JPS6252599A - Voice signal processor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to audio signals recorded on tape media such as audio tapes and video tapes, disk media such as video disks and compact disks, or to television or radio signals. The present invention relates to an audio signal processing device that removes or attenuates the sound contained in an audio signal that is broadcasted on a computer.

BACKGROUND ART FIG. 6 shows a block diagram of a conventional audio signal processing device. In Figure 6, 1 and 2 are input terminals, 3 and 4 are time delay circuits, 5 is a phase inversion circuit, 6°7 is an adder, 8 is a low-pass filter (hereinafter abbreviated as LPF), and 9 is an output It is a terminal.

The operation of the audio signal processing device having the above configuration will be explained below.

First, signal S1 input to input terminal 1 and input terminal 2
The signal S2 inputted to is the Lch and Rch signals of a commercially available music source. The signal S1 input to the input terminal 1 is branched into two by the branching means, and one signal is sent to the first
The signal is input to the time delay circuit 3 and becomes a time-delayed signal S3. On the other hand, the signal S2 inputted to the input terminal 2 is branched into two by the branching means, and one signal is inputted to the second time delay circuit 4 to become a time-delayed signal S4. The time delay value of the first time delay circuit 3 and the second time delay circuit 4 can be independently controlled by the clock signal 01 and the clock signal 02, respectively. The signal S4 becomes a signal S6 whose phase is inverted by the phase inversion circuit 5. Further, the other two-branched signal of the signal S1 and the other two-branched signal of the signal S2 are added by an adder 6 to form a signal S6. The signal S6 is L
The PFs results in a signal S7 with many low-frequency components. This LP
The optimal cutoff frequency of Fs is around 1 ooHz. The signal S3, the signal S5, and the signal S7 are added by an adder 7 to form a signal So, which is output to the output terminal 9.

Next, the contents of the operation will be explained using mathematical formulas. It is assumed that the signal S1 input to the 0 input terminal 1 is the L channel of a general ε age source, and the signal S2 input to the input terminal 2.
When it is assumed that S is the R channel of the source and is R, the signal S output to the output terminal is expressed as in equation (1).

S=L (t-tl)-1@R(t-t2)...
(1) Here, (11+) represents a delay by time t1, and 1a7fJ represents the ratio of amplitude control.

To simplify the formula, assuming that the time delay values t1 to t4 are 0 and the amplitude control ratio l-m is 1, the equation (1) can be expressed as the equation (2). It will be done.

S-L (t)-R(t) ・・・・・・・・・
(2) L (t) and R (t) are the L channel and R channel of the commercially available ε Nissic source, so in most sources, the localization of each instrument is the same as that 2.
Since the level difference control between channels is performed, the signal So at a certain time has only two conditions shown in equation (3) and equation (4).

L=R・・・・・・・・・・・・(3) L in R・・・・・・
・・・・・・・・・(4) Then, when equations (3) and (4) are substituted into equation (2), the signal So is shown in equations (6) and (6). There are two conditions.

5o=O・・・・・・・・・・・・(6) So:A,
M=I, -R-...A-(6) In other words, when the relationship between signal S1 and signal S2 satisfies the condition of equation (3), it disappears and the equation (
4) The condition of equation remains.

That is, it is possible to remove or attenuate the sounds contained in commercially available acoustic sources.

Problems to be Solved by the Invention FIG. 6 shows the frequency characteristics of the output signals of each circuit constituting a conventional audio signal processing device. The vertical axis shows the level and the horizontal axis shows the frequency.

