JPH0254559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a musical tone forming circuit, and is particularly applicable to electronic musical instruments.

As a method of forming musical tones in electronic musical instruments,
There is a waveform memory reading method in which waveform data of a musical tone to be formed is stored in a waveform memory in advance and the stored data is read out at a predetermined speed. Since this waveform memory reading method obtains waveform data based on musical tones generated by natural musical instruments, it is possible in principle to form musical tones that are similar to those of natural musical instruments. For example, if all the musical waveform data of a natural musical instrument's musical sound from its generation to its disappearance is stored in a waveform memory, it is theoretically possible to create a musical sound that is very similar to the musical sound of a natural instrument using an electronic musical instrument. It seems possible. However, in this case, the amount of waveform data to be stored becomes enormous, requiring a waveform memory with a very large memory capacity, and cannot be practically applied to electronic musical instruments.

In order to solve this problem, conventional methods focused on the fact that the waveform changes at the rising part of a musical tone of a natural musical instrument are large and irregular, whereas the waveform changes are small and regular in the subsequent sustaining part or falling part. Then, for irregular parts of the musical tones to be formed where the degree of difference in waveform is relatively large, the waveform data corresponding to the waveform is stored as is as a "total waveform", whereas For regular portions that are not very large, a method has been proposed in which waveform data corresponding to a portion of the waveform is stored as a "basic waveform" and this is repeatedly read out.

In this way, it is possible to form musical tones by using the waveform changes themselves of the musical tones of natural instruments for the waveform portions that have remarkable characteristics (i.e. irregular waveform changes at the rising edge) in correspondence with various natural instruments. It is possible to generate musical tones that approximate the tones of natural instruments,
In addition, for waveform parts with poor characteristics (i.e. parts where the waveform changes regularly), by repeatedly reading out the basic waveform of one to several cycles to form a musical tone, the size of the waveform memory can be significantly reduced and it can be used in practical applications. It is possible to generate musical tones by substituting the regular musical tones of natural musical instruments.

However, when comparing musical tones with musical waveforms formed by this conventional method with the musical tones of natural instruments, it is inevitable that the timbre will remain unnatural. The reason for this is thought to be that in the musical sounds of natural instruments, the timbre of the regular waveform part changes slightly over time, so it is not possible to fully respond to these subtle changes in timbre. .

This invention was made in consideration of the above points, and the waveform memory that stores regular waveform parts can produce musical tones that more closely resemble the subtle changes in the musical tones of natural instruments without sacrificing the advantage of small scale. The purpose of this paper is to propose a musical tone forming circuit that can form a musical tone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings as an embodiment in which the present invention is applied to an automatic rhythm performance device.

In FIG. 1, reference numeral 1 denotes a rhythm pulse generation circuit, which stores patterns representing sound timings corresponding to multiple rhythm types for each of a large number of percussion instrument sounds, and generates patterns according to the rhythm and tempo selected by the performer. A rhythm pattern related to each percussion instrument sound is read out, the sound generation timing signal S1 constituting the rhythm pattern of each read percussion instrument sound is time-division multiplexed and outputted as a serial data signal, and the waveform data of the entire waveform memory 2 is sequentially read out. The signal is supplied to the waveform memory readout circuit 3.

The full waveform memory 2 stores "full waveform" sample data of irregular waveform parts of all percussion instrument sounds with a series of addresses attached, and the full waveform memory reading circuit 3 stores the sound generation timing of the rhythm pulse generation circuit 1. By sequentially reading out the "full waveform" data using the address signal S2 generated in response to the signal S1, a "full waveform" signal is sent out, which is applied to the waveform switching circuit 4 as the first input S3. In this way, the waveform switching circuit 4 is provided with the irregular waveform portion W1 of the musical tone to be formed as shown in FIG. 2 through the first input S3.

When the full waveform memory read circuit 3 finishes accessing the full waveform memory 2 from its start address to its end address, it supplies a start signal S4 to the envelope forming circuit 5. Envelope formation circuit 5
is the initial value of the envelope with the maximum amplitude when the start signal S4 is given at time t ₁ in Figure 2.
An _envelope waveform signal S5 having a so-called percussive envelope waveform whose amplitude value attenuates as time passes is sent out.

