Design of an integrated angular sensor system

Sensor systems based on capacitive or inductive measurement principles usually require sophisticated analog and digital signal processing. Particularly in automotive applications, a high degree of integration with as few external components as possible is desirable. We describe the design of an integrated angular speed sensor system based on a carrier frequency approach. To optimize the performance, we combined a synchronous demodulation strategy with an external resonance filter serving as clock reference and noise protection. The filter was extended by an additional low-pass easing implementation of the demodulator and compensating for internal signal delays. For system simulation, a simple analytical model based on Fourier synthesis was found to be superior to a conventional SPICE simulation.