The straight line F1 is the signal S1 or the signal S2, or the signal S3 or the signal S4 or the signal S6 when it is assumed that the frequency characteristics of the first or second time delay circuits 3 and 4 are flat from 10 Hz to 20 KH2-1. Shows frequency characteristics. A curve F2 shows the frequency characteristic of the signal So when the signal S3 and the signal S5 are added by the adder 7. Curve F3 is signal S when signal S3, signal S6, and signal S are added by an adder.

shows the frequency characteristics of Straight line F1 in FIG. 6 to input terminals 1 and 2 of the conventional audio signal processing device shown in FIG.
The frequency characteristics of the output signal So of a circuit simply composed of the first time delay circuit 3, the second time delay circuit 4, the phase inverting circuit 6, and the adder 7 are , becomes a curve F2. In this case, although there is an effect of removing or attenuating the sound included in the audio signal, the signal is removed or attenuated in all bands, which is unsatisfactory in terms of the playback band. As a countermeasure, in the conventional audio signal processing device shown in FIG.
A signal S7 is obtained in which only the low frequency band is passed through Fa, and the adder 7 adds the signal S7. The frequency characteristic of the output signal So in that case is shown in a curve F3.

In this case, the cutoff frequency of the LPFs is 100Hz. This is based on the fact that the voice and musical instruments can be separated in the frequency domain since the frequency components of voice do not include frequencies below 100 Hz.

However, in region 2 indicated by the arrow in FIG. 7, the phenomenon of removal or attenuation of musical instruments occurs, and there is still a problem in terms of reproduction band.

In addition, as a method of reducing this region Z, the cutoff frequency of LPF8 is set to a value larger than 100Hz, for example, 2
00Hz, and/・Ipass filter (hereinafter H
When high frequencies are added using a PF (abbreviated as PF), the amount of sound attenuation decreases, resulting in a phenomenon in which the sound becomes audible.

In view of the above problems, the present invention provides an audio signal processing device with a wide playback frequency band by using a conventional audio signal processing device and a frequency conversion circuit that can change the frequency of an output signal with respect to an input signal. be.

Means for Solving the Problems In order to solve the above problems, the present invention provides first and second time delay circuits, and a phase inversion circuit that inverts the phase of the output signal of the second time delay circuit. A first adder that adds the first and second input signals, an LPF that passes only the low frequency of the output signal of the adder, and an output signal of the first time delay circuit and an output signal of the phase inversion circuit. a second adder for adding the output signals of the LPF;
It is composed of a frequency conversion circuit that converts the frequency of the output signal of F, or it is composed of an HPF and a frequency conversion circuit that passes only the high frequency range of the output signal of the audio signal removal means and the first adder.

Effect of the Invention The present invention converts the frequency of a musical instrument in a band that does not include audio using a frequency conversion circuit that converts the frequency of an output signal with respect to an input signal. This has the advantage that it is possible to reproduce sound in a wide reproduction frequency band by converting it into a 200 Hz range, which is the conventional audio frequency range.

Embodiment An audio signal processing apparatus according to the present invention will be explained with reference to FIGS. 1 to 4.

FIG. 1 is a block diagram of an audio signal processing device according to an embodiment of the present invention. In Figure 1, 1 and 2 are input terminals, 9
is the output terminal, 3 and 4 are the first . 2nd time delay circuit, 5 is a phase inversion circuit, 6 and 7 are 1st and 2nd adders, 8 is LPFl
ll is a frequency conversion circuit. Note that the same components as in the conventional example are given the same numbers.

First, the signal S1 input to the input terminal 1 is branched into two by the branching means, one signal is time-delayed by the first time delay circuit 3 and becomes the signal S3, and the other signal is sent to the adder 6.
is input to. On the other hand, the signal S2 inputted to the input terminal 2 is branched into two by the branching means, one signal is time-delayed by the second time delay circuit 4 and becomes the signal S4, and the other signal is sent to the first adder 6. is input. The signal S4 becomes a signal S6 whose phase is inverted by the phase inversion circuit 5.

The output signal S6 of the first adder 6 becomes a signal S7 through which only the low frequency band has passed through the LPF 51. The signal S7 is branched into two by the branching means, and one signal becomes a signal S8 whose frequency is increased by a frequency conversion circuit 11 that converts the frequency of the output signal with respect to the input signal. Signal 83. Signal S6.
The signal S7 and the signal S8 are input to the second adder 7, and the added signal S is obtained.

This is output to the output terminal 9. Incidentally, in FIG. 1, a conventional audio signal processing device 1o is shown surrounded by a broken line.