Further, the full waveform memory readout circuit 3 provides a start signal S4 to the musical tone waveform memory readout circuit 6.
At this time, the tone waveform memory reading circuit 6 accesses the tone waveform memory 7 from its start address to its end address. The musical waveform memory 7 stores, with a series of addresses, sample data of one wave or several waves of a "basic waveform" that is repeatedly obtained almost regularly when the sounds of various percussion instruments reach a stable state. The sample data of this basic waveform is sequentially and repeatedly read out in the tone waveform memory reading circuit 6 and applied to the variable characteristic filter circuit 8 as a "basic waveform" signal S6, and its output S7 is applied to the multiplication circuit 9.

The variable characteristic filter circuit 8 receives the envelope waveform signal S formed in the envelope forming circuit 5.
5, as the amplitude of the envelope waveform signal S5 changes over time as shown in FIG. 2, the frequency characteristics of the "basic waveform" signal S6 output from the musical waveform memory 7 are changed accordingly. Thereafter, the amplitude of the "fundamental waveform" signal S6 is given an amplitude envelope by the envelope waveform signal S5 in the multiplier circuit 9 and is then applied to the waveform switching circuit 4 as a second input S8.

In this way, the waveform switching circuit 4 is provided with the regular waveform portion W2 of the musical tone to be formed as shown in FIG. 2 by the second input S8.

The waveform switching circuit 4 receives the switching control signal S9 from the full waveform memory reading circuit 3, and synchronizes with the data reading operation of the full waveform memory 2 until it reads out the data of the full waveform memory 2 up to the end address. “Full waveform” signal S3 read from
The first input consisting of is passed through the sound system 10, and after all the data in the waveform memory 2 has been read up to the end address, the second input obtained based on the "basic waveform" signal S6 output from the multiplier circuit 9 is passed to the sound system 10. input S8 is passed to the sound system 10.

Thus, the sound system 10 generates a musical tone corresponding to the "full waveform" signal S3 read out from the full waveform memory 2 as the irregular waveform section W1 between time points _t0 and _t1 in FIG. point in time
It corresponds to the "basic waveform" signal S6 which is repeatedly read out from the musical sound waveform memory 7 as a regular waveform portion W2 between t ₁ and t ₂ , and whose frequency characteristics are also applied to the envelope waveform signal S5 of the envelope forming circuit 5. This generates a musical tone whose amplitude is controlled by the envelope waveform signal S5.

Therefore, according to the configuration shown in FIG. 1, it is possible to obtain a "full waveform" portion that fully represents the characteristics of percussion instrument sounds as the irregular waveform portion W1 of the musical tone, and to obtain a small-scale regular waveform portion W2 of the musical tone. It consists of a "fundamental waveform" part obtained by changing the frequency characteristics of the "fundamental waveform" obtained from the memory over time, and therefore sufficiently improves the unnaturalness that is similar to musical sounds obtained by natural instruments. It is possible to form musical tones.

The configuration shown in FIG. 1 can be realized, for example, by the detailed configuration shown in FIG. 3.

The rhythm pulse generation circuit 1 has a rhythm selection switch circuit 15 and a tempo setting means 16, and when the performer operates the rhythm selection switch 15, a plurality of rhythms (for example, march, samba, waltz, etc.) can be selected.
Roomba, Begin, etc.).
Tempo setting means 16 sets the speed of the selected rhythm.
It can be set by The tempo setting output of the tempo setting means 16 is applied to a tempo clock generating circuit 17, which drives a readout circuit 18 having an address counter configuration with a tempo clock pulse signal having a speed corresponding to the setting contents.

The pattern memory 19 is a series of timing pulses representing the timing of sounding a plurality of percussion instrument sounds (for example, snare drum, low conga, high bongo, maracas, etc.) used for all the rhythms that can be selected by the rhythm selection switch circuit 15. A pattern is stored in advance, and selected by the rhythm selection switch circuit 15 based on an address designation signal sent from the readout circuit 18 (increasing the content of the designated address by "1" at predetermined intervals). A pattern output S11 consisting of a timing pulse train corresponding to a plurality of percussion instrument sounds constituting a rhythm is sent in a parallel signal format. Here, 16 output lines of the pattern memory 19 are prepared, and one percussion instrument sound is assigned to each output line. This pattern output S11 is converted into a time-division signal in a serial signal format in a parallel-to-serial conversion circuit 20, and is applied to the full waveform memory reading circuit 3 as a sound generation timing signal S1 for the first to 16th channels.

