ブロッキング発振形計測制御用増幅器とその応用

抄録

The blocking oscillator type DC amplifier has a blocking oscillator as a voltage comparator. The pulsating output of the oscillator is amplified by a transistor switching amplifier and smoothed by a low pass filter. The DC output voltage is negatively fed back to the input.
In general, the amplifier for instrumentation and control must be very stable under severe operating conditions. Input to output isolation is necessary for this type of amplifiers. Therefore, the chopper-modulated amplifier has been used widely. The blocking oscillator type DC amplifier has such features as simple construction, high sensitivity, high efficiency and easy input to output isolation.
The blocking oscillator type amplifier has two operating modes. They are single pulse operation and multi-pulse operation. The characteristics of linearity and step response are also described. In comparison with the pulse-width modulator amplifier and the pulse frequency modulator, the blocking oscillator type DC amplifier is simple in circuit and various application circuits can be constructed by analogous circuit.
There are many applications for the blocking oscillator type DC amplifier. The amplifiers with multiple isolating outputs, a square-root converter, a multiplier/divider and a converter for a magnetic flow meter are described in this paper.