FIG. 3 shows the frequency characteristics of the output signal in the case of the embodiment of the present invention shown in FIG. 1 as curve G1, and the frequency characteristic of the conventional example as curve G.
It is shown in 2. It is shown that the effect of the frequency conversion circuit 11 improves the low frequency characteristics.

FIG. 2 is a block diagram of an audio signal processing device according to another embodiment of the present invention. In Fig. 2, 1 and 2 are input terminals,
9 is an output terminal, 3 and 4 are first . 2nd time delay circuit, 6 is a phase inversion circuit, 6 and 7 are 1st and 2nd adders, 8 is LPF
, 11 is a frequency conversion circuit, and 12 is an HPF. This embodiment differs from the embodiment shown in FIG. 1 in that the frequency conversion circuit 1
The output signal S6 of the first adder 6 is split into two by a branching means, and one of the signals is inputted to the -HPF 12 to form an output signal S9 in which only the high frequency band has passed. The signal S9 is turned into a signal S10 whose frequency is lowered by the frequency conversion circuit 11.

In FIG. 4, a curve G3 shows the frequency characteristic of the output signal in the case of the other embodiment of the present invention shown in FIG. 2, and a curve G4 shows the frequency characteristic in the case of the conventional example. It is shown that the high frequency characteristics are improved due to the effect of the frequency conversion circuit 11.

Effects of the Invention According to the present invention, it is possible to provide an audio signal processing device that reproduces an output signal having a wide reproduction frequency band by removing or attenuating the audio signal contained in a two-channel ε knee-sick source.

That is, by using the apparatus of the present invention, it is possible to create karaoke sauce from commercially available music sources and enjoy karaoke. Further, the signal to be removed does not need to be an audio signal, and the two channels do not need to be in phase.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an audio signal processing device according to a first embodiment of the present invention, FIG. 2 is a block diagram of the second embodiment, and FIG. 3 is an input/output frequency characteristic of the first embodiment. Figure, 4th
The figure is an input/output frequency characteristic diagram of the second embodiment, Figure 6 is a block diagram of the conventional example, Figure 6 is an input/output frequency characteristic diagram of the conventional example, and Figure 7 explains the problems of the conventional example. It is a frequency characteristic diagram of no use. 1.2...Input terminal, 9...Output terminal, 3,4...Time delay circuit, 6,7...
・Adder, 5... Phase inversion circuit, 8...
・LPF, 12... HPF, 11...
Frequency conversion circuit.

Claims (2)

[Claims] (1) First and second input terminals, a first branching means for branching the input signal of the first input terminal into two, and a second branching means for branching the input signal of the second input terminal into two; , a first time delay means receiving the first output signal of the first branching means; a second time delay means receiving the first output signal of the second branching means; phase inversion means for inverting the phase of the output signal of the second time delay means; and first addition means for adding the second output signal of the first branching means and the second output signal of the second branching means. and a low-pass filter means that receives the output signal of the first addition means as an input, a third branching means that branches the output signal of the low-pass filter means into two, and a first output signal of the third branching means. a frequency conversion means for converting the frequency of an output signal with respect to the input signal; an output signal of the first time delay means; an output signal of the phase inversion means; and a second output of the third branching means. An audio signal processing device comprising second addition means for adding a signal and an output signal of the frequency conversion means. (2) first and second input terminals, a first branching means for branching the input signal of the first input terminal into two, and a second branching means for branching the input signal of the second input terminal into two; , a first time delay means receiving the first output signal of the first branching means; a second time delay means receiving the first output signal of the second branching means; phase inversion means for inverting the phase of the output signal of the second time delay means; and first addition means for adding the second output signal of the first branching means and the second output signal of the second branching means. a third branching means for branching the output signal of the first adding means into two; a low-pass filter means receiving the first output signal of the third branching means; bypass filter means that receives a second output signal as input; and frequency conversion means that converts the frequency of the output signal of the bypass filter means;
an audio signal comprising: second addition means for adding the output signal of the first time delay means, the output signal of the phase inversion means, the output signal of the low-pass filter means, and the output signal of the frequency conversion means; Signal processing device.