In this embodiment, the parallel-to-serial conversion circuit 20 receives pattern outputs S11 in the form of parallel signals from the first to sixteenth output lines of the pattern memory 19, and converts them into 16 patterns that are repeated by a high-speed clock pulse φ. The first time slot formed by
~Assign to the 16th channel. Therefore, the first
~ This means that each channel 16 is assigned a pattern for a specific percussion instrument sound,
This means that the sound generation timing signals S1 regarding the assigned percussion instrument sounds are processed at the timings of the first to sixteenth channels. In this way, the musical tone forming circuit shown in FIG. 3 as a whole processes the data assigned to the 1st to 16th channels in a time-division manner, thus making it possible to simultaneously produce all percussion instrument sounds. ing.

As shown in FIG. 4, the total waveform memory 2 is made up of sample points obtained by sampling at predetermined time intervals the waveforms of each percussion instrument sound (i.e., snare drum, low conga, bongo, ... maracas) that change irregularly after the sound starts. The amplitude value is stored with a series of successive addresses such that the address increases by "1" from the start address to the end address. Furthermore, in this embodiment, the relationship between the waveform data of each percussion instrument sound is similarly such that the addresses continue in a series. In the case of Fig. 4, the memory area MA of the snare drum of the first percussion instrument sound is set to the range from the start address e to the end address f-1, and the memory area of the low conga drum of the second percussion instrument sound is set as the range from the start address e to the end address f-1.
MB is from start address f to end address g
The memory area MC of the maracas of the 16th percussion instrument sound ranges from the start address h to the end address i-1. Therefore, by specifying the address of each corresponding percussion instrument sound in sequence at each time slot corresponding to the 1st to 16th channels, 16 percussion instrument sound waveform signals can be produced at the same time. Can be sent as a time-division signal.

Here, the range of waveforms stored in the total waveform memory 2 is the range from when the percussion instrument sound starts producing until the "basic waveform" starts repeating, as described above with reference to FIG. A waveform portion W1 (referred to as an irregular waveform portion) having an amplitude envelope that is irregular, has poor periodicity, and therefore has a characteristic is stored.

The full waveform memory readout circuit 3 has the following configuration in which the address of the corresponding percussion instrument sound is specified from the start address to the end address every time the sound generation timing signal S1 arrives from the rhythm pulse generation circuit 1 for each of the 1st to 16th channels. have. The full waveform memory readout circuit 3 inputs and stores a 1-bit sound generation timing signal S1 of logic "H" via an OR circuit 22 when it arrives for each channel.
It has a busy register 23 configured as a 16-stage shift register. This busy register 23 uses a clock pulse φ to shift the tone generation timing signal of each channel that is sequentially input to each stage, and shifts the signal of each channel that overflows from the output terminal via an AND circuit 24 by the 16 clock pulses φ. Furthermore, this sound generation timing signal is dynamically stored by feeding it back to the input terminal via the OR circuit 22.

The contents stored in the busy register 23 are applied from the output end to the gate circuit 26 provided at the input end of the address increment register 25 as an enable signal. The address increment register 25 is composed of an n-bit 16-stage shift register.
The address data assigned to the channel is dynamically stored by circulating it through the "1" addition circuit 27 and the gate circuit 26 by the clock pulse φ, and each cycle is stored in the "1" addition circuit 27 each time it is circulated. ``1'' is added to the address data of the channel, thus incrementing the address by ``1''.

In this way, the content of the address of each channel can be increased by "1" from address "0" to address "k", and by specifying address "0", the irregular waveform part shown in FIG. The sample data at the rising time t= _t0 of W1 can be read out, and the sample data at the end time t= _t1 of the irregular waveform section W1 can be read out by specifying address "k". Therefore, address “0” ~ “k”
By sequentially specifying the addresses, sample data from the rising edge to the ending edge of the irregular waveform portion W1 in one waveform can be sequentially read out.

The irregular waveform portion W1 in one waveform is read out in the same way for each percussion instrument sound (almost simultaneously).
The addition circuit 2 specifies the memory area in which all waveform data of each percussion instrument sound is stored.
8, the start address data S given from the start/end address memory 29 to the output data S13 of the address increment register 25
This is executed by adding 14. Here, the start/end address memory 29 is a ROM, and each memory area stores the "full waveform" data of each percussion instrument sound in the full waveform memory 2 (Figure 4).
MA, MB...MC start address e, f...
...H is directly stored as start address data, and each memory area MA, MB...
MC end address f-1, g-1...i-1
The values obtained by subtracting the start addresses e, f...h from each are stored as end address data,
The channel counter 31 receives a channel flag signal S15 representing the channel number assigned to the data currently being sent out from the output end of the address increment register 25, and outputs the corresponding start address data S14 and end address data S16. Note that the channel counter 31 repeatedly counts the clock pulse φ.
It is a hexadecimal counter and sends out a channel flag signal S15 representing the channel number currently being processed by the tone forming circuit.

