JPS636796Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to an electronic musical instrument that generates musical tones by calculating numerical values proportional to the frequencies of musical tones (hereinafter referred to as frequency numbers), in which pitch deviation is caused by changing the frequency numbers. Conventionally, the following two methods have been considered for causing pitch shift by changing the frequency number. One is to uniformly multiply the frequency number generated in response to a key press by a constant indicating the amount of pitch shift to obtain a frequency number with pitch shift (detune).
The other method is to uniformly add a constant indicating the amount of pitch shift to the frequency number. However, in either method, constants are calculated uniformly regardless of the pitch to be generated, resulting in the following problem. In the former method, by uniformly multiplying by a constant, a pitch shift of a constant cent amount is always obtained. Therefore, if the constant is set so that an appropriate pitch shift or detune is applied in the high range, a problem arises in that only an insufficient pitch shift is obtained in the low range. This is because the frequency difference corresponding to the same amount of cents becomes larger in the higher range, and is slight in the lower range. On the other hand, in the latter method, constants are uniformly added to provide a detune corresponding to a constant beat. Therefore, if a constant is set so that appropriate detune is applied in the high range, a problem arises in that excessive detune is applied in the low range. This is because the amount of cents corresponding to the same beat increases as the frequency range becomes lower. Therefore, in the past, no matter which method was adopted, the only option was to apply detune to match the midrange to avoid excessively inconvenient detune in the high or low range; This results in the inconvenience that only half-finished detuning can be applied to both the low frequency range and the low frequency range. This idea was made in view of the above points,
The purpose is to make it possible to apply appropriate detune in any range. To achieve this purpose, this invention provides a table in which the relationship between keys and appropriate detune amounts is stored in advance, and the detune amount corresponding to the pressed key is read from the table and applied to the pressed key. It is characterized in that it is used for calculations with corresponding frequency numbers. Note that the relationship between keys and detune amounts to be stored in the table is not necessarily that each key corresponds to an individual detune amount; instead, it is not necessary to assign an appropriate detune amount to each key range (range). All you have to do is make it correspond. In the example shown below, 1/4
An appropriate detune amount is set for each octave (3 keys). An embodiment of this invention will be described in detail below with reference to the drawings. In FIG. 1, the key assigner 12 is
The on/off state of the key switch 11 corresponding to each key of 0 is detected, and the sound produced by the pressed key is assigned to one of the musical sound generation channels. For example, keyboard 10 is 88
It has a key (71/4 octave key range). The number of musical sound generation channels is, for example, 16, and the key assigner 12 generates a key code KC indicating the key assigned to each channel and a key-on signal KON indicating the key press or release at the timing corresponding to each channel. Output in parts. The key code KC is a 7-bit binary encoded signal, the upper 3 bits of which consist of octave codes B3 to B1 indicating the octave range, and the lower 4 bits consisting of note codes N4 to N1 indicating the note names within one octave. Become. The key-on signal KON is 1-bit data, and is "1" when the key assigned to that channel is being pressed, and "0" when the key is released. Table 1 shows an example of the relationship between the values of octave codes B3 to B1 and the octave range, and the relationship between the values of note codes N4 to N1 and note names.

[Table] The key code KC is input to the frequency number generation circuit 13. The frequency number generation circuit 13 generates a frequency number F' proportional to the tone frequency of the key represented by the input key code KC. A pitch control signal generation circuit 14 provided in connection with the frequency number generation circuit 13 generates a pitch control signal PC for performing pitch modulation such that the cent amount of pitch deviation is uniformly constant for all keys. This is the circuit where . Pitch control select switch 15
is for selecting the amount of cents of pitch deviation, and a constant corresponding to the amount of cents selected by switch 15 is read out from encoder 16 and given to frequency number generation circuit 13 as pitch control signal PC. As an example of the frequency number generation circuit 13, the second
As shown in the figure, it can be configured by a frequency number table 17 and a multiplier 18. The frequency number table 17 stores in advance an official frequency number F* proportional to the musical tone frequency of each key, and is addressed by the key code KC given from the key assigner 12 (FIG. 1). Read out the frequency number F* corresponding to KC.
The multiplier 18 multiplies this frequency number F* by the pitch control signal PC given from the pitch control signal generation circuit 14 (FIG. 1).
