| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that a conventional sine wave generating circuit extracts data of an address corresponding to an input value from a memory circuit, and D/A converts the extracted data to generate an analog output signal varying in a sine wave shape, consequently a memory circuit occupies a large area in a chip to raise its cost. SOLUTION: A sine wave generating circuit generates an increase and decrease value of a signal level 2a, which has the same period as an analog output signal sinωt and changes stepwise along a cosine wave cosωt whose phase advances by 90 degrees with respect to the analog output signal sinωt, in accordance with a counter valueωt. The increase and decrease value of the signal level 2a is integrated to generate a signal level value 3a which changes stepwise along a sine wave having the same phase as the analog output signal sinωt, and the signal level value 3a is D/A converted to generate the analog output signal sinωt. COPYRIGHT: (C)2012,JPO&INPIT |
