| 摘要 |
PURPOSE:To produce signals with high accuracy through a simple constitution by sweeping each data on the sine wave written into a ROM with the clock signal serving as the common frequency of each frequency and synthesizing then to obtain a standard signal. CONSTITUTION:The output of 9MHz of a crystal oscillator 1 is converted into address sweep clock clocks for 150Hz and 90Hz through a 1/80 divider 2, a 1/3 divider 3 and a 1/5 divider 4 respectively. Then ROMs 11 and 12 are segmented into eight memory areas, and the sine wave pattern data equivalent to one cycle is stored to each of these eight areas. The output data of both ROMs 11 and 12 are synthesized by a digital adder 13 and turned into audio signals through a D/A converter 14. These audio signals are delivered via an amplifier 15 after undergoing level control through a variable VR. |