In this way, the start/end address memory 29 and 51 to be described later are provided, and the step register 25 is used for the start address data S14 and S24 of the memory area allocated to each channel.
and 47 output address data S13 and S23
By adding , the end address detection circuit 3 when determining whether the contents of the step registers 25 and 47 have reached the end address.
The number of comparison bits for 3 and 52 can be made sufficiently small. By the way, all waveform memory 2 and musical waveform memory 7
If a comparison is made by directly using the addresses of , it is necessary to compare a considerably large number of bits, but the embodiment of FIG. 3 can eliminate this need.

Therefore, when the channel flag signal S15 sequentially specifies the 1st to 16th channels, the full waveform memory 2 stores the start/end address memory 29.
All waveform data is read out using the address that is the sum of the corresponding start address sent from the address increment register 25 and the address sent from the address increment register 25.

Such address increment operation continues while the enable signal of logic "H" is applied to the gate circuit 26, but when the enable signal becomes logic "L" and the gate circuit 26 closes, the address data of the channel concerned is The contents are reset. This reset is performed by inverting the end address detection output S17 obtained in the end address detection circuit 33 when the stored content of the address increment register 25 reaches the end address by the inverter 32 and adding it to the AND circuit 24. This is done by cutting the dynamic memory loops that have been formed. The end address detection circuit 33 receives the output data S1 of the addition circuit 27.
8 is compared with the end address data S16 of the start/end address memory 29, and when they match, the end address detection output S17 becomes logic "H".
Output.

This end address detection circuit 33 has a detection output S
17 to the envelope forming circuit 5 as a start signal S.
4 (Figure 1). The envelope forming circuit 5 has m bits 16 driven by a clock pulse φ.
It has an envelope waveform generation circuit 36 configured as a stage shift register, and when the selector 37 receives the detection output S17 of the end address detection circuit 33 and the content is logic "H", it outputs the initial value data S20 of the envelope initial value memory 38. It is applied to the envelope waveform generation circuit 36 through the selector 37.
The envelope initial value memory 38 stores the initial value of the envelope waveform (maximum amplitude value _Enax at time _t1 in FIG. 2) predetermined for each percussion instrument sound assigned to the 1st to 16th channels. It becomes
It is composed of a ROM, and each initial value is read out using a channel flag signal S15 of the channel counter 31.

The reason for setting the envelope initial value E _nax here is as follows. As shown in Figure 2, the waveform of each percussion instrument transitions to a regular waveform part W2 at time _t1 when the irregular waveform part W1 ends, but at this time the amplitude of the waveform must continuously attenuate or else it will be unnatural. Therefore, it is necessary to match the initial envelope value _Enax to the final amplitude value of the irregular waveform portion W1. Moreover, since the degree of attenuation of the waveform amplitude of this initial envelope value E _nax is not the same for each percussion instrument sound, the initial envelope value E _nax is reselected each time the channel changes.

When the envelope initial value data S20 of each channel entered into the envelope waveform generation circuit 36 overflows from the output terminal, it is subtracted by a predetermined value in the subtraction circuit 39 and then sent to the selector 3.
The signal is fed back to the input terminal of the envelope waveform generating circuit 36 via the signal line 7. Here selector 37
The end address detection output S17 given from the end address detection circuit 33 of the full waveform memory readout circuit 3 becomes logic "H" when a match is detected, and the memory of the busy register 23 is reset. 33 returns to logic "L" because no match is detected. Therefore, the selector 37 of the envelope forming circuit 5 is
The output data of 9 is sent to the envelope waveform generation circuit 36.
The state changes to the state where it can be inserted.

The envelope subtraction value memory 40 is composed of a ROM that stores predetermined envelope subtraction values for each percussion instrument sound respectively assigned to the 1st to 16th channels.
The envelope subtraction value data S21 corresponding to the percussion instrument sound assigned to the channel currently being processed by the channel flag signal S15 of No. 1 is applied to the subtraction circuit 39, and thus the envelope data of the corresponding channel of the envelope waveform generation circuit 36 is Each time it cycles, the envelope subtraction value is subtracted. Note that since the attenuation waveform of each percussion instrument sound is different for each percussion instrument sound, it is reset in the envelope subtraction value memory 40 each time the channel is switched.

