JPH05100666A - Lfo controller - Google Patents

Abstract

PURPOSE:To individually set the control information of a low-frequency signal for frequency modulation and amplitude modulation. CONSTITUTION:Saw tooth waves for vibratos and sound volume variation are generated (S1-S4 and S13-S15). Then a waveform which is previously specified and its crest value are obtained according to the saw tooth waveforms (S5 and S16) to generate a delay time (S6-S8 and S17-S19). A modulation value is obtained from the delay time, crest value, and depth (S10 and S21). Saw tooth waveform rates PLRV and ADRV, waveform specification data PWV and AWV, crest values PLW and ALW, delay initial values PDLCT and ADLCT, delay rates PDRV and ADRV, and depths PDPTH and ADPTH which are used are individually set.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION The present invention relates to an LFO controller.

[0002]

2. Description of the Related Art Since the effects of vibrato, tremolo, etc. in a conventional electronic musical instrument are controlled by using one low frequency oscillator (LFO), setting of various parameters for each vibrato, tremolo, that is, I cannot set different timings, select different waveforms, set different delay times, and set different sensitivities.
There is a problem in that there is no degree of freedom in use. In addition, an LFO control device that adds an effect such as vibrato, tremolo, or growl in a delay mode takes, for example, vibrato, 0 to 1 (maximum for the value corresponding to the set vibrato depth, that is, modulation). value)
Is multiplied by a coefficient that increases with time, and the value that changes with time obtained by this multiplication is multiplied by a constant amplitude vibrato waveform from the LFO, and the result is added to the key code obtained at the key pressing speed. I was trying to do it. For this reason, the number of multiplications is large, the scale of the circuit device is large, and particularly when controlling the LFOs for the sound generation channels independently, a long processing time is required.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an LFO control device for an electronic musical instrument in which modulation control information for frequency modulation and amplitude modulation can be individually set. Especially.

[0004]

In order to achieve the above-mentioned object, the present invention comprises a frequency modulation signal generating means for modulating frequency data and an amplitude modulation signal generating means for modulating amplitude data, both of which are provided. The main point is that the control information for controlling the low frequency signal from the modulation signal generating means can be individually set.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. <Structure of Embodiment> FIG. 1 shows an entire circuit of an electronic musical instrument constructed by applying the present invention. In FIG. 1, reference numeral 1 is a CPU for controlling the entire circuit, and a bus line 2 is provided in the CPU 1. Via the switch unit 3, the display unit 4, the key assigner 6, the RAM 7, the ROM 8, the musical tone creating unit 9, and the multiplying unit 10.
Is connected, and the output of the keyboard section 5 is input to the key assigner 6.

The switch section 3 includes a cursor switch 3a and a value switch 3b shown in the figure, a switch for designating frequency modulation such as vibrato, a switch for designating amplitude modulation such as tremolo or growl, and L.
The FO includes a waveform selection switch and a tone color selection switch.

The display unit 4 is used to display setting information about the LFO, and as shown in FIG. 3, the character "PITCH" indicating frequency modulation is displayed on the upper portion of the display panel surface. And the characters "AMP" indicating amplitude modulation are displayed, and on the left side thereof, various parameters of the LFO, that is, "WAVE" and "DELA" in order from the top.
"Y", "SPEED" and "DEPTH" are displayed. First, "WAVE" indicates the type of waveform. "D
“ELAY” indicates the time (corresponding to the contents of the register PDT and the register ADT) from the start of key depression until the effect starts to be applied. Similarly, "SPEED" is shown in FIG.
The vibrato counter and the volume change counter (whose contents correspond to the register PLCT and the register ALCT in FIG. 2) that produce the waveforms shown in (b) and (f) show the rate of increase per unit time. Finally, "DEPT
“H” indicates a value corresponding to the maximum modulation set (corresponding to the contents of the registers PDPTH and ADPTH in FIG. 2). Such setting information is displayed vertically and horizontally within a dotted frame, and the triangular wave (TRIANGLE) for the frequency modulation (PITCH) and the rectangular wave (SQUARE) for the amplitude modulation (AMP) as examples are the cursor switches shown in the lower right. 3a and a waveform selection switch (not shown) in the switch section 3, and the set value for each is determined by the position designation by the cursor switch 3a and the value designation by the value switch 3b.

