting the reproduction mode. And a system controller for cueing a program of a different series located in front of the program, so that in the absolute address selection in the reverse direction, the cue of the program before the program number "1" can be easily performed. . Further, if the present invention is used for a vehicle, it is free from a complicated operation, and has an effect of preventing an accident in terms of safety.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the embodiment of FIG. 1, and FIG.
FIG. 1 is a block diagram showing a conventional reproducing apparatus, FIGS. 4 and 5 are explanatory diagrams of absolute address selection, and FIGS. 6, 7, and 8 are bit structures such as a track format, a block format, and an ID code. FIG. 6 is a data configuration diagram showing In the figure, (4), (5) ... rotating head (6), (7) ... amplifier (8) ... switch circuit (9) ... timing signal generation circuit (10) ... equalizer (11) ... … Comparator (12)… PLL circuit (13)… Error correction circuit (18A)… System controller (28)… RS key Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A reproducing apparatus for reproducing a PCM audio signal recorded on a track oblique to a longitudinal direction of a magnetic tape by helical scanning using a rotary head, wherein a cue in a reverse direction of the magnetic tape is provided. A key and a program number are extracted from a subcode signal in a reproduction signal from the rotary head. When the program number is 1, when the reverse direction cueing key is pressed at least twice, a rewind mode is set. The magnetic tape is set to run in the reverse direction, and a start signal is extracted from the subcode signal in the reverse direction reproduction signal from the rotary head. When the start signal falls for the second time, the reproduction mode is set. As a result, the program of a different series located before the program of program number 1 being reproduced is Reproducing apparatus characterized by comprising a system controller for the beginning of.