JPH04336600A - Musical sound signal generation device - Google Patents

Abstract

PURPOSE:To enable a complicated musical sound signal to be generated by complicating a fundamental waveform signal to be inputted to a delay feedback circuit via the modulation of a phase signal for access to a waveform table, and storing only a simple fundamental waveform. CONSTITUTION:A musical sound signal generation device generates a musical sound signal by inputting a fundamental waveform signal to a delay feedback circuit comprising a loop of an adder, a delay circuit and a filter. The fundamental waveform signal to be inputted is read out from a waveform memory. In this case, a read address or rate for the waveform signal is randomized. A randomizing method is, for example, to modulate a frequency E given to a phase generator 7, according to a random signal generated by a random signal generator 3, or to modulate a phase signal generated by the phase generator 7, according to the random signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone signal forming apparatus for forming musical tone signals by feedback using a delay circuit.

0002

2. Description of the Related Art Conventionally, apparatuses for forming musical tones using a feedback circuit including a delay circuit have been proposed (Japanese Patent Publication No. 58-58679, Japanese Patent Application Laid-open No. 109093-1983, etc.).

This type of musical tone signal forming apparatus feeds back and circulates the signal input, and determines the pitch (frequency) of the signal by the delay time of the delay circuit. The input signal is short, about one cycle.

0004

[Problem to be Solved by the Invention] However, in conventional devices, the input signal is a simple waveform signal, so after the transient response of the delayed feedback section ends, the simple musical tone signal continues. There were drawbacks. In order to form a musical tone signal that includes complex fluctuations, it is sufficient to use an input waveform signal that includes complex fluctuations, but in order to store many types of such waveforms, a large capacity memory is required. There was a drawback.

SUMMARY OF THE INVENTION An object of the present invention is to provide a musical tone signal forming apparatus that solves the above problems by modulating a basic waveform signal input to a delay feedback circuit with a random value.

[0006]

[Means for Solving the Problems] The invention of claim 1 of this application connects an adder, a delay circuit, and a filter on a loop, and receives a basic waveform signal from one point on the loop while inputting a basic waveform signal to the adder. A waveform memory storing the basic waveform signal, a phase generation means for sequentially generating a readout phase signal of the waveform memory, and a delay feedback circuit for taking out an output signal, and randomly modulating the readout phase signal of the phase generation means. It is characterized by comprising a randomization means.

[0007]

The musical tone signal forming apparatus of the present invention forms musical tone signals by inputting a basic waveform signal to a delay feedback circuit in which an adder, a delay circuit, and a filter are connected in a loop. That is, the basic waveform signal input from the adder is delayed for a certain period of time by the delay circuit, and then fed back to the adder again via the filter.

The frequency of the musical tone signal to be formed is determined by this delay loop, and the timbre of the musical tone is determined by the input fundamental waveform signal and the cutoff characteristic of the filter. In such a musical tone signal forming apparatus, the input fundamental waveform signal is modulated by a random value. As a modulation method, there are a method of randomizing the speed of the phase signal for reading out the fundamental wave, and a method of adding a random value to the phase signal generated by the phase generating means. In either method, the basic waveform signal read out from the waveform memory has its phase modulated. By inputting this basic waveform signal to the delay feedback circuit, a timbre with complex fluctuations can be formed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the structure of a musical tone signal forming apparatus according to an embodiment of the present invention. This musical tone signal forming device can be applied to electronic musical instruments and the like. The control circuit 1 is composed of a microprocessor or the like, and outputs various control signals based on input signals from the input means 2. In the case of an electronic musical instrument, a keyboard or the like is connected as the input means. The information inputted to the control circuit 1 from this input means includes information such as pitch, touch data, note on/off, etc. In addition, timbre selection signals, parameter setting signals, etc. are inputted. This musical tone signal forming apparatus includes a delay feedback circuit 20, a waveform table 10, a phase generator 7, and a random signal generator 3. A random signal generated by the random signal generator 3 is input to amplifiers 5 and 8 via a filter 4. The gains of the amplifiers 5 and 8 are controlled by a gain control signal from the control circuit 1. The output of amplifier 5 is input to adder 6. A frequency number is inputted to the adder 6 from the control circuit 1 . The frequency number is numerical information that corresponds to the pitch and increases in value as the pitch increases. That is, the output of the adder 6 becomes a frequency number modulated with a random signal. This output is input to the phase generator 7. The phase generator 7 accumulates the input frequency numbers and outputs a phase signal (address signal). The output address signal is input to adder 9. On the other hand, amplifier 8
The output of is input to adder 9. The phase signal generated by the phase generator 7 is input to the adder 9 . That is, the output of the adder 9 becomes a phase signal to which a random signal is added. This phase signal is input to the waveform table 10. In the waveform table 10, the input phase signal (address signal)
The basic waveform signal is read out based on this. The waveform table 10 stores one cycle of waveforms corresponding to the tones to be generated. The waveform to be read out is selected by a control signal from the control circuit 1. The level of the read basic waveform signal is controlled by the amplifier 11 and then input to the adder 21 of the delay feedback circuit 20.

