JPS6313556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a musical waveform generation circuit for an electronic musical instrument,
More specifically, it is an electronic musical instrument that can generate musical sound waveforms of performance instruments such as pianos and organs, as well as musical sound waveforms of rhythmic instruments such as cymbals and drums, taking into account their frequency characteristics. This invention relates to a musical sound waveform generation circuit.

Many of the electronic musical instruments currently in use use so-called organ ICs that can simultaneously generate the musical sound waveforms of performance instruments such as pianos and organs in multiple channels. The sound waveforms of these instruments are for the organ.
This was generated by using a separate circuit separate from the IC or a separate dedicated IC. Therefore, the number of parts required to configure one electronic musical instrument or the number of parts required to configure one electronic musical instrument are
There are many types of ICs, making it extremely difficult to significantly reduce production costs. Furthermore, in conventional music waveform generation circuits for rhythm instruments of this type, the frequency characteristics of each output musical sound and the volume balance between output musical sounds were not taken into consideration.
It was not possible to output musical tones of sufficiently high quality.

The object of the present invention is therefore to
By adding small-scale hardware to the IC circuit, it is possible to selectively output either multiple musical sound waveforms for performance or multiple musical sound waveforms for rhythm, and also output high-quality musical sound signals. An object of the present invention is to provide a musical sound waveform generation circuit for an electronic musical instrument that is suitable for IC implementation.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows a block diagram of an embodiment of a tone waveform generating circuit according to the present invention. The musical sound waveform generation circuit 1 generates musical sound waveforms of performance instruments such as pianos and organs, or rhythm instruments such as cymbals and drums, according to the level of a musical sound waveform switching signal LM for performance/rhythm given from the outside. This is a circuit for selectively generating musical sound waveforms, and is configured to be able to simultaneously output eight musical sound waveforms for performance and rhythm by time-division processing of eight channels. This musical sound waveform generation circuit 1 generates several types of musical sound waveforms.
A waveform memory 2 in which cycles of waveform data are stored, and a maximum number of channels required to read out one type of waveform data at a desired pitch from among the plurality of types of waveform data stored in the waveform memory 2. The pitch generating circuit 3 outputs the pitch data _D1 .

Describing the configuration when the musical sound waveform generating circuit 1 is used as a musical sound waveform generating circuit for a performance instrument, the octave data D _2a and the note name data D _2b that constitute the key press information D ₂ from the keyboard 4 are The signals are input to the 1-pitch ROM 5 and the first selector 6, respectively. The pitch name data D _2b is converted by the first pitch ROM 5 into data D ₃ indicating a pitch according to the contents of the data D _2b , and is input to the second selector 7.
A musical sound waveform switching signal LM for performance/rhythm is applied to each selector 6, 7. The level of the signal LM is "0" level in the musical sound waveform generation mode for performance, and thereby each selector 6, 7 is switched so that data _D3 and octave data _D2a are selectively output. . As a result,
The data D _2a and D ₃ are input to the pitch generation circuit 3 via the respective selectors 6 and 7, and data for up to 8 channels is time-divisionally processed according to the key depression state of the keyboard 4, and from the waveform memory 2, Musical sound waveform data of a desired performance instrument according to the musical instrument type data _D4 is output at a pitch according to the keyboard operation.

Musical sound waveform data for performance obtained in this way
_D5 is input to the third selector 8. The third selector 8 is also controlled by the switching signal LM, and when the switching signal LM is at the "0" level, eight channels of musical waveform data _D5 are selectively output and input to the envelope counter 9. In addition to the clock CLK, the envelope counter 9 receives the key-on signal _S1 from the key-on detection circuit 10, and in response to the input of the key-on signal _S1 , the envelope of the musical sound waveform data output from the third selector 8. Process. The musical waveform data after envelope processing is sent to the D/A converter 1 via the fourth selector 11 whose switching is controlled by the switching signal LM.
2 and is converted into an analog musical tone signal _S2 . Analog musical tone signal S ₂ is passed through low pass filter 1
After high frequency noise components are removed by step 3, the level is adjusted by level adjuster 14, inputted to amplifier 16 via adder 15, and outputted from speaker 17 as musical tone for performance.

