Accurate propagation delay estimation for a novel thermal sensor
Such a delay line consists of a heater and a temperature sensor that are both realized in close proximity on a silicon chip. Since heat takes a finite amount of time to diffuse through silicon, a periodic signal applied to the heater will result in a phase-shifted (delayed) signal at the output of the temperature sensor. The thermal delay line thus behaves like an electrothermal filter. It turns out that this delay is very well defined AND is temperature dependent and so can be used as the basis of an accurate temperature sensor. Its behaviour can also be exactly captured by a simple mathematical equation.
However, compared to conventional sensors, the resulting thermal diffusivity sensor dissipates too much power, since a few mW of heater power is necessary to generate a detectable signal at the temperature sensor. The limiting factor on the SNR of the detected signal is the temperature sensor's thermal noise.
AssignmentThe result is a classical signal processing problem: what is the optimum method of estimating the phase-shift of the low-pass filtered sensor signal in the presence of AWGN? Right now a synchronous phase demodulator is used, but the sub-question is: how much performance are we leaving on the table? Obviously any improvement in the system's processing gain will lead to a reduction in the heater power required to achieve a certain SNR in the detected signal.
RequirementsA background in signal processing (estimation, detection) and/or physical layer telecommunication is required. Typical courses are ET4386 "Estimation and Detection", and ET4147 "Signal Processing for Communications".
prof.dr.ir. Alle-Jan van der Veen
Circuits and Systems Group
Department of Microelectronics
Last modified: 2014-11-28