JPS63167397A - Input controller for electronic musical instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an input control device for an electronic musical instrument such as an electronic guitar.

[Background of the Invention 1] Conventionally, a fundamental pitch frequency (hereinafter simply referred to as pitch) is extracted from a waveform signal generated by the playing operation of a natural musical instrument, and a sound source device composed of an electronic circuit is controlled to generate an artificial musical tone. A variety of devices have been developed to produce similar sounds.

In this type of electronic musical instrument, it is common to extract the pitch of an input waveform signal and then instruct the sound source device to generate a scale tone corresponding to the pitch.

By the way, in this type of device, even if a pitch change command for frequently changing the pitch is sent to each sound source bag, the sound source device cannot follow the command.

In particular, when determining the pitch of a generated sound based on pitch information representing a pitch of a semitone or less, the processing time required to process a single pitch change command from the sound source device becomes long, and A new command would arrive even though the processing for the command had not been completed.

Therefore, in order to prevent this kind of problem from occurring, it has been considered to perform processing by coarsening the resolution of the pitch information that specifies the pitch (in extreme cases, the minimum unit is a semitone). This type of processing has the problem of not being able to express subtle changes in pitch or vibrato.

[Purpose of the invention] This invention was made in view of the above circumstances.

To provide an input device for an electronic musical instrument that can improve pitch resolution and provide a musically favorable performance form on a controlled side without putting a burden on a sound source device.

[Summary of the Invention] That is, in the present invention, once a sound generation start command or a pitch change command is sent, the clocking means waits until a predetermined time is exceeded.
The main point is that by not sending out new pitch change commands, the time interval between each command is set to be longer than a certain period of time, so that processing operations according to each command can be performed on the sound source device side.

Therefore, since pitch change commands are sent to the sound source device at least at predetermined time intervals, processing can be performed without difficulty, and the resolution of the pitch of the generated musical tone can be improved (i.e., finer) regardless of the processing speed. ) becomes the turning point.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Circuit configuration Figure 1 shows the circuit configuration of the same embodiment. In this embodiment, the present invention is applied to an electronic guitar, and the signals of the six input terminals l are spread over the electronic guitar body. These are signals from pickups installed on each of the six strings that convert the vibrations of the strings into electrical signals.

The waveform signals from the input terminal l... are sent to the respective amplifiers 2 in the pitch extraction circuits P and -P6 (the figure shows the internal configuration only for the first string P)...
It is amplified by ... and low pass filter (LPF) 3.
The high frequency component is cut off and the basic waveform is extracted by ・・・-・, and the maximum peak detection circuit (MAX) 4...
It is given to the minimum peak detection circuit (MIN) 5 (old) and the zero cross point detection circuit (Zero) 6 (old). The cutoff frequency of the low-pass filter 3 is set to 4f, which is four times the vibration sound frequency f of the open string of each string. This is based on the fact that the frequency of the output sound of each string is within two octaves. The maximum peak detection circuit 4... detects the maximum peak point of the waveform signal, and at the rising edge of the detection pulse signal, the Q output of the flip-flop 14 connected to the subsequent stage becomes Hi.
gh level, this flip-flop 14...
The AND output of the output of the zero-crossing point detection circuit 6 and the output of the inverter 30 of the zero-crossing point detection circuit 6 is sent to the interrupt command signal lNTa+ via the AND gate 24. The minimum peak point of the waveform signal is similarly detected by the minimum peak detection circuit 5, and at the rising edge of the detection pulse signal, the minimum peak point of the waveform signal is applied to the CPU 100 as ~lNTa6.
The Q output of . . . becomes High level, and the AND output of the output of this flip-flop 15 . Interrupt command signal lN via...
It is given to the CPU 100 as Tb+ to lNTb6.

That is, the maximum peak point is detected and the flip-flop 14
is at High level, when the waveform crosses from positive to negative, that is, when a zero cross point is detected, interrupt command signals lNTa1 to lNTa6 are given to the CPU 100, and conversely, when the minimum peak point is detected, the clip drop 1
5 is at a High level, when the waveform changes from negative to positive, that is, when a zero cross point is detected, interrupt command signals lNTb+ to lNTb6 are input to the CPU 100.