In this way, the envelope waveform signal S5 obtained at the output terminal of the envelope generating circuit 36 of the envelope forming circuit 5 attenuates from time _t1 at a constant slope until time _t2 , as shown in FIG.

The musical waveform memory readout circuit 6 receives the end address detection output S17 from the full waveform memory readout circuit 3, and the content is set to logic "H" for each channel.
When this happens, it is input and stored in the busy register 44 via the OR circuit 43. This busy register 4
4 consists of a 1-bit 16-stage shift register, and the end address detection output S17 of each channel input to each stage is clocked by a clock pulse φ.
The overflow data of each channel is dynamically stored via an AND circuit 45 and an OR circuit 43.

The output signal S22 of the busy register 44 is applied as an enable signal to a gate circuit 48 provided at the input end of the address repeat step register 47 via an AND circuit 46. The address repeat step register 47 is composed of an n'-bit 16-stage shift register, and the address data assigned to the 1st to 16th channels is sent to ``1'' by the clock pulse φ via the adder circuit 49 and the gate circuit 48. By circulating it, it is dynamically memorized, and each time it circulates, it adds "1" to the circuit 4.
At step 9, "1" is added to the address data, thus incrementing the address by "1". In this way, the contents of the address data of each channel of the address repetition step register 47 can be increased by 1 address from address 0 to address m, and the output data S23 of this register 47 is transferred to the adder circuit. 50 to the tone waveform memory 7 as an address signal.

The musical sound waveform memory 7 stores the stable "basic waveform" of each percussion instrument sound for one waveform or multiple waveforms (in this embodiment, one waveform), and stores this "basic waveform" at a predetermined time interval. The sample point amplitude values sampled at the start address and the end address are sequentially incremented by "1" and stored with successive addresses attached thereto. Further, in this embodiment, the relationship between the waveform data of each percussion instrument sound is similarly such that the addresses continue in a series.

In order to designate a memory area corresponding to each percussion instrument sound in the musical waveform memory 7, the start address data S24 of the start/end address memory 51 is added to the output data S23 of the address repeat step register 47 in the adder circuit 50. Like the start/end address memory 29 described above, the start/end address memory 51 directly uses the start address of each memory area storing the "music waveform" data of each percussion instrument sound in the musical waveform memory 7 as start address data. It is a ROM that stores the contents obtained by subtracting the start address from the end address of each memory area as end address data, and receives the channel flag signal S15 output from the channel counter 31 to output the corresponding start address data S24. and outputs end address data S25.

Therefore, when the channel flag signal S15 sequentially specifies the 1st to 16th channels, the musical waveform memory 7 inputs the start/end address memory 51.
The "basic waveform" is read out using the address data that is the sum of the corresponding start address data S24 sent out from the address repetition step register 47 and the output data S23 sent out from the address repetition step register 47.

In this way, the address repeat step register 4
7 is in step operation, the output data S26 of the adder circuit 49 is compared with the end address data S25 of the start/end address memory 51 in the end address detection circuit 52,
The detection output S27, which becomes logic "H" when they match, is inverted by the inverter 53 and sent to the AND circuit 46.
The gate circuit 48 is closed through the channel, thereby resetting the contents of the address data of the channel.

However, when this reset address data of the channel is fed back to the addition circuit 49, the end address detection circuit 52 detects that it no longer matches the end address data S25, and the detection output S27 goes to logic "L". Become. At this time, the gate circuit 48 is opened via the inverter 53 and the AND circuit 46, and thus the address repeat step register 47 starts circulating again and increases the contents of the address data of the channel by "1". .

In the same manner, the address repeat step register 4
7 increases the content of the address data of each channel by "1", and when it eventually matches the end address data S25 of the start/end address memory 51, the content of the previous address data is reset and a new address is added. The basic waveform is repeatedly read out from the musical waveform memory 7.

