JPH11109990A - Interval converting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To nearly simultaneously output sound signals of plural intervals answering to input sound signals by containing at least the sound signal interval converted with an interval conversion circuit, selecting any one from plural sound signals with different intervals and outputting it. SOLUTION: An interval switch circuit 21 connects an output terminal of an A/D converter 13 and the output terminal of an interval conversion circuit 14 to two input terminals, and connects its output terminal to a D/A converter 15 for selectively selecting/outputting these output signals. Further, a switch time control circuit 22 controls a time interval that the interval switch circuit 21 switches the selection between two output signals according to the signal supplied to a Time input pin. In such a case, the interval switch circuit 21 selects alternately the outputs of the A/D converter 13 and interval conversion circuit 14 at the time ratio of 1 to 1 of the time specified by the switch time control circuit 22 to supply it to the D/A converter 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pitch converter, and more particularly, to a pitch converter suitable for mounting on a karaoke machine or a toy as a voice LSI.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional audio LSI for pitch conversion. In FIG. 2, UP, DW, and R of the audio LSI 10 are shown.
Each pin of ST is connected to the control circuit 11, and a low-pass filter (LP) is connected to an analog audio signal input pin AIN.
F) 12, an A / D converter (ADC) 13, and a pitch conversion circuit 14 are sequentially connected.

The output terminal of the pitch conversion circuit 14 has a D / A
Converter (DAC) 15, low-pass filter (LP)
F) 16, the analog audio signal output pin AOUT is sequentially connected. The LPF 12 is provided prior to A / D conversion by the A / D converter 13 to remove high-frequency noise exceeding the voice band. LPF16 is D / A
The converter 15 is provided to smooth the signal after the D / A conversion by the converter 15 and to remove high-frequency noise generated by the D / A conversion.

The two XT pins are used to connect an external crystal oscillator to an oscillation circuit 17 that provides a clock required for each of the above circuits.

The VDD pin is connected to all the circuits 11 to 17 to supply external power to the circuits 11 to 17 (depending on the configuration, it is unnecessary for the LPFs 15 and 16), and the GND pin is also connected to these circuits 11 to 17 with the ground potential. Are connected to all the circuits 11 to 17 in order to provide

According to the audio LSI 10 described above, A
While the pitch conversion circuit 14 converts the pitch of the voice signal input to the IN pin to a pitch one step higher than the pitch of the output voice signal by supplying a signal to the UP pin, the DW
By supplying a signal to the pin, the signal is converted into a pitch one step lower than the pitch of the output audio signal up to that point, and can be output from the AOUT pin as an audio signal having a desired pitch. Note that R
Depending on the signal supplied to the ST pin, the pitch of the audio signal input to the AIN pin is returned to a state where the pitch conversion circuit 14 does not convert the pitch.

Here, the pitch conversion circuit 14 has a general configuration for performing a process of converting the frequency of the pitch related to the audio signal at that time into the frequency corresponding to the converted pitch. Is omitted.

[0008]

However, there is a problem that the above-mentioned voice LSI (pitch conversion device) 10 cannot output two voices having different pitches almost at the same time as it is.

Then, in order to output almost simultaneously,
If the signal supply to the UP pin and the signal supply to the DW pin must be frequently and externally controlled using a microcomputer or the like, the price is increased, and if an attempt is made to respond to the frequent external control, It is necessary to design accordingly, and there is a problem that the design man-hour and the mounting area are greatly increased.

The above-mentioned audio LSI (pitch conversion device)
In order to realize a device (karaoke device or toy) capable of generating two sounds with different pitches using the device 10, it is necessary to mount two sound LSIs 10 in such a device, and the device becomes complicated and large. Let me do it.

[0011]

According to the present invention, there is provided a pitch conversion circuit comprising a pitch conversion circuit for converting a pitch of an externally input voice signal in accordance with a pitch control signal and outputting the converted pitch. The apparatus includes a selection unit that selects and outputs any one of a plurality of audio signals having different pitches, including a voice signal that has been pitch-converted by the pitch conversion circuit, and a selection control unit that controls the selection operation. It is characterized by the following.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, taking as an example a case where a pitch conversion device of the present invention is realized by a voice LSI. However, components corresponding to those of FIG. 2 relating to the conventional audio LSI are denoted by the same reference numerals, and detailed description thereof will be omitted.