In addition to the musical sound waveforms for performance described above, this musical sound waveform generation circuit 1 is capable of generating musical soundwaveforms for drum rhythms such as corbels and high conga, and musical soundwaveforms for noise rhythms such as cymbals and high hats. It includes a drum rhythm sound pitch data generation circuit 20 and a noise rhythm sound synthesis circuit 30. When generating a musical sound waveform for rhythm, this circuit is configured so that the type of musical instrument is assigned in advance to each of the eight channels from channel 0 to channel 7, and the musical sound waveform processing for the selected instrument is performed. , respectively, are performed on predetermined channels. In this example, the first
The allocation is determined as shown in the table.

Table 1 CH0 Cymbal (CY) CH1 Hi-hat 1 (HH ₁ ) CH2 Hi-hat 2 (HH ₂ ) CH3 Snare drum noise (SDN) CH4 Snare drum (SDT), claves (CL) CH5 Corbel (CB), high conga ( HC) CH6 Bass drum (BD) CH7 Low conga (LC) As you can see from this table, CH0 to CH3 are assigned to noise-type instruments, and CH4 to CH7 are assigned to drum-type instruments. Here, regarding the snare drum, its noise component is processed by CH3, and its repetitive frequency component is processed by CH4. Also,
Two types of musical instruments are assigned to each of CH4 and CH5, but neither of these is used at the same time. That is, the snare drum is used for rock rhythms, and the claves is used for Latin rhythms. Also, the corbel is used for samba rhythms, and the high conga is used for rhythms other than samba.

These rhythm instruments are designated by operating a rhythm instrument selection switch device 18, which sends 3-bit channel data _C0 to _C1 indicating the current processing channel. , instrument code data SD/CL and CB/HC indicating which instruments are assigned to channels CH4 and CH5, respectively, are output.

In addition, channel data C ₀ indicating each channel
The codes for C2 to _C2 are shown in Table 2.

Table 2 C ₂ C ₁ C ₀ CH0 0 0 0 CH1 0 0 1 CH2 0 1 0 CH3 0 1 1 CH4 1 0 0 CH5 1 0 1 CH6 1 1 0 CH7 1 1 1 Taiko rhythm sound pitch data generation circuit 20 is ,
This is a circuit for generating pitch data for reading the sine wave data stored in the waveform memory 2 at a pitch according to the type of drum rhythm instrument, and among the data from the rhythm instrument selection switch device 18, Instrument code data SD/CL, CB/
It has a ROM 21 into which HC and channel data C ₀ and C ₁ are input. From ROM21,
Based on these input data, CH4 to CH
Assignment data D _{6 indicating rhythm instruments assigned to each channel up to 7 and octave data D 7 for} rhythm instruments for each of these channels are output, and the octave data D ₇ is output to the first selector 6 .
is input. On the other hand, the assignment data D ₆ is input to the second pitch ROM 22, and data D ₈ indicating a predetermined read pitch corresponding to the drum rhythm instrument assigned to CH4 to CH7 based on the assignment data D ₆ is output. The signal is input to the second selector 7.

When the circuit 1 functions as a rhythmic musical waveform generation circuit, the level of the switching signal LM is "1", and therefore the first selector 6 outputs the rhythmic sound waveform data instead of the performance octave data _D2 . While the octave data D ₇ is selectively output and input to the pitch creation circuit 3, in the second selector 7, since the level of the switching signal LM becomes "1", the data D ₃
output is prohibited. And the other input, data D ₈ , is the channel data C ₂
The data _D8 is outputted only when the level of is "1" and inputted to the pitch generation circuit 3. That is, in the musical sound waveform output mode of a rhythm instrument, when the level of _C2 becomes "1" (in the case of a drum rhythm instrument), the data from the second pitch ROM 22 is
_D8 is connected to the pitch creation circuit 3 via the second selector 7.
is input. The pitch generation circuit 3 is configured as an 8-channel frequency dividing circuit, and divides the frequency of the clock CLK based on the input data.
A read clock with a desired cycle is output for each channel from CH4 to CH7. When this circuit 1 is operating to output a rhythmic musical waveform, waveform data is selected so that sine wave waveform data is read out from the waveform memory 2 by signal F. Therefore, sine wave data of a predetermined frequency determined for each channel CH4 to CH7 is output from the waveform memory 2. In this case, the output data from the waveform memory 2 is musical waveform data of a drum-type rhythm instrument sound.

