JP2014153434A - Electronic stringed instrument, musical sound generation method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress delay of generation of musical sound in an electronic stringed instrument.SOLUTION: An electronic guitar has strings having the same thickness and stretched for each string number. In the electronic guitar, a fret scan section detects a contact state between a plurality of frets and between the plurality of strings, and a pitch extraction circuit PC extracts a pitch of a picked string. A microcomputer MCP determines an initial musical interval in accordance with a pressed string state detected by the fret scan section and a picked string detected by the pitch extraction circuit PC and causes a sound source SS to generate musical sound. The microcomputer MCP corrects the extraction result (pitch), extracted by the pitch extraction circuit PC, of the picked string on the basis of correction information stored in a memory and, as sound generated by a string of the string number thereof, changes to musical sound of further exact musical interval.

Description

  The present invention relates to an electronic stringed musical instrument such as an electronic guitar, and more particularly to an electronic stringed musical instrument, a musical sound generating method, and a program that generate musical tones of various pitches by extracting pitches from input waveform signals.

Conventionally, musical tone generation is performed by extracting the pitch (fundamental frequency) from the waveform signal generated by the performance operation of a natural musical instrument and controlling the sound source device composed of electronic circuits to artificially obtain sounds such as musical sounds. Equipment has been developed.
For example, as described in Patent Document 1, in an electronic stringed instrument such as an electronic guitar, a fret for pressing a string with a finger and picking for playing the string are performed as performance operations, and musical sounds corresponding to these performance operations are performed. Is generated.

JP 2009-139745 A

  However, in conventional electronic stringed instruments, like actual instruments, strings with different thicknesses according to pitches are provided. For this reason, when picking is performed on a thick string for bass, since the frequency of vibration is low, the rise until picking is extracted may be delayed, and the generation of musical sounds may be delayed.

  The present invention has been made in view of such a situation, and an object thereof is to suppress a delay in the generation of musical sounds by an electronic stringed instrument.

  In order to achieve the above object, an electronic stringed musical instrument according to an aspect of the present invention stores a plurality of strings stretched on a fingerboard portion provided with a plurality of frets and correction information for each of the plurality of strings. Means, state detecting means for detecting a contact state between each of the plurality of frets and each of the plurality of strings, and a string detecting means for detecting that one of the plurality of strings has been played. In response to detection of a string by the string detection means, a tone generation instruction for a musical tone having a pitch obtained based on the string in which the string is detected and the frets in contact with the string by the state detection means A sound generation instruction means for performing on the connected sound source, a pitch detection means for detecting the vibration pitch of the string whose string has been detected by the string detection means, and the string of the string stored in the storage means. Correction information corresponding to the detected string Based on the correction means for correcting the vibration pitch detected by the pitch detection means, and the change means for changing the pitch of the musical sound generated by the connected sound source to the vibration pitch corrected by the correction means. And having.

  ADVANTAGE OF THE INVENTION According to this invention, the delay of generation | occurrence | production of the musical tone by an electronic stringed instrument can be suppressed.

It is a schematic diagram which shows the structure of the principal part of the electronic guitar which concerns on a present Example. It is a block diagram which shows the whole circuit. It is a figure which shows the fret detection circuit for detecting the stringing state of a fret. It is a block diagram which shows the concrete function structure of a pitch extraction circuit and a microcomputer. It is a schematic diagram which shows a fret-frequency data table. It is the figure which expanded and showed the detail (part enclosed by the thick line) of the fret-frequency data table. It is a figure which shows a pitch data conversion table. It is a schematic diagram which shows the outline | summary of the process at the time of a microcomputer generating a musical sound. It is a flowchart which shows the fret detection process routine which a microcomputer performs. It is a flowchart which shows the interrupt routine which shows a process when an interrupt is applied to the microcomputer. It is a flowchart which shows a main routine. It is a flowchart at the time of step 0 (STEP0) shown as M5 of FIG. It is the detail of the flowchart of STEP1 shown as M6 in FIG. FIG. 11 is a detailed flowchart of STEP2 shown as M7 in FIG. It is a flowchart of STEP3 shown as M8 in FIG. It is a figure which shows the detailed content of the subroutine of S311. It is a flowchart of STEP4 shown as M9 of FIG. It is a figure which shows the detailed content of the subroutine of P1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Example]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a case where the present invention is applied to an electronic guitar (guitar synthesizer) will be described as an example. Note that the present invention is not limited to this and can be applied to other types of electronic musical instruments.

FIG. 1 is a schematic diagram illustrating a configuration of a main part of an electronic guitar 1 according to the present embodiment.
As shown in FIG. 1, the electronic guitar 1 includes six strings STG1 to STG6 stretched on the fingerboard FB. By performing fret and picking on each string, the electronic guitar 1 The user can perform with the same operation as a natural musical instrument. As shown in FIG. 1, the electronic guitar 1 includes a scan pulse generator PG that is provided on each of the six strings STG1 to STG6 stretched on the fingerboard FB and inputs a scan pulse to each string. The electronic guitar 1 detects each operation by the fret scanning unit FS and the pitch extraction circuit PC when fret or picking is performed on each string.
FIG. 2 is a block diagram showing the entire circuit. The pitch extraction circuit PC converts the vibration of each string into an electrical signal, acquires the zero-cross point of the vibration waveform and the absolute value of the amplitude, and outputs them to the microcomputer MCP.

  The microcomputer MCP has a memory such as a ROM and a RAM including a pitch data conversion table (pitch table), which will be described later, and a timer TMR, and controls signals to be supplied to the sound source generator SOB. The sound generator SOB includes a sound source SS, a digital-analog converter circuit D / A, an amplifier circuit AMC, and a speaker SP. Note-on (sounding), note-off (silence) from the microcomputer MCP, and a pitch for changing the frequency. A musical tone having a pitch corresponding to the instruction signal is emitted. Note that an interface in the MIDI (Musical Instrument Digital Interface) format is provided between the input side of the sound source SS and the data bus BUS of the microcomputer MCP. Of course, when the sound source SS is provided in the guitar body, another interface may be used. When the address read signal AR from the microcomputer MCP is input, the address decoder DCD reads the string number read signal RDI, the time read signal RDj (j = 1 to 6), the peak values of MAX and MIN, and the current value at that time. Instantaneous value read signal RDAI (I = 1 to 18) is output to pitch extraction circuit PC.

The microcomputer MCP always detects the stringed state of each fret in each string as interrupt processing at regular intervals (for example, every 1 ms). The pressed state detection process is executed as a parallel process separately from pitch extraction by picking each string.
FIG. 3 is a diagram showing a fret detection circuit FDC for detecting a fret-pressed state. The fret detection circuit FDC is provided in the fret scan unit FS.
As shown in FIG. 3, the fret detection circuit FDC has a configuration in which 22 selection lines KI0 to KI21 corresponding to the number of frets and 6 signal lines KC0 to KC5 corresponding to the number of strings are arranged in a matrix. have.

The selection lines KI0 to KI21 are sequentially switched to an active state every predetermined time (for example, 1 ms). These selection lines KI0 to KI21 are pulled up to a high level (for example, 5v). If there is a string that is in contact with the fingerboard FB by pressing the selected line KI0 to KI21 in an active state, a high level signal is read from the signal lines KC0 to KC5 corresponding to the string.
That is, the fret detection circuit FDC switches the selection lines KI0 to KI21 to an active state one by one every predetermined time, reads the state (high level or low level) of the signal lines KC0 to KC5, and for all the frets, Detect which position is pressed.

FIG. 4 is a block diagram showing specific functional configurations of the pitch extraction circuit PC and the microcomputer MCP. The pitch extraction is executed mainly by functions described below of the pitch extraction circuit PC and the microcomputer MCP.
As shown in FIG. 4, the pitch extraction circuit PC includes a low-pass filter LPF, an amplifier circuit AMC, a zero-cross point capturing circuit ZCR, and an absolute value capturing circuit ABS.
A signal having a waveform generated in each string by picking is input to the low-pass filter LPF from the hex pickup, and the low-pass filter LPF cuts the high-frequency component of the input signal and passes only the low-frequency component. .
The amplifier circuit AMC amplifies the output signal of the low-pass filter LPF according to the set gain, and outputs the amplified signal to the zero-cross point capturing circuit ZCR and the absolute value capturing circuit ABS.

