Digital implementation of the capacitively coupled electrical substitution for resistive bolometers

Abstract

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A heat balanced sigma–delta uncooled bolometer

“…It shifts the bitstream signal to high frequencies by mixing it with a carrier. Doing this, the electrical and thermal working points are dissociated according to a frequency basis and both temperature sensing and power feedback can be performed on the same sensing resistor [12,16].…”

“…The closed-loop mode operation is interesting since it leads to systems almost independent of the sensor characteristics and therefore much less sensitive to fabrication process discrepancies [10]. Furthermore, as the closed-loop system becomes independent of sensor characteristics, its performance such as time response or sensitivity might be tuned by control electronics.…”

“…First proposed with a discrete analogue implementation [12], the CCES was then demonstrated with a discrete digital implementation [16] to take advantage of the power feedback linearization induced by the digital feedback [17]. Such implementation involved microcontroller, DAC and ADC.…”

Noise study of a heat balanced sigma-delta bolometer

“…1. Detailed description of the sigma-delta circuitry and of the closed-loop mode operation can be found in [5] and [2][3][4] respectively. The system is composed of 6 mains parts:…”

“…Such association results into a heat balanced bolometer. Heat feedback means implemented in this paper is Joule power through a digital implementation of the Capacitively Coupled Electrical Substitution [4]. Previous implementation used microcontroller and Pulse-Width Modulated (PWM) signals [4], here a sigma-delta modulator is considered for the generation of the digital feedback signal [5].…”