Patent Document ID: 4486688
Application ID: 06349694
Patent Flag: 1

Claim One:
1. A method of controlling a regulating device by supplying a comparator with a path-length input signal from a pressure-responsive unit and with a variable input control signal, comprising the steps of: forming a comparator output signal from said input signals; determining the absolute signal difference between the two input signals; utilizing the absolute signal difference to produce a clear signal as long as this difference is greater than the higher of two predetermined threshold values and thereafter is still greater than the lower of said two threshold values; alternately applying pressure to said unit from two differential sources of pressure in dependence upon said output signal and if said clear signal is present at the same time; the absolute signal difference dropping below said lower threshold value, and then increasing to above the same; another clear signal being then produced only after elapse of a first time period corresponding to the decay time of the device and lasting for a second time period dependent upon the magnitude of the absolute signal difference.