Further, an envelope waveform signal S5 from the envelope waveform generation circuit 36 of the envelope forming circuit 5
is received by the decay finish detection circuit 52, and when the amplitude of the envelope waveform signal S5 reaches a predetermined final value (eg, value "0"), the detection output S30 is set to logic "H". This detection output S30 is sent to the AND circuit 53 together with the output S22 of the busy register 44.
The AND output thereof is applied via the inverter 54 to the above-mentioned AND circuit 45 inserted into the closed loop of the busy register 44. In this way, the output of the channel storing the end address detection output S17 of logic "H" (in the logic "H" state) is sent from the busy register 44, and the logic "H" is detected from the decay finish detection circuit 52. When the output S30 is obtained, the AND circuit 45 is passed through the AND circuit 53 and the inverter 54.
opens a closed loop and resets the corresponding channel in busy register 44. At this time, the content of the channel becomes logic "L", and the gate circuit 48 is closed via the AND circuit 46, thereby returning the content of the channel in the address repetition register 47 to "0", and the tone waveform memory 7 The repeated read operation for .

“Basic waveform” signal S6 from musical waveform memory 7
is the controllable filter 58 of the variable characteristic filter circuit 8.
given to. The controllable filter 58 is a digital filter, and uses the filter characteristic determined by the filter characteristic constant output S35 of the filter characteristic constant memory 59 to determine the frequency characteristic (and thus the frequency characteristic) of the "basic waveform" signal S6 from the musical waveform memory 7. tone)
A relatively small change is applied to the signal and then sent to the multiplication circuit 9. The filter characteristic constant memory 59 is constituted by a ROM that stores a large number of filter characteristic constants, and is configured such that each filter characteristic constant can be selected and read out as required by a combination of readout input conditions. That is, the filter characteristic constant memory 59 receives the envelope waveform signal S5 from the envelope waveform generation circuit 36 and the channel flag signal S15 from the channel counter 31 as read input conditions, and thereby selects the values for each channel (therefore, for each percussion instrument sound). The frequency characteristics of the controllable filter 58 are controlled by reading out the filter characteristic constants while changing them according to changes in the envelope waveform signal S5.

In this embodiment, the filter characteristic constant memory 5
9 is supplied with the output of the random output generation circuit 60, and is designed to supply random data that changes slowly and randomly over time as a read signal to the filter specific constant memory 59. As a result, the filter characteristic constant memory 59 changes the frequency characteristic of the controllable filter 58 (therefore, the tone of the "fundamental waveform" signal S6) based on the change given in response to the change in the envelope waveform signal S5 for each channel as described above. You can change it randomly.

In this way, the "basic waveform" signal S6 read from the musical waveform memory 7 is transmitted to the controllable filter 58.
After the timbre is controlled in the multiplication circuit 9, the signal is multiplied by the envelope waveform signal S5 to give an amplitude envelope and is applied to the waveform switching circuit 4.

The waveform switching circuit 4 receives the output of the busy register 23 of the full waveform memory reading circuit 3 as a switching control signal S9, and when this control signal S9 is at logic "H" (forming the irregular waveform portion W1 in FIG. The "full waveform" signal S3 from the full waveform memory 2 is sent to the accumulator 60 of the sound system 10, and when the control signal S9 is logic "L" (meaning that the regular waveform part "basic waveform" from the multiplier circuit 9
An input S8 obtained based on the signal S6 is sent to the accumulator 60.

The accumulator 60 synthesizes data sent serially in a time-division manner for 16 channels, converts the synthesized musical tone data into an analog signal in a digital-to-analog conversion circuit 61, and then supplies it to a speaker 63 through an amplifier circuit 62.

In the above configuration, when the player selects and operates a desired switch of the rhythm selection switch circuit 15, stored patterns corresponding to a plurality of percussion instrument sounds used in the rhythm are selected in the pattern memory 19, and the player sets the tempo. The patterns stored in the pattern memory 19 are sequentially read out by the readout circuit 18 at a speed corresponding to the tempo set by the means 16, and the sound generation timing signals S1 are respectively generated.

This sound generation timing signal S1 is dynamically stored in the busy register 23 of the full waveform memory readout circuit 3 for each channel, and the switching control signal S9
The waveform switching circuit 4 is switched to the full waveform memory 2 side at the timing of the channel. On the other hand, since the gate circuit 26 of the address increment register 25 opens at the timing of the channel in which the sound generation timing signal S1 of the busy register 23 is stored,
Address increment register 2 in the channel
5 creates address data that increases by "1" from "0" through the "1" addition circuit 27 and the gate circuit 26, and sends this to the addition circuit 28. This adder circuit 28 includes a channel counter 3.
The start address data S14 specified by the channel flag signal S15 of No. 1 is given from the start/end address memory 29, and thus the entire waveform memory 2 stores the start address (e, f...h) of the corresponding channel (Fig. 4). The stored contents of the addresses are sequentially increased by "1" from 1 to 1, and the musical tone signal S37 generated at the output terminal of the waveform switching circuit 4 is read out from time t ₀ to _{t 1} in FIG. 2.
The irregular waveform portion W1 becomes the "full waveform" signal read out from the full waveform memory 2.