(A-1) Configuration of the First Embodiment As shown in FIG. 1, an audio LSI 20 according to the first embodiment has an output terminal of an A / D converter 13 and an output terminal of a pitch conversion circuit 14. Is connected to two input terminals, and the output terminal is connected to the D / A converter 15 to select and output these output signals alternatively.
1 and a switching time control circuit 22 for controlling a time interval at which the pitch switching circuit 21 switches the selection between the two output signals in accordance with a signal supplied to a Time (time) input pin.
Is further provided.

As components other than the pitch switching circuit 21 and the switching time control circuit 22, the same components as those of the above-described conventional audio LSI 10 are provided.

(A-2) Operation of the First Embodiment Hereinafter, the audio LSI (pitch conversion device) 2 of the first embodiment
The operation of 0 will be described.

FIG. 3 is a time chart of each part of the audio LSI 20 according to the first embodiment.

If the analog audio signal input from the AIN pin is related to, for example, a human voice, the analog audio signal shown in FIG.
This is a short-term periodic waveform as shown in FIG. In the initial state when the power is turned on, what is output from the AOUT pin is an original sound (an audio signal equal to the input analog audio signal) as shown in FIG.

If the signal input shown in FIG. 3D is input to the UP pin during the input of the audio signal shown in FIG.
By the pitch conversion operation of the pitch conversion circuit 14, FIG.
As shown in the figure, the output waveform of the pitch conversion circuit 14 changes from that point, and the converted pitch becomes higher. Here, for example, for one signal input to the UP pin, the pitch is increased by a semitone.

If there is no new signal input to the UP pin or the DW pin, the audio signal of the pitch is output, for example, as shown in FIG.
Output is continued as shown in FIG.

The pitch of the original sound can be further increased by adding a signal input to the UP pin, and can be lowered by adding a signal input to the DW pin. For example, for one signal input to the DW pin, the pitch is lowered by a semitone.

Even when the power is not turned on, R
When a signal is input to the ST pin, the pitch shown in FIG. 2B obtained by raising (or lowering) the signal by inputting the signal to the UP pin and the DW pin is reset to the initial state, that is, the original sound is changed to the pitch. The state returns to the state where the conversion circuit 14 allows the signal to pass through. An active level pulse signal is supplied to the RST pin even when the power supply is turned on to the system including the audio LSI 20, so that a power-on reset is performed.

The pitch switching circuit 21 includes a switching time control circuit 2
The output of the AD converter 13 and the output of the pitch conversion circuit 14 are alternately selected at a one-to-one time ratio of the time designated by 2 and supplied to the DA converter 15.

That is, when the signal input shown in FIG. 3G is applied to the Time pin, the time specified by the switching time control circuit 22 becomes shorter as shown in FIG. . That is, the switching interval between the two audio signals, which is approximately two cycles in FIG. 7H, becomes approximately 1 by the pulse of FIG.
It is a periodic interval.

When the time reaches the predetermined minimum limit, the time returns to the maximum limit again, and is shortened by a signal input to the Time pin. The maximum and minimum limits are determined in consideration of the human audible range. The switching interval changed by the signal input to the Time pin is also reset by the signal input to the RST pin, and the switching interval returns to the initial value, that is, the longest limit. Note that the longest limit is equivalent to, for example, infinity, and indicates a continuous output state of the original sound.

Therefore, while listening to the sound output from a speaker (not shown) or the like in response to the sound signal output from AOUT, for example, U
Only by appropriately inputting signals to the P, DW, and Time pins, the original sound shown in FIG.
A desired sound obtained by appropriately mixing the converted sound of (B) can be output.

(A-3) Effects of the First Embodiment As described above, according to the first embodiment, the original sound before the pitch conversion and the audio signal after the pitch conversion are alternately output, and the output sound is output. Can be changed by a signal input to the Time input terminal, so that a variety of sounds can be output without the assistance of an advanced control device such as a microcomputer. For example, high-speed pitch switching, which is difficult for humans to utter, can be performed, and this apparatus can output a voice effective for karaoke and a yodel voice requiring skill as shown in the example of FIG. 3C.

Further, by making the switching interval of the pitches as short as possible by the switching time control circuit, there is also an effect that two voices which are not strictly output at the same time are sensed as if they were being output simultaneously. Homy of Mongolian folk music is also possible.

(B) Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings, taking as an example a case where the pitch conversion device of the present invention is realized by a voice LSI. However, in the configuration of the present embodiment, like the first embodiment, the same reference numerals are given to the portions corresponding to the already described components of FIG. 2 and the detailed description thereof is omitted.

