Multi-standard wideband OFDM RF-PWM transmitter in 40nm CMOS

© 2015 IEEE. A fully digital 0.9GHz-2.6GHz multimode modulator based on the principle of RF-PWM is presented. It makes use of a delay-line based phase modulator which delays an incoming LO-signal with a resolution of 4ps. The modulator is designed to drive highly efficient switching power amplifiers and support carrier frequencies over a wide range. The modulator has been implemented in 40nm CMOS technology. It achieves an EVM of better than -29dB for a 802.11g 64-QAM OFDM signal. It has also been tested with 40MHz single carrier 64-QAM modulated signals. The measured ACPR is below -30dB up to 2GHz and possible improvements are demonstrated.status: publishe

Techniques for Wideband All Digital Polar Transmission

abstract: Modern Communication systems are progressively moving towards all-digital transmitters (ADTs) due to their high efficiency and potentially large frequency range. While significant work has been done on individual blocks within the ADT, there are few to no full systems designs at this point in time. The goal of this work is to provide a set of multiple novel block architectures which will allow for greater cohesion between the various ADT blocks. Furthermore, the design of these architectures are expected to focus on the practicalities of system design, such as regulatory compliance, which here to date has largely been neglected by the academic community. Amongst these techniques are a novel upconverted phase modulation, polyphase harmonic cancellation, and process voltage and temperature (PVT) invariant Delta Sigma phase interpolation. It will be shown in this work that the implementation of the aforementioned architectures allows ADTs to be designed with state of the art size, power, and accuracy levels, all while maintaining PVT insensitivity. Due to the significant performance enhancement over previously published works, this work presents the first feasible ADT architecture suitable for widespread commercial deployment.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201