Electronic musical instrument using amplitude modulation with feedback loop

Claim 2

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave having a frequency corresponding to a depressed one of said keys; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, whereby, as a result of said multiplying, the waveform of said musical tone signal, and hence the tone color of a musical tone corresponding thereto, will vary with the lapse of time.

Claim 3

An electronic musical instrument according to claim 1 wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is integer larger than 1) for generating respectively first to Nth modulation signals in accordance with said amplitude modulated carrier wave; a first to Nth additional carrier wave generating means for generating first to Nth carrier waves respectively; a first to Nth additional amplitude modulation means, which are connected to the first to Nth additional carrier wave generating means respectively and to the first to Nth modulation signal generating means respectively, for amplitude modulating the first to Nth carrier waves respectively in accordance with respective first to Nth modulation signals and for delivering first to Nth amplitude-modulated carrier waves respectively; and mixing means for mixing the first to Nth amplitude modulated carrier waves and for delivering a mixed carrier wave, the mixed carrier wave being said modulation signal.

Claim 4

An electronic musical instrument according to claim 1 wherein said feedback means includes a delay circuit for performing said delaying.

Claim 5

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave corresponding to a depressed one of said keys; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for amplitude-modulating said modified carrier wave by multiplying said modified carrier wave with said modulation signal, the resultant amplitude-modulated modified carrier wave being utilized to generate a musical tone signal; and feedback means for generating said modifying signal by delaying said amplitude-modulated modified carrier wave and providing said delayed amplitude-modulated modified carrier wave as said modifying signal.

Claim 6

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave corresponding to a depressed one of said keys; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for amplitude-modulating said modified carrier wave by multiplying said modified carrier wave with said modulation signal, the resultant amplitude-modulated modified carrier wave being utilized to generate a musical tone signal; and feedback means for generating said modifying signal by delaying said amplitude-modulated modified carrier wave and providing said delayed amplitude-modulated modified carrier wave as said modifying signal.

Claim 7

An electronic musical instrument according to claim 4 wherein said feedback means comprises: a modulation index generator for generating a modulation index; and a multiplier for multiplying said amplitude-modulated modified carrier wave with said modulation index, said multiplied amplitude-modulated modified carrier wave being provided as said modifying signal.

Claim 8

An electronic musical instrument according to claim 5 wherein said modulation index is a function of time.

Claim 9

An electronic musical instrument according to claim 4 wherein said feedback means comprises: a modulation index generator for generating a modulation index; a multiplier for multiplying said amplitude-modulated modified carrier wave with said modulation index; and modulation signal memory means for storing said modulation signal and for generating said modulation signal in accordance with a product output of said multiplier.

Claim 10

An electronic musical instrument according to claim 4 wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is an integer larger than 1) for generating respectively first to Nth modulation signals in accordance with said amplitude modulated modified carrier wave; a first to Nth additional carrier wave generating means for generating first to Nth carrier waves respectively; a first to Nth additional amplitude modulation means, which are connected to the first to Nth additional carrier wave generating means respectively and to the first to Nth modulation signal generating means respectively, for amplitude modulating the first to Nth carrier waves respectively in accordance with respective first to Nth modulation signals and for delivering first to Nth amplitude modulated modified carrier waves respectively; mixing means for mixing the first to Nth amplitude modulated modified carrier waves and for delivering a mixed carrier wave, the mixed carrier wave being said modifying signal.

Claim 11

An electronic musical instrument according to claim 4, wherein the frequency of said modulation signal from said modulation signal generating means is related to the frequency of said carrier wave.

Claim 12

An electronic musical instrument according to claim 4 which is digital and wherein: said carrier wave, said modified carrier wave, said modulation signal, said amplitude modulated carrier wave and said modifying signal all are represented as digital values at successive sample points occurring at regular time intervals, said carrier wave having a relatively simple waveform, said modification and amplitude modulation resulting in the production from said carrier wave of simple waveform of a resultant amplitude-modulated modified carrier wave having a relatively complex waveform appropriate for musical tone generation.

Claim 13

An electronic musical instrument according to claim 1 or 4 wherein said carrier wave generating means comprises: a phase angle information generator for generating a phase angle information having a value which progresses at a rate corresponding to said depressed key, and carrier wave memory means connected to said phase angle information generator for storing said carrier wave and for generating said carrier wave whose period is determined by said rate upon reception of said phase angle information.

Claim 14

An electronic musical instrument according to claim 1 or 4 which further comprises means for imparting an envelope to said musical tone signal.

Claim 15

An electronic musical instrument according to claim 2 or 8 wherein the frequency of at least one additional carrier wave generating means is related to the frequency of said carrier wave.

