JPH06168506A - Reproducing method of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To ensure the reproduction from the head of a music by releasing a mute in the manner of detecting a tracking control signal and a discrimination signal S-ID indicating the of music, when the mute period is required at the time head of reproduction by the change of a recording mode. CONSTITUTION:When a capstan speed is desired to be changed at the border of normal speed and half speed modes, the tape is once unwound to the position just before the signal S-ID if the signal S-ID exists on the way of the process, and after that, the reproduction is made again in the corresponded mode to release the mute at the head position of the signal S-ID. At the time of reproduction the signal recorded on the tape 8 is read by a magnetic head 7 and transmitted to a reproduction amplifier 9 through a rotary transformer 6 then processed by a digital signal processing circuit 10 and outputted from an output terminal 12. At this time, the subcode informations such as a frequency, the number of bits, time information, etc., are also processed by the circuit 10 and transmitted to a control circuit 20 to control motor servo circuits 17, 18, 19. Thus, the reproduction is attained by a double scan system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention records main information such as a voice signal on a magnetic tape, a tracking control signal, and an identification signal (start ID; hereinafter S-).
The present invention relates to a reproducing method of a magnetic recording / reproducing apparatus in which sub-code information such as an ID) and a song number is recorded by a rotary head.

[0002]

2. Description of the Related Art As such a magnetic recording / reproducing apparatus, a magazine "Electronic Life" published by the Japan Broadcasting Corporation has been published.
, March 1987, pages 11-66. In this DAT, a magnetic tape is alternately helical-scanned by a pair of recording / reproducing rotary heads having different azimuth angles provided on a rotary head cylinder, and PCM audio is time-axis compressed at the center of each track of the tape. Main information such as digital audio information made up of data is recorded, and tracking control signals called ATF signals and sub-code information such as S-ID and song number are recorded on both sides thereof in a time division manner.

Further, in such a DAT, the sampling frequency (hereinafter referred to as FS) is 48 kHz, 44.1 kHz, 32 k.
It is set to Hz, and at 32kHz, the tape speed is 4.05mm in addition to the normal speed mode of 8.15mm / sec.
There is a 75 mm / sec half speed mode. Then, in the reproduction in the half speed mode, it is general to use a reproduction method called a so-called double scan method.
Regarding this double scan, for example, Japanese Patent Laid-Open No.
3-64604 (G11B5 / 09). According to this double scan method, the cylinder speed is the same in the normal speed mode and the half speed mode, but the capstan speed, that is, the tape speed is different. Therefore, when switching between these two modes, Mute the playback signal for a certain period and switch the capstan speed.

[0004]

In such a DAT, it is conceivable that the normal speed mode and the half speed mode are mixed and recorded on one tape. For example, in satellite broadcasting, the audio modes are A mode and B.
There are two modes: FS is 32 kHz in A mode and 48 kHz in B mode. When these are switched depending on the program and the A mode is recorded in the half speed mode, the mixed tape as described above is created.
When such a tape is played back, the capstan speed changes at the boundary between the normal speed mode and the half speed mode, and normal audio output cannot be performed, so the playback output is muted. In particular, when the recording mode is switched immediately before the S-ID, there is a problem that the front part of the S-ID is muted and the beginning part of the music is not reproduced.

[0005]

In order to solve such problems, the present invention provides a tape-shaped magnetic recording medium with main information such as a voice signal and sub-information such as a start ID indicating the beginning of a song by a rotary head. It is possible to record in the standard mode and the long time mode in which the tape speed and the rotary head speed are set to half the standard mode. When reproducing the information recorded in the long mode, the tape speed is half the standard speed. And detecting the change of the recording mode from the sub information recorded on the tape in the reproducing method of the magnetic recording / reproducing apparatus configured to perform the reproduction by setting the speed of the rotary head to be the same as the standard mode. A step of muting for a predetermined time according to a change in the recording mode; a step of detecting the presence or absence of the start ID during the mute period; Comprising the steps of unwinding a certain amount of tape in response to the detection of bets ID, and is characterized in that comprising the step of releasing the mute upon detection of the beginning of the re-start ID and sets the subsequent playback state.

[0006]

[Function] While the capstan speed is changing at the boundary between the normal speed mode and the half speed mode,
If the S-ID exists, it is rewound once before the S-ID and then played back in the corresponding mode again.
Mute is released at the beginning position of the S-ID.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to DAT will be described below with reference to the drawings. In FIG. 1, 1 is an input terminal to which an information signal such as a voice signal is input, 2 is a digital signal processing circuit for interleaving this information signal, adding error correction code and performing processing such as time compression, 3 is a song number , A subcode generation circuit for generating time information such as absolute time, and an information signal such as an S-ID indicating the beginning of a song used when cuing a song. A servo signal generation circuit 5 for generating a signal is a recording amplifier, and a digital signal processing circuit 2
Output, sub-code generation circuit 3 output, and servo signal generation circuit 4 output are selected by the switch 23 in a time division manner. Reference numeral 6 denotes a rotary transformer that supplies the output from the recording amplifier 5 to the recording / reproducing heads 7 and 7, and supplies the reproduction output from the recording / reproducing heads 7 and 7 to the reproducing amplifier 9, and 10 denotes a PLL from the output from the reproducing amplifier 9. A digital signal processing circuit that creates a clock, extracts a data signal, and further performs error correction and other processing to demodulate the original analog signal. Reference numeral 11 denotes a sampling frequency processed by the digital signal processing circuit 10 and the number of quantization bits. Sub-code processing circuit for extracting sub-code signals such as information signals, song numbers, time information, etc., 12 demodulated analog signal output terminals, 13 and 16 reel motors, 17 controls reel motors 13 and 16. Reel motor servo circuit, 14 is a capstan motor, 15 is a cylinder motor, and 18 is a system for controlling the cylinder motor 15. Sunda motor servo circuit 19 extracts a servo signal for tracking control from the output of the reproducing amplifier 9, a ATF servo circuit for controlling the capstan motor 14.

