JPH0562751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic musical instrument that generates sound by adding an envelope to a musical waveform signal read out in accordance with a signal indicating pitch.

[Prior art]

Conventional methods for obtaining envelope waveform signals include methods that utilize charge-discharge curves obtained using resistors and capacitors, and methods that use an exponential function converter to convert the input signal into an exponential curve. .

[Problems with conventional technology]

In order to obtain an envelope waveform signal having an exponential curve, a dedicated charging/discharging circuit and a dedicated memory are required, resulting in an increase in cost.

[Object and main points of the invention]

Taking advantage of the fact that the scale frequency signal generator that inputs a pitch signal and obtains a scale frequency signal is an exponential converter, the output from the scale frequency signal generator is also used as an envelope waveform signal to generate an envelope waveform signal. An object of the present invention is to provide an electronic musical instrument that does not require a dedicated circuit.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a digital electronic musical instrument will be described with reference to the drawings.

FIG. 1 shows the overall circuit configuration. In the figure, reference numeral 1 indicates a keyboard consisting of a plurality of keys, and the key assignment control unit 2 detects the on or off operation of the key switch of each key (here, it has 61 keys) arranged on the keyboard 1, and detects whether the keys are pressed or not. The identified key is identified and assigned to one of the sounding channels (here, there are 8 channels). When the above-mentioned sound generation channel is specified, this key assignment control section 2 outputs signals S ₁ to _{S 8} (outputted while the key is on) corresponding to this sound generation channel, and also outputs key codes KC1 to KC8. The latches 3-1 to 3-8 are the key codes KC1 to KC above.
Enter 8 and latch. This latch 3-1~3
-8 uses clocks φ ₁ to _{φ 8} shown in FIG. 2 as latch signals. The gate circuits G-1 to G-8 use the clock signals φ ₁ to _{φ 8} as opening/closing control signals, and when these clock signals φ ₁ to φ ₈ are on, the output signals of the latches 3-1 to 3-8 are controlled. is input to the scale ROM 4 in which scale frequency information is stored.

The switch section 5 sends a signal specifying an arbitrary envelope waveform to the envelope counter sections 6-1 to 6-1.
Output to 6-8. The above-mentioned signals S ₁ to S ₈ are input to the envelope counter sections 6-1 to 6-8, and when these signals S ₁ to _{S 8} are turned on,
The envelope counters 6-1 to 6-8 start counting and generate an envelope waveform having attack, decay, and sustain characteristics. This state is shown in FIG. When these signals change from on to off, the envelope waveform becomes released. Gate circuits G-9 to G-16 use clock signals φ ₉ to _{φ 16} (see FIG. 2) as opening/closing control signals, and when these clocks φ ₉ to φ ₁₆ are on, the envelope counter section 6-1 The amplitude values E ₁ to _{E 8} from 6-8 are inputted to the scale ROM 4.

Figure 4 shows the addresses in scale ROM4,
This shows the value corresponding to this address.
Addresses 1 to 61 are 61 on keyboard 1.
Each corresponds to a key. The key code input to the scale ROM 4 is converted to scale frequency information and the latch 7
-1 to 7-8, and are latched by the clocks _φ1 to _φ8 . The accumulators 8-1 to 8-8 receive scale frequency information from the latches 7-1 to 7-8.
Accumulate F ₁ to F ₈ to obtain variable data qF ₁ to qF ₈ .
This variable data qF ₁ to qF ₈ is the waveform ROM9-1 to 9
This is address data for repeatedly reading out the sound source waveform stored in -8. It is assumed that one sine wave is stored as the sound source waveform as shown in FIG.

The latches 7-9 to 7-16 input the amplitude values E ₁ -E ₈ via the scale ROM 4, and input the above-mentioned clocks φ ₉ to
Latched by _φ16 .

Multipliers 10-1 to 10-8 are based on the above waveform ROM.
The waveform values from 9-1 to 9-8 and the latch 7-
Output signals EG1 to EG8 from 9 to 7-16 (6th
(see figure), output to an adder 11, add musical tones for eight channels, send to a DAC (digital/analog converter) 12, and emit sound via an amplifier 13 and a speaker 14.

The specific operation will be described below.

