JP2663496B2 - Signal interpolator for musical tone signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a musical tone provided with waveform signal generating means for generating first and second waveform signals having different waveforms at the pitch frequencies of musical tones to be generated. The present invention relates to a signal interpolator applied to a signal generating device, and particularly relates to the first waveform signal and the second waveform signal by generating a sounding time lapse, a key touch intensity, a sounding pitch,
A waveform signal that is smoothly changed from the first waveform signal to the second waveform signal according to a change in the tone control element value by interpolating according to a tone control element value such as an operation amount of a tone control operator. The present invention relates to a signal interpolator for a tone signal generating device for outputting a signal.

(Prior Art) Conventionally, this type of interpolator has a mixer for mixing first and second waveform signals having different waveforms output from waveform signal generating means, as shown in Japanese Patent Publication No. 55555/1983. Means for controlling the mixing ratio of the first and second waveform signals in the mixing means so that the first waveform signal gradually decreases and the second waveform signal gradually increases as time elapses from the start of sound generation. Mixing ratio control means for outputting a waveform signal that is smoothly changed from the first waveform signal to the second waveform signal.

(Problems to be Solved by the Invention) However, in the above-described conventional apparatus, during the change from the first waveform signal to the second waveform signal, the first waveform signal and the second waveform signal are simply changed. Because they are only mixed,
The listener hears the musical tone of the timbre relating to the first waveform signal and the musical tone of the timbre relating to the second waveform signal separately, and does not feel that the timbre is smoothly changed in terms of hearing.

The present invention has been devised in view of the above-mentioned hearing problem,
It is an object of the present invention to provide a signal interpolator for a tone signal generating device that makes a change from a first waveform signal to a second waveform signal feel as if the timbre changes smoothly in terms of hearing. Things.

(Means for Solving the Problems) In order to achieve the above object, a feature of the configuration of the present invention is that a first waveform having a different waveform output from a waveform signal generating means at a pitch frequency of a musical tone to be generated. The signal and the second waveform signal are used to determine the elapsed time of sounding, the strength of key touch, the pitch of sounding,
A signal interpolator for a tone signal generator for interpolating in accordance with a tone control element value such as an operation amount of a timbre control operator, a plurality of waveforms belonging to a plurality of different frequency bands for the first and second waveform signals, respectively. Filter means for separating and outputting signals, mixing means for mixing a plurality of waveform signals separated and output from the first and second waveform signals, and a plurality of waveform signals separated and output from the first waveform signal The mixing ratio in the mixing unit and the mixing ratio in the mixing unit for a plurality of waveform signals separated and output from the second waveform signal are determined by changing one of the mixing ratios according to the change in the tone control element value. Mixing ratio control means for controlling such that the mixing ratio gradually decreases and the other mixing ratios gradually increase with different change characteristics.

(Operation of the Invention) In the present invention configured as described above, the filter unit separates the first and second waveform signals into a plurality of waveform signals belonging to a plurality of different frequency bands, and outputs the signals.
The mixing ratio control unit is configured to control each mixing ratio in the mixing unit of the plurality of waveform signals separated and output from the first waveform signal and each mixing ratio in the mixing unit of the plurality of waveform signals separated and output from the second waveform signal. Is controlled so that one of the mixing ratios gradually decreases with different change characteristics and the other of the other mixing ratios gradually increases with different change characteristics in accordance with the change of the tone control element value. The waveform signal mixed and output from the means is gradually changed from the first waveform signal to the second waveform signal according to the change of the tone control element value, and is gradually changed at a different rate for each of a plurality of frequency bands. Will change.

(Effect of the Invention) As a result of acting as described above, according to the present invention, when changing from the first waveform signal to the second waveform signal, the first and second waveform signals are changed.
The waveform signal having the characteristic of the waveform signal and having a slightly different frequency component is mixed according to the change of the tone control element value, and the first waveform signal and the second waveform signal are simply mixed. Therefore, the sense of separation in audibility between the timbre relating to the first waveform signal and the timbre relating to the second waveform signal is reduced. As a result, the output waveform signal becomes the first
The second waveform signal is smoothly changed from the waveform signal to the second waveform signal.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the entirety of a keyboard electronic musical instrument as a tone signal generating apparatus to which a signal compensator according to the present invention is applied.