Immediately after receiving these interrupt command signals, the CPU 100 executes the corresponding flip flow 2 steps 14...
Clear signal CLal for ..., 15...
~CL6b, CLb+-CLbb are generated and reset. Therefore, no matter how many times the zero crossing point is passed until the next maximum peak point or minimum peak point is detected, the corresponding flip-flops 14, 15, . . . are in the reset state. This means that the CPU 100 will not be interrupted.

In addition, FIG. 2 shows a time chart of signal waveforms at each part in the pitch extraction circuit PI. The output of the detection circuit 5 is the output of the zero-crossing point detection circuit 6.

Then, in the CPU 100, an interrupt command signal XNTa1-INTa6 or lNT is generated based on the vibration output of the string.
b, ~lNTb6 are given, and a musical tone instruction is given to the sound source circuit 9 so as to generate a scale tone according to at least one of the respective time intervals. Note that at the start of sound generation, an open string tone is generated. The sound generation may be started and the frequency may be corrected after pitch extraction.The operation at the start of sound generation will be described later.

The above-mentioned time interval is determined using the counter 7 and the work memory 101, as will be described later. That is, the work memory 101 stores various data such as the count value of the counter 7 at the zero cross point immediately after the maximum peak point or the minimum peak point.

After the start of sound generation, the frequency of the musical tone being generated is variably controlled according to the time interval data determined sequentially.The pitch change command is issued by the timer 8 for a predetermined time, that is, by the sound source circuit 9. After measuring the time relative to the completion time, it is applied to the sound source circuit 9. That is, timer 8 is CP
A control signal is supplied from U100, and after measuring a predetermined time, an interrupt command signal lNTc is given to CPU100, and C
The PU 100 performs a predetermined interrupt process based on the interrupt command signal INTC, the details of which will be described later.

As a result, a musical tone signal having a corresponding frequency is generated from the sound source circuit 9, and the sound signal is emitted from the sound system IO.

Further, the musical tone signals from the low-pass filters 3 are given to the A/D converters 11 and converted into digital data according to their waveform levels.

The outputs of the A/D converters 11 . . . are latched in the latch 12. This latch 12...
The latch signal for... is the flip-flop 14
......, 15...... output is or game) 1
3..., and each time the maximum peak point or minimum peak point is passed, the latch 12...
... stores a signal indicating the level of the waveform at that time. Further, the latch signal L+=Lb from the OR gates 13 . . . is also given to the CPU 100.

The output from the latch 12 is then given to the CPU 100, and controls such as start and stop of sound generation, and the output level (volume) of the output sound are performed in accordance with this data.

That is, in the CPU 100, the A/D converter 11...
When the absolute value of the data indicating the waveform level given by ... exceeds a predetermined certain value, it starts producing musical tones, and when this data falls below a certain value, it issues a mute instruction. to end the sound emission. The details of the operation will be described later.

Although the A/D converters 11>( and pitch extracting circuits PI-P6 are provided independently in FIG. 1), it is of course possible to use - A/D converters in a time-sharing manner. It is.

The tone generator circuit 9 has at least six channels of musical tone generation system formed by time-division processing.

Seventh, the operation of this embodiment will be explained. Figure 3 shows the CPU
4 is a flowchart of an interrupt routine for interrupt command signals lNTa and INTb of CPU1
This is the flow of the ringing routine for the interrupt command signal engineer NTc of 00, and FIG. 5 is the main flow.

Although FIGS. 3 to 5 only show the processing for one string, the processing for all strings is exactly the same, so if we consider that the CPU 100 executes the processing for each string in a time-sharing manner, good.

Now, before explaining the specific operation of the CPU 100, the main registers in the work memory 101 will be explained.

The 5TEP register is 0. 1, 2.3, and as the string vibrates (see Figure 6(a) or Figure 7(a)), as shown in Figure 6(b) or Figure 7(b). Its contents change. When this 5TEP register is O, it represents a note-off (mute) state.

The 5IGN register determines whether the zero-crossing point for one cycle measurement is the next zero-crossing point after the maximum peak ('MAX) point.
This indicates whether it is the next zero-crossing point after the minimum peak (MIN) point; the former is entered when it is 1, and the latter is entered when it is 2.