When the switching signal LM is “1”, the third selector 8
When the level of _C2 is "1", this waveform data is selectively input to the envelope counter 9,
After the envelope is shaped into a predetermined shape, the fourth selector 11
is input. The fourth selector 11 also has LM,
The switching operation is performed according to the level of _C2 , and LM,
When both levels of _C2 are "1", the input data is output only to the output line A. Therefore, the musical sound waveform data of a drum-type rhythm instrument is input to the low-pass filter 13 via the D/A converter 12, and after high-frequency noise components are removed, it is sent to the speaker in the same way as musical tones for performance. 17 output as sound.

Next, the noise-based rhythm sound synthesis circuit 30 will be explained. The noise-based rhythm sound synthesis circuit 30 converts the noise-based rhythm sounds shown in Table 1 into CH0 to CH3.
This is a circuit for creating 7 Ex
-Mixing circuit 3 consisting of OR gates 31 to 37
8 and a signal generator 39 that generates a plurality of signals to be mixed in a mixing circuit 38. The signal generator 39 is a circuit for appropriately frequency-dividing the clock CLK to generate eight required signals _P1 to _P8 of mutually different frequencies.
CLK divided by 1/36, 1/28, 1/8 and 1/2600
Frequency dividers 40, 41, 42, 43 for frequency division
and a pitch creation circuit 3.
As already mentioned, the pitch creation circuit 3 is composed of a frequency dividing circuit, and therefore, the pitch creation circuit 3 is composed of a frequency dividing circuit.
Using CH0 to CH3, the clock CLK is divided by a desired frequency division ratio, thereby making it possible to generate signals of different frequencies for each channel. The 4-channel time-division multiplexed frequency-divided signal _S3 outputted from the pitch generation circuit 3 in this way is
Furthermore, the frequency is divided by 1/2 via the 1/2 frequency divider 44, and at the same time, it is taken out as a signal with a duty ratio of 1/2.
The signal is input to two latch circuits 45 to 48. Each latch circuit 45 to 48 has channel information D ₉
The channel signals CS0 to CS3 obtained by decoding by the decoder 19 are respectively input, and the signal from the 1/2 frequency divider 44 is latched at each channel timing, thereby outputting the signals _P1 to _P4 . It's getting old. Remaining signals P ₅ to
_P8 is output from frequency dividers 40 to 43. The frequencies of these signals P ₁ to P ₈ can be determined experimentally, and are selected in the range of several tens of Hz to about 50 KHz in the illustrated embodiment. these signals
P ₁ to P ₈ are mixed in the mixing circuit 38 and outputted from the mixing circuit 38 as three mixed outputs O ₁ , O ₂ , O ₃ . The mixed outputs O ₁ , O ₂ , O ₃ are the adder 4
The added output data D ₁₀ is converted into logarithmic data D ₁₁ by the logarithmic conversion ROM 50 and then input to the third selector 8 .

Note that if frequency division is performed using the pitch generation circuit 3, the highest frequency will be 1/8 of the clock CLK, as well as 1/8 of the clock CLK due to the time division operation of the pitch generation circuit 3. You can only do laps. Therefore, among the frequencies determined through experiments, it may not be possible to realize the frequency by the pitch generation circuit 3, or there may be a limit on the frequency division number, so there is a risk that the frequency may deviate from the desired frequency. Therefore, in order to generate the desired eight signals, it is necessary to decide whether to use the frequency divider or the pitch generation circuit 3 in consideration of the above.