This keyboard electronic musical instrument includes a key switch circuit 11. The key switch circuit 11 has a plurality of key switches corresponding to each key of the keyboard, and outputs a key code KC representing a key pressed on the keyboard and a key-on signal KON representing the key pressed. An address generator 12 is connected to the key switch circuit 11, and the generator 12 generates an address signal that changes at a rate corresponding to a pitch frequency of a key pressed based on the supplied key code KC. The data is supplied to the memories 13 and 14, and the reading of the memories 13 and 14 is controlled.

Each of the waveform memories 13 and 14 is composed of a plurality of sampling data and stores waveform data representing a musical tone, and the waveform memory 13 stores waveform data containing many high-frequency harmonic components representing the musical tone at the start of sounding. The waveform memory 14 stores waveform data that does not include too many high-frequency harmonic components representing musical tones at the time of continuation of sounding (at the end). In such a case, these waveform memories 13,1
Numeral 4 may store waveform data for one cycle of a musical tone, or may store waveform data for a plurality of cycles.

These waveform memories 13, 14 have low-pass filters 15, 1
6, band pass filters 17, 18 and high pass filters 21, 2
2 are connected in parallel, and the filter groups 15, 17, 2
1 separates and outputs the tone waveform signal represented by the waveform data from the waveform memory 13 into low, middle, and high frequencies, and the filter groups 16, 18, and 22 represent the waveform data from the waveform memory 14. The resulting musical tone waveform signal is separated into a low band, a middle band, and a high band and output. In such a case, the low-pass filter 15
Frequency characteristics of the low-pass filter 16 and the frequency characteristics of the band-pass filter 17 and the band-pass filter 18.
And the frequency characteristics of the high-pass filter 21 and the high-pass filter 22 may be the same or different.

A mixing circuit including multipliers 23, 24, 25 and an adder 26 is connected to the outputs of the filter groups 15, 17, 21. Multiplier 2
3, 24, and 25 multiply the tone waveform signals from the filters 15, 17, and 21 by the interpolation coefficient signals from the interpolation coefficient generators 27, 28, and 31, respectively, and output the result. , 24 and 25 are added and synthesized and output. Interpolation coefficient generator
27, 28 and 31 are 2A according to the lapse of time from the start of musical tone
As shown by a solid line, a broken line, and a dashed line in the figure, an interpolation coefficient signal that gradually decreases at different rates of change is output. A time function generator 32 is connected to the interpolation coefficient generators 27, 28 and 31. The time function generator 32 starts generating a musical tone based on a key-on signal KON supplied from the key switch circuit 11 (keyboard). , And outputs the signal to the interpolation coefficient generators 27, 28, 31 to control the formation of the interpolation coefficient signals of the coefficient generators 27, 28, 31.

In addition, multipliers 33, 34,
A mixing circuit composed of 35 and an adder 36 is connected. The multipliers 33, 34, 35 multiply the tone waveform signals from the filters 16, 18, 22 by the complement signals from the complement generators 37, 38, 41, respectively, and output the result. , 34, 35 are added and synthesized and output. The complement generators 37, 38, 41 are each constituted by an inversion circuit for inverting each bit of each interpolation coefficient signal from each interpolation coefficient generator 27, 28, 31 so-called "one's complement circuit", and each tone is generated. As time elapses from the start, an interpolation coefficient signal that gradually increases at a different rate of change is output as shown by a solid line, a broken line, and a dashed line in FIG. 2B.

An adder 42 is connected to the outputs of the adders 26 and 36, and the adder 42 adds and combines the tone waveform signals from the adders 26 and 36 and outputs the resultant signal. A multiplier 43 is connected to the output of the adder 42, and the multiplier 43 multiplies the tone waveform signal from the adder 42 by an envelope waveform signal from an envelope generator 44 and outputs the result. The envelope generator 44 is a key switch circuit 11
, And forms and outputs an envelope waveform signal representing the amplitude envelope of the musical tone based on the signal KON.