The REVER5E register is a register that stores data for checking whether interrupt processing has been performed due to the arrival of a zero-crossing point after the peak point opposite to the zero-crossing point represented by the 5IGN register.

The T register stores the value of the counter 7 at a specific point for measuring the period of the input waveform. Note that the counter 7 performs a free running operation of counting at a predetermined clock.

The AMP (i) register stores the maximum or minimum peak value (
Actually, it is a register that stores the absolute value), and is a register that stores AMP (1
) is the register for the maximum peak, and AMP(2) is the register for the minimum peak.

Data representing the measured period is input to the PERIOD register, and based on the contents of this register, the CPU 10
0 performs pitch extraction and finally performs frequency control on the sound source circuit 9.

The FLAG register is a control register that becomes 0 when the timer 8 measures a predetermined time, and becomes 1 before that time.

Further, the P and P' registers are pitch storage registers that store frequency data (also representing values in the frequency range of semitones or less) that represent the extracted pitch.

Furthermore, as will be described later, this embodiment uses three methods for various judgments.
One constant (threshold level) is CPU100
is set within.

The first one is 0NLEVI, Fig. 6(a),
As shown in FIG. 7(a), it is in a note-off state,
When a peak value larger than the value of 0NLEVI is detected, the CPU 100 assumes that a string has been picked, etc., and starts executing an operation for period measurement.

0NLEVII is in the note-on state (sounding), and if the difference between the previous detection level and the current detection level is greater than this value, it is assumed that there has been an operation such as tremolo playing, and the sound starts again (relative on, relative
on ) processing.

0FFLEV is as shown in Figure 8(a).
If a peak value less than this value is detected in the note-on (sounding) state, note-off (silence) processing is performed.

Now, from the above explanation, it will be easy to understand the operations of the interrupt routine and main routine described below.

Now, the zero cross point detection interrupt command signal I N which is the output of the AND gate 24 or the AND gate 25
When Ta and I N Th arrive at the CPU 100, the interrupt processing shown in FIG. 3 is performed.

That is, when the interrupt command signal I N T a is input,
First, the process of step P1 is performed, and the a register in the CPU 100 is set to 1. When the 2nd interrupt command signal lNTb is input, the a register is set to 2 by the process of step P2.
Set.

Then, in step P3, t in the CPU 100
Preset the value of counter 7 in the register. In the subsequent step P4, the peak level data of the A/D converter 11 is read from the latch 12 and set in the b register in the CPU 100.

Then, in step P5, 7 lip flows, 1 lip flow,
Clear 4 or Flip Plop 15.

In the following step P6, the contents of the a, b, and t registers are transferred and stored in the work memory 101, and the interrupt processing is ended.

Further, when the interrupt command signal INTC arrives, the interrupt processing shown in FIG. 4 is performed, that is, in step 51, F
Set the contents of the LAG register to 0. Then, this interrupt processing ends.

In the main routine (FIG. 5), in step Q1, the work memory 101 is
The contents of a', b', and t' are shown as a', b', and t' because they are the same as a, b, and t above, and were recorded last time.
It is judged whether or not it has been written, and if no interrupt processing is being performed, the judgment is No, and this step Q+ is repeatedly executed.

Then, if you make a YES decision in step Q+ above,
Proceed to the next step Q2 and read out the contents a', b', b'. Next, in step Q3, the AMP(a'
) register, that is, the peak value of the same type (maximum/minimum) peak point is read out to the C register in the CPU 100, and the peak value b' extracted this time is stored in the above AMP (
a') Set in register.

Next, in steps Q4 to Q6, it is determined whether the contents of the 5TEP register are 3 and 2.1, respectively. If this is the first state, the 5TEP register is 0, so the determination of NO is made in steps Qs, Qs, and Q6. Then, in step Q7, it is judged whether the peak value b' detected this time is greater than 0NLEVI.

If the peak value b' is smaller than 0NLEVI, the process returns to step Q+ since the process of starting sound generation is not yet performed. Suppose that 0NL as shown in Figures 6(a) and 7(a)
Assuming that an input greater than EVI is obtained, step Q
The determination in step 1 is YES, and the process advances to step Q8.

