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Bandpass Sigma-Delta Modulators with one and two op-amp resonators

Abstract : Software defined radio receiver is a promising technique for future receivers which provides a variety of protocols. It digitizes the RF signal directly to low-frequency. We propose an SDR receiver based on a bandpass sigma delta modulator. The most essential element is the loop filter, there are two main configurations, an LC tank resonator and an active RC resonator. We focus on the active RC resonators for a low chip area. We target applications in the vicinity of 400 MHz, namely Advanced Research and Global Observation Satellite, Medical Implant Communication Service. We introduce a new comparison between the two-op-amp resonator CT BP sigma delta modulator and the one-op-amp resonator CT BP sigma delta modulator. We study the sensitivity of the quality factor and the signal to noise ratio to the DC-gain op-amps in two-op-amp resonator sigma delta modulator. It also shows how, in one-op-amp resonator sigma delta modulator, the quality factor and the signal to noise ratio, are very sensitive to any variations in the capacitors values for limited DC-gain op-amps. We establish a mathematical model of the thermal-noise behaviour for two-op-amp resonator CT BP sigma delta modulator. This model matches the circuit simulator results with a good accuracy. Furthermore, we demonstrate that a high quality factor (>100) of the two-op-amp resonators can be achieved by selecting the proper value of the integrator gain at a moderate DC-gain op-amp (35dB). Both sigma delta modulators are designed using flipped-well devices on fully depleted silicon on insulator technology, where we use body biasing to compensate the process, voltage and temperature variations.
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Submitted on : Thursday, February 10, 2022 - 5:41:08 PM
Last modification on : Saturday, July 9, 2022 - 3:29:57 AM
Long-term archiving on: : Wednesday, May 11, 2022 - 7:10:17 PM


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  • HAL Id : tel-03565076, version 1


Doaa Mahmoud. Bandpass Sigma-Delta Modulators with one and two op-amp resonators. Micro and nanotechnologies/Microelectronics. Sorbonne Université, 2021. English. ⟨NNT : 2021SORUS288⟩. ⟨tel-03565076⟩



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