A frequency number F' with a pitch shift of a certain amount of cents is output. In the case of Figure 2, if no pitch shift is applied, the pitch control signal PC
The value is "1" in decimal notation, and the frequency number F' is the same value as F* read from the table 17. Another example of the frequency number generation circuit 13 can be constructed by an adder 19 and a logarithmic-linear conversion circuit 20, as shown in FIG. The adder 19 is a multi-bit adder (for example, 13 bits), and the key code KC is input to the upper 7 bits of the input (A), and the lower 2 bits N2, N2, and KC of the key code KC are input to the remaining lower bits. Input N1 repeatedly. In this way, a signal representing a numerical value (frequency number) proportional to the musical tone frequency of the key represented by the key code KC in logarithmic form with a base of 2 is generated.
logF' is output from adder 19. The reason for this will not be explained since it is not the gist of this invention, but it is explained in detail in the specification of Japanese Patent Application No. 54-50012. The other input (B) of the adder 19 receives the pitch control signal PC applied from the pitch control signal generating circuit 14 (FIG. 1). In the example of FIG. 3, it is assumed that the pitch control signal PC is expressed in logarithmic form.
Therefore, when pitch shift is not applied, the value of pitch control signal PC is "0", and adder 1
The output signal logF' of 9 has the same value as the signal applied to input (A). The output signal logF' of the adder 19 is converted into a linearly expressed frequency number F' by a logarithmic-linear conversion circuit 20. In the example shown in FIG. 1, the pitch control signal output from the pitch control signal generation circuit 14 is
Although the value of PC does not change over time, it may be changed over time to obtain a temporal pitch modulation effect such as a vibrato effect or a glide effect. Of course, it is not the point of this invention to uniformly apply a pitch shift of the same cent amount to each key, so the pitch control signal generation circuit 1
4 may be deleted. In that case, the input (B) of the multiplier 18 in FIG. 2 or the adder 19 in FIG. 3 is unnecessary. In FIG. 1, the top five bits B3, B of the key code KC output from the key assigner 12
2, B1, N4, and N3 are input into the detune table 21 and the random detune table 22 by address. First, Dechun table 2
1 will be explained, and the series of the random detune table 22 will be described later. The detune table 21 stores in advance the relationship between each key and its corresponding appropriate detune amount (this is called a key scaling characteristic). For details, please refer to all keys of keyboard 10 (88 keys) by 1/4
It is divided into octaves (3 keys) and stores data ΔF1 indicating an appropriate detune amount corresponding to each 1/4 octave range (30 ranges in total). More specifically, not only one but multiple sets of data indicating the amount of detune for each 1/4 octave range (consisting of 30 pieces of data △F1 corresponding to 30 ranges) are stored. There is. That is, a plurality of types of key scaling characteristics are stored in the detune table 21. The key scaling characteristic selection switch 23 is for selecting a desired key scaling characteristic, and the encoder 24 outputs data KSS indicating one key scaling characteristic selected by the switch 23. It is added to the detune table 21 as another address input. In the detune table 21, the data KSS given from the encoder 24
Select one data set corresponding to the key scaling characteristic shown by , and select 1/4 of the data set shown by the upper 5 bits of the key code KC from B3 to B1, N4, N3 from the selected data set. Data ΔF1 corresponding to the octave range is read out. As shown in Table 1 above, the upper two bits N4 and N3 of note codes N4 to N1 have the same value for every 1/4 octave, so the key code
The upper five bits B3 to B1, N4, and N3 of KC can identify the tone range for each 1/4 octave. In this embodiment, it is assumed that the data ΔF1 stored in the detune table 21 is a numerical value proportional to the frequency difference (beat) expressed in a linear format. Data ΔF1 indicating the detune amount read from the detune table 21 is given to the adder 25, and the data ΔF1 indicating the detune amount is read from the frequency number generation circuit 13.
It is added to the frequency number F' given to 5.
Note that the adder 25 is also provided with data △F2 from the series of the random detune table 22, but for convenience of explanation, this data △F2
Explain by assuming that there is no value (zero).
In the adder 25, data △ is added to the frequency number F'.