The zero-cross point capturing circuit ZCR detects a zero-cross point of the input waveform signal, and outputs a high-level signal when the signal is positive from the zero-cross point and a low-level signal when the signal is negative. Note that both the inverted signal (inverted output) and the non-inverted signal (non-inverted output) are input to the microcomputer MCP as the output signals of the zero-cross point capturing circuit ZCR.
The absolute value fetch circuit ABS detects peak values on both positive and negative sides of the input waveform signal, and inputs the absolute value and sign of the peak value to the microcomputer MCP.

The microcomputer MCP includes an interrupt control circuit IC, a timer TMR, an analog-digital conversion circuit A / D, and a memory MEM.
The interrupt control circuit IC receives the non-inverted output and the inverted output of the zero-cross point capturing circuit ZCR, and generates an interrupt signal at these rising edges. That is, the interrupt control circuit IC generates an interrupt signal at the timing when the waveform signal generated in each string by picking crosses zero. The interrupt control circuit IC outputs the generated interrupt signal to the timer TMR.

When an interrupt signal is input from the interrupt control circuit IC, the timer TMR outputs the input time t (in the case of an interrupt signal by non-inverted output) and time T (in the case of an interrupt signal by inverted output) to the memory MEM. To do.
The analog-digital conversion circuit A / D converts the absolute value of the peak value input from the absolute value acquisition circuit ABS into a digital signal and outputs it to the memory MEM. The analog-to-digital conversion circuit A / D outputs the code input together with the absolute value of the peak value together with the digitized peak value to the memory MEM.

The memory MEM stores the times t and T input from the timer TMR, the absolute value (digital value) of the peak value, and the sign. The times t and T stored in the memory MEM are calculated by calculating the difference between the times t and T stored last time by the microcomputer MCP and the times t and T stored this time, and calculating the frequency (pitch which is the pitch of the musical sound to be generated). Used when seeking.
Further, the memory MEM stores a fret-frequency data table indicating the relationship between the frets of each string and the frequency.

FIG. 5 is a schematic diagram showing a fret-frequency data table. FIG. 6 is an enlarged view showing a part of a fret-frequency data table (a part surrounded by a thick line).
5 and 6, in the fret-frequency data table, the scale A4 is set to 442 Hz, and each string corresponds to which frequency, and a pitch code (key code) according to the fret position is stored in association with each other. .

  In this embodiment, a string used as the first string in a natural musical instrument guitar is stretched to the position of another string, for example, the second string, and a tension within a preset range is applied to the string. In this state, the sound when the second string is picked is used as an actually measured reference sound (for example, 3,013 μs surrounded by a solid line in FIG. 6) by obtaining the frequency by pitch extraction processing. The actually measured reference sound is converted into pitch data (key code) proportional to cent by the pitch data conversion table shown in FIG. In the case of 3,013 μs, the pitch is converted to 64.04 by the pitch data conversion table shown in FIG. The integer part (64) is a key code, and the decimal part (0.4) is pitch vent data. The actually measured reference sound is stored in the memory MEM (for example, 4,031 μs surrounded by a broken line in FIG. 6).

The theoretical reference frequency of the second string is stored in advance in the memory MEM as 4,031 μs = 59.00 (pitch data) (for example, the key code 59 surrounded by a broken line in FIG. 6).
When picking is performed while referring to these data stored in the memory MEM, the microcomputer MCP determines a pitch according to the result of the fret scan and the result of the pitch extraction, and generates a musical sound.

Hereinafter, a procedure for determining a pitch (frequency) when a musical sound is generated when the second fret of the second string is pressed and choked is performed will be described.
First, as a pressed state, a key code 61 (decimal) is determined by fret scanning (key code 61 surrounded by a solid triangle in FIG. 6). Then, a musical tone is tentatively generated by using a preset trigger with the pitch 61 as an initial value of the pitch.
Next, by the pitch extraction process, 2,387 μs (pitch data 68.07) is extracted as a frequency currently played (physically generated by picking) (encircled by a one-dot chain line in FIG. 6). 2,387 μs and key code 68).

The new pitch determined by the extraction result is the currently playing frequency 68.07− (the second reference string actual measurement frequency 64.04−theoretical reference frequency 59.00) = 63.03.
Currently, provisional pronunciation is performed with the key code 61, so that 63.03-61 = 2.03, that is, the 203cent pitch may be corrected. The correction amount of 203 cent is the pitch vent data.

Next, an outline of processing when the microcomputer MCP generates musical sounds will be described.
FIG. 8 is a schematic diagram showing an outline of processing when the microcomputer MCP generates a musical sound.
In FIG. 8, if the signal having the waveform shown in FIG. 8C is input to the pitch extraction circuit PC, the non-inverted output of the zero cross point capturing circuit ZCR corresponding to this is the waveform shown in FIG. The output has the waveform shown in FIG.

  When executing the pitch extraction process, the microcomputer MCP discards the waveform signal by regarding the pitch smaller than the predetermined peak value as noise (STEP 0 to 2). When the microcomputer MCP becomes equal to or higher than a predetermined peak value, the peak value and sign of the waveform are taken in as the value of the velocity VEL when the wave is the first input (STEP 3). At this time, the microcomputer MCP detects the pitch (the initial value of the pitch) from the information on each fret detected in the fret string detection processing executed in parallel with the pitch extraction processing. Then, the microcomputer MCP produces a sound of the pitch based on the velocity VEL value detected in the pitch extraction process (note-on). Specifically, the microcomputer MCP issues a sound generation instruction to the sound source SS by outputting the pitch and velocity VEL values. Thereafter, the pitch extraction process is continued, and the microcomputer MCP calculates the frequency (pitch) from the difference between the time t, T stored last time and the time t, T stored this time (TP (b), TP (b ')) This frequency is used to correct the pitch that is already sounding.

Hereinafter, the operation of the microcomputer MCP will be described with reference to flowcharts and drawings showing waveforms.
First, reference numerals in the drawings will be described.
AD: Input peak value (instantaneous value) obtained by directly reading the input waveform of the pitch extraction circuit PC by the instantaneous value read signals RDA13 to 18 in FIG.
AMP (0, 1)... Positive or negative previous (old) peak value AMRL1... The previous amplitude value for checking the relative off stored in the amplitude register. . Here, the relative off corresponds to the silencing process when the fret operation is stopped and the string is moved to the open string by muting based on the fact that the crest value has suddenly attenuated.
AMRL2... The previous amplitude value stored in the amplitude register for the relative off, and the value of AMRL1 is input thereto.

CHTIM: Period corresponding to the highest sound fret (22 fret) CHTIO: Period corresponding to the open string fret CHTRR: Time constant conversion register, inside the time constant conversion control circuit TCC (FIG. 2) Is provided.
DUB: Flag indicating that the waveform has continued in the same direction FOFR: Relative off counter HNC: Waveform number counter

K: Pitch data consisting of pitch codes of more than half tone and less than half tone MT: Flag on the side from which pitch is to be extracted (positive = 1, negative = 0)
NCHLV ... No change level (constant)
OFTIM ... off time (e.g. equivalent to the open string period of the string)
OFPT: Normal off check start flag ONF: Note off flag RIV: Flag for switching the processing route in step (STEP) 4 described later ROFCT: Constant for determining the number of checks for relative off

STEP: Register (1-5) that specifies the flow operation of the microcomputer MCP
T: Period data TF: Previous zero cross time data that became valid TFN (0, 1): Previous zero cross time data immediately after positive or negative peak value TFR: Time memory register THLIM ..Frequency upper limit (constant)
TLLIM ... Frequency lower limit (constant)

TP (0, 1) ... Positive or negative previous cycle data TRLAB (0, 1) ... Positive or negative absolute trigger level (note-on threshold)
TRLRL: Relative on (re-pronounced)
TRLRS: Resonance elimination threshold

TTLIM ... Lower frequency limit when triggering TTP ... Cycle data extracted last time TTR ... Cycle register TTU ... Constant (product of 17/32 and current cycle information tt)
TTW: Constant (product of 31/16 and current cycle information tt)
VEL is information that determines the velocity (velocity), and is determined by the maximum peak value of the waveform at the start of sound generation.