(B-1) Configuration of the Second Embodiment As shown in FIG. 4, a voice LS according to the second embodiment
In order to output two pitches at a pitch interval corresponding to an input signal to the CORD pin from the pitch conversion circuit 14 for converting an original sound into three or more pitches, I30
A pitch switching stage control circuit 31 having an output terminal connected to the control terminal of No. 4 is provided.

The difference from the first embodiment is that the pitch conversion circuit 14 has a function of simultaneously converting an original sound (input voice signal) into three or more pitches (for example, in a chord relation). The configuration of the pitch conversion circuit 14 for simultaneously converting into three or more pitches may be the same as the configuration provided with a plurality of pitch conversion circuits in the related art and the first embodiment.

Further, unlike the first embodiment, the pitch switching circuit 21 is not provided.

(B-2) Operation of the Second Embodiment Hereinafter, the audio LSI (pitch conversion device) 3 of the second embodiment will be described.
The operation of 0 will be described.

The three or more types of pitches generated in the pitch conversion circuit 14 rise when a signal is input to the UP pin and fall when a signal is input to the DW pin, while substantially maintaining the interval between the pitches. Then, the signal returns to the initial state, that is, the intermediate level between the rising and falling, by the signal input to the RST pin.

On the other hand, when there is a signal input to the CORD pin, the pitch switching stage control circuit 31 outputs two or more pitches from the three or more pitches.
By selecting one of these pitches, the two
The pitch conversion circuit 14 alternately outputs the signals at time intervals according to the input to the me pin.

(B-3) Effects of the Second Embodiment As described above, according to the second embodiment, the pitch of the converted pitch rises and falls, and the time of the converted pitch that is output alternately. In addition to changing the interval, two types of pitches after pitch conversion can be freely selected, so that even more varied voices can be output without the support of advanced control devices such as microcomputers. For example, even a single speaker can enjoy the chorus.

(C) Other Embodiments In the above-described first and second embodiments, two types of voices are output alternately at equal time intervals.
Three or more types of voices may be output sequentially or at different time intervals, for example, 2: 1 or 3: 2: 1. Further, the pitch conversion device does not necessarily need to be configured by an integrated circuit such as an LSI.

Although the first and second embodiments are digital circuits, for example, the pitch conversion circuit 14 is constituted by a plurality of analog active filters connected in parallel.
, Or an analog circuit.

[0038]

As described above, according to the present invention, it is possible to output audio signals of a plurality of pitches corresponding to an input audio signal almost simultaneously without external control by an advanced control device such as a microcomputer. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a voice LSI (pitch conversion device) according to a first embodiment.

FIG. 2 is a block diagram showing an outline of a conventional audio LSI (pitch conversion device).

FIG. 3 is a time chart of each unit according to the first embodiment.

FIG. 4 is a block diagram illustrating an overview of a voice LSI (pitch conversion device) according to a second embodiment.

[Explanation of symbols]

20, 30: voice LSI (pitch conversion device), 11: control circuit, 14: pitch conversion circuit, 21: pitch switching circuit, 22
... Switching time control circuit, 31.

Claims (6)

[Claims] 1. The pitch of an audio signal input from the outside,
A pitch conversion device provided with a pitch conversion circuit that converts and outputs a pitch in accordance with a pitch control signal, including at least a voice signal whose pitch has been converted by the pitch conversion circuit, and selects any one of a plurality of voice signals having different pitches. A pitch conversion device, comprising: selection means for outputting the selected output; and selection control means for controlling the selection operation. 2. The pitch conversion device according to claim 1, wherein said selection means selects and outputs an audio signal whose pitch has been converted by said pitch conversion circuit or an audio signal before pitch conversion. Pitch converter. 3. The pitch conversion device according to claim 1, wherein the pitch conversion circuit converts a pitch of the audio signal input from the outside into a plurality of pitches belonging to a first pitch group having a predetermined pitch relationship. The selecting means selects the second pitch group selected from the first pitch group.
A pitch conversion device for outputting a further selected pitch from the pitch group. 4. The pitch converter according to claim 3, wherein the second pitch group is two pitches. 5. The pitch conversion device according to claim 1, wherein said selection control means controls said selection means so as to equalize a time ratio between output pitches. Pitch converter. 6. The pitch conversion device according to claim 1, wherein said pitch conversion device is constituted by a single integrated circuit.