| 摘要 |
PURPOSE:To enable the usage of a normal counter circuit for a sawtooth wave data forming means, and to reduce a limitation at the time of integration as a result by forming keying signal by using an incremental sawtooth wave data and a decremental sawtooth wave data as sawtooth wave data. CONSTITUTION:A normal counter circuit 1 outputs added values from sawtooth wave output terminals 1b, 1c, 1d at every input of a clock signal ck Zero-third bit data output from the sawtooth wave output terminals 1b, 1c are input to a comparison section 4 as incremental sawtooth wave data d1. On the other hand, a third bit is inverted by a NOT circuit 20, and input to a comparison section 34 as incremental sawtooth wave data d2 having phase shift of 90 deg. to the incremental sawtooth wave data d1. The incremental sawtooth wave data d1 input to the comparison section 4 are input to one input terminal 5a of a comparator 5 while being input to a NOT circuit 7. Each bit is inverted and output as decremental sawtooth wave data e1 having phase shift at 180 deg.. |