Now, returning to FIG. 1 again, the set value set by operating the switch unit 3 is displayed on the display unit 4 and stored in various corresponding registers (FIG. 2) in the RAM 7. ..

A key code given through a key depression operation on the keyboard section 5 is assigned to a predetermined sound generation channel by a key assigner 6, and then modulated by the CPU 1 only when frequency modulation is designated, and then a musical tone is generated. It is given to the creating unit 9. The tone data created by the tone creating unit 9 is used only in the multiplication unit 1 when the amplitude modulation is designated.
After being subjected to modulation processing at 0, it is converted to an analog value at the D / A converter 11 and is emitted as a predetermined musical sound by the sound system 12. The ROM 8 stores a program for the CPU 1 to control the entire circuit.

FIG. 4 shows the configuration of main registers among the registers used for frequency modulation (vibrato), and the waveform designation register PWV uses 6 bits out of 8 bits and has 6 types. Waveform is specified, and the vibrato counter register PLCT has 16 bits (0 to FFF
F), and a register PL for vibrato waveform
W has an 8-bit structure, the most significant bit (MSB) is used for sign (1: minus), and the lower 7 bits are used for absolute value, that is, for peak value. Similarly, of the registers used for amplitude modulation (volume change), the waveform designating register A corresponding to the one described above is used.
WV, volume change counter register ALCT, and
The volume change waveform register ALW has the same configuration.

<Operation of Embodiment> The operation of this embodiment will be described below. FIG. 5 is a diagram showing the main flow of the operation. This flow chart starts with key-on (corresponding to FIG. 7A), and the CPU 1 in step S1
The vibrato counter register PLCT and the volume change counter register ALCT are set to 0, the delay counters PDLCT and ADLCT are set to predetermined initial values larger than the settable depth, and the contents of the register PLCT are set to the contents of the register PLRV. The contents are added and set in the register PLCT (step S2). That is, in step S2, the sawtooth wave shown in FIG. 7B is created.

Next, in step S3, the register PLC
It is determined whether the content of T is larger than a predetermined maximum value (max), and if it is larger, YES is set and 0 is set in the register PLCT for initialization (step S4). Go to S5,
Therefore, after obtaining the peak value based on the contents of the waveform designation register PWV and setting it in the vibrato waveform register PLW to create a triangular vibrato waveform (see FIG. 7C), the delay counter register PDLCT It is determined whether it is 0 (step S6).

Since the register PDLCT is initially set to an initial value larger than the depth setting value, step S
The result of the determination in 6 is NO, and the contents of the delay value register PDRV are subtracted from the contents of the register PDLCT and set in the register PDLCT (step S).
7). That is, in step S7, as shown in FIG. 7D, the value of the waveform that decreases with time from the initial value is set in the register PDLCT.

Next, it is judged whether or not the delay time set in the register PDT has elapsed (step S8),
If it has not elapsed, 0 is set in the register F (step S9). Conversely, if the delay time has elapsed, the complement of the contents of the register PDLCT is multiplied by the contents of the register PLW and the register PDPTH to shift the pitch. Minutes are created (inclined portion with broken line in FIG. 7E), the value is set in the register F (step S10), and the key code obtained by changing the contents of the register F in addition to the original key code, that is, Pitch data is created (solid line portion in FIG. 7E), the data is set in the register K (step S11), and the content of the register K is set in the musical sound creating unit 9
(Step S12), the tone creating section 9 produces tone data with vibrato. After that, in step S13, the contents of the register ALRV are added to the contents of the register ALCT and set in the register ALCT. That is, in this step, the sawtooth wave shown in FIG. 7F is created.

