Spatial Thermal Gradient Mapping Micro-Machined Accelerometer Arrays
Spatial thermal gradient mapping in micro-machined accelerometer arrays decouples linear motion from external board heat using differential thermopile matrices.
Thermal Bandwidth
Dynamic Range
Frequency domains within which a thermal sensor can accurately track temperature fluctuations define the speed of the measurement system. Thermal bandwidth refers to the range of frequencies over which the sensor response remains within a specified decibel level of its steady-state value. A wide bandwidth allows the device to capture rapid transients in a gas stream or a chemical reaction.
This limit is often determined by the physical size of the sensing element.
Mass Influence
Large sensors have high heat capacity and low thermal bandwidth. Small thin film resistors or micro-thermopiles provide the fastest response times.
Electronic Filtering
Signals from the sensor are often passed through low-pass filters to remove high frequency noise. This electronic thermal bandwidth must be matched to the physical response of the sensor to avoid signal distortion. Oversampling can help in recovering fast transitions if the signal to noise ratio is sufficient.
Calibration Bound
Measuring the frequency response involves exposing the sensor to a modulated heat source, such as a laser or a chopped infrared beam. The resulting thermal bandwidth data is used to set the limits for the dynamic error of the instrument. Readings taken at frequencies beyond this limit are subject to large phase shift and attenuation.