Claim 16

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein said feedback means comprises: modulation index generating means for generating a modulation index; and a multiplier for multiplying said amplitude-modulated carrier wave by said modulation index, said multiplied amplitude-modulated carrier wave being delayed and provided as said modulation signal.

Claim 17

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein said feedback means comprises: modulation index generating means for generating a modulation index; and a multiplier for multiplying said amplitude-modulated carrier wave by said modulation index, said multiplied amplitude-modulated carrier wave being delayed and provided as said modulation signal.

Claim 18

An electronic musical instrument according to claim 14 wherein said modulation index is a function of time.

Claim 19

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein said feedback means comprises: a modulation index generator for generating a modulation index; a multiplier for multiplying said amplitude-modulated carrier wave with said modulation index, and modulation signal memory means for storing said modulation signal and for generating said modulation signal in accordance with a product output of said multiplier.

Claim 20

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein said feedback means comprises: a modulation index generator for generating a modulation index; a multiplier for multiplying said amplitude-modulated carrier wave with said modulation index, and modulation signal memory means for storing said modulation signal and for generating said modulation signal in accordance with a product output of said multiplier.

Claim 21

An electronic musical instrument according to claim 7 or 16 wherein said modulation index comprises a function of time.

Claim 22

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave having a frequency corresponding to a depressed one of said keys; amplitude modulation means for amplitude-modulating said carrier wave in accordance with a modulation signal and for delivering an amplitude-modulated carrier wave to be used for producing a musical tone signal; feedback means for generating said modulation signal in accordance with said amplitude-modulated carrier wave, and wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is an integer larger than 1) for generating first to Nth modulation signals respectively, said first modulation signal being generated in accordance with said amplitude-modulated carrier wave; a first to N-1th additional carrier wave generating means for generating first to N-1th carrier waves respectively; a first to N-1th additional amplitude modulation means, which are connected to the first to N-1th additional carrier wave generating means respectively and to the first to N-1th modulation signal generating means respectively, for amplitude modulating the first to N-1th carrier waves respectively in accordance with respective first to N-1th modulation signals and for delivering first to N-1th amplitude modulated carrier waves respectively, the first to N-1th amplitude modulated carrier waves being applied to the second to Nth modulation signal generating means respectively and the Nth modulation signal being said modulation signal.

Claim 23

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave having a frequency corresponding to a depressed one of said keys; amplitude modulation means for amplitude-modulating said carrier wave in accordance with a modulation signal and for delivering an amplitude-modulated carrier wave to be used for producing a musical tone signal; feedback means for generating said modulation signal in accordance with said amplitude-modulated carrier wave, and wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is an integer larger than 1) for generating first to Nth modulation signals respectively, said first modulation signal being generated in accordance with said amplitude-modulated carrier wave; a first to N-1th additional carrier wave generating means for generating first to N-1th carrier waves respectively; a first to N-1th additional amplitude modulation means, which are connected to the first to N-1th additional carrier wave generating means respectively and to the first to N-1th modulation signal generating means respectively, for amplitude modulating the first to N-1th carrier waves respectively in accordance with respective first to N-1th modulation signals and for delivering first to N-1th amplitude modulated carrier waves respectively, the first to N-1th amplitude modulated carrier waves being applied to the second to Nth modulation signal generating means respectively and the Nth modulation signal being said modulation signal.

Claim 24

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave corresponding to a depressed one of said keys; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for amplitude-modulating said modified carrier wave in accordance with said modulation signal and for delivering an amplitude-modulated modified carrier wave utilized to generate a musical tone signal; feedback means for generating said modifying signal in accordance with said amplitude-modulated modified carrier wave, and wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is an integer larger than 1) for generating first to Nth modulating signals respectively, said first modulation signal being generated in accordance with said amplitude-modulated modified carrier wave; a first to N-1th additional carrier wave generating means for generating first to N-1th carrier waves respectively; and a first to N-1th additional amplitude modulating means, which are connected to the first to N-1th additional carrier wave generating means respectively and to the first to N-1th modulation signal generating means respectively, for amplitude-modulating the first to N-1th carrier waves respectively in accordance with the respective first to N-1th modulation signals and for delivering first to N-1th amplitude-modulated modified carrier waves respectively, the first to N-1th amplitude-modulated modified carrier waves being applied to the second to Nth modulation signal generating means respectively and the Nth modulation signal being said modifying signal.

