A fully differential R-MOSFET-C fourth-order Bessel active lowpass filter employing fully differential operational amplifier,passive resistors,and current-steering MOS transistors as a variable resistor is proposed.T...A fully differential R-MOSFET-C fourth-order Bessel active lowpass filter employing fully differential operational amplifier,passive resistors,and current-steering MOS transistors as a variable resistor is proposed.This proposed implementation relies on the tunability of current-steering MOS transistors operating in the triode region counteracting the concert deviation of resistor in the integrated circuit manufacturing technology in orde r that the group delay of Bessel active filter could be designed accurately.The amplifier is not only with voltage common-mode negative feedback,but also with current common-mode negative feedback,which will benefit for the stability of its D C operating point.0.75μs group delay fourth-order Bessel lowpass filter,whic h is synthesized according to passive doubly terminated RLC prototype lowpass filter,demonstrates better than -65dB THD using 100kHz,2.5V pp signal in Taiwan UMC 2P2M(2-poly,2-metal)5.0V,0.5μm CMOS technology.展开更多
An accurate frequency response characterization method for photoreceivers with optical heterodyne technique is presented in this paper.The characterization is implemented with two single-mode tunable lasers operating ...An accurate frequency response characterization method for photoreceivers with optical heterodyne technique is presented in this paper.The characterization is implemented with two single-mode tunable lasers operating near the wavelength of 1.55 μm.The errors introduced by extra fixtures as well as laser output fluctuations are considered and calibrated simultaneously.Compared with previous works,the proposed calibration procedures are more complete.Experimental results indicate that the significant improvement in measurement precision has been achieved with the proposed method in the frequency range from 0 to 30 GHz,which proves the proposed frequency response characterization method to be feasible and reliable.展开更多
文摘A fully differential R-MOSFET-C fourth-order Bessel active lowpass filter employing fully differential operational amplifier,passive resistors,and current-steering MOS transistors as a variable resistor is proposed.This proposed implementation relies on the tunability of current-steering MOS transistors operating in the triode region counteracting the concert deviation of resistor in the integrated circuit manufacturing technology in orde r that the group delay of Bessel active filter could be designed accurately.The amplifier is not only with voltage common-mode negative feedback,but also with current common-mode negative feedback,which will benefit for the stability of its D C operating point.0.75μs group delay fourth-order Bessel lowpass filter,whic h is synthesized according to passive doubly terminated RLC prototype lowpass filter,demonstrates better than -65dB THD using 100kHz,2.5V pp signal in Taiwan UMC 2P2M(2-poly,2-metal)5.0V,0.5μm CMOS technology.
文摘An accurate frequency response characterization method for photoreceivers with optical heterodyne technique is presented in this paper.The characterization is implemented with two single-mode tunable lasers operating near the wavelength of 1.55 μm.The errors introduced by extra fixtures as well as laser output fluctuations are considered and calibrated simultaneously.Compared with previous works,the proposed calibration procedures are more complete.Experimental results indicate that the significant improvement in measurement precision has been achieved with the proposed method in the frequency range from 0 to 30 GHz,which proves the proposed frequency response characterization method to be feasible and reliable.