By adding F1, a detuned frequency number F is obtained. This frequency number F is a value proportional to the frequency shifted from the frequency corresponding to the frequency number F' to the treble side or the bass side by the frequency difference corresponding to the data ΔF1. Normally, the absolute value of the data ΔF1 (sign can be positive or negative) indicating the amount of detune is much smaller than the value of frequency number F', therefore, the frequency number F to which detune has been applied is the detune amount. This value is somewhat shifted from the frequency number F' before being applied. Of course, depending on how the key scaling characteristics are set, zero may be read as data △F1 in response to a certain key code KC, but in that case, frequency numbers F' and F will have the same value. becomes. The frequency number F output from the adder 25 is
It is added to the modulo M accumulator 26 and repeatedly added at the timing of the sampling pulse φ. The signal q·F (where q is 1, 2, 3, etc., which corresponds to the number of repeated additions) outputted from the accumulator 26 at each sampling timing as a result of repeated addition corresponds to the value of frequency number F. This is a signal that repeatedly increases from O to M in frequency. That is, in the modulo M accumulator 26, the portion where the repeated addition result is M or more overflows and is not used for subsequent repeated additions. In this embodiment, the key assigner 12 has 16
Key codes KC for channels are output in a time-division manner. Therefore, in the frequency number generation circuit 13, detune table 21, and adder 25, calculations are executed in real time at each timing based on the key code KC given at the timing of each channel.
Frequency number F of the key assigned to each channel
can be obtained in a time-sharing manner. Therefore, the accumulator 26 adopts a configuration in which the frequency numbers F of individual channels are repeatedly added in a time-division manner. In that case, the period of the sampling pulse φ is
The period is set to one cycle of the repetition cycle of the time division timing of each channel. Signal q・F output from accumulator 26
is applied to the tone generator 27, a musical tone signal having a frequency corresponding to the repetition frequency of the signal q·F is generated from the tone generator 27, and this musical tone signal is outputted via the sound system 28. The tone generator 27 includes a tone waveform memory 29, and tone waveform signals are read from the memory 29 using the output signals q and F of the accumulator 26 as address signals. The frequency of the musical waveform signal read from the memory 29 corresponds to the repetition frequency of the signal q·F, that is, the value of the frequency number F. In this way, a musical sound waveform signal subjected to detune corresponding to data ΔF1 indicating the amount of detune is obtained. The tone waveform signal read out from the tone waveform memory 29 is added to a multiplier 30 and multiplied by an envelope waveform signal provided from an envelope generator 31. A key-on signal KON output from the key assigner 12 is applied to the envelope generator 31, and an envelope waveform signal is generated in response to this key-on signal KON. The musical waveform signal whose amplitude has been scaled according to the envelope waveform signal is sent from the multiplier 30 to the musical tone processing circuit 3.
2, and after being subjected to appropriate processing, is provided to the sound system 28. Musical sound processing circuit 32
For example, the musical waveform signals (musical waveform amplitude data of one sample point) sequentially given at the timing of each channel are summed at each sampling timing to obtain a musical waveform signal that is a composite of the musical waveform signals of all channels. This is converted into an analog signal and output, and appropriate musical tone formation processing (expression processing, timbre formation processing, etc.) is performed as necessary. Next, the series of the random detune table 22 will be explained. Detune table 2 mentioned above
In the series No. 1, the detune amount for each key is uniformly the same, or the detune amount is changed so that when a certain key is specified, the detune amount for that key is a predetermined size determined from the selected key scaling characteristics. administered. For example, if key C4 is C4
The detune amount for the signal does not change unless the key scaling characteristic select switch 23 is switched. On the other hand, in the series of random detune table 22, random detune is applied. 1 to create randomness
As one method, the example in FIG. 1 shows that the detune amount is slightly changed depending on which channel the signal is assigned to. Like the detune table 21, the random detune table 22 includes multiple data sets of data ΔF2' indicating the detune amount corresponding to multiple types of key scaling characteristics, and each data set has a 1/4 octave data set. It consists of 30 pieces of data ΔF2' corresponding to each musical range. Data RKSS indicating one key scaling characteristic selected by the random key scaling characteristic selection switch 33 is output from the encoder 34,
It is added to the other address input of the random detune table 22. The random detune table 22 selects one data set corresponding to the key scaling characteristic indicated by the data RKSS given from the encoder 34,
Key code KC from selected dataset
Data ΔF2' corresponding to the range indicated by the upper five bit data B3 to B1, N4, and N3 is read out. The read data △F2' is sent to the shift circuit 35
The value is inputted into the digit and shifted to the upper or lower digit as appropriate, and the value is changed. Shift circuit 3
Detune amount data whose value was changed in 5 △F
2 is input to the adder 25 and added to the frequency number F' and the detune amount data ΔF1 read from the table 21. Therefore, the frequency number
F' is further changed not only by data △F1 but also by data △F2, and the random detune table 2
A frequency number F subjected to random detuning based on a sequence of 2 is obtained. Here, the key scaling characteristic select switch 23 is turned off and the data ΔF output from the detune table 21 is
By setting 1 to zero, it is possible to obtain from the adder 25 a frequency number F subjected to only random detune based on the sequence of the random detune table 22. Now, the random detune is the shift circuit 3
This is achieved by setting different shift amounts for each channel in step 5. The channel counter 36 counts clock pulses φ ₀ synchronized with the channel timing and outputs a 4-bit binary coded signal CHC for identifying the channel name of each channel timing. This 4-bit signal CHC allows the 1st to 16th channels to be
Up to 16 channels can be identified. The decoder 37 receives the signal CHC and decodes it into signals S ₁ to S ₁₆ indicating the amount of shift. The shift circuit 35 shifts the data ΔF2' by an amount (number of bits) corresponding to the signals S ₁ to _{S 16} applied from the decoder 37 to obtain data ΔF2.
