JPS61185798A - Sound interval controller - Google Patents

Abstract

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

Description

TECHNICAL FIELD The present invention relates to a pitch control device, and more particularly to a pitch control device that controls the pitch between an original sound and a reproduced sound by changing the frequency of an audio signal.

LLL Conventionally, in this type of device, as shown in Fig. 1, an audio signal input from an input terminal 1 is subjected to pitch control by changing its frequency in a pitch control circuit 2, and then outputted to an output terminal. It was output via 3. That is, if the frequency of the input signal is f, an output signal with a frequency of 1 (-f is obtained at the output terminal of the pitch control circuit 2. For example, if the input signal of 440H2 is raised by a semitone, K = 1 .06, so 466.2Hz
This results in an output signal of .

In conventional pitch control devices configured in this way, the output signal is a form in which the frequency band of the input signal is shifted as is, so when the pitch is changed significantly, the balance of the sound is lost in terms of frequency distribution. There was a drawback. In other words, if the original sound has a frequency component of 100H2 to 10Kl-1z, if this signal is doubled, the frequency component of the output signal will be 200Hz to 20KHz, and this output signal cannot be heard as it is as a playback output. This results in a lack of bass. Also, 1z2
If it is doubled, the frequency components will be from 50Hz to 5KH2, resulting in a lack of treble.

The present invention has been made in order to eliminate the drawbacks of the conventional devices as described above, and an object of the present invention is to provide a pitch control device that can control pitch while maintaining an appropriate balance of sound in terms of frequency. Purpose and fru.

The pitch control device according to the present invention compensates for the frequency band that is insufficient when the pitch is controlled by superimposing a harmonic of a high frequency component or a subharmonic of a low frequency component of the pitch-controlled output signal. The structure is as follows.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention.

In the figure, in the pitch control circuit 2, the frequency of the input signal is doubled or doubled (1≦to≦oo), as in the conventional example.
), the pitch is controlled. As this pitch control circuit 2, for example, the one proposed in Japanese Patent Application No. 59-30996 by the applicant of the present invention may be used. The output signal of this pitch control circuit 2 becomes one input of an adder 4, and also serves as an input to an HPF (bypass filter) 5 and an LPF.
It is supplied to a harmonic generation circuit 7 and a subharmonic generation circuit 8 via a (low-pass filter) 6. The HPF 5 extracts the high frequency component of the output signal of the pitch control circuit 2 and supplies it to the next stage harmonic generation circuit 7. The LPF 6 extracts the low frequency component of the output signal and supplies it to the next stage harmonic generation circuit 7. This is for supplying the circuit 8.

The harmonic generation circuit 7 is for generating harmonics that are 2n times (n=1 to oo) the high frequency component extracted by the HPF 5, and is configured by, for example, connecting a plurality of multipliers in series. Ru. In addition, the subharmonic generation circuit 8 is LP
1/2m times the low frequency component extracted by F6 (m-1
~oo), and is constructed by, for example, connecting a plurality of 1/2 frequency dividers in series. One of the output signals of the harmonic generation circuit 7 and the subharmonic generation circuit 8 is selected by a selection switch 9, and becomes the other input of the adder 4. The selection switch 9 is activated by a control signal issued from the controller in the pitch control circuit 2 in response to a command to raise or lower the pitch, and the selection switch 9 is switched to the subharmonic generation circuit 8 side when raising the pitch, and to the harmonic generation circuit when lowering the pitch. Normally, switching control is performed to the 7 side. Note that the selection switch 9 may be directly switched and controlled by a command signal supplied to the pitch control circuit 2 from the outside to indicate whether to raise or lower the pitch. In the adder 4, the harmonic signal or subharmonic signal selected by the selection switch 9 is superimposed on the output signal of the pitch control circuit 2.

Next, the operation of the pitch control device according to the present invention will be explained.

First, assume that the original sound has frequency components of 100H7 to 10KH2, and consider a case where the pitch is doubled.

At this time, the selection switch 9 has been switched to the subharmonic generation circuit 8 side. By doubling the pitch, the output signal of the pitch control circuit 2 will have a frequency component of 200 Hz to 20 KHz. If this output signal is used as a playback output as it is, the bass range will be insufficient. However, in the present invention, the low frequency component of the output signal of the pitch control circuit 2 is
The subharmonics extracted by F6 are obtained by a subharmonic generation circuit 8, and are superimposed on the output signal of the pitch control circuit 2 by an adder 4, thereby correcting the insufficient frequency band. This makes it possible to reproduce frequency-balanced sound.

In addition, when increasing the pitch by 1/2, the pitch control circuit 2
The output signal has frequency components of 50H7 to 5KI-12, and the high frequency range is insufficient, so the HPF 5 and harmonic generation circuit 7 generate harmonic components of 5KH2 or higher and output the output signal of the pitch control circuit 2. By correcting the missing band due to overlapping, it is possible to reproduce frequency-balanced sound.

In the above embodiment, signal processing for frequency band correction was performed at the analog signal stage, but as shown in FIG. 3, it is also possible to perform signal processing at the digital signal stage. In FIG. 3, the pitch control circuit 20 is
An A/D converter 10 that converts an analog audio signal input through an input terminal 1 into a digital signal, a controller 11 that generates various control timing signals, address signals, etc., and a write address from this controller 11. R that stores digital signals according to the read address and outputs two different stored data according to the read address.
AM (random access memory) 12 and RAM 12
The RAM
RAM1 for writing speed of digital signal to 12
The device is configured to control the pitch between the original sound and the reproduced sound by changing the readout speed for reading out the digital signal from the audio signal, that is, by changing the frequency of the audio signal.

The output signal of the pitch control circuit 20 is sent to the digital filter 14.
becomes one input of the adder 15 via the RAM1
6. The RAM 16 controls the pitch by storing and reading digital signals according to the address signal from the controller 11, and the pitch control circuit 2
By controlling the pitch at 0, a signal is generated to compensate for the insufficient band. 2 of different addresses from RAM16
These two data are cross-faded by a cross fader 17, and the output thereof is passed through a digital filter 18 and becomes the other input of the adder 15, which then passes through the digital filter 14 to the pitch control circuit 20. is added to the output signal of The output of the adder 15 is converted into an analog audio signal by a D/A converter 19 and becomes a playback output.

According to this configuration, there is no need to separately provide the harmonic generation circuit 7 and the subharmonic generation circuit 8 as in the embodiment shown in FIG. 2, and the pitch controller has the same configuration as the original pitch control circuit 20. (consisting of RAM 16 and crossfader 17) can produce the effects of the present invention. Further, by configuring the two systems of pitch controllers, adders, etc. as one digital IC, it is possible to reduce costs.

As described in detail, the pitch control device according to the present invention generates harmonics of high frequency components or subharmonics of low frequency components of a signal after pitch control, and adjusts the harmonics according to the direction of pitch change. Alternatively, by superimposing subharmonic waves, the missing frequency band is corrected by pitch control, so that it is possible to control the pitch while appropriately maintaining the balance of the sound in terms of frequency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional example, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. Explanation of symbols of main parts 2.20... Pitch control circuit 4.15... Adder 7... Harmonic generation circuit 8... Subharmonic generation Circuit 9... Selection switch 12.16... RAM

Claims (1)

[Claims] pitch control means for controlling the pitch between the original sound and the reproduced sound by changing the frequency of the audio signal; and a generator for generating harmonics of high frequency components or subharmonics of the low frequency components of the output signal of the pitch control means. A pitch control device comprising: means for superimposing the output signal of the generating means on the output signal of the pitch control means.