Dynamic linearization system for a radiation gauge

In a radiation gauge for measuring the thickness of objects, apparatus for converting a thickness representative non-linear analog signal to a thickness representative linear analog signal exhibiting the same degree of resolution inherent in said non-linear signal, comprising:

• a. a programmable read only memory for storing a set of precalculated correction coefficient signals each of which is associated with a preselected range of possible values for said non-linear signal;
• b. a digital to analog converter responsive to said non-linear signal to address said memory and output the stored coefficient signal associated therewith;
• c. a digital to analog multiplier, coupled to said memory, responsive to both said non-linear signal and said output coefficient signal to develop a correction term signal exhibiting the same degree of resolution inherent in said non-linear signal;
• d. scaling circuitry, coupled to said multiplier, for varying the range of possible correction term signals by generating a scaled correction term signal;
• e. summing means, coupled to said scaling circuitry, responsive to said non-linear signal and said scaled correction term signal to develop a linearized signal exhibiting the same resolution inherent in said non-linear signal;
• and
• f. averaging circuitry, coupled to said summing means, for averaging said linearized signal over a period of time to develop an accurate linear analog output signal.

In a radiation gauge for measuring the thickness of objects a method for converting a thickness representative non-linear analog signal to a thickness representative linear analog signal exhibiting the same degree of resolution inherent in said non-linear signal, comprising the steps of:

• a. storing a set of precalculated correction coefficient signals, each of which is associated with a preselected range of possible values for said non-linear signal, in a memory;
• b. converting said non-linear signal into an address signal representing the location in said memory of the coefficient signal associated therewith;
• c. outputting the coefficient signal stored at the memory location represented by said address signal;
• d. developing a correction term signal exhibiting the same degree of resolution inherent in said non-linear signal by forming the product of said non-linear signal and the output coefficient signal;
• and
• e. summing said non-linear signal and said correction term signal to develop a linearized signal exhibiting the same degree of resolution inherent in said non-linear signal.