In the delay feedback circuit 20, the fundamental waveform signal input to the adder 21 is delayed by a delay circuit 22 for a certain period of time, and then fed back to the adder 21 via a loop filter 23. The loop filter 23 has a function of controlling the mixing ratio of the basic waveform signal newly input from the waveform table 10 and the feedback signal. The delay amount of the delay circuit 22 and the filter characteristics of the loop filter 23 are changed by a control signal input from the control circuit 1. Also, adder 2
The output of No. 1 is taken out as the musical tone signal output of this musical tone signal forming device.

Here, the random signal generated by the random signal generator 3 is applied to both the input side and the output side of the phase generator 7 via the amplifiers 5 and 8.
The gain of either one may be set to 0 and the gain may be applied to either the input side or the output side. When the count value is modulated with the output of the amplifier 5, the phase readout speed changes and so-called FM modulation is applied to the phase signal, and when the phase signal read out with the output of the amplifier 8 is modulated, so-called AM modulation is applied. Modulation is applied. Waveform table 1 with this signal
By accessing 0, even if the waveform data is simple, the read waveform signal can be made to have a wide variety.

Note that the filter 4 for random signals may be omitted. Furthermore, the phase is usually determined by modulo addition and the periodic waveform is accessed, but it may also be read out in one shot like a normal attenuated sound model. In this case, it is necessary to provide a filter to prevent the address from exceeding the access range due to modulation.

[0013] Furthermore, when performing modulation using a waveform that repeats at a sufficiently long period, a technique such as FM modulation may be used instead of the random signal generator 3. Random filters, modulation levels, input levels, etc. can be changed based on input performance information. That is, so-called key scaling can be performed.

[0014]

[Effects of the Invention] As described above, according to the musical tone signal forming device of the present invention, since the fundamental waveform signal input to the delay feedback circuit can be modulated by a random signal, it is possible to memorize a small number of fundamental waveform signals. , by modulating it, it is possible to form a varied and complex signal. By controlling the random signal based on performance information, it is possible to form musical tone signals that closely reflect the performance operations of the electronic musical instrument.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a musical tone signal forming apparatus according to an embodiment of the present invention.

[Explanation of symbols]

3-random signal generator, 7-phase generator, 10-waveform table, 20-delay feedback circuit, 21-adder, 22-delay circuit, 23-loop filter.

Claims (1)

[Claims] Claim 1: An adder, a delay circuit, and a filter are connected in a loop, and a basic waveform signal is input to the adder, and
a waveform memory that includes a delay feedback circuit that takes out an output signal from one point on the loop and stores the basic waveform signal; a phase generation means that sequentially generates a readout phase signal of the waveform memory; and a readout phase of the phase generation means. A musical tone signal forming device comprising: randomizing means for randomly modulating a signal.