Then, in step QB, 1 is set in the 5TEP register, then in step Q9, O is set in the REVER3E register, and then in step Q r o, a' (that is, 1 at the zero cross point immediately after the maximum peak point, 1 at the minimum peak point, At the zero cross point immediately after the point, input the value of 2) to the 5IGN register.

Then, in step Q++, the value of t' is set in the T register. As a result, the contents of a' are stored in the 5IGN register (now 5IGN becomes l) (Figure 1O(a),
1)), the contents of b' are set in the AMP register, and the contents of t' are set in the T register.

Then return to step 9 again.

Now, with the above explanation, the processing of the main routine immediately after the zero cross point Zero1 in FIGS. 6(a) and 7(a) will be completed.

Now, next, the processing in the main routine immediately after the zero cross point Zero2 will be explained. In that case, step Q above
+-+Q2→Q3→Q4→Q5→Q6 is executed, YES is determined in this step Q6, and then step Q1
Go to 2.

Now, when the waveform changes in the positive direction at the time of input as shown in Fig. 6 (a) and Fig. 7 (L), the 5IGN register is l, and since the negative peak has passed this time, the a register is is 2, so the decision is NO. Incidentally, if a zero cross point arrives immediately after the peak value of the same polarity, a YES determination is made in step Q+2 and the process returns to step Q+ without any further operation.

Now, in this step Q12, the judgment is NO, and the process goes to step QI3, where the 5TEP register is set to 2. (See FIGS. 6(b) and 7(b)).

Then, following step QI3, step Q+4 is executed to compare the previous peak value (AMP (SIGN)) and the current peak value (b'). Now, as shown in Fig. 6 (a), if the previous value XO is smaller than the current value (xl > (See (C)) Execute steps Q+o and Q + + from step QI4, set the 5IGN register to 2, and transfer the contents of the t register to the T register.

Conversely, if the previous peak value is larger than the current peak value, that is, if xH<XO as shown in FIG. do. Note that the 5IGN register will keep its previous value. Therefore, in this case, the previous zero crossing point (Zerol) is the starting point for period measurement (see FIG. 7(c)).

When the main flow is executed for the first time after passing the first-order zero cross point (Zero3).

YES judgment is made in step Q5 and step Q
+ Proceed to 6, this time a' is l, and in the case of Figure 6,
5IGN is 2. In the case of Fig. g47, 5IGN is 1, so in the case of Fig. 6, a negative judgment is made in step Q16, and the process goes to step Q+s and returns to step Q1. In other words, the CPU 100 recognizes that the first peak (amplitude X2) has been passed since the start of period measurement.

In the case of FIG. 7, YES is determined at step Q + 6, and the process goes to step Q I 7 to RE.
Check whether the VER5E register is 1 or not. If it is not 1, it makes a No judgment and returns to step Q1, but as mentioned above, this register has become 1 by executing step Q+s, and from step Q+7 to step Q+s
Set the 5TEP register to 3 (see Figure 7(b))
Then, at step Q+9, subtract the value in the T register, that is, the time of zero cross point Zero, from the value of counter 7, which was accepted by the current interrupt, in the T register, and calculate P.
Store in ERIOD register.

In other words, the size shown in FIG. 7(C) is the length of one cycle, and the following step Qzo-I? The contents of t' are transferred to the T register and a certain period measurement is started.

In step Q40, the pitch of the musical tone to be generated is calculated based on the contents of the PERIOD register, and pitch frequency information representing it (or some information specifying it) is recorded in the P register. This pitch frequency information is desirably expressed in units of cents, in addition to octaves and scales, as well as pitches below semitones.

Then, in the following step Q21, the CPU 100 issues a sound generation command to the tone generator circuit 9 based on the contents of the P register described above, so that musical tones are generated from this point onwards. Continuing to step Qs+, the timer 8 is controlled to count for a predetermined time, the timer 8 is started, and in the following step Q12, 1 is set in the FLAG register.