Eventually, at time _t1 in FIG.
1), (g-1)...(i-1) (Fig. 4), the end address detection circuit 33 detects this and sets the detection output S17 to logic "H". Selector 37 of envelope forming circuit 5
The envelope initial value data S20 of the envelope initial value memory 38 is entered into the corresponding channel of the envelope waveform generation circuit 36 through the subtraction circuit 39 and the selector 37, and then dynamically stored. In this way, the envelope subtraction value memory 40 is obtained from the envelope waveform generation circuit 36 from the envelope initial value E _nax at time t ₁ in FIG.
An envelope waveform signal S5 is obtained that attenuates at a slope corresponding to the subtracted value data S21.

In addition to this, secondly, the fact that the end address detection circuit 33 has become logic "H" is stored in the corresponding channel of the busy register 44 of the tone waveform memory readout circuit 6, and the address repetition step register 47
The gate circuit 48 is opened. In this way, the address repeat register forms repeat address data S23 that increases by "1" from "0" via the "1" adder circuit 49 and the gate circuit 48, and sends this to the adder circuit 50. This addition circuit 50
is the start address data S of the memory area assigned to the corresponding channel in the musical waveform memory 7.
24 is given from the start/end address memory 51, and thus the tone waveform memory 7 reads out the stored contents of addresses sequentially increasing by "1" from the start address. In the meantime, when the contents of the address repetition step register 47 become equal to the end address of the musical waveform memory 7, the output S27 of the end address detection circuit 52 becomes logic "H".
As a result, the gate circuit 48 closes and the contents of the corresponding channel in the address repeat step register 47 are returned to "0". At this time, the output S27 of the end address detection circuit 52 returns to logic "L" and opens the gate circuit 48, and thus the address repeat step register 47 again starts the address data newly incremented by "1" from "0". Start making it. Thereafter, the address repeat advance register 47 repeats the contents of the address data to "0" in the same manner.
to the end address.

In response to this, the musical waveform memory 7 stores the "basic waveform".
is repeatedly read out and sent to the controllable filter 58.

The envelope waveform signal S5 formed in the envelope forming circuit 5 is given to the filter characteristic constant memory 56, and the filter characteristic constant data S35 corresponding to the channel is read out and supplied to the controllable filter 58. A timbre change is applied to the "basic waveform" signal S6 from , which corresponds to a change in the envelope waveform signal S5. In addition, by the output of the random output generation circuit 60, a timbre change that changes randomly over time is applied to the "basic waveform" signal S6 from the musical waveform memory 7.

The output S7, which is a "basic waveform" signal with timbre changes, is given an amplitude envelope in the multiplication circuit 9 and sent to the waveform switching circuit 4.
The end of amplitude attenuation is performed by the tone waveform memory readout circuit 6.
The day-key finish detection circuit 52 detects that the envelope waveform signal S5 becomes "0" and resets the contents of the corresponding channel in the busy register 44, thereby closing the gate circuit 48 of the address repetition register 47. Finish by letting

In this way, after the full waveform memory readout circuit 3 detects the end address at time t1 in FIG. ₂ , the envelope waveform signal S5 is detected at time _t2 .
Until this is completed, a regular waveform portion W2 is formed by adding changes in the amplitude envelope and frequency characteristics to the tone waveform having the basic waveform repeatedly read out by the tone waveform memory 7.

In this way, according to the configurations of FIGS. 1 and 3,
The characteristics of the rising part of each percussion instrument sound can be approximated by reading out the data stored in the entire waveform memory and forming an irregular waveform part W1, and a regular waveform part W2 corresponding to the stable part of each percussion instrument sound can be approximated. By adding an amplitude envelope and a timbre change to the "basic waveform," it is possible to create a timbre close to that of a natural instrument. In this way, the memory capacity of the waveform memory for forming the regular waveform portion W2 can be kept small.

Furthermore, in the case of the embodiment shown in FIG. 3, by using control based on the output of the random output generation circuit 60 to change the frequency characteristics of the controllable filter 58, it is possible to impart timbre fluctuation to the generated musical tone. By doing this, the natural feel of musical tones can be enhanced.