On the other hand, the output signal O ₃ having the highest frequency component among the output signals is converted into logarithmic data D ₁₂ by another logarithmic conversion ROM 51 and input to the third selector 8 . Data D ₁₁ is used as a cymbal sound waveform, while data D ₁₂ is used as a snare drum noise sound waveform. When the level of C ₂ is “0”, the third selector 8 replaces the data from the waveform memory 2 with these data D ₁₁ ,
_D12 is selected and output and input to envelope counter 9. The envelope counter 9 determines the shape of the envelope of each data D ₁₁ D ₁₂ , and thereby outputs the musical instrument sound waveform data shown in Table 1 to CH0 to CH3. The fourth selector 11 is configured to output the input data to the output line B when the level of the switching signal LM is "1" and the level of ^C2 is "0". Therefore, the musical waveform data of these noise-based rhythm instrument sounds is input to the D/A converter 60 and converted into an analog musical tone signal _S4 , and after level adjustment is performed by the level adjuster 61, it is input to the adder 15. , amplifier 16
After the signal is amplified by the speaker 17, it is output as a musical tone. The reason why the fourth selector 11 is provided to separate the drum rhythm sound signal and the noise rhythm sound signal is that the noise rhythm sound signal has a high main frequency component of 8000 to 10000 Hz, and is low-pass. If it were passed through a filter, the sound would be different from the actual instrument sound, but in the case of drum rhythm sounds, the main frequency component is below 2000Hz, and the filter is used to remove system noise components. This is because it is necessary to insert a low-pass filter into the transmission path.

As a result of dividing the output into two systems in this way, it is possible to completely remove high-frequency noise components from drum-type rhythm sounds, while noise-type rhythm sounds have a sound that extends well into the high range, allowing cymbals, It is possible to output the sound of an electronic musical instrument such as a high-hat as a sound that is extremely close to the sound of a natural musical instrument.

FIG. 2 shows a circuit diagram of an embodiment in which the pitch generation circuit 3 is used to constitute the signal generation source of the noise-based rhythm sound synthesis circuit 30.

The pitch creation circuit 3 includes a 5-bit 8-channel shift register 70 and an adder 71 that adds output data from the shift register 70 to input data Din related to pitch information.
1 is configured to be input again to the shift register 70 via an AND gate 72 whose opening/closing is controlled by the ENTRY signal. In this configuration, the input data Din is data regarding a desired frequency division number created based on the data input to the pitch creation circuit 3, and the addition result is influenced according to the value of this data Din.

The result of this addition is returned to the AND gate 72 and is used as data indicating the timing for reading data from the waveform memory 2, and the data is read from the waveform memory 2 at a pitch based on this data.

The pitch creation circuit 3 further includes another set of frequency dividing circuits, and this frequency dividing circuit is a 10-bit 8
A channel shift register 73, an adder 74 that adds either 1 or 0 to the output data of the shift register 73 according to the output of the upper two bits of the adder 71; and an AND gate 75 into which the output data of is input. This frequency divider circuit is
This circuit is used to further divide the frequency division result from the adder 71 into 1/2, 1/4, etc. using octave data, and when the output of the NAND gate 76 becomes "1" It works as a 1/2 frequency divider.