X: Flag indicating abnormal or normal state b: Current positive / negative flag stored in the working register B (1 at the zero point next to the positive peak, 0 at the next zero point after the negative peak)
c: Current peak value (peak value) stored in working register C
e ・ ・ ・ Previous peak value (peak value) stored in working register E
h: Period data extracted last time stored in the working register H t: Current zero crossing time stored in the working register T0 tt: Current period information stored in the working register TOTO

FIG. 9 is a flowchart showing a fret detection processing routine executed by the microcomputer MCP.
In F1, the microcomputer MCP selects one of the selection lines KI0 to KI21 (for example, the selection line KI0) to make it active.
In subsequent F2, the microcomputer MCP reads the signal levels of the signal lines KC0 to KC5. At this time, the signal level corresponding to the string being pressed has a high signal level, and the signal level corresponding to the string not being pressed has a low level.

In F3, the microcomputer MCP determines whether or not the string is pressed. The microcomputer MCP shifts to the process of F4 when the string is pressed, that is, when yes (hereinafter referred to as Y), and shifts to the process of F1 when the string is not pressed, that is, when it is no (hereinafter referred to as N). To do.
In F4, the microcomputer MCP calculates a pitch code. At this time, the microcomputer MCP calculates a pitch code at the string-pressed position.
By repeating such processing, the microcomputer MCP detects the pressed state of each string for all the frets.

  FIG. 10 is an interrupt routine showing processing when an interrupt is applied to the microcomputer MCP. In I1, the microcomputer MCP gives a string number read signal RDI to the zero-cross time acquisition circuit ZTS via the address decoder DCD. Read the string number that specifies the string that interrupted. Then, the time information corresponding to the string number, that is, the zero cross time information is read by supplying the zero cross time acquisition circuit ZTS corresponding to any one of the time reading signals RD1 to RD6. This is t. Thereafter, at I2, the peak value read signal RDAI (any one of I = 1 to 12) is similarly applied to the peak value acquisition circuit PVS to read the peak value. Let this be c.

  In the subsequent I3, information b indicating whether the peak value is a positive or negative peak is obtained from the zero cross time acquisition circuit ZTS. Then, at I4, the values of t, c, b obtained in this way are set in the buffer registers T0, C, B in the microcomputer MCP. Each time interrupt processing is performed in this buffer, such time information, peak value information, and information indicating the type of peak are written as one set, and processing for information on each string is performed in the main routine. Is made.

  FIG. 11 is a flowchart showing the main routine. By turning on the power, various registers and flags are initialized in M1, and the register STEP is set to zero. In M2, it is determined whether or not the above-described buffer is empty. If no, the process proceeds to M3, and the contents of the registers B, C, and T0 are read from the buffer. As a result, several register STEPs are determined in M4, STEP0 in M5, STEP1 in M6, STEP2 in M7, STEP3 in M8, and STEP4 in M9.

  If the buffer is empty at M2, that is, if yes, the process proceeds sequentially from M10 to M16, where normal note-off algorithm processing is performed. This note-off algorithm is an algorithm that performs note-off when a state below an OFF (OFF) level continues for a predetermined off-time period. In M10, it is determined whether STEP = 0. If N, the process proceeds to M11. At M11, the input peak value AD at that time is directly read. This can be achieved by supplying any of the peak value acquisition signals RDA13 to RDA18 to the peak value acquisition circuit PVS. Then, it is determined whether or not the value AD is the input peak value AD ≦ off level. If Y, the process proceeds to M12. In M12, it is determined whether or not the previous input peak value AD ≦ off level. If Y, the process proceeds to M13, where it is determined whether the value of the timer TMR ≧ off time OFTIM (for example, the constant of the open string period of the string). To be judged. In the case of Y, the process proceeds to M14, and 0 is written in the register STEP. In M15, it is determined whether or not the note is on. In the case of Y, the note-off process is performed in M16 and the process returns to M on the entry side of M2. . If M12 is N, the process proceeds to M17, the microcomputer MCP internal timer TMR is started, and the process returns to the entry side M of M2. If M10 is Y and M11, M13, and M15 are N, all return to M on the entry side of M12.

As described above, when the waveform input level is attenuated, the microcomputer MCP sends a note-off instruction to the sound source SS when the input peak value AD below the off level continues for a time corresponding to the off time OFFTIM. In the snap M15, Y is determined in a normal state. However, the register STEP may take a value other than 0 even when the generation of a musical tone is not instructed by the processing described later. (For example, due to noise input.) In such a case, the initial setting is performed by returning to M2 after the processing of M14 and M15.
In FIG. 11, only the processing for one string is shown, but the microcomputer MCP executes the processing as shown in FIG. 11 by multiplexing the processing for six times corresponding to the number of strings. Of course, a plurality of processors may be provided and the same processing may be executed separately and independently.

Next, details of each routine that branches at M4 and performs the corresponding processing will be described.
FIG. 12 is a flowchart at step 0 (STEP 0) shown as M5 in FIG. 11. In S01, it is determined whether or not the absolute trigger level (note-on, threshold) TRLAB (b) <current peak value c. In the case of Y, the process proceeds to S02 and the resonance removal is checked. The trigger level is checked for each of positive and negative polar peaks. TRLAB (0) and TRLAB (1) are set to appropriate values through experiments or the like. In an ideal system, TRLAB (0) and TRLAB (1) may be the same. In S02, it is determined whether or not resonance elimination threshold TRLRS <[current peak value c−previous peak value (b)], that is, whether or not the difference between the current peak value and the previous peak value is equal to or greater than a predetermined value.

  When picking one string causes other strings to resonate, the vibration level of the other strings gradually increases, and as a result, the change in peak value between the previous time and this time is very small. Thus, the difference does not exceed the resonance elimination threshold TRLRS. However, in normal picking, the waveform suddenly rises (or falls), and the peak difference exceeds the resonance elimination threshold TRLRS.

  If it is determined in S02 that the case is Y, that is, the case of resonance, the following processing is performed in S03. That is, the current positive / negative flag b is written in the flag MT, 1 is written in the register STEP, and the current zero cross time t is set as TFN (b) in the previous zero cross time data. In S04, other flags are initialized, and the process proceeds to S05. In S05, the current peak value c is set as the previous peak value AMP (b), and then the process returns to the main flow of FIG.

  In FIG. 12, A is an entry for Relative On (re-sounding start), and jumps to this S06 from the flow of STEP 4 described later. In step S06, the musical tone output so far is muted once, and the process proceeds to step S03 to start re-sounding. The process for starting the re-sounding is the same as that for starting the normal sounding, and will be described in detail below.

If the answer is N in S01 and N in S02 (when the current peak value c−the previous peak value AMP (b) is not greater than or equal to a predetermined value), the process proceeds to S05. Therefore, the process for starting sound generation does not proceed.
In STEP0 described above, the contents of the B register (b = 1) are written to the flag MT, the contents (t) of the register T0 are written to the previous zero-crossing time data TFN (1), and the peak value ( c) is written in the previous peak value AMP (1).

  FIG. 13 shows the details of the flowchart of STEP1 shown as M6 in FIG. 11. In S11, it is determined whether or not the contents (b) of the register B and the flag Mt are inconsistent. If Y, the process proceeds to S12. . In S12, it is determined whether or not the absolute trigger level (note-on threshold) TRLAB (b) <current peak value c. If YES, the process proceeds to S13. In the case of Y in S12, 2 is set in the register STEP, the content (1) of the register T0 is set as TFN (b) in the previous zero cross time data in S14, and the current peak value c is set in S15 in S15. Set to peak value AMP (b). In S11, if the input waveform signal comes in the same direction in N, the process proceeds to S16, and it is determined whether or not the current peak value c> the previous peak value AMP (b). In the case of Y, that is, the current peak value c is If it is larger than the peak value AMP (b), the process proceeds to S14. On the other hand, in the case of N in S12, the process proceeds to S15, whereby only the peak value is updated. In S16, the process returns to the main flow (FIG. 11) in the case of N and at the end of the process of S15.

  In STEP 1 described above, since the current positive / negative flag b (= 0) and the flag MT = 1 do not match, the current zero cross time t is set as the previous zero cross time data TFN (0), and the current peak value c is further set. Write as the previous peak value AMP (0).