Reference numeral 20 denotes a control circuit for controlling the entire apparatus. This control circuit controls each motor servo circuit according to a flow chart described later, and at the same time, information from the key input terminal 21 and the mechanism switch input terminal 22 is used. Control each block.

Operation key signals from the input terminals 21 and 22,
When the tape 8 is set to the normal recording mode by the mechanism detection signal, the control circuit 20 controls the tape 8 to move in the normal direction at the normal speed of 1 × the normal mode, and the cylinder rotates at the standard speed to set the normal speed recording mode. Is set. When the long-time recording mode is set, the tape 8 runs in the normal direction at the normal half speed of the standard mode, and the cylinder also rotates at the normal half speed, so that the half-speed recording mode is set. In these recording modes, the signal input from the input terminal 1 is processed by the digital signal processing circuit 2, the subcode processing circuit 3 processes subcode information such as the sampling frequency and the number of quantization bits, and the servo signal is processed. The recording amplifier 5 together with the output of the generation circuit 4
And is recorded on the tape 8 through the rotary transformer 6 and the magnetic head 7.

At the time of reproduction, the signal recorded on the tape 8 is read by the magnetic head 7, sent to the reproduction amplifier 9 through the rotary transformer 6, further processed by the digital signal processing circuit 10, and then the analog signal is outputted from the output terminal 12. Is output as. At this time, the recorded sub-code information such as the sampling frequency, the number of quantization bits, and time information is also processed by the digital signal processing circuit 10 and sent to the control circuit 20 via the sub-code processing circuit 11. Based on this subcode information, the control circuit 20 determines the tape speed and the rotation speed of the cylinder, and the motor servo circuits 17 and 1
8 and 19 are controlled. That is, in the half speed mode, the tape 8 is run at the normal half speed of the standard mode, the cylinder speed is set to the standard speed, and the reproduction is performed by the so-called double scan method.

FIG. 2 shows the operation when the normal speed mode is changed to the half speed mode during reproduction. When the normal speed mode is changed to the half speed mode during reproduction, the mute is applied for a certain period of time, the tape speed is set to 1/2, and the mute is released while the tracking servo is locked.

However, as shown in FIG. 3, when there is a change immediately before the S-ID, muting is applied at the S-ID portion, and the beginning of the song is not reproduced. Therefore, in the present invention, when the S-ID is detected during the mute period by controlling according to the flowchart shown in FIG. 4, the tape is wound by a certain amount at a faster tape speed than usual, and the mute is canceled again from the S-ID portion. And play.

That is, when the switching from the normal speed mode to the half speed mode is detected by the subcode information in step 24, the mute is applied in step 25 and the tape speed is set to 1/2 of the standard mode in step 26. To do. If the S-ID is not detected in step 27 during this period, step 28
When the lock of the ATF servo is detected at, the mute is released at step 29. On the other hand, when the S-ID is detected in step 27, the tape is rewound at the reverse triple speed in a certain section in step 30, the tape speed is set again to 1/2 of the standard mode in step 31, and the S-ID is set in step 32. When the beginning of the ID is detected, the mute is released in step 33.

Thus, according to the present invention, the S-ID
Will be reproduced normally from the beginning. In addition, the reproduction of the tape changed from the normal speed mode to the half speed mode has been described. Similarly, for the tape changing from the half speed mode to the normal speed mode, the mute is released from the beginning of the S-ID and the normal operation is performed. It is possible to perform various reproductions.

[0015]

As described above, according to the present invention, even if a mute period is required at the time of reproduction due to a change in the recording mode, the S-ID is detected and the mute is canceled. Can be played back.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a diagram showing an operation of the present invention.

FIG. 3 is a diagram showing an operation of the present invention.

FIG. 4 is a flowchart showing the operation of the present invention.

[Explanation of symbols]

 7 magnetic head 11 sub-code processing circuit 14 capstan motor 15 cylinder motor 19 ATF servo circuit 20 control circuit

Claims (1)

[Claims] 1. A tape-type magnetic recording medium is provided with main information such as a voice signal and sub-information such as a start ID indicating the beginning of a song by a rotary head in a standard mode and a tape speed and a rotary head speed which are half the standard mode. It is possible to record in the set long time mode, and when reproducing the information recorded in the long time mode, set the tape speed to half the standard speed and set the rotary head speed to the same as the standard mode. In a reproducing method of a magnetic recording / reproducing apparatus configured to reproduce, a step of detecting a change of a recording mode from the sub information recorded on the tape, a step of muting for a predetermined time by the change of the recording mode, A step of detecting the presence or absence of the start ID during the mute period, and a step of rewinding a certain amount of tape according to the detection of the start ID. Then, the reproducing method is set, and when the head of the start ID is detected again, the mute is released.