A D / A converter 45 is connected to the output of the multiplier 43,
The converter 45 converts the supplied digital signal into an analog signal and supplies the analog signal to the sound system 46. The sound system 46 includes an amplifier, a speaker, and the like, and emits a musical tone corresponding to the supplied analog signal.

Next, the operation of the embodiment configured as described above will be described. Now, when any key is depressed on the keyboard, the key switch circuit 11 outputs a key code KC and a key-on signal KON in response to the key depression. This key code KC is supplied to the address generator 12, which controls the reading of the waveform data stored in the waveform memories 13, 14 at a rate corresponding to the key pitch frequency of the depressed key. I do. Thereby, tone waveform signals having the pitch frequency are output from the waveform memories 13 and 14, respectively, and the output tone waveform signals are output by the filter groups 15, 17, 21 and the filter groups 16, 18, 22 respectively. Multiplier 2 is separated into low, middle and high
A mixing circuit composed of 3, 24, 25 and an adder 26 and multipliers 33, 34, 3
5 and a mixing circuit comprising an adder 36.

On the other hand, the time function generator 32
Based on the key-on signal KON output from the key-on signal, a signal representing the lapse of time from the key depression is formed to generate an interpolation coefficient generator 27,2.
8 and 31, and the generators 27, 28 and 31 supply the respective interpolation coefficient signals shown in FIG. 2A to the multipliers 23, 24 and 25 according to the supply signal. The low-, middle- and high-frequency components of the tone waveform signal from the waveform memory 13 multiplied by 25 and added and synthesized by the adder 26 have different change characteristics as shown in FIG. It gradually decreases over time. Further, the complement generators 37, 38, 41 are the interpolation coefficient generators.
The interpolation coefficient signals shown in FIG. 2B are supplied to the multipliers 33, 34, 35 in accordance with the interpolation coefficient signals from 27, 28, 31.
The low, middle and high frequency components of the tone waveform signal from the waveform memory 14 multiplied by 4 and 35 and added and synthesized by the adder 36 have different variations as shown in FIG. It gradually increases with time in the characteristics.

Then, the two musical sound waveform signals added and synthesized by the adders 26 and 36 are added and synthesized by the adder 42,
After the amplitude envelope is given by the multiplier 43 and the envelope generator 44, the amplitude envelope is supplied to a sound system 46 via a D / A converter 45, and is generated as a musical sound from the system 46.

As a result of interpolating the respective waveform signals from the waveform memories 13 and 14 with the passage of time in this manner, according to the above-described embodiment,
The musical sounds produced by the sound system 46 are stored in the waveform memory 13.
The tone waveform signal from the waveform memory 14 is gradually changed to the tone waveform signal from the waveform memory 14, and at the time of the change, the tone waveform signals are mixed with different changing characteristics for each frequency band. This allows
At the time of the change, the tone waveform signal from the waveform memory 13 that was previously sounded and the tone waveform signal from the waveform memory 14 that will be sounded in the future are not simply mixed, and have the characteristics of both tone waveform signals. Since the musical sound waveform signals having slightly different frequency components are mixed, it is possible to reduce the sense of separation between the two musical sound waveform signals at the time of the change (at the time of interpolation).

The present invention can be implemented even if the above embodiment is modified as follows.

(1) In the above embodiment, an example is shown in which the signal interpolator according to the present invention is used for interpolation of two kinds of musical tone waveform signals in accordance with the passage of time. It may be used for signal interpolation according to the key touch intensity, the operation amount of the tone control operator, and the like. In such a case, as shown by a broken line in FIG. 1, the time function generator 32 outputs a function signal (a second signal) corresponding to the pitch, the intensity of the key touch, or the operation amount of the tone control operator.
2A and 2B) are replaced with a function generator that generates the key code KC from the key switch circuit 11 and a key touch detection circuit.
Key touch signal K indicating the key touch intensity detected by 51
T or a tone control signal TC representing the operation amount of the tone control operator detected by the tone control operator circuit 52 may be supplied. In such a case, the waveform memories 13 and 14 may store sampling data representing all waveforms from the start to the end of sound generation.

(2) In the above embodiment, the change characteristic of the interpolation is linearized, and the change rate is increased in the order of low frequency, middle frequency, and high frequency at the same time. Alternatively, the order of the rate of change may be reversed, or the rate of change in the middle range may be maximized or minimized. Also,
The change start timing may be shifted with the same change rate.

