JPS6028074A - Digital audio signal reproducer - Google Patents

Abstract

PURPOSE:To reduce the dynamic range of a reproduced sound by extracting an amplitude information signal out of the signal which is read out of a recording medium and demodulated and controlling the output level of an analog audio signal. CONSTITUTION:The signal read by a pickup 3 is demodulated by a demodulating circuit 4, and the audio signal and the control signal are delivered to an audio signal decoding circuit 6 and an amplitude information decoding circuit 9 respectively via a signal separating circuit 5. Then the amplitude information is decoded by the circuit 9, and a reproduced amplitude information signal 12 is delivered to an output level control circuit 10. The circuit 10 controls an output variable circuit 8 in response to the signal 12 to change the level of the audio signal develiverd to a terminal 11. Therefore the output level of the audio signal is controlled by the amplitude information after obtaining the coincidence between the delay of the audio signal and the delay, etc. of the amplitude information signal. Thus the dynamic range of a reproduced sound can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a DAD (Digital Audio Di
sk) and DAT (Digital Auclio
The present invention relates to a digital audio signal reproducing device that reads and reproduces digital audio signals from media such as tape.

DAD-? When reproducing an audio signal recorded on a DAT or the like, the dynamic range of the reproduced audio signal is wider than that of a conventional analog record. For this reason, when playing, please do not use it in a noisy place such as inside a car, or use it in a noisy place such as inside a car.
(Background Music) etc. When playing back at a low volume, the low recording level parts were often difficult to listen to.

This invention was made in view of the above points, and DAD-?
Using a medium such as 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, and the decoded amplitude is 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 cutting level of an analog audio signal obtained by decoding analog conversion from a demodulated signal using an 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, and FIG. 2 shows a digital audio signal and
A disk on which control signals including amplitude information are recorded (
2) is a motor that rotates the disk (1), (3) is a pickup that reads the signal recorded on the disk (1), (4) is a demodulation circuit that demodulates the signal read by the backup (3), (5) is a signal separation circuit that separates and extracts a digital audio signal and a control signal from this demodulated signal, and (6) is an audio signal decoding circuit that signals the digital audio signal.

(7) is a digital-to-analog conversion circuit, (8) is a variable output circuit such as a voltage-controlled variable gain amplifier, and (9) is an amplitude information decoder that decodes amplitude information of the control signal output from the signal separation circuit (5). α1 is an output level control circuit that controls the output variable circuit +1111 according to the output from the amplitude information decoding circuit (9), and Qυ is an audio signal output terminal.

Next, its operation will be explained. The motor (2) rotates the disc (1), and the pickup (3) picks up the disc (1).
Read the signal recorded in 1. On the disk (1), a signal is recorded, for example, in the format shown in Figure 2, a signal obtained by continuously modulating signal blocks in which a synchronization pattern is added to a multiplexed signal of an encoded control signal and an audio signal. ing. The signal read by the pickup (3) is demodulated by the demodulation circuit (4) to reproduce the signal as shown in FIG. In the signal separation circuit (5).

Separate audio signals and control signals by detecting signal blocks with synchronization patterns.

The audio signal is sent to the audio signal decoding circuit (6).

The control signal is output to the amplitude information decoding circuit (9). The digital audio signal decoded and error-corrected by the audio signal decoding circuit (6) is sent to the digital-to-analog conversion circuit (6).
7) to convert it into an analog audio signal.

The amplitude information decoding circuit (6) decodes the amplitude information of the control signal and outputs a reproduced amplitude information signal 0 to the blade level control circuit 0. The output level control circuit Q[I controls the blade variable circuit (8) according to this amplitude information signal α.
The level of the audio signal output to the output terminal (111) is made variable.The output variable circuit (8) is composed of a voltage-controlled variable gain amplifier whose gain can be changed in proportion to the control voltage α. The relationship between the reproduced amplitude information signal aa input to the output level control circuit aQ and the control voltage (I:1) output to the variable blade circuit (8) is set using a low-pass filter, for example, so that the relationship is as shown in FIG. 3A and B. If the output level control circuit (lI) is configured with a non-analog arithmetic circuit, when the level of amplitude information is large, the gain of the blade variable circuit (8) is lowered,
When the amplitude information level is small (1), control is performed to increase the gain of the output variable circuit (8).

Therefore, the audio signal is delayed in the audio signal decoding circuit (6) and the digital-to-analog conversion circuit (7).

Amplitude information decoding port % (9) In order to match the delay and control response time of the amplitude information signal by the output level control circuit a, the output level of the audio signal is controlled by the amplitude information, and the dynamic range is A reproduced audio signal with a reduced value is obtained at output terminal a.

Although the above-mentioned embodiment shows an example of a DAD playback device, the present invention may also be applied to other digital audio signal playback devices 2, such as a DAT playback device, in which control signals and audio signals are recorded on separate tracks. may have been done. Furthermore, in the above embodiment, the amplitude information is converted into an analog signal to output the analog audio signal.

This may be performed using a reproduced digital signal of amplitude information.

As described above, according to the present invention, a digital audio recording medium is used in which the amplitude information of a recorded audio signal is recorded including it in a control signal, and a signal obtained by reproducing the amplitude information is used. The dynamic range can be reduced by controlling the level of the audio signal, so it can be used in noisy places such as cars,
This has an excellent effect in that an easy-to-listen reproduced sound can be obtained in a portion where the recording level is low when reproducing BGM or the like at a low volume.

[Brief explanation of the drawing]

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.
The figure is a diagram showing the relationship between amplitude information and control voltage of the output variable device for detailed explanation of the present invention. In the figure, (11 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 the output variable device, (9) is the amplitude information decoding circuit, α1 is the output level control circuit, αυ is the audio signal output terminal, 2 is the reproduced amplitude information signal, and αhiro is the output change circuit suppressing voltage. Yes. Agent Masuo Oiwa (and 2 others) 1st W4 Tate 211 Figure 3

Claims (1)

[Claims] A recording medium on which a digital audio signal and a control signal including amplitude information of the audio signal are recorded, a pickup for reading out the recorded signal from the recording medium,
Means for demodulating the signal read out by this pickup; means for separating this demodulated signal into a digital audio signal and a control signal; means for decoding this separated digital audio signal and converting it into analog to obtain an analog audio signal; means for extracting amplitude information from the separated control signal and obtaining a signal corresponding to the amplitude of the audio signal;
and means for controlling the output level of the analog audio signal using a signal corresponding to the amplitude.