  FIG. 14 shows the details of the flowchart of STEP2 shown as M7 in FIG. 11. In S20, it is determined whether or not the current positive / negative flag b = flag MT, that is, whether the same zero cross point as the direction of STEP0 has arrived. In this case, the process proceeds to S21. In S21, the open string period CHTIO is set in the register CHTRR, and the process proceeds to S22. In S22, it is checked whether or not the current peak value c> (7/8) × previous peak value AMP (b), that is, whether the peak value is substantially the same between the previous peak and the current peak. In this case, the process proceeds to S23, the flag DUB is set to 0, and the process proceeds to S24. In S24, a cycle calculation is performed, and the current zero cross time t−the previous zero cross time data TFN (b) is input to the previous cycle data TP (b), and the current zero cross time t is set as the previous zero cross time data TFN (b). input. TF (b) in S24 is used as a note-on (1.5 wave) condition in STEP3. In S24, the register STEP is set to 3. Further, the largest value among the current peak value c, the previous peak value AMP (0), and the previous peak value AMP (1) is registered as the velocity VEL. Further, the current peak value c is written into the previous peak value AMP (b).

In S241, the fret (pressed string) state corresponding to this string is checked. In subsequent S242, the pitch code calculated in the fret detection processing routine is acquired.
In step S243, the pitch code and velocity VEL are output and the note is turned on. That is, in S243, regardless of the pitch extraction result, the initial value of the pitch is first pronounced by the pitch code and the velocity VEL in the result of the fret detection process. After S243, the process returns to the main routine (RET).

  In the case of N in S20, the process proceeds to S25, in which the flag DUB, that is, the flag indicating that the input waveform in the same direction has come is set to 1, and the process proceeds to S26. In S26, it is determined whether or not the current peak value c> the previous peak value AMP (b). If Y, the process proceeds to S29. In S29, the previous peak value AMP (b) is rewritten to the current peak value c, and the previous zero cross time data TFN (b) is rewritten to the contents t of the register T. In S22, if N, the process proceeds to S27, where it is checked whether or not the flag DUB = 1, that is, whether or not the previous STEP2 was executed. If Y, that is, if it is double, the process proceeds to S28. . In S28, the flag DUB is set to zero. In this case, the process proceeds to S29 and returns to the main routine. After the process of S24 and also when S26 is N, the process returns to the main routine (RET).

  In STEP 2 described above, the flag MT = 1 is rewritten as the current positive / negative flag b, the 0 fret period, that is, the open string period CHTIO is rewritten in the register CHTRR, the flag DUB is set to 0, and t-TFN (1) → The period calculation of TP (1) is performed, and the previous zero-cross time data TFN (1) is rewritten at the current zero-cross time t, and the current peak value c, the previous peak value AMP (0), and the previous peak value AMP ( The largest value in 1) is set as the velocity VEL, and the previous peak value AMP (1) is set as the current peak value c.

FIG. 15 is a flowchart of STEP3 shown as M8 in FIG. 11. In S30, it is determined whether or not the flag MT is not the current positive / negative flag b. In S31, if (1/8) c <AMP (b), X is set to 0, and in the opposite case, X = 1 is set, and the process proceeds to S32. In S32, the previous peak value AMP (b) is rewritten as the current peak value c.
In S33, if the current peak value c is larger than the VEL obtained in STEP 2, the current peak value c is input to the velocity VEL. If vice versa, this velocity VEL does not change. Next, the flag MT is transferred to the current positive / negative flag b, thereby reversing the pitch change side. This means that the meaning of the flag MT is changed from STEP 4 described later, and means the pitch change side. Then, a period calculation of [t-TFN (b) → TP (b)] is performed in S34. Also, TFN (b) is rewritten with the previous zero cross time data as the current zero cross time t.

Next, in S35, it is determined whether or not X = 0. If Y, the process proceeds to S36, where frequency upper limit THLIM <previous period data TP (b) is checked, that is, pitch extraction upper limit is checked. If it has a period larger than the period of the highest sound, it is Y because it is within the allowable range, and the process proceeds to S37. In S37, whether the frequency lower limit TTLIM at the time of trigger> previous cycle data TP (b) is checked, that is, the pitch extraction lower limit is checked. Then, the process proceeds to S38. The pitch extraction lower limit of S37 is different in constant from the pitch extraction lower limit of STEP 4 described later.
Specifically, the upper frequency limit THLIM corresponds to the pitch period 2 to 3 semitones above the highest note fret, and the lower frequency limit TTLIM at the time of triggering is the pitch period 5 semitones below the open string fret of the open string. It shall be equivalent.

In S38, the previous cycle data TP (b) is set as the previously extracted cycle data TTP, that is, the pitch extracted on the pitch extraction side is saved (this is used in STEP 4 described later), and the process proceeds to S39. In S39, a 1.5-wave pitch extraction check is performed to check whether the previous cycle data TP (b) ≈TP (b ′), that is, a substantially equal cycle between zero-cross points having different polarities. In S301, the following processing is performed.
That is, the time storage register TFR is rewritten as the previous zero cross time data TFN (b ′), and the current zero cross time t is set as the previous zero cross time data TF, and the waveform number counter HNC is cleared. This counter HNC is used in STEP 4 described later. The register STEP is set to 4, the note-on flag ONF is set to 2 (sounding state), the constant TTU is set to 0, that is, (MIN), and the constant TTW is set to the maximum MAX. These are all used in STEP 4 described later. Also, the previous peak value register AMRL1 for the relative off is cleared.

  Next, in S310, the period data of TP (b) obtained now is input to the T register, and in S311 jumps to a subroutine PITCH (FIG. 16) for obtaining a pitch code K. In step S312, a sound generation start instruction is output to the sound source SS. By the way, pitch codes of less than a semitone (less than 100 cents) are rounded off (K ← INT (K + 0.5)) at this time, and the sound source SS is instructed to start the chromatic pitch. Will be. Further, the volume of the generated musical sound is determined according to the velocity value stored in the register VEL.

FIG. 16 shows the detailed contents of the subroutine of S311.
First, in P1, the microcomputer MCP executes a subroutine (PITCHCAL) for calculating a pitch, and calculates a pitch corresponding to picking.
In P2, the microcomputer MCP calculates a pitch difference by subtracting the difference between the actually measured reference sound frequency B and the theoretical reference frequency A from the pitch code K currently being played.
Subsequently, in P3, the microcomputer MCP corrects the pitch by a pitch difference (cent).
After the process of P3, the process returns to the main routine (RET).

FIG. 18 shows the detailed contents of the subroutine P1.
The microcomputer MCP first sets the octave value OCT to 0 (S181), and whether the extracted pitch data T is smaller than the reference pitch data T0 “4525” in the pitch data conversion table (FIG. 7) stored in the microcomputer MCP. Is determined (S182). If the extracted pitch data is “9800”, for example, this data T “9800” is larger than the reference pitch data T0 “4525”, so that the process proceeds to S183 and the extracted pitch data T “9800” is halved to “ 4900 ", the octave value OCT is set to -1 to" -1 "(S184), the process returns to S182 again, and is" 4900 "smaller than the reference pitch data T0" 4525 "in the extracted pitch data set to l / 2? Judge whether or not.

  This time, since it is larger than the reference pitch data T0, the processes of S183 and S184 are repeated again, the extracted pitch data T is set to 1/2, “2450”, the octave value is set to −1, “−2”, and the extracted pitch It is determined whether or not the data T “2450” is smaller than the reference pitch data T0 “4525” (S182).

  This time, since it becomes smaller than the reference pitch data T0, the process proceeds to S185, where it is determined whether or not the extracted pitch data T “2450” is larger than the half reference pitch data T0 “2262.5”. Since the extracted pitch data T “2450” is larger, the process proceeds to S188, and the extracted pitch data T “2450” is subtracted from the reference pitch data T0 “4525” to obtain fractional data t “2075” less than an octave. m is set to “0” (S189), and it is determined whether or not the fraction data t “2075” is smaller than the differential pitch data dTm “129” corresponding to the order data m of “0” (S190).

