| 摘要 |
PURPOSE:To simplify the operation of make high-precision control possible by comparing outputs of upper limit value and lower limit value setters with the output of an oscillator frequency counter and inputting comparison results to a comparator to determine a sweep direction. CONSTITUTION:A digital comparator 13 for frequency upper limit value compares a count signal (i) from a frequency counter 11 with a signal (g) from an upper limit value setter 15, and a digital comparator 14 compares a count signal (j) from the frequency counter 11 with a signal (f) from a lower limit value setter 16. If the signal (i) larger than the upper limit value (g) is inputted to the digital comparator 13, a pulse P is sent to a comparator 7 to invert the sweep direction. In accordance with determination of the sweep direction in the comparator 7, an output voltage (c) of an integrator 9 is inverted from increase or reduction to reduction or increase. A voltage control oscillator 10 is oscillated with an oscillation frequency proportional to this voltage (c). |
