JPH0612841A - Fade-out system in dcc system - Google Patents

Abstract

PURPOSE:To realize accurate fade-out operation by unwinding by a tape length equivalent to a time required for changing an attenuate level from a minimum value to a maximum value from an end and recording a fade marker. CONSTITUTION:First of all, an audio signal is recorded on a tape 22 till the end without attenuating. Thereafter, a capstan motor 15 or 16 is reversed, and the tape 22 is unwound from the end by the tape length equivalent to the time required for changing the attenuate level to the audio signal from the minimum value to the maximum value. In such a case, the unwinding amt. of the tape 22 is measured by counting the pulse of frequency generators attached to the capstan motors 15, 16. At the point of time when the tape unwinding amt. arrives at the tape length equivalent to the time required for increasing the attenuate level from the minimum value to the maximum value, the fade marker is recorded on the auxiliary track of the tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention records various sub-codes on one auxiliary track among a plurality of tracks extending in the tape longitudinal direction of a signal recording tape, and records on a plurality of other audio tracks. Relates to a DCC (Digital Compact Cassette) system having a multi-channel head for recording audio signals.

[0002]

2. Description of the Related Art As described in "Nikkei Electronics", September 2, 1991, pp. 134-141, DCC is applicable to cassette tapes having substantially the same shape as analog compact cassette players. , An audio signal is recorded digitally, and the digitized audio signal is data-compressed by high-efficiency coding called PASC method and recorded on an 8-channel audio track of a magnetic tape. Further, in the DCC, signals such as time information and music number information are recorded on a 1-channel auxiliary track of the magnetic tape.

FIG. 2 shows a head assembly (27) equipped in the DCC, which corresponds to one side area of the magnetic tape (22) in the width direction and has a recording thin film multi-head (6) and a channel (9) each. Reproducing thin film multi-heads (7) are arranged. The recording thin film multi-head (6) has an auxiliary head chip (23) at the uppermost stage and eight audio head chips (24) at the lower stage, and the reproducing thin film multi-head (7) is
The auxiliary head chip (25) is provided at the top and the eight audio head chips (26) are provided at the bottom.

Further, the head assembly (27) is equipped with a pair of head chips (28) and (29) for reproducing analog signals, corresponding to the other side area of the magnetic tape (22). By reversing the head assembly (27) 180 degrees,
It is possible to record and reproduce data on both sides A and B of the magnetic tape (22).

By the way, in the DCC standard, subcodes such as a marker ID, a sector marker, and a future marker are defined as additional information in addition to time information and music number information. There are a label ID indicating a part, a sector marker ID indicating a program area, etc., a sector marker includes a reverse marker, a next marker, a home marker, a stop marker, a use again marker, etc., and a future marker includes a skip marker, There are mute markers and fade markers.

The user can realize various recording and reproducing operations by recording these markers and IDs on the magnetic tape.

[0007]

However, at present, it is premised that the user manually records various markers and IDs, so that the user is familiar with the functions of various markers and IDs. The recording operation must be performed in a timely manner to record the desired marker or ID. This is extremely complicated and difficult for general users.

On the other hand, in the conventional analog audio tape recorder, when an audio signal reproduced from another audio device such as a CD or DAT is dubbed and recorded on a magnetic tape, as shown in FIG. The recording level is gradually lowered (attenuation). As a result, during signal reproduction, the reproduction level automatically decreases to zero when the tape approaches the end.

In the case of realizing such a fade-out operation, in the conventional audio tape recorder, at the time of signal recording, the remaining tape amount is measured by a rotation period detecting sensor provided coaxially with the tape take-up reel, and the tape remaining amount is measured. The attenuating process was started when the amount became a certain value or less.

However, in this method, an error is unavoidable in the measurement of the tape remaining amount by the rotation cycle detection sensor, and as a result, the tape position (point B) where the reproduction level becomes zero as shown in FIG. May shift forward. As a result, for example, during the auto-reverse operation, the silent reproduction state E during the transition from the A side to the B side becomes long, and the user feels uncomfortable.

