JPS6223318B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is based on BBD (Bucket Brigade).
This invention relates to a modulation device for electronic musical instruments that applies delay time modulation to a musical tone signal using a variable delay device such as a CCD (charge coupled device) or a CCD (charge coupled device).

As a conventionally proposed modulation device of this type, there is one disclosed, for example, in Japanese Patent Publication No. 52-38888. Such a modulator is
It is suitable for electronically simulating the sound image movement effect (so-called tremolo effect or chorus effect) produced by rotating a speaker or a rotating body provided in front of it with a motor, but the sound image movement effect by motor rotation is The disadvantage is that there is little change in volume compared to .

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel modulation device for an electronic musical instrument that can produce a sound image movement effect with rich volume changes.

The modulation device according to the present invention includes an amplitude modulation means in series with the delay time modulation means, and controls the modulation depth in the amplitude modulation means according to a frequency change (increase or decrease in frequency) of a modulation signal for delay time modulation. Hereinafter, an embodiment shown in the accompanying drawings will be described in detail.

The figure shows a modulation device for an electronic musical instrument according to an embodiment of the present invention, in which 10 indicates a musical tone signal TS corresponding to the operated key each time a key (not shown) is operated.
The musical tone signal TS is supplied to the amplitude modulation circuit 12 and amplitude-modulated, and the amplitude-modulated musical tone signal TS' is sent to the analog shift registers 20, 22, 24 consisting of BBD.
are input in parallel. These BBDs 20, 22, 24 are connected to corresponding voltage controlled variable frequency oscillators (VCO) 21, 2.
The VCOs 21, 23, and 2 are driven by shift pulses with opposite phases supplied from
By periodically changing the control input voltages R, S, and T of No. 5 as described later and frequency modulating the output pulses, delay time modulation is applied to the musical tone signals passing through the BBDs 20, 22, and 24. .

Modulated musical tone signals sent from the BBDs 20, 22, 24 are supplied to sound systems 40, 42, 44 via corresponding low pass filters (LPF) 30, 32, 34, respectively, and are generated. Here, the LPFs 30, 32, and 34 are for reducing noise caused by shift pulses. The musical sounds generated from the sound systems 40, 42, and 44 are accompanied by a so-called tremolo effect or chorus effect in which a sound image moves in space, and when producing these effects, the amplitude modulation circuit 12
, the volume change due to amplitude modulation becomes noticeable. This will become clearer from the explanation below.

Next, to explain the circuits that form the modulation signals R, S, and T, which are the control input voltages of the VCOs 21, 23, and 25, 50 and 52 are low-frequency oscillators ( LFO), the output signal of LFO 50 is supplied to the phase shift circuit 60 when gate element G ₁ conducts, and the output signal of LFO 52 is supplied to gate element G ₂
to the phase shift circuit 60 and the gate element when conductive.
They are respectively supplied to the phase shift circuit 62 when G ₃ is conductive. Phase shift circuits 60 and 62 phase shift each input signal by 120 degrees, and each output signal is supplied to phase shift circuits 64 and 66 for further processing.
The phase is shifted by 120 degrees, and eventually the phase shift circuits 64 and 66
The output signal is generated with a phase shift of 240° with respect to the 0° input signal of phase shift circuits 60 and 62.
Here, the gate elements G ₁ and G ₃ are in a non-conducting state and a conducting state, respectively, in response to the control signal R _T taking the levels “0” and “1”, and the gate element G ₂ is in a non-conductive state and a conductive state, respectively. When the control signal R _C takes the respective levels of "0" and "1", it becomes non-conductive and conductive, respectively.

In the circuit that forms the control signals R _T and R _C for the gate elements G ₁ to _{G 3} , _ST1 and _ST2 are tremolo effect addition switches that are interlocked with each other, and S _C is a chorus effect addition switch. They are connected in such a way that priority is given to adding effects. That is, when the switches S _T1 and S _T2 are switched from the illustrated position to the opposite side to select the addition of the tremolo effect, the control signal R _T changes from the "0" level to the "1" level.
As long as the control signal R C remains at the "1" level, the control signal R _C will not go to the "1" level even if the switch S _C is switched from the illustrated position to the opposite side. The addition of a chorus effect can be selected by setting the control signal to the "1" level when the switches S _T1 and S _T2 are in the state shown in the figure. In this case, switch S _C is switched from the position shown in the figure to the opposite side. That's fine.

The modulation signal R is obtained by mixing a 0° signal derived through gate element _G1 or _G2 and a 0° signal derived through gate element _G3 through resistors _R11 and _R21 , respectively. The modulation signal S is formed by passing the 120° output signals of the phase shift circuits 60 and 62 through the respective resistors.
The _modulated signal _T
are formed by mixing the 240° output signals of the phase shift circuits 64 and 66 via resistors R ₁₃ and R ₂₃ , respectively. As mentioned above, the tremolo effect addition switch S
When _T1 and S _T2 are operated to set the control signal R _T to the “1” level, gate elements G ₁ and G ₃ become conductive, so
At this time, the modulation signals R, S, and T are all 7.0Hz.
is a mixture of a 0.7Hz sine wave signal and a 0.7Hz sine wave signal. Also, chorus effect addition switch S _C
When the control signal R _C is set to the "1" level by operating the gate element G 2 , the gate element G ₂ becomes conductive, and at this time G ₁ and G ₃ are always non-conductive, so the modulation signals R, S, and T become
It is a 0.7Hz sine wave signal alone.