Assume that the Kth key from the bass side on keyboard 1 is turned on. Assume that the key assignment control section 2 specifies, for example, the first sound generation channel. Then the signal KC
1, the key code "K" is output, and the key code "K" is latched into the latch 3-1 by the clock _φ1 , and is input to the scale ROM 4 via the gate circuit G-1. The scale ROM 4 uses the key code "K" as address data and outputs scale frequency information "1/2 ^{- K/12} ". This scale frequency information (hereinafter referred to as _F1 ) is latched into latch 7-1 at clock _φ1 . The scale frequency information F ₁ from this latch 7-1 is sequentially accumulated by an accumulator 8-1 and outputs variable data qF ₁ (q=1, 2...).
The sine wave of the waveform ROM 9-1 is read out at a predetermined period.

On the other hand, the key assignment control section 2 outputs a signal _S1 to activate the envelope counter section 6-1. The amplitude value _E1 from the envelope counter section 6-1 is input to the scale ROM 4 via the gate circuit G-9. Values are sequentially read out from the scale ROM 4 using the amplitude value E ₁ as address data, and the latch 7
-9, it is latched by clock _φ9 . Therefore, the output signal EG1 obtained from this latch 7-9 is
As shown in FIG. 6, it has an exponential curve.

The waveform value obtained from the waveform ROM 9-1 and the output signal EG1 are multiplied by the multiplier 10-1, and this multiplied value is input to the adder 11. Now, only the Kth key is on, so only the multiplication value from the multiplier 10-1 is output from the adder 11, and the DAC 12 and
Sound is emitted via the amplifier 13 and speaker 14.

Here, when other keys are turned on while the K-th key is turned on, the second sound generation channel is specified in the key assignment control section 2, the same operation as described above is performed, and the adder 11 selects the second sound channel. The musical tones corresponding to the number of minutes are added, and the sound is emitted via the DAC 12, amplifier 13, and speaker 14.

Note that although only sine waves are stored in the waveform ROMs 9-1 to 9-8, the waveform ROMs 9-1 to 9-8 are not limited to this and may store various types of waveforms. In this case, a timbre switch may be provided, and the waveform may be selected according to the setting of the timbre switch.

In addition, envelope counter sections 6-1 to 6-8
Although the type of operation of the envelope counter is selected by the switch section 5, it may be set in accordance with the tone color switch.

Furthermore, although the above embodiments have been described with respect to digital electronic musical instruments, the present invention can also be applied to analog electronic musical instruments. In this case, the key code is changed to a signal having a voltage according to the pitch, the scale ROM 4 is changed to an inverse logarithmic amplifier, and the envelope counter sections 6-1 to 6-8 are changed to envelope generators, and the voltage according to the pitch is changed. What is necessary is to alternately switch between the signal having the input signal and the signal output from the envelope generator, and input the signal to the inverse logarithm amplifier. Then, the output from this anti-logarithmic amplifier is connected to the VCO,
Input it into the VCA, create a musical sound waveform, and emit the sound.

〔Effect of the invention〕

As explained above, in this invention, the circuit conventionally used to obtain a scale frequency signal is also used to form an envelope waveform signal, so it is very convenient to be able to perform good musical tone generation control without increasing the circuit scale. .

[Brief explanation of the drawing]

FIG. 1 is an overall circuit diagram of an embodiment of the present invention.
Figure 2 is a diagram showing the relationship between clocks φ ₁ to _{φ 16} ;
4 is a waveform diagram showing the operating states of the envelope counter units 6-1 to 6-8, and FIG. 4 is a diagram showing addresses of the tone ROM 4 and values corresponding to these addresses.
FIG. 5 is a diagram showing the sine waves stored in the waveform ROM 9-1 to 9-8, and FIG. 6 shows the amplitude values of the envelope counter sections 6-1 to 6-8 are
FIG. 4... Scale ROM, 6-1 to 6-8... Envelope counter section, 8-1 to 8-8... Accumulator.

Claims (1)

[Claims] 1. Pitch signal generation means for generating a signal according to pitch, envelope generation signal generation means for generating an envelope, and different signals from the pitch signal generation means and the envelope generation signal generation means. a selection section that selects and outputs at timing; an index conversion section that receives a signal from the selection section and outputs an index-converted signal; and a signal outputted from the pitch signal generation means via the index conversion section. and a musical tone generating means for generating musical tones based on the signal outputted from the envelope generating signal generating means via the index conversion section.