|
|
|
Guibord Technical Writing Services –
Electronics |
|
Fundamentals
of Design and Engineering - Electronics Hardware and Software, by Daniel J.M. Guibord Fundamentals of
Troubleshooting - Electronics & Photonics, by Daniel J.M. Guibord Lock-in
and Signal Averaging Circuits for an NDIR Gas Spectroscopy Based Carbon
Monoxide Detector, (231 KB – PDF), by Daniel J.M. Guibord This application note
describes two circuits (lock-in and signal averaging) for detection and
measurement of low levels of Carbon Monoxide (CO), using Non-Dispersive Infrared (NDIR) gas spectroscopy.
NDIR gas detection and measurement offers reliability, sensitivity, and
immunity from false alarms for such applications as CO detectors. The lock-in
circuit is analog in nature and enables the measurement of CO levels down to
1 ppm, and meets CSA requirements for residential CO detectors; while the
signal averaging circuit uses a mixed-signals (analog and digital) approach,
inherently capable of much higher resolution than that of the analog circuit. The fundamental
approach of signal averaging described in this application note is suitable
for the detection of other types of gas as well, with resolution levels being
limited only by the time required for signal averaging. Stable
Preload Provides Wide Range Trimming To DC-DC Converter, (194 KB - PDF), by Daniel J.M. Guibord |