(3) In the above embodiment, the tone waveform signals from the waveform memories 13 and 14 are separated into three types using the low-pass filters 15 and 16, the band-pass filters 17 and 18, and the high-pass filters 21 and 22. The waveform signal may be separated into two types only by a low-pass filter and a high-pass filter, or may be separated into four or more types by further providing a plurality of band-pass filters having different signal pass bands. Also,
The filter is not limited to the filter having the frequency characteristic of the above-described embodiment, but may be a filter having two or more types of signal pass bands or having a complicated frequency characteristic.

(4) In the above embodiment, two waveform memories 13 and 14 are used as a source of the tone waveform signal, and the output tone waveform signal is converted from the tone waveform signal from the waveform memory 13 to the tone waveform from the waveform memory 14. Although the signal is switched to a signal, a source based on an FM operation, a source based on a harmonic synthesis operation, or a source obtained by filtering an oscillator output may be used as the generation source. Also, three or more such sources may be provided, and the outputs of the three or more sources may be sequentially switched and output while interpolating, or the outputs of the three or more sources may be interpolated simultaneously. .

(5) In the above embodiment, the read operation of the waveform data from the waveform memories 13 and 14 and the filters 15, 16, 17, 18, 21, 22
Filtering operation, the arithmetic operation of the multipliers 23, 24, 25, 33, 34, 35 and the adders 26, 36, 42, the generation of the interpolation coefficient signals of the interpolation function generators 27, 28, 31 and the like in parallel. Although the operation is performed, such an operation may be performed in a time-division manner. In particular, regarding filters, a computing unit for filtering is commonly used, connection of the computing unit and filter coefficients for filtering operation are supplied in a time-division manner, and apparently one filter has different frequency characteristics on a time axis. It is good to have it.

(6) In the above embodiment, the signal interpolator according to the present invention is applied to a tone signal generating apparatus having a keyboard and generating a tone signal based on a key depression of the keyboard, but the present invention does not have a keyboard. The present invention is also applied to a tone signal generator that generates a tone signal based on external key information. Also,
The present invention is also applied to a musical sound signal generator such as a rhythm sound generator for generating a percussion instrument sound signal such as a cymbal or a bass drum which is not related to a keyboard operation.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of a tone signal generating apparatus to which a signal interpolator according to an embodiment of the present invention is applied, FIGS. 2A and 2B are graphs showing an example of a change characteristic of an interpolation coefficient signal, and FIG. FIG. 6 is a state diagram showing a change state of a musical tone waveform signal. Description of symbols 13,14 …… Waveform memory, 15,16 …… Low-pass filter, 1
7, 18 Band pass filter, 21, 22 High pass filter, 23 to 25, 33 to 35 Multiplier, 26, 36, 42 Adder, 27, 28, 31 Interpolation coefficient generator , 32 ... time function generator, 37, 38, 41 ... complement generator.

Claims (1)

(57) [Claims] The present invention is applied to a tone signal generating apparatus provided with a waveform signal generating means for generating first and second waveform signals having different waveforms at respective pitch frequencies of musical tones to be produced, wherein the first waveform signal is provided. And the second waveform signal are interpolated according to tone control element values such as sounding time lapse, key touch intensity, tone pitch, and operation amount of a tone control operator, thereby obtaining the tone control element value. A signal interpolator for a tone signal generator that outputs a waveform signal that is smoothly changed from the first waveform signal to the second waveform signal according to the change of the first and second waveform signals. Filter means for separating and outputting a plurality of waveform signals belonging to a plurality of different frequency bands; mixing means for mixing a plurality of waveform signals separately output from the first and second waveform signals; Waves The respective mixing ratios of the plurality of waveform signals separated and output from the signal in the mixing unit and the respective mixing ratios of the plurality of waveform signals separated and output from the second waveform signal in the mixing unit are represented by the tone control element values. Mixing ratio control means for controlling one of the mixing ratios to gradually decrease with different change characteristics and the other to gradually increase with different change characteristics, respectively. Interpolator for the tone signal generator.