| 摘要 |
PURPOSE:To obtain an odd number frequency division waveform whose duty ratio is 50% by combining outputs of two counters counting clocks whose phases are shifted by 180 deg. to each other. CONSTITUTION:In putting '1' to a NAND 11 and '0' to ORs 4, 5 and a NAND 13 from the output of a decoder 12, counters 1, 2 count '2' then load '0'. The counters 1, 2 are simultaneously cleared then keep counting clocks whose phases are deviated by 180 deg. each other, respectively. Thus, an output QB of the counter 1 counting the advancing clock and an output QA of the counter 2 counting the retarded clock are ORed by the OR 5 and the result is extracted by a selector 9, resulting that a 1/3 frequency division output waveform whose duty ratio is 50% is obtained. Inputting '0' to the NAND 11 and '1' to the NAND 13 and the OR 5 from the decoder 12, and selecting the output of an OR 7, a 1/5 frequency division output is obtained. |