Since the difference pitch data dTm is smaller, the process proceeds to S191, and the first difference pitch data dTm “129” is subtracted from the fraction data t “2075” to become “1946”, and the order data m is incremented by 1 to “1”. (S192). Then, until the fraction data t becomes smaller than the differential pitch data dTm, the processes of steps S191 and S192 are repeated, and the differential pitch data dTm is sequentially subtracted from the fraction data t.
When the difference pitch data dTm is subtracted to “73” and the order data m becomes “21”, the fraction data t remains “17”, which is smaller than the next difference pitch data dTm (m = 21) “70”. Therefore, the process proceeds to S193, and an operation of K = K0 + 12 × OCT + (m + t / dTm) /2=57.0+12× (−2) + (21 + 17/70) /2=43.62 is executed to obtain a new sound. Find high code K. This pitch is slightly higher than G1 #.

In this way, pitch data of another octave can be obtained from only the difference data dTm of the pitch of one octave A3 to A4 stored in the pitch data conversion table.
Also, if the extracted pitch data T is smaller than the reference pitch data T0 / 2 “2262.5” of l / 2, the extracted pitch data T is increased by 2 ⁿ times (n in S185 to S187 until the extracted pitch data T becomes larger than “2262.5”. = 1, 2, 3,...), And thereafter, the processing of S188 to S193 described above is performed to obtain the pitch data K.

In summary, the microcomputer MCP multiplies the extracted pitch data T by ²ⁿ (n =..., -2, -1, 0, 1, 2,...) In S181 to S187. The octave value OCT which is the value of n is obtained by being within the range of the pitch data stored in the pitch data conversion table, and less than the octave of the extracted pitch data T in S188 to S192. The pitch name can be obtained from the correspondence between the fraction data and the accumulated data of the differential pitch data dTm.

In the above embodiment, the pitch is displayed as a serial number. However, the pitch may be represented by an octave, a scale name (code), data of less than a semitone, and any other representation form. It may be.
Further, in the above embodiment, the pitch data is held in units of 50 cents (half semitone), but may be in units of 100 cents (every semitone), or may be further subdivided. You may have such data in excess of one octave.
In this way, the corresponding pitch code can be obtained from the periodic data. During the processing of STEP 3 in FIG. 16, the pitch code is set to a semitone or more (S311), and the pitch at the time of pronunciation is chromatic. Will be specified.

  In S30 of FIG. 16, in the case of N (in the case of zero cross point detection in the same direction), the process proceeds to S303, where it is determined whether or not the previous peak value AMP (b) <current peak value c. The process proceeds to S304. In S304, the current crest value c is set as the previous crest value AMP (b), and the velocity VEL is set to a velocity VEL whichever is greater of the velocity VEL or the value c of the register C. If any of S303, S35, S36, S37, and S39 is N, the process returns to the main routine (RET).

In S31, when X = 1, that is, when there is an abnormality, the judgment when 1 / 8b1 <b0 and 1 / 8a2 <a1 do not satisfy the condition, and X = 1.
That is, the peak of the waveform input at the initial stage of waveform input or the like is due to noise, and if the period of these noises is detected and the start of sound generation is instructed, a completely strange sound will be generated. Therefore, in S31, it is detected that the peak value has changed significantly, X = 1, and N is determined in S35. Then, after it is detected in S31 that the waveform changes normally, the start of sound generation is instructed.

Here, note-on occurs when TP (b) ≈TP (b ′) is detected.
In STEP 3 described above, MT = 1 ≠ b, AMP (0) ← c, max [VEL, c (whichever is greater)] → VEL, MT ← b = 0, TP (0) ← [t−TFN (0)], TFN (0) ← t, TTP ← TP (0), TFR ← TFN (1), TF ← t, HNC ← 0, ONF ← 2, TTU ← 0 (MIN), TTW ← MAX, AMRL1 Processing for ← 0, note-on condition TP (0) ≈TP (1) is performed. Then, in response to an appropriate waveform input, a musical tone having a chromatic pitch according to the extracted pitch is started in STEP3. That is, after the period detection is started, l. A sound generation instruction is given to the sound source SS after about five cycles. Of course, as described above, if the various conditions are not satisfied, further processing is performed.

  FIG. 17 is a flowchart of STEP 4 shown as M9 in FIG. 11. In this case, there is a route (1) for performing only pitch extraction and a route (2) for actually changing the pitch. First, the route (1) shown in S40, S41, S42, and S63 to S67 will be described. In S40, the waveform number counter HNC> 3 is determined. If Y, the process proceeds to S41. In S41, it is determined whether or not the relative on threshold value TRLRL <[current peak value c−previous peak value AMP (b)]. If N, the process proceeds to S42. In S42, it is determined whether or not the current positive / negative flag b = flag MT, that is, the pitch change side. If Y, the process proceeds to S43.

  By the way, in the initial state, the waveform number counter HNC is 0 (see S301 in FIG. 15), so in S40, N is determined and the process proceeds to S42. For example, in the case of an ideal waveform input, since b = 1 and MT = 0, the process proceeds from S42 to S63.

  In S63, it is determined whether or not the register RIV = 1 in order to check whether the same polarity peak has been continuously input (doubled) or not. If Y, the process proceeds to S68. , N (when not double), the process proceeds to S64, where the following processing is performed. That is, in S64, the current peak value c is input to the previous peak value AMP (b), and the previous amplitude value AMRL1 is input to the previous amplitude value AMRL2 for the relative off process. In this case, the content of AMRL1 is 0 (see S30 in STEP 3). Furthermore, in S64, the larger one of the previous peak value AMP (b ') and the current peak value c is input to the previous amplitude value AMRL1. That is, a peak value having a large value for two positive and negative peak values in the cycle is set as the amplitude value AMRL1. Then, in S65, it is determined whether or not the waveform number counter HNC> 8. Here, the waveform number counter (zero cross counter not on the pitch change side) NHC is incremented by 1 and counted up.

  Therefore, the upper limit of the waveform number counter HNC is 9. And it progresses to S67 after the process of S65 or S66. In S67, the register RIV is set to 1, and the contents of the time storage register TFR are subtracted from the current zero crossing time and input to the period register TTR. Then, the current zero crossing time t is saved in the time storage register TFR, and thereafter, the process returns to the main routine (RET).

In the case of Y in S63, the process proceeds to S68, and it is determined whether or not the current peak value c> the previous peak value AMP (b). If Y, the process proceeds to S69. In S69, the previous peak value AMP (b) is rewritten to the current peak value c, and the process proceeds to S70. In S70, it is determined whether or not the current peak value c> the previous amplitude value AMRL1, and if Y, the process proceeds to S71, where the current peak value c is input to the previous amplitude value AMRL1.
If N is determined in S68, the process returns to the main routine as soon as possible. Accordingly, only when the peak of the new input waveform is large, the amplitude value of the new waveform is registered. (In that case, it seems that the peak of overtones is not widened.)

Similarly, when the answer is N in S70 and when the process of S71 is completed, the process returns to the main routine.
As described above, route (1) is processed as follows. MT = 0 ≠ b, RIV = 0, AMP (1) ← c, AMRL2 ← AMRL1 ← max [AMP (0), c (whichever is greater)], HNC ← (HNC + 1) = 1, RIV ← 1, TTR ← (t−TFR) and TFR ← 1 are processed. Therefore, the difference in time information from the previous zero-crossing point of the same polarity (from STEP2 → 3) to the current zero-crossing point, that is, the period information, is obtained in the period register TTR. Then, the process returns to the main routine and waits for the next zero cross interrupt.

  Next, a description will be given of a case where the route proceeds to route (2) shown in S40 to S62. Since the waveform number counter HNC = 1 (see S66), the process proceeds from S40 to S42. In S42, since MT = 0 and b = 0, the result is Y, and the process proceeds to S43. In S43, it is determined whether or not the register RIV = 1. Since the register RIV is already set to 1 in the route (1) (see S67), the determination in S43 is Y in this case, and the process proceeds to S44.

  In S44, it is determined whether or not the register STEP = 4. If Y, the process proceeds to S45. In S45, it is determined whether or not the current peak value c <60H (H indicates hexadecimal notation). Since the peak value is now large, the result is Y, and the process proceeds to S46. In S46, it is determined whether or not the previous amplitude value AMRL2−previous amplitude value AMRL ≦ (l / 32) × previous amplitude value AMRL2, the process proceeds to S47 in the case of Y, and the relative off counter FOFR is set to 0. The The relative off process will be described later. In S48, a period calculation is performed. Specifically, (current zero crossing time t−previous zero crossing time data TF) is set in the register TOTO as the current cycle information tt. In S49, it is determined whether or not current frequency information tt> frequency upper limit THLIM (upper limit after starting sound generation). If Y, the process proceeds to S50.

