| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital multiplier circuit for multiplying a digital signal SN by a periodic waveform, i.e., a sinusoidal waveform, as a rule. SOLUTION: A digital generatorΦhaving saw-tooth phase is used and an approximation of sample of a function KsinΦ, determined by an algebraic sum of two positive integers, is used for each phase value. K is a same coefficient for all phase values. SN can be obtained easily along with the sum and product thereof without requiring any sine table. A decoder 12 receiving phaseΦdefines a power of 2 to be set up and a routing circuit 14 performs an operation for multiplying the power of 2 under control of the decoder 12. Adders ADD1, ADD2 provide the sum of the power of 2. The results represent an approximation of the product SN.K.sinΦ.
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