By the way, the modulation signal X for amplitude modulation is 7.0Hz or 0.7Hz derived via the gate element _G1 or _G2 .
It consists of a sine wave signal of Hz and is supplied to the amplitude modulation circuit 12 via a resistor _R1 . Here, _{a series circuit of a resistor R 2 and} a gate element G ₄ is connected as shown in the figure between the transmission path of _the modulated signal It is controlled by an effect addition control signal _RT . Therefore, if you do not select tremolo effect addition (that is, if you select chorus effect),
When the control signal R _T is at the "0" level, the gate element G ₄ is non-conductive, and the modulation signal X is supplied to the amplitude modulation circuit 12 via the resistor R ₁ at a relatively large amplitude level. Furthermore, when adding the tremolo effect is selected, the control signal R _T is at the "1" level and the gate element G ₄ is conductive, so the modulation signal X is at a relatively small amplitude level corresponding to the voltage drop across the resistor R ₂ . and is supplied to the amplitude modulation circuit 12.

In the operation of the modulation device described above, the switch S
When selecting tremolo effect addition by operating _T1 and S _T2 , the modulation signals R, S, and T are all 7.0Hz.
-Since it is formed by a 0.7Hz mixed signal, BBD20,
As a result of the delay time modulation at 22, 24, musical sounds are generated from the sound systems 40, 42, 44 with a tremolo effect in which the sound image moves relatively quickly. In this case, since a volume change is added to the tremolo effect by the amplitude modulation effect by the 7.0 Hz modulation signal X, a tremolo effect that is very similar to the tremolo effect caused by motor rotation is produced. Furthermore, the amplitude level of _the modulated signal can.

On the other hand, when adding chorus effect is selected by operating switch _SC , 0.7Hz modulation signal R,
S, T, and X produce a chorus effect that is a slowed-down version of the tremolo effect described above, accompanied by changes in volume due to amplitude modulation. The chorus effect in this case also has amplitude modulation, so it closely approximates the chorus effect caused by motor rotation.
_Moreover , the amplitude level of the modulation signal
Because the amplitude modulation is made relatively large and the modulation depth is made deeper than in the case of the tremolo effect, this shows an appropriate volume change due to amplitude modulation.

In the above embodiment, as the modulation signal X, the mixed signals R, S, T or a low frequency signal from an oscillator provided separately from the oscillators 50 and 52 may be used as necessary. Furthermore, although an example in which a variable resistance circuit is provided as the amplitude modulation depth control means has been shown, a variable low-pass filter circuit, a voltage-controlled variable gain amplifier (VCA), or the like may also be used.

As described above, according to the present invention, since the amplitude modulation means is provided in series with the delay time modulation means, it is possible to obtain a sound image movement effect with a rich variation in volume. Furthermore, since the depth of amplitude modulation is controlled according to the frequency change of the modulation signal for delay time modulation, there is an advantage that a comfortable modulation effect that is not difficult to hear can be obtained.

Further, as shown in the above embodiment, an amplitude modulation circuit is provided in common in front of the plurality of variable delay devices, and at least one of the plurality of modulation signals for delay time modulation is used as a modulation signal for amplitude modulation. If the depth of amplitude modulation is controlled by controlling the amplitude level using the above-described method, there is an advantage that a comfortable sound image moving effect can be achieved with a simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a modulation device for an electronic musical instrument according to an embodiment of the present invention. 12... Amplitude modulation circuit, 20, 22, 24...
Analog shift register, S _T1 , S _T2 , S _C ...
Effect addition switch, _G1 to _G3 ...Gate element for modulation speed control, _G4 ...Gate element for modulation depth control.

Claims (1)

[Claims] 1 (a) a modulation signal generating means for generating a modulation signal; (b) a frequency setting means for variably setting the frequency of the modulation signal; and (c) a frequency setting means for variably setting the frequency of the modulation signal; (d) a second modulation means that is provided in series with the first modulation means and that applies amplitude modulation to the musical tone signal and transmits it; (e) ) the second
(f) means for converting the musical tone signal modulated by the first and second modulation means into sound; Device. 2 (a) modulation signal generation means for generating a plurality of modulation signals having different phases and the same frequency; (b) frequency setting means for variably setting the frequency of the plurality of modulation signals while maintaining their identity; (c) amplitude modulation means for applying amplitude modulation to a musical tone signal and transmitting it in accordance with at least one of the plurality of modulation signals; (d) amplitude modulation means for transmitting a modulation signal for amplitude modulation in accordance with the frequency setting by the frequency setting means; control means for controlling the modulation depth in the amplitude modulation means by controlling the amplitude level; and (e) a plurality of variable delay devices having a common input of musical tone signals sent from the amplitude modulation means;
delay time modulation means configured to transmit a delay time modulated musical tone signal from each variable delay device by changing the delay time of each of these variable delay devices according to the plurality of modulation signals; f) A modulation device for an electronic musical instrument, comprising: means for converting the musical tone signal sent from the delay time modulation means into sound.