The frequency upper limit THLIM in S49 is the upper limit of the allowable frequency range at the time of trigger (starting sound generation) used in S36 of STEP 3 (thus, the minimum period corresponds to the pitch period two to three semitones of the highest sound fret). Is the same.
Next, in S50, the following processing is performed. That is, the register RIV is set to 0, the current zero cross time t is input as the previous zero cross time data TF, the previous peak value AMP (b) is input to the previous peak value, and the current peak value c is further changed to the previous peak value c. It is input to the high value AMP (b).

Then, after the process of S50, the process proceeds to S51. In S51, it is determined whether or not the frequency lower limit TLLIM> current cycle information tt. The process proceeds to S52.
In this case, the lower frequency limit TLLIM is set, for example, one octave below the open string scale. That is, the allowable range is widened compared to the lower frequency limit TTLIM (see S37) of STEP3. By doing so, it becomes possible to further cope with frequency changes due to operation of the tremolo arm or the like.
Accordingly, the process proceeds to S52 only when the upper and lower limits of the frequency are within the allowable range. Otherwise, the process returns to the main routine from S49 and S51.

Next, in S52, the cycle data TTP is input to the cycle data h extracted last time, and the current cycle information tt is input to the cycle data TTP extracted last time. In S53, the current peak value c is written into the velocity VEL, and the process proceeds to S54. In S54, it is determined whether or not the no-change level NCHLV> (previous peak value e−current peak value c). If Y, the process proceeds to S55.
That is, if the previous peak value (e = AMP (b)) of the same polarity and the current peak value c have changed greatly, the difference will exceed NCHLV. If the pitch is changed based on the periodic information, there is a high possibility that an unnatural pitch change will be exhibited. Therefore, if a determination of N is made in S54, the process returns to the main routine without performing the processes in and after S55.

Next, in the case of Y in S54, it is determined whether or not the relative off counter FOFR = 0. When the relative off process described later is being performed, the relative off counter FOFR is not 0, and in such a case, N is determined in S55 without performing the process of changing the pitch (see S602). Return to the main routine. When the determination of Y is made in S55, the process proceeds to S56 and S57 in order.
Here, the two-wave ternary matching condition is determined. In S56, current cycle information tt × 2 ⁻⁷ <| current cycle information tt−previous cycle data h | is determined. If Y, the process proceeds to S57, and in S57, current cycle information tt × 2 ⁻⁷ < The current cycle information tt—the contents of the cycle register TTR | is determined. If Y, the process proceeds to S58.

That is, in S56, it is determined whether or not the current cycle information tt (see S43) substantially matches the value of the previous cycle data h (= TTP) (see S52). In S57, the current cycle information tt It is determined whether or not the value of the value substantially coincides with TR in the overlapping period. The limit range is 2 ⁻⁷ × tt, and its value changes depending on the period information. Of course, this may be a fixed value, but a better result can be obtained by the technique employing the present embodiment.

  In next S58, it is determined whether or not current cycle information tt> constant TTU. If Y, the process proceeds to S59. Here, it is determined whether current cycle information tt <constant TTW, and if Y, the process proceeds to S60. Note that S58 and S59 are judgments for preventing a rapid pitch change.

  That is, the constant TTU of S58 is set to 0 at S301 of STEP3, and the constant TTW is similarly set to the value of MAX. When this flow is first passed for the first time, a determination of Y is always made at S58 and S59. Thereafter, in S62, which will be described later, (17/32) tt (approximately 1 octave treble period information) is set in the constant TTU, and (31/16) tt (approximately 1 octave) in S62 in the same manner in the constant TTW. Low frequency information) is set. Therefore, when there is a sudden octave up (this occurs when the mute operation is performed with the frets released) or an octave down (this occurs when a waveform peak is missed, etc.) If the pitch is changed, it becomes unnatural, so the branch is made so as not to change the pitch.

  If YES is determined in S58 and S59, the process proceeds to S60. In S60, it is determined whether or not the register STEP = 4 is set. If Y, the process proceeds to S601, the period information tt is set in the register T, and the pitch code is obtained in S602. S602 means execution of a subroutine PITCH (FIG. 16) for obtaining a pitch code similar to S311 described above.

As a result, a pitch code K including a pitch code of less than a semitone is obtained, and a pitch change instruction is given to the sound source SS.
Next, in S62, the time constant is changed corresponding to the current cycle information tt, the constant TTU is rewritten to (17/32) × current cycle information tt, and the constant TTTW is also (31/16) ×. It is rewritten to the current cycle information tt.

  That is, as will be described later, STEP = 5 only when the relative-off process is performed. At that time, the time constant is changed without changing the pitch. This process of changing the time constant means that the microcomputer MCP sets data based on the value of the current cycle information tt in a register. This is as already described.

Then, the process returns to the main routine at the end of the process of S62. Therefore, as described above, the route (2) is subjected to the following processing.
That is, HNC = 1, MT = 0 = b, RIV = 1, FOFR ← 0, tt ← (t−TF), RIV ← 0, TF ← t, e ← AMP (0), AMP (0) ← c, h ← TTP, TTP ← tt, VEL ← c,

further,
(1) TTP≈TTR≈tt,
(2) TTU <tt <TTW,
(3) AMP (0) -c <NCHLV
When the three conditions are satisfied, the pitch is changed including the pitch change of less than a semitone (less than 100 cents) according to tt. Thereafter, TTU ← (17/32) × tt and TTW ← (31/16) × tt are made.

  Accordingly, the pitch change for the actual sound source SS is performed in the route (2), and the processing of the route (1) is performed at the subsequent zero cross interrupt, and similarly the processing of the route (2) is performed at the subsequent zero cross interrupt. In this way, in the route (1), the period is simply extracted (see S67), in the route (2), the actual pitch is changed (see S602), and the time constant change process (see S62) is performed. .

  In S40 in STEP 4, after counting up so that the waveform number counter HNC exceeds 3 in S66 of route (1), a determination of Y is made, and then the process goes to S41 to detect the condition of relative on To do. This is c-AMP (b)> TRRLL, and when the current amplitude value exceeds the threshold value TRLRL as compared to the previous amplitude value AMRL1, that is, this is the same string picking after the string operation. When this occurs (according to the tremolo technique, etc.), in this case, in S41, the process proceeds from S41 to S78 to perform the relative on process, and the highest sound fret is sent to the time constant change register CHTRR of the time constant conversion control circuit TTC. Set period CHTIM (for example, 22 frets). Thereafter, the process proceeds to S60 in FIG. 17, and the musical tone being sounded is note-off, and then re-sounding is started.

According to the normal performance operation, the process proceeds to S40, S41, S42, and proceeds to the route (1) or the route (2) described above.
Next, the relative off process will be described. That is, when the state of fret operation is shifted to the open string state, the amplitude level of the waveform drops rapidly, and the difference between the previous peak value AMRL2 and the previous peak value AMRL1 is (l / 32) AMRL2. If it exceeds, the process proceeds from S46 to S74. Then, the process proceeds from S74 to S75 so as to count up until the relative off counter FOFR exceeds the constant ROFCT. At this time, the process goes from S75 to S48 to perform the processes of S49 to S55. However, since FOFR = 0 is not satisfied, the process returns to the main routine without changing the pitch immediately before entering the relative off process.

If it is determined as Y in S74, when the value of FOFR becomes 3 (ROFCT is 2), the process proceeds from S74 to S75.
However, if the judgment of Y is once even at the judgment of S46, the process proceeds from S46 to S47 and the FOFR is reset. Therefore, if the condition of S46 is not satisfied continuously for the number of times specified by ROFCT, the relative off process is not performed. In addition, if the value of ROFCT is set to a large value for a string with a high pitch, the relative off processing can be performed for any string in a substantially constant time.

  When the process goes from S74 to S76, the relative off counter FOFR is reset, the register STEP is set to 5, and the process goes to S77 to instruct the sound source SS to perform note-off. In this state of STEP 5, the pitch extraction process is executed in the same manner as in STEP 4, but since the process proceeds from S60 to S62 without going through S601 and S602, the pitch is not changed for the sound source SS. However, the time constant change process is performed according to the period extracted in S62.