Claim 25

An electronic musical instrument comprising: keyboard means having a plurality of keys; carrier wave generating means for generating a carrier wave corresponding to a depressed one of said keys; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for amplitude-modulating said modified carrier wave in accordance with said modulation signal and for delivering an amplitude-modulated modified carrier wave utilized to generate a musical tone signal; feedback means for generating said modifying signal in accordance with said amplitude-modulated modified carrier wave, and wherein said feedback means comprises: a first to Nth modulation signal generating means (where N is an integer larger than 1) for generating first to Nth modulating signals respectively, said first modulation signal being generated in accordance with said amplitude-modulated modified carrier wave; a first to N-1th additional carrier wave generating means for generating first to N-1th carrier waves respectively; and a first to N-1th additional amplitude modulating means, which are connected to the first to N-1th additional carrier wave generating means respectively and to the first to N-1th modulation signal generating means respectively, for amplitude-modulating the first to N-1th carrier waves respectively in accordance with the respective first to N-1th modulation signals and for delivering first to N-1th amplitude-modulated modified carrier waves respectively, the first to N-1th amplitude-modulated modified carrier waves being applied to the second to Nth modulation signal generating means respectively and the Nth modulation signal being said modifying signal.

Claim 26

An electronic musical instrument according to claim 18 or 19 wherein the frequency of at least one additional carrier generating means is related to the frequency of said carrier wave.

Claim 27

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein; said carrier wave is a digitalized carrier wave, and said amplitude modulation means and said feedback means are digitalized, and which further comprises; an averaging circuit for eliminating undesirable hunting phenomena.

Claim 28

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal, and wherein; said carrier wave is a digitalized carrier wave, and said amplitude modulation means and said feedback means are digitalized, and which further comprises; an averaging circuit for eliminating undesirable hunting phenomena.

Claim 29

An electronic musical instrument according to claim 21 wherein said feedback means includes said averaging circuit.

Claim 30

An electronic musical instrument according to claim 21 wherein said averaging circuit is provided at the output side of said amplitude-modulation means.

Claim 31

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected note; amplitude modulation means for multiplying said carrier wave by a modulation signal and for delivering the resultant signal as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by multiplying said amplitude-modulated carrier wave by a selected modulation index, the resultant product being delayed and provided as said modulation signal.

Claim 32

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected note; amplitude modulation means for multiplying said carrier wave by a modulation signal and for delivering the resultant signal as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by multiplying said amplitude-modulated carrier wave by a selected modulation index, the resultant product being delayed and provided as said modulation signal.

Claim 33

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave corresponding to a selected note; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for multiplying said modified carrier wave with said modulation signal and for delivering the resultant signal as an amplitude-modulated modified carrier wave utilized to generate a musical tone signal; and feedback means for generating said modifying signal by multiplying said amplitude-modulated modified carrier wave by a selected modulation index, the resultant product being delayed and provided as said modifying signal.

Claim 34

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave corresponding to a selected note; modifying means for modifying said carrier wave in accordance with a modifying signal and for delivering a modified carrier wave; modulation signal generating means for generating a modulation signal; amplitude modulation means for multiplying said modified carrier wave with said modulation signal and for delivering the resultant signal as an amplitude-modulated modified carrier wave utilized to generate a musical tone signal; and feedback means for generating said modifying signal by multiplying said amplitude-modulated modified carrier wave by a selected modulation index, the resultant product being delayed and provided as said modifying signal.

Claim 35

A digital electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note, said carrier wave being represented by successive sample point amplitude values provided at regular time intervals; amplitude modulation means for amplitude-modulating said carrier wave by multiplying the sample point amplitude values of said carrier wave with a time sampled modulation signal, the resultant signals being delivered as sample point amplitude data of an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying the sample point amplitude data of said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave sample point amplitude data as said time sampled modulation signal; whereby the tone color of a musical tone corresponding to said musical tone signal will vary according to the lapse of time.

Claim 36

A digital electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note, said carrier wave being represented by successive sample point amplitude values provided at regular time intervals; amplitude modulation means for amplitude-modulating said carrier wave by multiplying the sample point amplitude values of said carrier wave with a time sampled modulation signal, the resultant signals being delivered as sample point amplitude data of an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying the sample point amplitude data of said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave sample point amplitude data as said time sampled modulation signal; whereby the tone color of a musical tone corresponding to said musical tone signal will vary according to the lapse of time.

Claim 37

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note and having a relatively simple waveform; amplitude modulation means for multiplying the successive amplitudes of said carrier wave with successive values of a modulation signal, the resultant successive signals being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave signals and providing said delayed amplitude-modulated carrier wave signals as said successive modulation signal values, whereby an amplitude-modulated carrier wave having a time varying complex waveform, suitable to production of a corresponding musical tone having a time varying tone color, is created out of a carrier wave of simple waveform.

Claim 38

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note and having a relatively simple waveform; amplitude modulation means for multiplying the successive amplitudes of said carrier wave with successive values of a modulation signal, the resultant successive signals being delivered as an amplitude-modulated carrier wave to be used for producing a musical tone signal; and feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave signals and providing said delayed amplitude-modulated carrier wave signals as said successive modulation signal values, whereby an amplitude-modulated carrier wave having a time varying complex waveform, suitable to production of a corresponding musical tone having a time varying tone color, is created out of a carrier wave of simple waveform.