Next, in step S14, the register AL
It is determined whether or not the content of CT is larger than a predetermined maximum value (max), and if it is larger, YES is set and 0 is set in the register ALCT for initialization (step S15). Proceeding to S16, the peak value is obtained based on the contents of the waveform designation register AWV, set in the volume change waveform register ALW, and the rectangular wave volume change waveform (see FIG. 7 (g)).
After creating, the delay counter register ADLC
It is determined whether T is 0 (step S17).

Since the register ADLCT is initially initialized to a value larger than the depth setting value, step S
The result of the judgment in 17 is NO, and the contents of the delay value register ADRW are subtracted from the contents of the register ADLCT and set in the register ADLCT (step S
18). That is, in step S18, as shown in FIG. 7H, the value of the waveform that decreases from the initial value over time is set in the register ADLCT.

Next, it is judged whether the delay time set in the register ADT has elapsed (step S1).
9) If 0 has not elapsed, 0 is set in the register A (step S20). Conversely, if the delay time has elapsed, the register AL is added to the complement of the contents of the register ADLCT.
After multiplying the contents of W and ADPTH to create a volume coefficient (the sloped portion of the broken line in FIG. 7I) and setting the value in register A (step S21), the contents of register A are multiplied by the multiplication unit 10 (Step S22),
It will be the end. That is, in the multiplication unit 10, as shown in FIG. 7 (i), musical tone data to which the tremolo or growl effect is added is created.

FIG. 6 is a flow chart showing the flow of the waveform generation operation, which is "0 to FFF of the counter register LCT.
The peak value of the designated waveform is stored in the waveform register LW with F "as one cycle, and the route is branched to each route according to the contents of the waveform designation register LWV) 0-5). In the flowchart, the register LWV commonly corresponds to both the registers PLWV and ALWV described above.
CT corresponds to the above-mentioned registers PLCT and ALCT,
The waveform register LW corresponds to the registers PLW and ALW described above.

First, if the content of the register LWV is 0 and the triangular wave (TRIANGLE) is designated, the CPU 1 at step T1 registers LC
The most significant bit of T, that is, the content of bit 15 is set to the most significant bit of register LW, that is, bit 7, and the first half of the cycle is positive and the second half is negative. Next, it is judged whether the content of bit 14 of the register LCT is 0 or 1 (step T2). If the result of the determination in step T2 is 0, the contents of bits 13 to 7 of register LCT are set in bits 6 to 0 of register LW (step T3).
If it is 1, the contents of bits 13 to 7 of the register LCT are inverted (complement) and set in bits 6 to 0 of the register LW (step T4). That is, in the processing of steps T1 to T4, the movements of the registers LCT and LW are as follows: LCT ... 0 → 3FFF, 4000 → 7FFF 8000 → BFFF, C000 → FFFF LW …… 0 → 7F, 7F → 0, 80 → FF, FF → 80, the absolute value of the lower 7 bits of the register LW repeats increasing and decreasing twice in one cycle, and the sign bit of the same is half cycle.

[Outer 1] From

[Outside 2] Once, the waveform data as shown in FIG. 8A is generated.

Secondly, if the content of the register LWV is 1 and the sow up (SAWUP) is designated, C
In step U1, PU1 determines whether the content of bit 15 of register LCT is 0 or 1, and if it is 0, sets 1 to bit 7 (MSB) of register LW (in the first half of the cycle).

[External 2]) is set (step U2), and the register LC is set.
The contents of bits 14 to 8 of T are inverted (complement) and set in bits 6 to 0 of the register LW (step U3).
On the other hand, if 1 is determined in step U1, bit 7 (MSB) of register LW is set to 0 (the latter half of the cycle

[External 1]) is set (step U4), and the register LC is set.
The contents of bits 14 to 8 of T are set as they are in bits 6 to 0 of the register LW (step U5). That is, in the processing of steps U1 to U5, the movements of the registers LCT and LW are as follows: LCT ... 0 → 7FFF, 8000 → FFFF LW ... FF → 80, 0 → 7F, and the absolute value in the lower 7 bits of the register LW. Performs a decrease to an increase, and its sign bit is

[Outside 2]

Moving to [External 1], data having a waveform as shown in FIG. 8B is generated.

