A Continuous Calibration Method For the Transfer Stabilization of Successive Detection Logarithmic Amplifiers

To ensure efficient and reliable operation of power amplifiers it is very important to precisely measure and control the power of the signal they transmit. A device most often used to do precise power measurements of RF systems is the so-called RF power detector. As this detector is used as measurement device the precise measurement ability of the RF power detector is very important. For the precise predictability of the output power of power amplifiers the transfer of the RF power detector has to be fixed and accurately known. In this thesis we develop a new calibration method for the transfer stabilization of logarithmic power detectors. Via thorough investigation at system level and circuit level it is shown that the proposed method can be used to continuously calibrate the transfer of a logarithmic RF power detector to a predefined and fixed position over mismatch, part-to-part spread, temperature and input frequency. The method depends on a novel switching algorithm around a log device that is capable to do continuous slope, intercept and dynamic range correction on the transfer of the logarithmic power detector. When accurate enough, the method would make calibration of each individual device unnecessary. Furthermore a new method is presented that can be used to extend the dynamic range of log detectors. System simulations show that the calibration method leads to the wanted transfer stabilization of the logarithmic power detector. A critical part of the new logarithmic transfer calibration method is the need of an accurate multiplication procedure at the input of the logarithmic device. For this accurate multiplication a new accurate gain fixation procedure for a non-linear high bandwidth gain stage was developed. A big part of the thesis is dedicated to the investigation and circuit implementation of this new accurate and fast gain fixation procedure. The gain stabilization method leads to the implementation of a new innovative gain fixation system, including several new architectural innovations. One of these innovations is the implementation of a new accurate ripple blocking system with relative small form factor and fast response time. Simulation results of the circuit implementation of the gain stabilization system prove that the accuracy of the gain stabilization of the non-linear high bandwidth gain stage is well within the required specifications.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc