| 摘要 |
<p>PURPOSE:To obtain simply a trigonometric function value, by generating the tigonometric function value corresponding to an input digital signal in the form of a digital signal by a storage element of a comparatively small capacity and with accuracy approximately equal to that of a conventional process. CONSTITUTION:A parallel digital signal (x) is decomposed by a word decomposer 1 into high-order and low-order word signals (a) and (b). The word (a) is branched to two parts and supplied to a signal switch 3 and a phase converter 2, respectively. The converter 2 performs an operation of an output signal (c) as c=pi/2-a. The switch 3 uses its output (d) to deliver the signal (a) for a period from a time point t1 through t2 and then the signal (c) at and after the time point t2. A storage element 4 delivers the cosine function value e(cosa) to the signal (a) and the sine function value e(sina) to the signal (c) respectively. A multiplier 6 obtains a product (g) of a signal f(cosa) and the signal (b), and an adder 7 adds this product (g) with the signal (e). Thus it is possible to obtain an output signal y=sinx at and after the time point t2.</p> |