On the other hand, in the DCC, the fade-out operation can be realized by using the above-mentioned fade marker, but the recording position of the marker must be determined by the user and the recording operation must be performed as described above. , The same problem as the conventional audio tape recorder remains.

It is an object of the present invention to provide a fade-out system in a DCC system which can realize an accurate fade-out operation without requiring a user's judgment or operation.

[0013]

A fade-out method in a DCC system according to the present invention is used when recording an audio signal supplied from an external audio device on a tape.
First, the audio signal is recorded to the end of the tape without applying attenuation, and then the tape is rewound from the end by the tape length corresponding to the time t required to change the attenuation level of the audio signal from the minimum value to the maximum value. Record a fade marker at the rewound tape position.

[0014]

The time t required to change the attenuation level from the minimum value to the maximum value is known in advance, and the tape length corresponding to the time t is, for example, from the frequency generator attached to the capstan motor. Accurate measurement can be performed by counting the pulses, and tape rewinding control based on the measurement can be easily performed by a microcomputer or the like.

The operation of automatically recording the fade marker at the tape position rewound by the length of the tape can be easily realized by a microcomputer or the like.

When the DCC recorded by the fade-out method is reproduced, when the fade marker is detected, the attenuation level changes from the minimum value to the maximum value from that point, and the signal reproduction level gradually decreases to the final value. The reproduction level becomes the lowest, and the tape reaches the end.

[0017]

According to the fade-out method in the DCC system of the present invention, an accurate fade-out operation can be realized without requiring the user's judgment and operation, and the silent reproduction state during the auto-reverse operation is avoided. You can do it.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. First, the circuit configuration of the DCC system will be described with reference to FIG.

Information signals such as audio signals are input terminals.
The signal is input from (1) to the A / D conversion circuit (2) and converted into a digital signal. The digital signal is supplied to a well-known PASC processing circuit (3), and is subjected to data compression and high efficiency encoding.

The digital signal output from the PASC processing circuit (3) is input to the digital signal processing (4) to be interleaved, added with an error correction code, and further added with a subcode, and then a recording amplifier ( After 5), a recording signal for 9 channels is sent to the recording thin film multi-head (6). Then, the recording thin film multi-head (6) records a signal on the magnetic tape (22).

The 9-channel signal reproduced from the magnetic tape (22) by the reproducing thin film multi-head (7) is supplied to the equalizer circuit (9) through the reproducing amplifier (8) and subjected to waveform equalization. , A PLL clock for data extraction is generated.

The output of the equalizer circuit (9) is sent to the digital signal processing circuit (10) and subjected to processing such as error correction. The processed signal is further supplied to the PASC processing circuit (11), and the original digital signal is obtained after time axis expansion and decoding.

The digital signal is converted into an analog signal through the D / A conversion circuit (12) and output from the output terminal (13) to the subsequent circuit.

The DCC magnetic tape (22) is a reel motor.
(14) and (17) perform winding and rewinding, and the capstan motors (15) and (16) convey the tape. The rotation of the capstan motor (15) (16)
It is controlled by the motor control circuit (18).

A control circuit for controlling the entire system
(19) is equipped with the motor control circuit according to the information from the key input terminal (20) and mechanical switch input terminal (21).
Control signals are issued to mechanisms such as (18), reel motors (14) and (17), and the tape running system.

Furthermore, a code generation / decoding circuit (30) for generating and decoding subcodes such as various markers and IDs is provided, and a subcode is created according to data exchange with the control circuit (19). It is sent to the digital signal processing circuit (4) or the subcode from the digital signal processing circuit (10) is decoded.

Here, the control circuit (19) and the code generation / decoding circuit (30) are not limited to dedicated hardware but can be configured by a microcomputer.

FIG. 3 shows the structure of main data recorded on 8 tracks of the magnetic tape. One tape frame is composed of 32 data blocks and an inter-frame gap.
(IFG). The tape block has a header (3
Individual symbols) and a body (48 symbols), and one symbol has 10 bits. Also, one header is divided into a synchronization pattern, a frame address and a block address (previously “Nikkei Electronics”).