Thirdly, if the content of the register LWV is 2 and the sow down (SAWDOWN) is designated, the CPU 1 determines in step V1 the register LC.
Judge whether the content of bit 15 of T is 0 or 1, and if 0,
Set bit 7 (MSB) of register LW to 0 (first half of cycle

[External 1]) is set (step V2), and the register LC is set.
The contents of bits 14 to 8 of T are inverted and set in bits 6 to 0 of the register LW (step U3). On the other hand, if it is 1 in the judgment in step V1, 1 is set in bit 7 (MSB) of the register LW (the latter half of the cycle

[External 2]) is set (step V3) and the register LC is set.
The contents of bits 14 to 8 of T are set as they are in bits 6 to 0 of the register LW (step U5). That is, in the processing of steps V1 to V3, U3, and U5, the register LC
The movements of T and LW are as follows: LCT …… 0 → 7FFF, 8000 → FFFF LW …… 7F → 0,80 → FF, and the absolute value of the lower 7 bits of the register LW is executed from increase to decrease, and its sign bit Is one cycle

[Outside 1]

Moving to [External 2], data having a waveform as shown in FIG. 8C is generated.

Fourthly, if the content of the register LWV is 3 and a rectangular wave (SQUARE) having a duty ratio of 1: 1 is designated, the CPU 1 determines in step W1
It is determined whether the content of bit 15 of the register LCT is 0 or 1, and if it is 0 (first half of the cycle), all 0s are set in the register LW (step W2), but if 1 (second half of the cycle), all is written in the register LW. 1 (plus maximum value of 7F) is set (step W3), and data having a waveform as shown in FIG. 8D is generated.

Fifthly, if the content of the register LWV is 4 and a rectangular wave (SQUARE) with a duty ratio of 1: 3 is designated, the CPU 1 determines in step X1 that
It is determined whether the contents of bits 15 and 14 of the register LCT are 0, and if YES (corresponding to the first half of the cycle), all 0s are set in the register LW (step W2), but if NO. For example, all 1s are set in the register LW (step W3), and the waveform data as shown in FIG. 8E is generated.

Finally, if the content of the register LWV is 5 and a rectangular wave (SQUARE) with a duty ratio of 3: 1 is specified, the CPU 1 determines in step Y1 that
It is determined whether the contents of bits 15 and 14 of the register LCT are both 1, and if YES, the register LW
All is set to 0 (step W2), but if NO, all 1 is set to the register LW (step W3), and the waveform data as shown in FIG. 8F is generated.

[0025]

As described in detail above, the present invention has the following advantages.
A low-frequency signal for modulating the frequency data of the musical tone and a low-frequency signal for modulating the amplitude data are prepared, and control information for both low-frequency signals can be set individually, so vibrato, tremolo, etc. There is an effect that various parameters of the effect of are determined separately.

[Brief description of drawings]

FIG. 1 is an overall circuit diagram of an electronic musical instrument constructed according to the present invention.

FIG. 2 is a diagram showing various registers used during operation.

FIG. 3 is a diagram showing a configuration of a display panel surface and an example of setting information.

FIG. 4 is a configuration diagram of main registers among the registers in FIG.

FIG. 5 is a diagram showing a flowchart for explaining the flow of operation.

FIG. 6 is a diagram showing a flowchart for explaining the flow of waveform generation.

7 is a waveform chart mainly used for explaining the operation of FIG.

FIG. 8 is a waveform diagram mainly used for explaining the waveform generation in FIG. 6.

[Explanation of symbols]

 1 CPU 3 Switch part 4 Display part 5 Keyboard part 6 Key assigner 7 RAM 8 ROM 9 Music tone creating part 10 Multiplying part

Claims (1)

[Claims] 1. A frequency modulation signal generating means for generating a low frequency signal for modulating frequency data of a musical tone, and an amplitude modulation signal generating means for generating a low frequency signal for modulating amplitude data of a musical tone, An LFO control device comprising: control information setting means for individually setting control information for controlling a low frequency signal from the frequency modulation signal generation means and the amplitude control signal generation means.