Now, in the case of FIG. 6 described above, in the main flow processing after the next zero cross point (Zero4), the process jumps from step Q5 to step Q+6 again. now,
Since the 5IGN register is 2, a YES decision is made in step Q+b, and then step Q+1+ is made in the same manner as above.
Q+a-+Qu=Qzo1Qzo+Q2++Qi++Q
s2 is executed, and this time, one period is from the zero cross point Zero2 to ZerO4 shown in FIG. 6(c).
10'O is recognized and a musical tone having a frequency based on this length is started to be produced (see FIG. 6(d)).

In this way, period measurement processing starts from the zero-crossing point next to the peak point with a large value, and ends at the zero-crossing point next to the peak point on the same side as the peak point, and the low-pass filter One period of the waveform of 3 outputs is extracted.

After this sound generation start processing, the main routine proceeds from step Q4 to step Q22, and checks whether the value of b', which is the peak value captured this time, exceeds 0FFLEV as shown in FIG. judge.

If this level is currently exceeded, the process proceeds to step Q23, where it is judged whether relative on processing is to be performed. That is, specifically, the current peak value (b') is 0N lower than the previous peak value (C).
It is judged whether the extracted peak value is large by LEV■, that is, whether the extracted peak value suddenly becomes large during sound generation.

Normally, if the string is vibrated, it will naturally attenuate, so the answer to step Q23 will be No. However, if the string is manipulated again before the previous string vibration has finished damping due to tremolo playing, etc. As a result, the extracted peak value may suddenly become large, and as a result, the determination in step Q23 may become YES.

In that case, step Q23 makes a YES judgment, jumps to step Q8, and executes step Q9 to step Q. As a result, the 5TEP register becomes 1,
From then on, exactly the same operation as that at the time of starting the sound generation described above is executed. That is, step Q+6NQ20 again. Q4
0. Q21. Q41 and Q42 are then executed to process the start of re-sounding.

Now, in the normal state 1, as described above, step Q23 is followed by step 92s to compare the contents of a' and the contents of the 5IGN register, and if they do not match, proceed to QCs and proceed to the next zero-crossing point interrupt processing. If they match, it is already a peak with opposite characteristics (positive/negative peak)
Since each has passed, proceed to step Q25 and RE
It judges whether the vER8E register is 1 or not, and if it is NO, it returns to step Q+ without any processing.
If YES is determined in step Q2S, the process proceeds from step Q25 to step Q26, and in order to obtain a new period, the contents of the T register are subtracted from the contents of the t' register and set in the PERIOD register.

Then, in step 92F, the contents of the t register are changed to T
Transfer to the register and then REVER in step Q29.
The contents of the 5E register are set to 0, and the next cycle measurement is performed.

In the following step Q43, it is determined whether the above-mentioned FLAG register is O or not, and if it is NO, the process returns to step Q+ and no pitch change processing is performed based on the periodic data obtained in the PERIOD register as described above, however. , if the judgment is YES in step Q41, that is, if the timer 8 has counted the predetermined time since the previous sound generation start processing or pitch change processing, and if the interrupt processing (see Fig. 4) is performed, the sound source circuit 9 is newly activated. Even if an instruction is given to perform frequency change control, the sound source circuit 9 can accept the instruction and process it appropriately.

Therefore, proceed to step Qaa next, which is step Q
Same as a o, but the determined pitch frequency information is set to the P register. In step Q45, the frequency information already stored in the P register is compared with the frequency information obtained this time and stored in the P register.

Then, if the - amount is detected, there is no need to change the frequency, so the process returns from step Q45 to step Q+. However, if a discrepancy is detected, it is assumed that the frequency of the input waveform has changed due to the guitar string operation, etc. Follow the steps below to change the frequency of the output musical tone.
The PU 100 does so.

That is, if NO is detected in step Q45, the process goes to step Q28, where the pitch frequency information etc. in the P register is transferred to the sound source circuit 9, and a frequency change process is performed. Therefore, in the sound source circuit 9, the frequency of the musical tone that has been generated so far is changed to the newly specified frequency based on this provided information.

Continuing to step Q28, the CPU 100 executes P
Move the register to the P register, then step Q s
+ and Q s 2 to prepare for the next frequency change process.

In this way, in this embodiment, changes in the vibration frequency of the string are detected moment by moment, and frequency control is performed in real time accordingly.