In the state where STEP is 5, the relative on process is accepted (S41, S78). In other cases, the M14 is detected by detecting that the vibration level has decreased in the main flow of FIG. Then, STEP becomes 0 and the initial state is restored.
The AMRL1 and AMRL2 used in S46 are created in S64, and the peak with the larger level (one of the maximum peak and the minimum peak) in one cycle is set to this value, and the maximum peak a _k Is always larger than the minimum peak b _K −1, and the difference between an + 1 and an + 2, an + 2 and an + 3, and an + 3 and an + 4 all exceed a predetermined value.

At this time, in the processing of the route (2), since the minimum peaks bn + 1, bn + 2, and bn + 3 are extremely decreased, the determination of N is made in S54, the process returns to the main routine, and the pitch changing process is not performed. Not.
Next, a description will be given of processing when an overtone having an octave relation, that is, an octave higher sound or a lower octave sound is continuously detected during pitch extraction.

As already described, when the tt does not exceed the TTU in S58, that is, when it becomes smaller than the value TTU that is 17/32 times the previously extracted period, the process proceeds to S76. In other words, when a sound with a high octave is extracted, it is considered that the mute operation is performed by releasing the finger from the designated fret, and the process goes from S58 to S76 without outputting a high octave sound. , S77 stops the sound generation.
In S59, when tt does not exceed TTW, that is, when it becomes larger than the value TTW which is 31/16 times the previously extracted period, the process returns to the main routine without proceeding to S60.

Normally, when the waveform is very small near the note-off, the waveform is picked up by the picking up crosstalk or the resonance of the body due to other picking. Then, an input waveform that is one octave below may be detected continuously.
In such a case, if no processing is performed, a sound under octave is suddenly output, which is extremely unnatural. For this reason, even if Tan + 2≈Tan + 3≈Tbn + 2 is detected in S57 and S56, Tan + 3> Tan + 1 × (31/16), so that the routine returns from S59 to the main routine without changing the pitch.

Next, a case where a double waveform is extracted, that is, a case where a zero-cross point having the same polarity is wiped out will be described. Considering an example in the case of MT = 1, since the fundamental wave period and the period of the harmonic component are in a non-integer multiple relationship, the phase of the harmonic will be shifted, and a zero cross of the same polarity will be detected. For this reason, it is necessary to prevent incorrect pitch changes.
Therefore, in the process of STEP 4 at the time of zero crossing, which is written as “double” in the figure, the process goes from S42 to S43, and in S43, the determination of Y is made and the process goes to S72. Here, the magnitudes of (an + 3) and (an + 2) are compared. If (an + 3) is larger than (an + 2), the determination of Y is made in S72, and the value of (an + 3) is set in AMP (1). If the reverse is true, no change processing is performed.

By the way, since the extracted time data is not used in the case of this double, the cycle information Tan + 3 is not changed at all. Of course, the pitch is not changed based on the period data.
Similarly, in the case of a double wave, that is, in a state where MT = 0, when a double state occurs, the process goes from S42 to S63, and the determination of Y is made, and the process goes to S68. In S68, (an + 2) is compared with (an + 3) in this case, and only when (an + 3) is larger than (an + 2), the process goes to S69 to rewrite AMP (1). In this case, the previous amplitude value AMRL1 is compared with the current amplitude information (crest value c) in S70. If Y, the process proceeds to S71, and the current amplitude information c is set to the previous amplitude value AMRL1. .
In this way, even when the waveform is doubled due to the influence of overtones, the pitch changing process is not performed unless S56 and S57 are satisfied.

As described above, the electronic guitar 1 according to this embodiment includes a plurality of strings, a memory, a fret scan unit FS, a pitch extraction circuit PC, and a microcomputer MCP. The plurality of strings are stretched on a fingerboard portion provided with a plurality of frets, and the memory stores correction information for each of the plurality of strings. The fret scanning unit FS detects a contact state between each of the plurality of frets and each of the plurality of strings, and the pitch extraction circuit PC detects that any of the plurality of strings has been played. In response to the detection of the string by the pitch extraction circuit PC, the microcomputer MCP generates a musical tone having a pitch obtained based on the string in which the string is detected and the frets that are in contact with the string by the fret scanning unit FS. Gives pronunciation instructions to the connected sound source. The pitch extraction circuit PC detects the vibration pitch of the string from which the string has been detected. The microcomputer MCP corrects the vibration pitch detected by the pitch extraction circuit PC based on correction information corresponding to the detected string of the bullet string stored in the memory. The microcomputer MCP changes the pitch of the musical sound produced by the connected sound source to the corrected vibration pitch.
That is, in the electronic guitar 1 according to the present embodiment, strings of the same thickness (for example, the first string) are stretched around the strings of the respective string numbers. The electronic guitar 1 detects the contact state between each of the plurality of frets and each of the plurality of strings by the fret scanning unit FS, and extracts the pitch of the string that has been played by the pitch extraction circuit PC.
Then, the microcomputer MCP determines an initial pitch according to the string-pressed state (contact state between the string and the fret) detected by the fret scanning unit FS and the string from which the string is detected by the pitch extraction circuit PC. The musical sound is generated in the sound source SS. Further, the microcomputer MCP corrects the extraction result (pitch) by the pitch extraction circuit PC of the struck string by the correction information (fret-frequency data table and pitch data conversion table) stored in the memory MEM, Change the sound of the string with the string number to a more accurate pitch.

Therefore, in the electronic guitar 1, the delay until the pitch is extracted when the string is played can be suppressed, and the string number is determined from the pitch of the waveform in which a string having a thickness different from the string corresponding to the string number is generated. Can be corrected to the pitch of the waveform generated by the original thick string corresponding to.
Therefore, according to the electronic guitar 1 according to the present embodiment, it is possible to suppress a delay in the generation of musical sounds.

The microcomputer MCP has a pitch data conversion table for storing a pitch determined based on each of the plurality of strings and each of the plurality of frets, and is in contact with the string where the string is detected and the string. The corresponding pitch is obtained from the pitch data conversion table based on the fret.
In other words, a pitch data conversion table (pitch table) is stored in the memory MEM, and a pitch corresponding to the pitch is obtained by referring to the pitch data table based on the string from which the string was detected and the fret contacting the string. It is done.
Therefore, since the musical sound can be generated prior to extracting the pitch from the vibration of the struck string, it is possible to suppress the delay in the generation of the musical sound.

  The pitch data conversion table of the memory MEM includes, as correction information, a pitch when the string is vibrated in the open state, and a pitch when the string is stretched with a reference tension and vibrated in the open string state. Is stored, it is possible to appropriately correct the pitch of the generated musical tone in accordance with the picking of the actual string.

  The microcomputer MCP calculates the difference between the pitch when the string is vibrated in the open string state and the pitch when the string is vibrated in the open string state by stretching the string with the reference tension, Since the calculated difference is subtracted from the vibration pitch detected from the string, it can be corrected to a more accurate pitch.

In the above embodiment, the period is extracted from the interval of each zero cross point next to the maximum peak point and the minimum peak point. However, other methods, for example, the time between the maximum peak points and the time between the minimum peak points, Period extraction may be performed from the interval. Further, the circuit configuration can be variously changed in accordance with it.
In the above embodiment, the present invention is applied to an electronic guitar (guitar synthesizer). However, the present invention is not limited to this. Any instrument or device of a type that performs pitch extraction and generates an acoustic signal different from the original signal can be applied.

The series of processes described above can be executed by hardware or can be executed by software.
In other words, the configurations of FIGS. 2 and 4 are merely examples, and are not particularly limited. That is, it is sufficient that the electronic guitar 1 has a function capable of executing the above-described series of processing as a whole, and what functional configuration and circuit configuration are used in order to realize this function are particularly shown in FIGS. It is not limited to the example.
In addition, one functional block may be constituted by hardware alone, software alone, or a combination thereof.

When a series of processing is executed by software, a program constituting the software is installed on a computer or the like from a network or a recording medium.
The computer may be a computer incorporated in dedicated hardware. Further, the computer may be a computer that can execute various functions by installing various programs, for example, a general-purpose personal computer.

