Design of a low power impulse-radio ultra-wide band wireless electrogoniometer

In this paper, a wireless electrogoniometer is described using a pair of ultra-wide band (UWB) wireless smart sensor nodes that are interfaced to low power 3-axis accelerometers. A high resolution SAR ADC as well as a low power asynchronous continuous sampling event-driven ADC are integrated for the digitization of the input signal under different operation modes. An anti-self-locking circuit is included in the asynchronous event-driven ADC to improve the robustness. A tri-channel UWB transceiver is designed particularly for the data transmission of the 3-axis accelerometers. A power consumption of 4.6pJ/bit is achieved for the transmitter at 10Mbps while operating under 1.2V power supply. The receiver power consumption can be as low as 0.32nJ/bit at 10Mbps under 1.8V supply. To demonstrate one application of the device, the electrogoniometer was used to quantify the in-vivo response of a somatosensory neuron to joint angle changes.