Then, as mentioned above, the string vibration is damped and the quasi-8
As shown in the figure, when the peak value falls below 0FFLEV, the process goes from step Q22 to step Q30 and 5TE
The P register is set to 0, and a note-off process (mute process) is performed in the subsequent step Q3+, so that the CPU 100 instructs the sound source circuit 9 to mute the musical tones that have been generated so far.

Since this embodiment performs such processing, after giving a sound generation start command or a pitch change command to the sound source circuit 9, the timer 8 indicates a predetermined time, that is, a time corresponding to the completion of the processing in the sound source circuit 9 or more. Since a new pitch change command is given to the sound source circuit 9 after the time has elapsed, even if the pitch resolution is fine, it can be processed sufficiently regardless of the processing speed regarding data exchange between the CPU 100 and the sound source circuit.

Furthermore, when a new sound generation start or mute start is detected, the CPU 100 immediately performs the corresponding processing and gives a predetermined instruction to the sound source circuit 9, resulting in good responsiveness.

In the above embodiment, the CPU 100 performs interrupt processing at the zero cross point immediately after each peak point to start sound generation,
Processing such as cycle calculation, relative on, and start of muting is performed, but these processes may be performed directly at the time of detecting each peak point, and in that case, exactly the same result can be obtained. others.

For example, by detecting the zero crossing point just before the peak point,
Processing similar to the above may be performed, and the method of determining reference points can be changed in various ways. Furthermore, there are various circuit systems for pitch extraction. For example, the pitch extraction may be obtained by taking an autocorrelation function of a waveform, and any other pitch extraction method can be used.

Further, in the above embodiment, each process is executed in the main flow, but similar processes may be executed in the interrupt process.

Further, in the above embodiment, the present invention was applied to an electronic guitar, but the present invention is not necessarily limited to this, and pitch extraction may be performed from an audio signal or an electrical vibration signal input from a microphone or the like. , any type of system may be used as long as it generates an acoustic signal different from the original audio signal at a corresponding pitch or scale frequency. Specifically, a system having Wll, such as an electronic The present invention can be similarly applied to electronic pianos, wind instruments, and stringed instruments such as violins and kotos.

[Effects of the Invention] As detailed above, in this invention, once a sound generation start command or a pitch change command is sent, no pitch change command is sent until a predetermined time is exceeded by the timing means. As a result, the frequency of pitch change commands can be kept low.
This has the effect of providing an input control device for an electronic musical instrument with high frequency resolution t.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a diagram showing the circuit configuration of the embodiment; FIG. 2 is a time chart showing waveforms appearing at various parts in FIG. 1; and FIG. Figure 4 is a flowchart of the CPU zero-crossing point interrupt routine, Figure 4 is a flowchart of the CPH timer interrupt routine, Figure 5 is a flowchart of the CPU main routine, and Figures 6 and 7 are the flowcharts for the CPU's main routine. FIG. 8 is a time chart showing the operation of each part at the time of starting. FIG. 8 is a time chart showing the operation at the start of muting. 1...Input terminal, 4...Maximum peak detection circuit, 5...Minimum peak detection circuit, 6...
... Zero cross point detection circuit, 7 ... Counter, 8 ... - Timer, 9 ... Sound source circuit, 1
4.15...Flip-flop, 100...
...CPU, 101...Work memory, Pl
-P6...Pitch extraction circuit. Patent Applicant Casio Computer Co., Ltd. Figure 2 Figure 3 30 Cross ", Pa [11 included, 171, 1,000 th 4 FjA da 4 Ma,!・1・Ninil rain (b) sTEP Figure 6 <d )ft'* !4=n7゛
V * rJA −
ra]]::. Figure 7 Figure 8

Claims (1)

[Claims] Pitch detection means for detecting a fundamental pitch frequency from an input waveform signal, and instructions to generate a musical tone of a corresponding pitch based on the fundamental pitch frequency detected by the pitch detection means. In an input control device for an electronic musical instrument having an instruction means, the input control device includes a timer for measuring the elapsed time each time after the instruction means issues a sound generation start command or a pitch change command; An input control device for an electronic musical instrument, comprising: means for causing the instruction means to give a new pitch change command based on the fundamental pitch frequency detected by the pitch detection means;