JPS6142277B2 - - 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 an analog shift register such as a charge coupled device (device) or a charge coupled device (CCD).

As a conventionally proposed modulation device of this type, there is one disclosed in Japanese Patent Publication No. 52-38888, for example. Such a modulator is
This 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 it is similar to when the motor is started. At present, we have not yet reached the point where we can sufficiently produce the inertial effect. In other words, it has been considered to gradually increase the frequency of the modulation signal at the start of modulation in order to produce such an inertial effect.
This alone did not represent a sufficient inertial effect.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a modulation device for an electronic musical instrument that is improved so as to produce a sufficient inertial effect.

The modulation device according to the present invention gradually increases the frequency of the modulation multiphase signal at the start of modulation, and gradually changes the phase difference between the modulation multiphase signals from an uneven state to an even state. Hereinafter, embodiments shown in the accompanying drawings will be described in detail.

FIG. 1 shows a modulation device for an electronic musical instrument according to an embodiment of the present invention, in which numeral 10 indicates a musical tone signal corresponding to the operated key each time a key (not shown) is operated.
This is a musical tone signal forming circuit that synthesizes and sends TS, and the musical tone signal TS is input in parallel to analog shift registers 20, 22, and 24 consisting of BBDs. And these BBD2
0, 22, and 24 are driven by mutually opposite phase shift pulses supplied from the corresponding voltage-controlled variable frequency oscillators (VCOs) 21, 23, and 25, respectively, and the control input voltages RS,
BBD20, by periodically changing T as described later and frequency modulating the output pulse.
The musical tone signals passing through 22 and 24 are subjected to delay time modulation.

Modulated musical tone signals sent from the BBDs 20, 22, 24 are supplied to sand 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 in which a sound image moves in space.

Next, the circuits that form the modulation signals R, S, and T, which are the control input voltages of the VCOs 21, 23, and 25, will be explained. A time constant circuit 54 converts the switch status signal A generated when the switch is switched to control signals B and C that rise exponentially with a predetermined time constant, respectively, to 7.0 Hz and 0.7 Hz gradually according to the control signal C. A low frequency oscillator (LFO) that generates a pair of sine wave signals so as to rise to a steady frequency of Hz; 56 a phase shift circuit that shifts the phase of the pair of output signals of the LFO 54 by 120 degrees; 58 a phase shift circuit 56; By shifting the phase of a pair of output signals by 120°,
Phase shift circuit that outputs a pair of signals shifted by 240 degrees with respect to the 0 degree output signal of LFO54, M ₁ , M ₂ , M ₃
are mixing circuits that mix the output signals of each pair of LFO 54, phase shift circuit 56, and phase shift circuit 58, respectively.

The modulation signal R consists of the 0° output signal of the mixing circuit _M1 , which is derived via the resistor _R11 , and the 240° output signal of the mixing circuit _M3 , which is derived via the gate element _G1 and the resistor _R21 .
It is formed by mixing the output signal of .degree. with the resistance ratio of R ₁₁ and R ₂₁ at a ratio of, for example, 10:8. Further, the modulation signal S consists of the 240° output signal of the mixing circuit _M2 . Furthermore, the modulation signal T is
The 240° output signal of the mixing circuit M ₃ derived via R ₁₂ and the 0° output signal of the mixing circuit M ₁ derived via the gate element G ₂ and the low resistor R ₂₂ are defined as R ₁₂ .
It is formed by mixing with _R22 in a resistance ratio of, for example, 10:8. Note that the gate elements G ₁ and G ₂ receive the control signal B from the time constant circuit 50.
The conduction state changes from conduction to non-conduction as the control signal B rises.

In the operation of the modulation signal forming circuit described above, the tremolo effect addition switch SW is changed from "0" to "1".
, time constant circuits 50 and 52 generate control signals B and C, respectively. As the control signal C gradually rises, the LFO 54 gradually increases its oscillation frequency toward the steady frequency of 7.0 Hz and 0.7 Hz. As the oscillation frequency of the LFO 54 increases, the gate element controlled by the control signal B
G ₁ and G ₂ gradually become non-conductive, specifically, become non-conductive 1 to 2 seconds after the switch SW is turned on. That is, during this 1 to 2 seconds, signal mixing is performed via the gate elements G ₁ and G ₂ , and then signal mixing is no longer performed. Therefore, at the time of switching the switch SW, the modulation signals R and T are close to 180 degrees with respect to the modulation signal S as a result of signal mixing at a ratio of 10:8, as shown in R' and T' in Figure 2. 120 for the modulated signal S as shown by arrows a and b.
It comes to a position showing a phase shift difference of °. That is, the modulated signals R and T are initially almost in phase with the modulated signal S.
Thereafter, the phase difference between the modulated signals R, S, and T gradually becomes equal to each other by 120 degrees.

Therefore, according to the above-mentioned modulation device, the number of phases of the modulation signal substantially changes from two phases to three phases as the modulation signal frequency increases, so that the sense of sound image movement gradually expands and the inertial effect is reduced. It is something that will be emphasized.

In the above embodiment, gate type different phase signal mixing circuits R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , G ₁ , and G ₂ are used as means for controlling the phase difference between modulated signals. , a suitable variable phase shift circuit may also be used.

[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, and FIG. 2 is a diagram for explaining the modulation control operation in the device of FIG. 20, 22, 24...Analog shift register, _R11 , _R12.R21 , _R22 ...Resistance for mixing different phase signals, _G1 , _G2 ... _Gate element for mixing control.

Claims (1)

[Claims] 1. A signal generation circuit that generates at least three phases of low frequency signals for modulation so that the steady frequency gradually rises based on the operation of a modulation effect addition switch, and at least three analog shift registers that use musical tone signals as a common input. a modulation circuit that applies delay time modulation to the input musical tone signal by frequency modulating the shift pulses of these registers with the modulation low frequency signal, respectively, and transmits the input musical tone signal; and a modulation circuit that converts the output signal of this modulation circuit into sound. In the modulation device for an electronic musical instrument, as the modulating low frequency signal rises to a steady frequency, the phase difference between the signals is gradually changed from an uneven state to an equal state. A modulation device for an electronic musical instrument, characterized in that it is provided with.