| 摘要 |
PURPOSE:To prevent the fluctuation of the oscillation frequency for the sweep oscillation device used for the spectrum analyzer or the like through the feedback control, thus obtaining the steady sweep output. CONSTITUTION:An addition is given at adder circuit S to output (a) and (f) of ramp voltage generator R and voltage holding circuit H, and sweep oscillator O is controlled. Then the output of oscillator O and the output of reference oscillator K are applied to mixer M and then to pulse generator P via low pass filter L. Here if filter L transmits the output of a fixed frequency, pulse (c) is applied to time- voltage converter T. Pulse (b) generated for the pause period of generator R is applied to converter T to deliver voltage (d) corresponding to the time from the rise of the ramp voltage to pulse (c) to gate G for sampling. Thus pulse (e) is supplied to circuit H. With increase of output voltage (a) of generator R, the time (t) from the rear edge of pulse (b) to pulse (c) decreases. And accordingly output volgage V of converter T decreases to reduce voltage (a), thus preventing the fluctuation of the oscillation frequency. |
