Tsuyoshi Futamase

Sound effect imparting device for an electronic musical instrument

A sound effect imparting device for an electronic musical instrument is capable of imparting a plurality of desired sound effect such as vibrato and reverberation effects to a digital musical tone generated from the electronic musical instrument. The device comprises a digital arithmetic operation unit constructed with a combination of adders, multipliers, delay circuits, etc., a control unit, a parameter memory and a read-out unit. By control data and parameter data which are respectively read out from the control unit and the parameter memory by means of the read-out unit, switching of the operation mode of the digital arithmetic operation unit is controlled in a time-sharing manner, whereby a plurality of sound effects are imparted to a musical tone through digital arithmetic operations.

Modulation effect device for use in electronic musical instrument

A modulation effect device for use in an electronic musical instrument which utilizes, as a digital modulation circuit, a digital memory device for storing digitized musical tone signals. The digital memory device is accessed by modulation coefficient generating means which supplies a modulated address information to the digital memory device to read out from the memory device a musical tone signal modulated in accordance with the modulated address.

Electronic musical instruments provided with reverberation tone generating apparatus

In an electronic musical instrument, a reverberation tone most suitable for a selected tone color is applied to a musical tone with the selected tone color. In a modification, the electronic musical instrument is provided with a plurality of keyboards and to musical tones to be produced corresponding to the keyboards reverberation tones are applied independently. In another modification, one of the reverberation tones has a reverberation characteristic different from the other reverberation tone.

System for generating tone source waveshapes

The system comprises a frequency number memory device for storing information regarding the frequencies of respective tones, a keyboard switch for reading out frequency number information corresponding thereto from the memory device, an address generator including an adder for adding a predetermined number of the frequency number information thereby producing an address signal consisting of plural bits, address composers for processing the bits of the address signal and thereby composing digital tone signals constituting a saw-tooth, square and triangular waveshape, and digital-analog converters for converting the digital tone signals into analog tone signals, which are thereafter used to synthesize waveshapes of any tone.

Electronic musical instrument having an electronic filter with time variant slope

An electronic musical instrument capable of changing a slope portion of a filter characteristic continuously from start to completion of production of a musical tone. The inventive electronic musical instrument changes a filter slope in a frequency region above or below a cut-off frequency with lapse of time and, in order to achieve such change in the filter slope, changes a slope factor continuously from start to completion of production of the tone. The instrument is also capable of changing the cut-off frequency. An example of a low-pass filter is shown in which a desired form of a successively changing filter slope can be obtained by employing four slope factor values and three values representing a speed of change of the slope factors as well as three cut-off frequency values and two values representing a speed of change of the cut-off frequencies.

Function generators of time-dependent variable type

A function generator of time-dependent variable type especially suitable for use as an envelope waveshape generator of an electronic musical instrument is constituted by means for setting multi-bit digitalized information which represents time information in terms of a logarithm, dividing means for dividing the bits of the time information into upper order bits and lower order bits at a bit of a predetermined order, means for converting a portion of the information represented by the lower order bits into linear information, a timing pulse generator which produces a timing pulse having a period corresponding to a value obtained by converting a portion of the information represented by the higher order bits into a natural number, and an accumulator for accumulating the output produced by the information converting means at a period of the timing pulse thereby producing an accumulated value as the time function waveshape which varies with time at a rate corresponding to the time information.