In order to use this frequency division function as a frequency divider with an arbitrary frequency division number, there are four multi-input AND gates 77, 78, 7 on the output side of the shift register 73.
9 and 80 are connected, and each AND gate is
When all of its input levels are "1", its output is set to "1". These AND gates 77 to 8
Further, on the output side of 0, AND gates 81 to 8
4 are connected to these AND gates, and in addition to inputting the switching signal LM, the channel signal SC from the decoder 19 (see Figure 1) is also input to these AND gates.
0 to SC3 are input as shown. Therefore, when the level of the signal LM is "1" and the corresponding channel signal is "1", one of these AND gates 81 to 84 is opened.
As a result, the output level of the corresponding multi-input AND gate is taken out via the opened AND gate. The outputs from these AND gates 81 to 84 are respectively input to an OR gate 85, and the output of the OR gate 85 is directly connected to a 1-bit adder 86 and also connected to the inhibit terminal INH of the AND gate 75 via a NOR gate 87. ing. If the level of the output of the NOR gate 76 is forced to "1" and the adder 74 repeatedly adds +1, the contents of each channel of the register 73 will increase by 1 every cycle. , therefore each multi-input AND gate 77
When the contents of the corresponding channel of the shift register 73 reach a predetermined value, the output of the circuits 80 to 80 becomes 1, and at that time, the AND gate provided on the output side is opened and the level of the 1NH terminal is set to "0". Therefore, the output from the adder 74 is the shift register 7
3 is not input, and zero is set in the shift register 73. That is, each channel CH0 to
In CH3, the clock frequency division operation is performed in a time-division manner using a desired frequency division number.

As a result of the frequency division operation described above, the pulses output from the OR gate 85 are sequentially stored in a 1-bit 8-channel shift register 88 via a 1-bit adder 86. This adder 86 and shift register 88 constitute a 1/2 frequency divider 44, and a frequency-divided signal of a desired frequency is output at the timing of channels CH0 to CH3. Note that, as already explained, this 1/2 frequency divider 44 allows the duty ratio to be 1/2. The ENTRY signal is input directly to the AND gate 72, and is also applied to one input of the AND gate 89.
Further, a signal inverted by inverter 90 is applied to the other input of NOR gate 87. Therefore, when the ENTRY signal becomes "0", all the outputs of the AND gate 72 become "0", and the contents of the shift register 70 also become all zero.
Further, in this case, since the content of the input data Din is also zero, the output of the NOR gate 76 becomes "1". Similarly, shift register 73,
The contents of 88 also become zero, and the pitch generation circuit 3 is thereby reset. When the ENTRY signal reaches the "1" level, the above operation becomes executable.

In this way, in addition to the frequency dividing circuits 40 to 43, the frequency dividing circuit of the pitch generating circuit 3 is used for four channels as a signal generation source necessary for generating the musical tones of a noise-based rhythm instrument. Even when generating a series of musical instrument sounds, the pitch generation circuit can be fully utilized, resulting in an extremely efficient circuit configuration.

With this configuration, it is possible to generate rhythmic musical tones by simply adding a simple circuit to the conventional performance musical tone generating circuit, and moreover, it is possible to generate rhythmic musical tones by setting the level of one signal line to "1". Or, by setting it to "0", either one of the functions can be executed. Therefore, when integrated into an IC, it can be used for a variety of purposes, and cost reductions can be expected through mass production.

Furthermore, two output transmission paths are provided on the output side of the envelope counter 9, and the fourth selector 11
The drum rhythm sound waveform data and the noise rhythm sound waveform data are output separately to separate output lines A and B, and high-frequency noise components are filtered out using a low-pass filter only for the drum rhythm sound data. Since it is configured to remove high-frequency noise components, in the case of drum-type rhythm sounds whose main frequency components are below 2000 Hz, high-quality musical instrument sounds with high-frequency noise components removed without distorting the desired waveform are produced. Obtainable. On the other hand, noise rhythm waveform data whose main frequency component is 8,000 to 10,000 Hz passes through output line B without passing through such a filter element, so it is of high quality that is close to that of a natural instrument and contains high frequency components. Obtained as a signal. Furthermore, since the output is divided into two systems in this way, not only can the frequency characteristics of the signals transmitted through each output transmission path be changed independently, but also the levels can be adjusted independently using the level adjusters 14 and 61. Therefore, it has the advantage that the volume balance between the drum rhythm sound and the noise rhythm sound can be arbitrarily adjusted.

