Polyphonic electronic musical instrument

Claim 2

A polyphonic electronic musical instrument comprising: note designation means for designating a note of a tone to be produced; assignment means for assigning the note which has been designated by said note designation means to an available one of plural tone generation channels; phase data generation means for generating phase data corresponding respectively to frequencies of notes which have been assigned to the respective channels; tone generation means for generating, in time division, tone waveshape sample point data in a digital form of the notes assigned to the respective channels in response to the phase data of the respective channels supplied from said phase data generation means; and digital-to-analog conversion means provided commonly for the respective channels for converting in time division the digital waveshape data of the respective channels supplied from said tone generation means into an analog signal individually for each of the channels.

Claim 3

An electronic musical instrument as defined in Claim 1 further comprising a plurality of analog memory means provided in correspondence to the respective channels, said analog memory means sampling and holding, channel by channel, the analog waveshape signals for the respective channels supplied in time division from said digital-to-analog conversion means.

Claim 4

3 . An electronic musical instrument as defined in Claim 2 further comprising readout means for reading out the analog waveshape signals held in said analog memory means of the respective channels separately for each of the channels in synchronism with the pitches of the notes assigned to the respective channels.

Claim 5

An electronic musical instrument as defined in Claim 3 wherein said readout means reads out the analog waveshape signals of the respective channels in synchronism with change in the phase data of the respective channels generated by said phase data generation means.

Claim 6

An electronic musical instrument as defined in Claim 4 further comprising an output circuit which holds and mixes the analog waveshape signals of the respective channels read out by said readout means.

Claim 7

An electronic musical instrument as defined in Claim 2 further comprising an output circuit which mixes the analog waveshape signals of the respective channels held in said respective analog memory means.

Claim 8

An electronic musical instrument as defined in Claim 1 further comprising an analog adder which accumulates the analog waveshape signals of the respective channels supplied in time division from said digital-to-analog conversion means.

Claim 9

An electronic musical instrument as defined in Claim 1 wherein said phase data generation means generates the phase data for the respective channels in time division and said tone generation means supplies the digital waveshape data of the respective channels in a time division multiplexing manner by generating the digital waveshape data respectively at individual time slots corresponding to the respective channels in response to the phase data provided in time division.

Claim 10

An electronic musical instrument as defined in Claim 4 wherein said readout means comprises a circuit for generating a readout pulse separately for each of the channels in synchronism with change of the phase data for the respective channels generated by said phase data generation means and a sampling circuit for sampling and delivering out the analog waveshape signal held in one of said analog memory means corresponding to the channel in which the readout pulse has been generated.

Claim 11

An electronic musical instrument as defined in Claim 9 wherein said phase data generated by said phase data generation means comprises numerical data which repeats change from a certain value to another value at a rate corresponding to the frequency of the note represented by the phase data and said readout pulse generation circuit generates a read out pulse each time the numerical value of the phase data changes.

Claim 12

An electronic musical instrument as defined in Claim 9 wherein said phase data generation means comprises an accumulator which repeatedly accumulates a frequency number corresponding to the frequency of the note at a regular time interval and generates a carry out signal each time there occurs a carry from a decimal section to an integer section in contents of said accumulator and said readout pulse generation circuit generates the readout pulse in response to the carry out signal.

Claim 13

An electronic musical instrument as defined in Claim 9 wherein said phase data generation means generates the phase data in response to note clock pulses corresponding to the frequencies of the respective notes assigned to the respective channels and said readout pulse generation circuit generates the readout pulse in response to the note clock pulses of the respective channels.

Claim 14

A polyphonic electronic musical instrument comprising: note designation means for designating a note of a tone to be produced; assignment means for assigning the note which has been designated by said note designation means to an available one of plural tone generation channels; phase data generation means for generating phase data corresponding respectively to frequencies of notes which have been assigned to the respective channels in a time division multiplexing manner among said plural channels in accordance with a first time division rate; time division rate conversion means for converting the time division rate of the time division multiplexed phase data into a second time division rate which is lower than said first time division rate; tone generation means for generating tone waveshape same point digital data of respective notes assigned to the respective channels supplied from said time division rate conversion means; and digital-to-analog conversion means provided commonly for the respective channels for converting the digital waveshape data of the respective channels supplied from said tone generation means into analog signals individually for each of the channels in a time division multiplexed state.

Claim 15

A polyphonic electronic musical instrument comprising: note designation means for designating a note of a tone to be produced; assignment means for assigning the note which has been designated by said note designation means to an available one of plural tone generation channels; phase data generation means for generating phase data corresponding respectively to frequencies of notes which have been assigned to the respective channels in a time division multiplexing manner among said plural channels in accordance with a first time division rate; time division rate conversion means for converting the time division rate of the time division multiplexed phase data into a second time division rate which is lower than said first time division rate; tone generation means for generating tone waveshape same point digital data of respective notes assigned to the respective channels supplied from said time division rate conversion means; and digital-to-analog conversion means provided commonly for the respective channels for converting the digital waveshape data of the respective channels supplied from said tone generation means into analog signals individually for each of the channels in a time division multiplexed state.

Claim 16

An electronic musical instrument as defined in Claim 13 further comprising: a plurality of analog memory means provided in corre- s p ondence to the respective channels, said analog memory means demultiplexing and holding, channel by channel, the analog waveshape signals for the respective channels supplied in time division from said digital-to-analog conversion means in accordance with said second time division rate; and readout means for reading out the analog waveshape signals held in said analog memory means for the respective channels individually for each of the channels in synchronism with change of the phase data for the respective channels.

Claim 17

An electronic musical instrument as defined in Claim 14 which further comprises a circuit for generating strobe pulses for the respective channels for establishing time slots of the respective channels in accordance with said second time division rate, and in which said time division rate conversion means latches the phase data of the respective channels provided by said phase data generation means in response to a corresponding one of said channel strobe pulses thereby effecting the conversion into said second time division rate, and said readout means comprises a circuit for generating a readout pulse individually for each of the channels in synchronism with change of the phase data for the respective channels generated by said phase data generation means and at a time slot of each the channels in response to said first time division rate, a circuit for converting timing of generation of the readout pulse of each of the channels into a time slot corresponding to said second time division rate in response to said channel strobe pulse and a circuit for sampling and delivering out the analog waveshape signal from one of said analog memory means corresponding to the particular channel in accordance with the converted readout pulse.