A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications ...A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications in a UWB wireless body area network. The source degeneration structure applied in typical small transconduc- tance circuit is improved to provide a highly linear range for the OTA-C filter. Moreover, to reduce the passband attenuation of the filter, a cascode structure is employed as the output stage of the OTA. The OTA-based circuit is operated in weak inversion due to strict power limitation in the biomedical chip. The filter is fabricated in a SMIC 0.18-μm CMOS process. The measured results for the filter have shown a passband gain of -6.2 dB, while the -3-dB frequency is around 276 Hz. For the 0.8 Vpp sinusoidal input at 100 Hz, a total harmonic distortion （THD） of-56.8 dB is obtained. An electrocardiogram signal with noise interference is fed into this chip to validate the function of the designed filter.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.61161003,61264001,61166004)the Guangxi Natural Science Foundation(No.2013GXNSFAA019333)
文摘A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications in a UWB wireless body area network. The source degeneration structure applied in typical small transconduc- tance circuit is improved to provide a highly linear range for the OTA-C filter. Moreover, to reduce the passband attenuation of the filter, a cascode structure is employed as the output stage of the OTA. The OTA-based circuit is operated in weak inversion due to strict power limitation in the biomedical chip. The filter is fabricated in a SMIC 0.18-μm CMOS process. The measured results for the filter have shown a passband gain of -6.2 dB, while the -3-dB frequency is around 276 Hz. For the 0.8 Vpp sinusoidal input at 100 Hz, a total harmonic distortion （THD） of-56.8 dB is obtained. An electrocardiogram signal with noise interference is fed into this chip to validate the function of the designed filter.