According to the present invention, as described above, the performance musical sound waveform generating function and the rhythm musical sound waveform generating function are provided,
You can select one of these functions with an extremely simple switching operation, so for example,
If it is made into a multifunctional device, it will become a multifunctional device and can be used in larger quantities, so it can be expected to reduce costs through mass production. In addition, in order to realize these two functions, as mentioned above, we devised a way to use most of the circuit in common.
It does not significantly increase the circuit scale, and from this point of view as well, it is highly economical and extremely practical. Furthermore, since the rhythm sounds are divided into two systems and output according to their characteristics, it is possible to independently adjust the volume of various waveform manipulations, making it possible to generate higher quality musical sounds through fine-grained adjustment. It has the advantage of being able to

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
This figure is a circuit diagram of the main part of the pitch creation circuit shown in FIG. 1. 1... Musical waveform generation circuit, 2... Waveform memory,
3... Pitch creation circuit, 4... Keyboard, 6... First
Selector, 7... Second selector, 8... Third selector, 9... Envelope counter, 10... Key-on detection circuit, 11... Fourth selector, 12,
60...D/A converter, 13...Low pass filter, 14...Level adjuster, 15, 49, 7
1, 74, 86...adder, 16...amplifier, 1
7...Speaker, 18...Rhythm instrument selection switch device, 19...Decoder, 20...Drum rhythm sound pitch data generation circuit, 30...Noise rhythm sound synthesis circuit, 38...Mixing circuit, 39...Signal Generator, 40 to 43... Frequency divider, 44...1/
2 frequency divider, 45 to 48...Latch circuit, 61...
...Level adjuster, 70,73,88...Shift register, 72,75,77 to 84,89...And gate, 76,87...Noah gate, 85...
...OR gate, 90...Inverter, _D1 ...Pitch data, D2...Key press information, D2 _{- a} ...Octave data, D2 _- b...Pitch name data, _D3 ...
Data, D ₄ ... Instrument type data, D ₅ ... Musical sound waveform data for performance, D ₆ ... Allocation data, D ₇ ... Octave data, D ₈ ... Data, D ₉ ... Channel information, Din ... Input data, CLK...clock, CS0 to CS3...channel signal, LM...
...Music waveform switching signal for performance/rhythm, _S1 ...key-on signal, _S3 ...divided signal, _O1 to _O3 ...mixed output.

Claims (1)

[Claims] 1. Means for generating a clock, a waveform memory in which predetermined musical waveform data is stored, and a means for dividing the frequency of the clock in response to keyboard operations and reading waveform data from the waveform memory. a pitch generation circuit for outputting first pitch data; and a first pitch generation circuit for performing a waveform data read operation according to the first pitch data in multiple channels by time-sharing processing.
A musical sound for an electronic musical instrument, comprising a control means and a second control means for enveloping control of the data read from the waveform memory, and generating a musical sound waveform for performance or a musical sound waveform for rhythm by applying a predetermined switching signal. The waveform generation circuit includes an instrument selection means for selecting a rhythm instrument, a circuit for outputting second pitch data regarding the pitch of the drum rhythm instrument selected by the instrument selection means, and a plurality of frequency dividers for dividing the clock. a frequency generator; means for inputting the second pitch data to the pitch creation circuit in place of the first pitch data in response to the switching signal to obtain desired drum rhythm sound waveform data from the waveform memory; and the switching signal. means for causing a part of the pitch generating circuit to perform a frequency division operation on the clock in response to the pitch generation circuit; means for generating data; means for inputting the drum rhythm sound waveform data and the noise rhythm sound waveform data to the second control circuit in response to the switching signal; means for separating and outputting noise-based rhythm sound waveform data and drum-based rhythm sound waveform data to separate first and second output transmission paths, respectively; 1. A musical waveform generation circuit for an electronic musical instrument, comprising means for synthesizing outputs. 2. Claim 1, wherein the second output transmission path through which the drum rhythm sound waveform data passes has a transmission characteristic that prevents the passage of signals with frequency components higher than a predetermined frequency. The musical sound waveform generation circuit for electronic musical instruments described above. 3. The musical sound waveform generating circuit for an electronic musical instrument according to claim 1, wherein a level adjusting member is included in the first and/or second output transmission path.