Further, FIG. 4 shows the data structure of the subcode recorded on the auxiliary track. In order to suppress errors, the bit rate is reduced to 1/8 of that of the main data. Here, the above-mentioned various markers and IDs are recorded in the body of each tape block.

When the recording mode is set according to the operation key signals and the mechanism detection signals of the operation input terminals (20) and (21) at the time of recording , the recording on the A side is performed under the control of the control circuit (19). At times, the tape (22) runs in the forward direction at the normal 1x speed of the standard mode, and the recording thin film multihead
(6) scans the upper half of the tape (22). On the other hand, at the time of recording on the B side, the magnetic tape (22) runs in the reverse direction at the reverse speed of the standard mode in the opposite direction, the head assembly is reversed, and the recording thin film multi-head (6) is placed under the tape (22). Scan half.

At this time, for the digital signal processing circuit (4), the subcode generated by the code generation / decoding circuit (30), that is, various IDs and markers such as LABEL indicating the beginning of each song, and time information. , The track number, etc., and the error correction code is added to the subcode information,
It is supplied to the recording thin film multi-head (6) via (5) and recorded on the auxiliary track of the magnetic tape (22).

FIG. 5 shows a procedure for dubbing and recording an audio signal reproduced by another audio device such as a CD or DAT on the A side of the tape. Incidentally, B
Similar dubbing recording is possible on the surface.

First, the audio signal is recorded up to the end of the tape without applying attenuation (attenuation processing). Thereafter, the capstan motor (15) or (16) is reversed to rewind the tape from the end by the tape length corresponding to the time t required to change the attenuation level for the audio signal from the minimum value to the maximum value.

At this time, the rewinding amount of the tape is measured by counting the pulses from the frequency generator (not shown) attached to the capstan motors (15) and (16). The fade marker is recorded on the auxiliary track of the tape when the tape rewind amount reaches the tape length corresponding to the time t required to increase the attenuation level from the minimum value to the maximum value.

Operation at the time of reproduction When reproducing the side A of the magnetic tape on which the audio signal and the fade marker are recorded in this way, as shown in FIG. 6, the attenuation is started from the time when the fade marker is detected (point A). The level increases from the minimum value to the maximum value, the signal reproduction level gradually decreases, and the signal level becomes zero at the tape end position.

The operation of increasing the attenuation level from the minimum value to the maximum value based on the detection of the fade marker can be easily performed by gain adjustment by digital signal processing, for example.

Therefore, even in the automatic reverse operation in which the B side is reproduced after the A side is reproduced, the silent reproduction state is avoided, and the user does not feel uncomfortable.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a DCC system according to the present invention.

FIG. 2 is a perspective view of a head assembly mounted on the DCC.

FIG. 3 is a diagram illustrating a data structure of main data.

FIG. 4 is a diagram illustrating a data structure of sub data.

FIG. 5 is a flowchart showing a fade-out method of the present invention.

FIG. 6 is a diagram for explaining changes in recording level and reproduction level in the present invention.

FIG. 7 is a diagram for explaining a defect of a conventional recording level change and fade-out operation.

[Explanation of symbols]

 (22) Magnetic tape (6) Recording thin film multi-head (7) Reproducing thin film multi-head (30) Code generation / decoding circuit

Claims (1)

[Claims] 1. A sub-code is recorded on one auxiliary track of a plurality of tracks extending in the longitudinal direction of a signal recording tape, and an audio signal is recorded on the other plurality of audio tracks. In a DCC (Digital Compact Cassette) system equipped with a multi-channel head, when recording an audio signal supplied from an external audio device on a tape, first the audio signal is recorded to the end of the tape without applying attenuation, and then the audio signal is recorded. The tape is rewound from the end by a tape length corresponding to the time t required to change the attenuation level for the signal from the minimum value to the maximum value, and a fade marker is recorded at the rewound tape position. The attenuation level must be the minimum value from the time when the fade marker is detected. Fade-out method in DCC system and changing to the maximum value.