  A recording medium including such a program is provided not only to a removable medium distributed separately from the apparatus main body in order to provide the program to the user, but also to the user in a state of being incorporated in the apparatus main body in advance. It consists of a recording medium. The removable medium is composed of, for example, a magnetic disk (including a floppy disk), an optical disk, a magneto-optical disk, or the like. The optical disk is composed of, for example, a CD-ROM (Compact Disk-Read Only Memory), a DVD (Digital Versatile Disk), or the like. The magneto-optical disk is configured by an MD (Mini-Disk) or the like. In addition, the recording medium provided to the user in a state of being preinstalled in the apparatus main body is configured by, for example, a ROM or a hard disk in which a program is recorded.

  In the present specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in chronological order according to the order, but is not necessarily performed in chronological order, either in parallel or individually. The process to be executed is also included.

  As mentioned above, although several embodiment of this invention was described, these embodiment is only an illustration and does not limit the technical scope of this invention. The present invention can take other various embodiments, and various modifications such as omission and replacement can be made without departing from the gist of the present invention. These embodiments and modifications thereof are included in the scope and gist of the invention described in this specification and the like, and are included in the invention described in the claims and the equivalent scope thereof.

The invention described in the scope of claims at the beginning of the filing of the present application will be appended.
[Appendix 1]
A plurality of strings stretched on a fingerboard portion provided with a plurality of frets;
Storage means for storing correction information in each of the plurality of strings;
State detecting means for detecting a contact state between each of the plurality of frets and each of the plurality of strings;
String detection means for detecting that one of the plurality of strings has been stringed;
In response to detection of a string by the string detection means, a tone generation instruction for a musical tone having a pitch obtained based on the string in which the string is detected and the frets in contact with the string by the state detection means A sounding instruction means for performing sound on the connected sound source;
Pitch detection means for detecting the vibration pitch of the string detected by the string detection means;
Correction means for correcting the vibration pitch detected by the pitch detection means based on correction information corresponding to the detected string of the bullet string stored in the storage means;
Changing means for changing the pitch of the musical sound produced by the connected sound source to the vibration pitch corrected by the correcting means;
Electronic stringed instrument with
[Appendix 2]
The sound generation instructing means has a pitch table that stores a pitch determined based on each of the plurality of strings and each of the plurality of frets, and is in contact with the string on which the string is detected and the string. The electronic stringed instrument according to appendix 1, wherein a corresponding pitch is obtained from the pitch table based on a fret.
[Appendix 3]
The storage means stores, as the correction information, a pitch when the string is vibrated in an open string state and a pitch when the string is stretched with a reference tension and vibrated in an open string state. The electronic stringed instrument according to appendix 1.
[Appendix 4]
The correction means calculates a difference between a pitch when the string is vibrated in an open string state and a pitch when the string is stretched with a reference tension and vibrated in an open string state; The electronic stringed instrument according to appendix 3, wherein the detected vibration pitch is corrected by subtracting the calculated difference from the vibration pitch detected by the pitch detection means.
[Appendix 5]
Between a plurality of strings stretched on a fingerboard portion provided with a plurality of frets, storage means for storing correction information on each of the plurality of strings, and between each of the plurality of frets and each of the plurality of strings. A state detecting means for detecting the contact state of
Detecting that one of the plurality of strings is struck;
In response to the detection of the string, connected to the tone generation instruction of the musical tone of the pitch obtained based on the string where the string is detected and the fret contacting the string by the state detection means To the sound source,
Detecting the vibration pitch of the detected string of the string;
Correcting the vibration pitch of the detected string of the string based on the correction information corresponding to the detected string of the string stored in the storage means;
A musical sound generation method of changing a pitch of a musical sound generated by the connected sound source to the corrected vibration pitch.
[Appendix 6]
Between a plurality of strings stretched on a fingerboard portion provided with a plurality of frets, storage means for storing correction information on each of the plurality of strings, and between each of the plurality of frets and each of the plurality of strings. A state detection means for detecting the contact state of
A string detection step of detecting that one of the plurality of strings has been played;
In response to the detection of the string, connected to the tone generation instruction of the musical tone of the pitch obtained based on the string where the string is detected and the fret contacting the string by the state detection means Pronunciation instruction steps to be performed on the sound source;
A pitch detection step for detecting a vibration pitch of the detected string of the string;
A correction step of correcting a vibration pitch of the detected string of the string based on correction information corresponding to the detected string of the string stored in the storage unit;
A change step of changing a pitch of a musical sound generated by the connected sound source to the corrected vibration pitch;
A program that executes

  DESCRIPTION OF SYMBOLS 1 ... Electronic guitar, PG ... Scan pulse generator, FS ... Fret scan part, FDC ... Fret detection circuit, PC ... Pitch extraction circuit, LPF ... Low pass filter, AMC ... Amplification circuit, ZCR ... Zero cross point acquisition circuit, ABS ... Absolute value acquisition circuit, FB ... Fingerboard, MCP ... Microcomputer, IC ... Interrupt control circuit, TMR ... Timer, A / D ... Analog-to-digital conversion circuit, MEM ... Memory, SOB ... Sound source generator, SS ... Sound source, D / A ... Digital-to-analog conversion circuit, AMC ... Amplifier circuit, DCD ... Address decoder

Claims (6)

A plurality of strings stretched on a fingerboard portion provided with a plurality of frets;
Storage means for storing correction information in each of the plurality of strings;
State detecting means for detecting a contact state between each of the plurality of frets and each of the plurality of strings;
String detection means for detecting that one of the plurality of strings has been stringed;
In response to detection of a string by the string detection means, a tone generation instruction for a musical tone having a pitch obtained based on the string in which the string is detected and the frets in contact with the string by the state detection means A sounding instruction means for performing sound on the connected sound source;
Pitch detection means for detecting the vibration pitch of the string detected by the string detection means;
Correction means for correcting the vibration pitch detected by the pitch detection means based on correction information corresponding to the detected string of the bullet string stored in the storage means;
Changing means for changing the pitch of the musical sound produced by the connected sound source to the vibration pitch corrected by the correcting means;
Electronic stringed instrument with   The sound generation instructing means has a pitch table that stores a pitch determined based on each of the plurality of strings and each of the plurality of frets, and is in contact with the string on which the string is detected and the string. The electronic stringed instrument according to claim 1, wherein a corresponding pitch is obtained from the pitch table based on a fret.   The storage means stores, as the correction information, a pitch when the string is vibrated in an open string state and a pitch when the string is stretched with a reference tension and vibrated in an open string state. The electronic stringed instrument according to claim 1.   The correction means calculates a difference between a pitch when the string is vibrated in an open string state and a pitch when the string is stretched with a reference tension and vibrated in an open string state; The electronic stringed instrument according to claim 3, wherein the detected vibration pitch is corrected by subtracting the calculated difference from the vibration pitch detected by the pitch detection means. Between a plurality of strings stretched on a fingerboard portion provided with a plurality of frets, storage means for storing correction information on each of the plurality of strings, and between each of the plurality of frets and each of the plurality of strings. A state detecting means for detecting the contact state of
Detecting that one of the plurality of strings is struck;
In response to the detection of the string, connected to the tone generation instruction of the musical tone of the pitch obtained based on the string where the string is detected and the fret contacting the string by the state detection means To the sound source,
Detecting the vibration pitch of the detected string of the string;
Correcting the vibration pitch of the detected string of the string based on the correction information corresponding to the detected string of the string stored in the storage means;
A musical sound generation method of changing a pitch of a musical sound generated by the connected sound source to the corrected vibration pitch. Between a plurality of strings stretched on a fingerboard portion provided with a plurality of frets, storage means for storing correction information on each of the plurality of strings, and between each of the plurality of frets and each of the plurality of strings. A state detection means for detecting the contact state of
A string detection step of detecting that one of the plurality of strings has been played;
In response to the detection of the string, connected to the tone generation instruction of the musical tone of the pitch obtained based on the string where the string is detected and the fret contacting the string by the state detection means Pronunciation instruction steps to be performed on the sound source;
A pitch detection step for detecting a vibration pitch of the detected string of the string;
A correction step of correcting a vibration pitch of the detected string of the string based on correction information corresponding to the detected string of the string stored in the storage unit;
A change step of changing a pitch of a musical sound generated by the connected sound source to the corrected vibration pitch;
A program that executes

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