In the above description, an embodiment has been described in which the present invention is applied to an automatic rhythm performance device, but the present invention can be widely applied to electronic musical instruments. It can be applied when generating musical sounds etc. In this case, in order to generate a musical tone signal with a pitch corresponding to the pressed key, the "1" adding circuit 27 of the full waveform memory reading circuit 3 and the "1" adding circuit 27 of the musical waveform memory reading circuit 6 shown in FIG. ''In place of the adder circuit 49, an adder circuit that adds a value corresponding to the pitch (so-called frequency information value) may be used, and the keyboard can also be used as a trigger signal to the busy register 23 of the full waveform memory readout circuit 3 in FIG. A key-on pulse signal generated when a key is pressed may be used.

In addition to the percussive envelope, the musical tones to be generated may be those having the envelope of organ sounds or other musical instrument sounds. In this case, the envelope waveform signal S5 formed by the envelope forming circuit 5 may be a sustained envelope waveform having a sustain part.

Furthermore, in the above description, the sample amplitude value of the "basic waveform" for one waveform or multiple waveforms is used as the data stored in the musical waveform memory 7, but instead of this, the "basic waveform" for half a wave It is also possible to use sample amplitude values of . By the way, in general, the "fundamental waveform" in a stable state is almost the same except for the difference in polarity between the positive half-cycle waveform and the negative half-cycle waveform, so half-wave data is prepared as storage data and read out. By inverting the sign of the data, a "basic waveform" for one waveform can be formed. In this way, the memory capacity of the waveform memory can be further reduced.

Furthermore, in the above description, the envelope waveform signal S
Although 5 is made to change linearly, it may be made to change exponentially.

Further, in the above description, the controllable filter 58 is provided at the output end of the tone waveform memory 7, but instead, it may be provided at the output side of the multiplication circuit 9.

Further, in the above embodiment, in order to change the frequency characteristics of the controllable filter 58, the filter characteristic constant memory 59 uses both the envelope waveform signal S5 and the output of the random output generation circuit 60.
Although reading control is performed, either one of these may be used instead.

Further, in the above-mentioned embodiment, the envelope forming circuit 5 uses the envelope waveform generating circuit 36 and the subtracting circuit 39 having a shift register configuration to form a closed loop to obtain the envelope waveform signal S5 through calculation. The envelope waveform signal S5 may be obtained using a waveform memory.

As described above, according to the present invention, the irregular waveform portion W1 of the musical tone to be formed is formed by reading out the entire waveform memory, and the regular waveform portion W2 following the irregular waveform portion W1 is repeatedly read out from the musical waveform memory. By doing this, it is possible to obtain a musical tone forming circuit that sufficiently approximates a natural musical instrument and can sufficiently reduce the memory capacity. By changing the value over time, it is possible to create a musical tone with an even richer natural feel.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a musical tone forming circuit according to the present invention, FIG. 2 is a signal waveform diagram showing a musical tone signal to be formed, FIG. 3 is a block diagram showing the detailed configuration of FIG. 1, and FIG. The figure is a schematic diagram showing the configuration of the full waveform memory. 2...Full waveform memory, 3...Full waveform readout circuit, 4...Waveform switching circuit, 5...Envelope formation circuit, 6...Tone waveform memory readout circuit, 7...
... Musical sound waveform memory, 8 ... Variable characteristic filter circuit, 9 ... Multiplication circuit, 10 ... Sound system, 58 ... Controllable filter, 59 ... Filter characteristic constant memory, 60 ... Random output generation circuit.

Claims (1)

[Claims] 1. (a) A first waveform memory that stores first waveform data regarding the irregularly changing entire waveform portion of the rising portion of a musical tone, and (b) Basic information after the rising portion of the musical tone. a second waveform data for a partial waveform of the target waveform portion;
(c) the first and second waveform memories are read out to output the first and second waveform data, and after outputting the first waveform data, (d) a waveform reading/output means for repeatedly outputting the second waveform data; (d) changing the frequency characteristics of the second waveform data output from the second waveform memory over time; A filter characteristic is controlled by a coefficient generating means for generating filter coefficients that sequentially change in response to completion of output of the first waveform data in the output means, and a filter coefficient generated from the coefficient generating means. variable characteristic filter means having a digital filter, and forming musical tones based on the first waveform data and the second waveform data whose frequency characteristics are controlled by the variable characteristic filter means. musical tone formation circuit.