Claim 39

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note; amplitude modulation means for multiplying the amplitudes of said carrier wave at regular time intervals within each cycle of said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; and feedback means for generating said modulation signal by modifying said amplitude-modulated carrier wave and providing said modifying amplitude-modulated carrier wave signals as said modulation signal, said modifying being one or both of delaying and multiplying by a selected modulation index value; whereby said musical tone signal will exhibit a time varying waveshape and hence a musical tone corresponding to said musical tone signal will exhibit a time varying tone color.

Claim 40

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a frequency corresponding to a selected musical note; amplitude modulation means for multiplying the amplitudes of said carrier wave at regular time intervals within each cycle of said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; and feedback means for generating said modulation signal by modifying said amplitude-modulated carrier wave and providing said modifying amplitude-modulated carrier wave signals as said modulation signal, said modifying being one or both of delaying and multiplying by a selected modulation index value; whereby said musical tone signal will exhibit a time varying waveshape and hence a musical tone corresponding to said musical tone signal will exhibit a time varying tone color.

Claim 41

In a digital electronic musical instrument, a system for producing a relatively complex musical tone waveform from a carrier wave of relatively simple waveform which is supplied as an input to said system, comprising: means for multiplying successive amplitude samples of said carrier wave with successive values of a modulation signal, the resultant signals being used as a musical tone signal; and feedback means for delaying said resultant signals and providing said delayed resultant signals as said modulation signal successive values, said multiplying means and said feedback means being operative in real time and producing by said multiplying a musical tone signal having a waveform which varies with the lapse of time, so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with the lapse of time.

Claim 42

In a digital electronic musical instrument, a system for producing a relatively complex musical tone waveform from a carrier wave of relatively simple waveform which is supplied as an input to said system, comprising: means for multiplying successive amplitude samples of said carrier wave with successive values of a modulation signal, the resultant signals being used as a musical tone signal; and feedback means for delaying said resultant signals and providing said delayed resultant signals as said modulation signal successive values, said multiplying means and said feedback means being operative in real time and producing by said multiplying a musical tone signal having a waveform which varies with the lapse of time, so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with the lapse of time.

Claim 43

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; modifying means for modifying said amplitude-modulated carrier wave, said modifying being one or both of delaying and multiplying by a selected modulation index value; and modulation signal providing means for providing said modified amplitude-modulated carrier wave as said modulation signal, whereby the waveform of said delivered amplitude-modulated carrier wave, and hence the tone color of a musical tone corresponding thereto, will vary in accordance with the lapse of time.

Claim 44

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; modifying means for modifying said amplitude-modulated carrier wave, said modifying being one or both of delaying and multiplying by a selected modulation index value; and modulation signal providing means for providing said modified amplitude-modulated carrier wave as said modulation signal, whereby the waveform of said delivered amplitude-modulated carrier wave, and hence the tone color of a musical tone corresponding thereto, will vary in accordance with the lapse of time.

Claim 45

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; feedback means for generating said modulation signal by modifying said amplitude-modulated carrier wave and providing said modified amplitude-modulated carrier wave as said modulation signal, said multiplication by said provided modulation signal thereby causing the waveform of said resultant signal to vary with lapse of time so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with lapse of time.

Claim 46

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; feedback means for generating said modulation signal by modifying said amplitude-modulated carrier wave and providing said modified amplitude-modulated carrier wave as said modulation signal, said multiplication by said provided modulation signal thereby causing the waveform of said resultant signal to vary with lapse of time so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with lapse of time.

Claim 47

An electronic musical instrument according to claim 31, wherein said means for generating modifies said amplitude-modulated carrier wave by delaying the same.

Claim 48

An electronic musical instrument according to claim 31, wherein said means for generating modifies said amplitude-modulated carrier wave by multiplying the same by a modulation index.

Claim 49

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal; said delaying and said multiplying causing said musical tone signal to have a waveshape which varies with lapse of time, so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with lapse of time.

Claim 50

An electronic musical instrument comprising: carrier wave generating means for generating a carrier wave having a certain frequency; amplitude modulation means for amplitude-modulating said carrier wave by multiplying said carrier wave with a modulation signal, the resultant signal being delivered as an amplitude-modulated carrier wave to be used as a musical tone signal; feedback means for generating said modulation signal by delaying said amplitude-modulated carrier wave and providing said delayed amplitude-modulated carrier wave as said modulation signal; said delaying and said multiplying causing said musical tone signal to have a waveshape which varies with lapse of time, so that the tone color of a musical tone corresponding to said musical tone signal likewise will vary with lapse of time.