Claims
- 1. A stage for generating audio musical tone samples, comprising:
- a first adder with a first input for connection to the output of a previous stage, and a second input for connection to the output of a stage previous to said previous stage;
- a second adder having a first input connected to an output of the first adder through a multiplier, and a second input for connection to a phase drive distinct in phase from a phase drive applied to said previous stages or a subsequent stage;
- a waveform generator connected to receive an address from an output of the second adder and for outputting a waveform as addressed by said address; and
- a multiplier connected to modify said waveform output by the waveform generator by an input multiplication factor "B" before being output from said stage as a stage output when the present stage is an intermediate stage and as a final tone output when said present stage is a final stage in a chain of stages.
- 2. The stage of claim 1, further comprising:
- a latch connected between the multiplier and said stage output and having a clock input for latching said stage output at the occurrence of a clock pulse common to all stages arranged in said chain of stages, wherein each clock pulse allows a stage calculation to ripple through to a next subsequent stage.
- 3. A multi-stage device for generating audio musical tone samples, comprising:
- a first stage having a pair of daisy-chain inputs connected to ground and a phase input connected to a first phase drive and means for calculating a waveform based signals present on said pair of daisy-chain inputs and first phase input and for outputting said calculation to a first stage output;
- at least one intermediate stage in a daisy-chain beginning with the first stage and having a pair of daisy-chain inputs connected one to a stage output of a previous stage and the other one to a second one of said daisy-chain inputs of said previous stage output, and a phase input connected to an intermediate phase drive distinct from said first phase drive, and means for calculating a waveform based signals present on said pair of daisy-chain inputs and said intermediate phase input and for outputting said calculation as an intermediate stage output; and
- a final stage terminating said daisy-chain of stages beginning with the first stage and having a pair of daisy-chain inputs connected one to a stage output of a previous intermediate stage output and the other one to a second one of said daisy-chain inputs of said previous intermediate stage output, and a phase input connected to an final phase drive distinct from said other phase drives, and means for calculating a waveform based signals present on said pair of daisy-chain inputs and said final phase input and for outputting said calculation to a final tone output.
- 4. The device of claim 3, wherein each of the first, intermediate and final stages comprise:
- a first adder with a first input for connection to the output of a previous stage, and a second input for connection to the output of a stage previous to said previous stage;
- a second adder having a first input connected to an output of the first adder through a multiplier, and a second input for connection to a phase drive distinct in phase from a phase drive applied to previous stages or a subsequent stage;
- a waveform generator connected to receive an address from an output of the second adder and for outputting a waveform as addressed by said address; and
- a multiplier connected to modify said waveform output by the waveform generator by an input multiplication factor "B" before being output from said stage as a stage output when the present stage is one of said intermediate stages and as a final tone output when said present stage is said final stage in a chain of stages.
- 5. The device of claim 4, wherein each stage further comprises:
- a latch connected between the multiplier and said stage output and having a clock input for latching said stage output at the occurrence of a clock pulse common to all stages arranged in said chain of stages, wherein each clock pulse allows a stage calculation to ripple through to a next subsequent stage.
- 6. The device of claim 5, wherein:
- there are a total of twenty-nine first, immediate and final stages in said daisy-chain; and
- said phase drive is a phase address signal calculated by adding a phase step value to the phase address of a previous stage.
- 7. A recirculating arithmetic circuit for the calculation of musical tone samples from intermediate products feed-forwarded to be included in subsequent intermediate products, comprising:
- phase step latching means for an initial loading of a starting phase value and for incrementing a step value by a fixed amount for each of a plurality of intermediate products;
- a first adder connected to the phase step latching means for adding said step value to an intermediate feed-forward value;
- a waveform generator connected to receive an address value from the first adder and for outputting a waveform representation as addressed by said address value;
- a first multiplier connected to modify said waveform output by the waveform generator by an input multiplication factor "B" held constant during each tone sample before being output from said stage as a stage output when the present recirculation is an intermediate recirculation and as a final tone output when said present recirculation is a final one;
- latching means for shifting through said output of the first multiplier and a previous cycle output of the multiplier simultaneously to a second adder during an intermediate recirculation and for loading zeros at an initial recirculation to said second adder; and
- a second multiplier connected to modify an output of said second adder by an input multiplication factor "X" held constant during each tone sample and provided to said first adder as said intermediate feed-forward value.
- 8. An integrated circuit (IC) for synthesis of musical and electronic tones, comprising:
- a first digital adder having a first parallel digital input and a second parallel digital input and an output;
- a first digital multiplier having an input connected to said output of the first digital adder and an output;
- a second digital adder having a first parallel digital input connected to receive a modulation address phase signal "XN" and a second parallel digital input connected to said output of the first digital multiplier and an output;
- waveform generator means having an input connected to said output of the second digital adder and an output for generating a waveform output; and
- a second digital multiplier having a first digital input connected to said output of the waveform generator means and a control input connected to receive a common multiplication factor "B" and output.
- 9. The IC of claim 8, further comprising:
- a digital latch connected to said output of the second digital multiplier for latching a digital product on the occurrence of a clock pulse.
- 10. The IC of claim 9, further comprising:
- a first digital latch having an input connected to said output of the second digital multiplier for latching a digital product on the occurrence of a clock pulse and having an output connected to said first parallel digital input of the first digital adder; and
- a second digital latch having an input connected to said output of the first digital latch and an output connected to said second parallel digital input of the first digital adder.
- 11. The IC of claim 10, further comprising:
- initialization means for zeroing said first and second digital latches at the start of a computation cycle; and
- phase address computational means for inputting discrete stepwise address phases X1 . . . XN to said first parallel digital input of said second adder at said occurrence of said clock pulse.
- 12. A method of generating complex musical wave forms, comprising the steps of:
- digitally adding a first digital input signal to a second digital input signal to produce a first sum in a two-input adder;
- digitally multiplying said first sum by a first multiplication factor "x" to produce a first product;
- digitally adding said first product to a single digital modulation address phase, in the range X1 . . . XN, to produce a second sum "y" in a two-input adder;
- digitally converting said second sum "y" into a function "f(y)" with a waveform generator; and
- digitally multiplying said function "f(y)" by a common multiplication factor "B" to produce an output product.
- 13. The method of claim 12, further comprising the subsequent step of:
- digitally latching said output product on the occurrence of a clock pulse.
- 14. The method of claim 12, further comprising the subsequent steps of:
- digitally latching said output product on the occurrence of a clock pulse in a first digital latch having a second digital latch cascaded behind the first and providing the respective latched outputs of the first and second digital latches as said first and second digital input signals.
RELATED APPLICATION
A application, Ser. No. 08/, filed Sep. 1994, entitled, METHOD AND INTEGRATED CIRCUIT FOR THE FLEXIBLE COMBINATION OF FOUR OPERATORS IN SOUND SYNTHESIS, is incorporated herein by reference.
US Referenced Citations (30)