Development of Digital Signal Processor Controlled Quantum Cascade Laser Based Trace Gas Sensor Technology

This paper reports the design and integration of a custom digital-signal-processor (DSP) system into a pulsed quantum-cascade-laser (QCL)-based trace gas sensor to improve its portability, robustness, and operating performance. Specifically, this paper describes the implementation of a custom prototype DSP data acquisition and system controller based on the Texas Instruments TMS320F2812 for embedded control and processing. In addition, the sensor incorporates oversampling by taking advantage of the high-speed conversion capabilities of an analog-to-digital converter, which is embedded within the DSP. A carbon monoxide sensor, employing a thermoelectrically cooled, pulsed 4.6-mum distributed feedback QCL as a mid-infrared radiation source, is used to evaluate the performance characteristics of such a DSP controlled spectroscopic gas sensor