JPH0430108B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a DAD (Digital Audio Disk) or
The present invention relates to a digital audio signal reproducing device that reads and reproduces digital audio signals from a medium such as a DAT (Digital Audio Tape).

When reproducing audio signals recorded on a DAD or DAT, the dynamic range of the reproduced audio signal is wider than that of conventional analog records. For this reason, when playing back, there was a drawback that it was difficult to hear parts of the recording at a low level when using it in a noisy place such as in a car or when playing background music (BGM) at a low volume.

This invention was made in view of the above points,
Using a medium such as DAD or DAT that records the amplitude information of the recorded audio signal including the control signal, the amplitude information is extracted from the demodulated signal read from this recording medium and decoded. It is an object of the present invention to provide a digital audio signal reproducing device that can reduce the dynamic range of reproduced sound by controlling the amplitude of an output audio signal using an amplitude information signal.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1 is a disk on which digital audio signals and control signals including amplitude information are recorded, 2 is a motor that rotates the disk 1, and 3 is a motor that rotates the disk 1. A pick-up that reads the signal recorded on disk 1; 4 a demodulation circuit that demodulates the signal read by pick-up 3; and 5 a signal separator that separates and extracts a digital audio signal and a control signal from this demodulated signal. 6 is an audio signal decoding circuit that decodes a digital audio signal, 7 is a digital-to-analog conversion circuit, 8 is an output variable circuit such as a voltage-controlled variable gain amplifier, and 9 is an amplitude of the control signal output from the signal separation circuit 5. An amplitude information decoding circuit decodes information; 10 is an output level control circuit that controls the variable output circuit 8 according to the output from the amplitude information decoding circuit 9; and 11 is an audio signal output terminal.

Next, its operation will be explained. A motor 2 rotates the disk 1, and a pickup 3 reads the signal recorded on the disk 1. On disk 1, for example, in the format shown in Figure 2, a signal is recorded in which a signal block in which a synchronization pattern is added to a multiplexed signal of a coded control signal and an audio signal is continuously modulated. . The signal read by the pickup 3 is demodulated by the demodulation circuit 4 to reproduce the signal as shown in FIG. The signal separation circuit 5 separates the audio signal and the control signal by detecting a signal block with a synchronization pattern, and outputs the audio signal to the audio signal decoding circuit 6 and the control signal to the amplitude information decoding circuit 9. . The digital audio signal decoded by the audio signal decoding circuit 6 and subjected to error correction is converted into an analog audio signal by the digital-to-analog conversion circuit 7. The amplitude information decoding circuit 6 decodes the amplitude information of the control signal and outputs the reproduced amplitude information signal 12 to the output level control circuit 10. Output level control circuit 1
0 controls the output variable circuit 8 in accordance with this amplitude information signal 12 to vary the level of the audio signal output to the output terminal 11. Output variable circuit 8
is composed of a voltage-controlled variable gain amplifier whose gain is changed in proportion to the control voltage 13. Reproduction amplitude information signal 12 inputted to the output level control circuit 10 and control voltage 13 outputted to the output variable circuit 8
If the output level control circuit 10 is configured with, for example, a low-pass filter and an analog arithmetic circuit so that the relationship between the , when the amplitude information level is small, the gain of the variable output circuit 8 is controlled to be increased. Therefore, if the delay of the audio signal in the audio signal decoding circuit 6 and the digital-to-analog conversion circuit 7 is made to match the delay and control response time of the amplitude information signal in the amplitude information decoding circuit 9 and the output level control circuit 10, the audio The output level of the signal is controlled by the amplitude information, and a reproduced audio signal with a reduced dynamic range is obtained at the output terminal 11.

In the above embodiment, an example is shown for a DAD playback device, but the present invention may be applied to other digital audio signal playback devices, such as a DAT playback device, in which the control signal and the audio signal are recorded on separate tracks. may be done. Further, in the above embodiment, the amplitude information is converted into an analog signal to control the output of the analog audio signal, but the output control of the analog audio signal may be performed using a reproduced digital signal of the amplitude information.

As described above, according to the present invention, a digital audio recording medium in which amplitude information of a recorded audio signal is included in a control signal and recorded is used, and a signal obtained by reproducing the amplitude information is used to generate a reproduced audio signal. The dynamic range can be reduced by controlling the output level of the
This has an excellent effect in that an easy-to-listen reproduced sound can be obtained at a low recording level when playing back at a low volume.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing an example of a digital recording format of control signals and audio signals recorded in a recording medium, and FIG. 3 is a diagram showing an example of a digital recording format of control signals and audio signals recorded in a recording medium. FIG. 3 is a diagram showing the relationship between amplitude information and control voltage of the output variable device for explaining the operation. In the figure, 1 is a recording medium such as a disk, 3 is a pickup, 4 is a demodulation circuit, 5 is a signal separation circuit,
6 is an audio signal decoding circuit, 7 is a digital-to-analog conversion circuit, 8 is an output variable device, 9 is an amplitude information decoding circuit, 10 is an output level control circuit, 11 is an audio signal output terminal, 12 is a reproduced amplitude information signal, 13 is a This is the output variable circuit control voltage.

Claims (1)

[Claims] 1. A recording medium on which a digital audio signal and a control signal including amplitude information of the audio signal are recorded, means for reading out the recorded signal from this recording medium, and means for demodulating the signal read out by the reading means. , means for separating the demodulated signal into a digital audio signal and a control signal, means for extracting amplitude information from the separated control signal to obtain a signal corresponding to the amplitude of the audio signal, and a means for extracting amplitude information from the separated control signal to obtain a signal corresponding to the amplitude of the audio signal. and means for controlling the amplitude of an output audio signal.