Table 2 shows an example of the relationship between the signal CHC indicating the channel name and the output signals S ₁ to _{S 16} of the decoder 37, and the relationship between the shift amounts corresponding to the signals S ₁ to S ₁₆ .

[Table] The shift amount 1/2 is to shift the data ΔF2' by 1 bit to the lower digit. A shift amount of 1 indicates that data ΔF2' is not shifted. The shift amount 1/4 indicates that the data ΔF2' is shifted by 2 bits to the lower digits. Shift amount 1/8 is data △F
2' is shifted to the lower digits by 3 bits. By shifting the data by n bits to the lower digits, it is multiplied by 2 ^-n , that is, 1/2 ⁿ .
Conversely, if you shift n bits to the upper digits, you have multiplied by 2 ⁿ . In this way, data △F2' is multiplied by a number corresponding to the shift amount, and the result is data △F2
is obtained. As shown in Table 2, the output signals S ₁ to _{S 16} of the decoder 37 do not simply indicate the shift amount, but also indicate the sign (+ or -). Therefore, the shift circuit 35 is provided with not only a simple shift function but also a code conversion function. For example, if a negative shift amount is specified, the complement may be obtained after shifting by that shift amount. The contents of the 4-bit signal CHC output from the channel counter 36 change sequentially from the first channel ("0000") to the 16th channel ("1111") every time the channel timing changes. Along with this, the output signals S ₁ to _{S 16} of the decoder 37 sequentially become “1”.
Therefore, the shift amount in the shift circuit 35 is the second
As shown in the table, it changes for each channel timing. Therefore, even if the key is the same, the shift amount differs depending on which channel the key is assigned to, and as a result, the value of the data ΔF2 also differs. For example, if pressed key C4 is assigned to the second channel, the key code of this key C4 is
When data ΔF2' is read from the table 22 at the second channel timing corresponding to KC, the output of the decoder 37 is that the signal _S2 corresponding to the second channel timing becomes "1" and the shift amount becomes " −1/2”. Therefore, at the second channel timing, data △F2 with a value of "-1/2 △F2'" is output from the shift circuit 35, and the detune corresponding to this value "-1/2 △F2'" is the key. This is applied to frequency number F' of C4. On the other hand, the same key C4 is sent to another channel e.g.
15 channels, the data ΔF2' read from the table 22 corresponding to the key code KC of the key C4 is the same as above, but
Since the shift amount set corresponding to the 15th channel timing is "+1/8", the value of the obtained detune amount data ΔF2 is "1/8·ΔF2'", which is different from the above. Therefore, even for the same key, the amount of detune differs depending on which channel it is assigned to, making it possible to perform seemingly random detune. Note that the channel counter 36 and decoder 37 can be replaced by a 16-stage/1-bit shift register (not shown).
For example, if a sampling clock pulse φ having a cycle of one cycle of the channel timing is input to the first stage of this shift register and shifted sequentially by a clock pulse φ ₀ synchronized with the channel timing, the decoder 3
The same signals as the output signals S ₁ to _{S 16} of 7 can be sequentially obtained from each stage of the shift register. By the way, in the example shown in FIG. 1, the top five bits B of the key code KC are stored in the random detune table 22.
