EP0082335A2
Expired / Lapsed
EP
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Digital sine wave synthesizing method and apparatus
Assignee: International Business Machines Corp
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Filing: 1982-11-23
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Granted: —
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Expires: 2002-11-23
Abstract
Abstract A digital accumulator is driven at a basic counting rate to accumulate increments representative of phase with the total sum representative of total phase angle of a sine wave. The accumulator operates at a first rate until a total phase angle of approximately 45° is accumulated. Then accumulation value additions are at 1/2 the rate until 67.5° of total phase angle are accumulated. Then accumulation is at 1/4 the basic rate until 90° is reached. The symmetry of the sine wave allows the 0° through 90° samples to be used to generate the full 360° wave from by simple inversion or reverse counting of the counter and inversion of the algebraic sign as necessary. The resulting count is applied to a digital to analog converter to derive the output analog voltage. A binary slope approximation to the sine function is achieved by this technique.
Inventors
- 👤 Gardner Dulaney Jones
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 09:23
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/60; G06F7/62; G06F1/00; G06F1/02; G06F1/022; G06F2101/00; G06F2101/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
149 words
A method of synthesizing a sine wave characterized in that it comprises the steps of : supplying a digital value representative of a phase angle increment; driving a gating clock'connected to said digital value at a fixed rate; accumulating gated phase angle increments in an accumulator connected to said digital value by said clocking means; changing said accumulating of increments of phase angle as a digital representation of the sine of the angle to accumulate on a one for one basis until a 45° total accumulated phase angle has occurred and then halving the accumulation rate until a total accumulated phase of 67.5° is accumulated and then halving the accumulation rate again until 90° total accumulated phase angle is reached; and taking the digital value of said accumulated phase angle increments as the value of the sine function and converting said digital value to an analog voltage level output.
Claim 2
Independent Claim
149 words
A method of synthesizing a sine wave characterized in that it comprises the steps of : supplying a digital value representative of a phase angle increment; driving a gating clock'connected to said digital value at a fixed rate; accumulating gated phase angle increments in an accumulator connected to said digital value by said clocking means; changing said accumulating of increments of phase angle as a digital representation of the sine of the angle to accumulate on a one for one basis until a 45° total accumulated phase angle has occurred and then halving the accumulation rate until a total accumulated phase of 67.5° is accumulated and then halving the accumulation rate again until 90° total accumulated phase angle is reached; and taking the digital value of said accumulated phase angle increments as the value of the sine function and converting said digital value to an analog voltage level output.
Claim 3
Dependent Claim
191 words
Apparatus for synthesizing a sine wave characterized in that it comprises : a source of digital values representative of phase angle increments; a clocking means connected to said source for applying said digital values at a fixed rate; a digital binary accumulator connected to said clocking means for accumulating said digital values; a sine approximation means connected to said accumulator for converting said digital values to digital representations of a sine function; a control means connected to said accumulator and to said line approximation means, respectively, for altering the approximation value of said sine approximation means responsive to the total accumulated value occuring in said accumulator, said altering being to reduce the approximation value accumulation rate to 1/2 of said fixed rate when a combined 45° value accumulation appears in said accumulator and to reduce said accumulation rate to 1/4 that of said fixed rate when the accumulated value-count in said accumulator is 67.5°; and means to reverse said accumulator's rate changes and direction every 90°; means connected to said accumulator for converting said accumulated value in said accumulator to a step wise analog output voltage approximating a sine wave function.
Claim 4
Dependent Claim
191 words
Apparatus for synthesizing a sine wave characterized in that it comprises : a source of digital values representative of phase angle increments; a clocking means connected to said source for applying said digital values at a fixed rate; a digital binary accumulator connected to said clocking means for accumulating said digital values; a sine approximation means connected to said accumulator for converting said digital values to digital representations of a sine function; a control means connected to said accumulator and to said line approximation means, respectively, for altering the approximation value of said sine approximation means responsive to the total accumulated value occuring in said accumulator, said altering being to reduce the approximation value accumulation rate to 1/2 of said fixed rate when a combined 45° value accumulation appears in said accumulator and to reduce said accumulation rate to 1/4 that of said fixed rate when the accumulated value-count in said accumulator is 67.5°; and means to reverse said accumulator's rate changes and direction every 90°; means connected to said accumulator for converting said accumulated value in said accumulator to a step wise analog output voltage approximating a sine wave function.
Claim 5
Dependent Claim
55 words
Apparatus as described in Claim 2, characterized in that : said accumulator comprises a binary shift register means in which said accumulation rate changes are accomplished by shifting the content of the low order bit positions one stage lower to create the effect of inserting an additional 0 or of halving the exisiting accumulation rate.
References Cited (Backward Citations)
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