Implementation of a Filter and Multiplier for Next Generation Transceivers

Abstract: A new sub-sampling technology is presented to greatly lower the sampling frequency of the transceivers with wideband inputs. The innovation of the theory is the flexible selection and conversion of any single band out of a multiband spectrum. According to the theoretical work on a sub-sampling wideband receiver, such a technology enables demodulation of wideband inputs with a sampling frequency much lower than the carrier frequencies, and converts the band of interest to a low frequency band simultaneously. The purpose is to make it easier for the subsequent ADC to process a single band when applying a low-pass filter after the demodulation. The technology is also fit for the transmitter, which inversely converts wideband inputs to a high frequency band and make the band of interest located on the carrier frequency point. Compared with traditional demodulation, we generate a waveform containing a multiple set of sinusoids instead of using a single local oscillator, and pass them through a carefully designed band-pass filter. The filter eliminates all the harmonics except the one located at the band of our interest. Then both the multiband inputs and the output of the filter are mixed by an analog multiplier. After such a process, the band we want is now converted to a low frequency. The objective of this master thesis is verification and implementation of the principle in order to evaluate which best performance can be reached. The whole architecture is simulated and finally validated in circuit level using 90nm CMOS technology.