Detune amount data △F according to key scaling characteristics by inputting addresses of 3 to B1, N4, and N3
2' is read out. However, if the purpose is only to create randomness, it is not necessary to store the key scaling characteristics in the random detune table 22. In that case, the address input to the random detune table 22 is only the output signal RKSS of the encoder 34, and the key code
There is no need to input the address for the upper 5 bits of KC data. That is, a single piece of data ΔF2' corresponding to a desired detune amount is selected by the select switch 33, and the data ΔF2' is continuously read out from the random detune table 22. Even if the data ΔF2' has the same value for any channel (any key), the shift amount for each channel specified by the output signals S ₁ to _{S 16} of the decoder 37 is different, so the shift circuit 35 outputs data ΔF2 having a different value for each channel. Therefore, even if the key is the same, a different detune will be applied depending on which channel it is assigned to, making it possible to perform seemingly random detune. In this way, even if the series of random detune tables 22 does not perform detune according to the key scaling characteristics, the series of detune tables 21 performs detune according to the key scaling characteristics, which impairs the characteristics of this invention. Never. In addition, in the above embodiment, the detune table 21
Alternatively, in the random detune table 22, detune amount data is stored for each 1/4 octave (3 keys), but the data is not limited to this, and it may be stored for each key, or a wider range ( For example, it may be stored in units of half an octave. Also, the calculation between the frequency number F' and the detune amount data △F1 or △F2 is performed by the adder 2.
5 is used, but a multiplier may also be used. In addition, in the above embodiment, the key code KC of each channel is output from the key assigner 12 in a time-sharing manner, but this is not limited to this, and this can also be done when the key code KC corresponding to the pressed key is continuously output. Of course, the idea can be applied. In the above embodiment, only the musical tone generation series to which detune is applied is shown, but it is also possible to provide a plurality of musical tone generation sequences to which detune is not applied or to which detune is applied as in FIG. Musical tones with somewhat different pitches may be generated simultaneously in each series. If this is done, a favorable ensemble effect can be expected. As explained above, according to this invention, the detune amount corresponding to the pressed key is generated according to the desired key scaling characteristic and used for calculation with the frequency number corresponding to the pressed key. This has the excellent effect of being able to apply appropriate detune (pitch shift) across the range. Further, according to this invention, a plurality of sets of detune data with the range as a variable are stored in advance in a detune table corresponding to different key scaling characteristics, and one set of detune data corresponding to the desired key scaling characteristics is stored in advance in the detune table. Since the detune data can be selected, the performer can select a desired key scaling characteristic very easily, which is an excellent effect.
Further, by applying this idea to generate a pitch shift between a plurality of musical tone generation sequences in accordance with a desired key scaling characteristic, a desirable ensemble effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an electronic musical instrument according to the invention, and FIGS. 2 and 3 are block diagrams showing an example of the frequency number generation circuit of FIG. 1, respectively. 13... Frequency number generation circuit, 15... Pitch control select switch, 18... Multiplier, 21... Detune table, 22... Random detune table, 23... Key scaling characteristic select switch, 25... Addition vessel, 3
3...Random key scaling characteristic selection switch. KC...key code, B3~B1...octave code, N4~N1...note code,
KON...key-on signal, F*, F', F...frequency number, △F1, △F2...data indicating detune amount.

Claims (1)

[Scope of Claim for Utility Model Registration] A keyboard equipped with a plurality of keys, a key code generating means for generating a key code indicating the key pressed on the keyboard, and a frequency corresponding to each pitch according to a predetermined tuning. a frequency number generating means for generating a frequency number and outputting the frequency number corresponding to the pitch of the pressed key according to the key code of the pressed key generated by the key code generating means; and a plurality of key scalings. a selection means for selecting a desired key scaling characteristic from among the characteristics; and a plurality of sets of detune data in which the range is a variable are stored in advance in correspondence with different key scaling characteristics, and a selection means for selecting a desired key scaling characteristic from the key code generating means; According to the predetermined upper bits of the key code of the generated pressed key, the value of the predetermined upper bits of the key code is set among the set of detune data corresponding to the key scaling characteristic selected by the selection means. a detune table for reading detune data of a corresponding sound range; and a calculation for calculating a new frequency number by calculating the frequency number output from the frequency number generation means and the detune data read from the detune table. 1. An electronic musical instrument, comprising means and for setting a frequency of a musical tone to be generated based on a new frequency number obtained by the calculation means.