The servo system has a fluid damped moving mass, a pickoff providing a signal indicative of the position of the moving mass, and a torquer disposed to move the mass. A single operational amplifier has a pair of inputs and an output. One input is connected to the pickoff signal and the other is connected to a reference signal. A feedback path extends between the operational amplifier input and output, and includes a temperature sensitive combination in series with a feedback resistor. A basic gain control resistance is connected between the node located intermediate of the temperature sensitive combination and feedback resistor and the reference signal. Basic gain and gain change over a temperature range are independent of interaction therebetween as each is set, and a selected servo system operational characteristic is maintained substantially constant over the temperature range.

The present invention provides an apparatus including a laser scanner wherein the apparatus further includes a scanner temperature detector (3) located in the proximity of a position sensor (2), an environment temperature detector (4) and temperature controlling mechanism adapted to perform controlling operation so as to allow the temperature of the position sensor to be kept constant on the basis of an output from the environment temperature detector and an output from the scanner temperature detector. Further, the present invention provides an apparatus including a laser scanner wherein the apparatus further includes a scanner temperature detector (3) for detecting the temperature of the position sensor, a table setting mechanism for setting a data correction table while a positional deviation caused by variation in temperature has been previously detected and a scanner controlling mechanism (16) for controlling the driving of a scanner on the basis of a value of correction derived from referring of a value detected by the scanner temperature detector to the data correction table.

A mathematical expression is converted and approximations applied to remove complex processes, simplifying the circuitry of system which controls compressor speed in dependence on ambient temperature.

Precision incremental-output integrator of the type comprising: an operational amplifier mounted as analog summing integrator, which sums currents I.sub.1 and I.sub.2 at the integrator input, characterized by the fact that current I.sub.2 is obtained by the discharge of a capacitor C.sub.2 and that the symmetrical reference voltage generator (Vr-), (Vr+) is replaced by a simple voltage generator (Vr) and incremental-output servosensors resulting from utilization of the said precision incremental-output integrator in which the measured magnitude, originally electrical, becomes a physical magnitude, evidenced by an electromechanical force generator by the fact that the analog amplifier of the precision incremental-output integrator (terminals A-S, FIG. 2) is replaced by the force generator of the servosensor (FIG. 3), the return current of which is current I.sub.2 discharged from capacitor C.sub.2.

A digitized pickoff system is provided for sensing displacement of complementary elements of a dual element pickoff assembly in an inertial sensor for use in an inertial navigation system comprising a relaxation oscillator adapted to sequentially select each of the pickoff elements with the reactance of the selected element determining the oscillating frequency thereof, a data converter adapted to measure the oscillating period thereof, and logic means having an output of a digital number which is proportional to the difference of oscillator periods of the two elements of the dual element pickoff assembly and which is a digital representation of the pickoff displacement.