On-chip Data Compression Scheme for Lung EIT Signal Acquisition and Recovery

An on-chip data compression scheme, suitable for electrical impedance tomography signal acquisition and recovery is proposed. For typical 16 electrode lung electrical impedance tomography system, 13 channel high frequency signals are acquired and I/Q demodulated to different frequencies. Frequency division signals are summed up and sampled by only two delta sigma modulators with high resolution. Thus 84.6% reduction of ADC usage is achieved, and the output data is repacked with compression ratio of 9.75. After decimation, each I/Q signal is recovered with 10-bit resolution by applying Blackman window corrected fast Fourier transformation algorithm.