Pade′ Approximant based compensation for integrated sensor modules and the like
View Patent ↗Methods and systems using Pade' Approximant expansion ratios provide mappings between nonlinear sensors and a more linearized output domain. In one embodiment (a) a variable gain amplifier receives a supplied input signal, the amplifier has at least a first input terminal, an output terminal, and a gain control terminal; (b) a first summer coupled to the output terminal of the variable gain amplifier adds in a first offset signal; (c) a first multiplier coupled to an output of the first summer receives a proportional feedback factor signal and correspondingly generates a multiplied feedback; (d) a second summer coupled to an output terminal of the first multiplier adds in a corresponding second offset signal; and (e) a second multiplier coupled to an output of the second summer receives a gain factor signal and generates a multiplied gain signal; where the gain control terminal of the variable gain amplifier is operatively coupled to an output terminal of the second multiplier.
1. A system comprising:
(a) a variable gain amplifier having a first input terminal coupled to receive a first input signal, the amplifier further having a first output terminal for outputting a first output signal that is a function of the first input signal, and a gain control terminal controlling a variable gain applied to the first input signal;
(b) a first summer, operatively coupled to the first output terminal for adding a first offset signal to the first output signal, the first summer having a second output terminal;
(c) a first multiplier, operatively coupled to the second output terminal, the first multiplier having a feedback factor terminal for receiving a proportional feedback factor signal and the first multiplier having a third output terminal for outputting a multiplied feedback signal representing the offset first output signal multiplied by the proportional feedback factor signal;
(d) a second summer, operatively coupled to the third output terminal, for adding a second offset signal to the multiplied feedback signal, the second summer having a fourth output terminal; and
(e) a second multiplier, operatively coupled to the fourth output terminal, the second multiplier having a gain factor terminal for receiving a gain factor signal and the second multiplier having a fifth output terminal for outputting a multiplied gain signal representing the output of the fourth output terminal multiplied by the gain factor signal;
wherein the gain control terminal of the variable gain amplifier is operatively coupled to the fifth output terminal.
2. The system of claim 1 and further comprising:
(f) a primary sensor operatively coupled to supply said first input signal to the first input terminal of the variable gain amplifier.
3. The system of claim 2 and further comprising:
(g) coefficient defining means, coupled to at least one of the first summer, first multiplier, second summer and second multiplier, for respectively defining at least one of the first offset signal, proportional feedback factor signal, second offset signal and gain factor signal.
4. The system of claim 3 and further comprising:
(h) a temperature sensor operatively coupled to the coefficient defining means for causing the coefficient defining means to define at least one of the first offset signal, proportional feedback factor signal, second offset signal and gain factor signal in response to a sensed temperature.
5. The system of claim 3 and further comprising:
(h) a threshold detector operatively coupled to the coefficient defining means for causing the coefficient defining means to re-define at least one of the first offset signal, proportional feedback factor signal, second offset signal and gain factor signal in response to a sensed crossing of the first input signal across a first predetermined threshold.
6. The system of claim 5 wherein said primary sensor is packaged in a module together with said variable gain amplifier.
7. The system of claim 5 wherein:
(h.1) said threshold detector is also for causing the coefficient defining means to re-define at least one of the first offset signal, proportional feedback factor signal, second offset signal and gain factor signal in response to a sensed crossing of another operational signal across a second predetermined threshold.
8. The system of claim 3 and further comprising:
(h) an excitation source operatively coupled to the primary sensor to supply an excitation signal to the primary sensor, wherein the coefficient defining means is coupled to and responsive to the excitation source.
9. The system of claim 3 and further comprising:
(h) calibration means, coupled to the coefficient defining means, for causing the coefficient defining means to define at least one of the first offset signal, proportional feedback factor signal, second offset signal and gain factor signal in accordance with a plurality of predefined physical parameters applied to the primary sensor.