Modulation and frequency synthesis for wireless digital radio [thesis]

Walter Bax
The author has granted a nonexclusive licence dowing the National Library of Canada to reproduce, loan, distribute or sell copies of this thesis in microfonn, paper or electronic formats. The author retains ownership of the copyright in this thesis. Neither the thesis nor substantial extracts fiom it rnay be printed or otherwise reproduced without the author's permission. L'auteur a accordé une licence non exclusive permettant à la Bibliothèque nationale du Canada de reproduire, prêter,
more » ... er ou vendre des copies de cette thèse sous la fonne de microfiche/film, de reproduction sur papier ou sw fonnat électronique. L'auteur conserve la propriété du droit d'auteur qui protège cette thèse. Ni la thèse ni des extraits substantiels de celle-ci ne doivent être imprimés ou autrement reproduits sans son autorisation. Abstract A new wideband modulator architecture. that is suitable for continuous-phase constantenvelope modulation schemes, is presented in this thesis. The technique is based on direct niodulation of a high resolution AZ frequency discriminator based synthesizer to produce the modulated W signal without up-conversion. The advantage of this architecture is that ir does no1 require mixers or D/A converters to generate the In-phase and Quadrature sipals as in conventional GMSK modulators. This eliminates many of the analog problems associated with mixing and filtering and results in an architecture suitable for monolithic integration. A high modulation data rare is possible, without sacrificing phase noise performance. through digital equalization of the synthesizer closed-loop response. A digital GMSK transmit filter pre-shapes the data symbols and additionally compensates for die synthesizer closed-loop response. This permits the use of a narrower synthesizer bandwidth CO attenuate the A. Z quantization noise, while equalization effectively widens the modulation bandwidth to handle high data rates. The digital equaiization filter adds little complexity to the transminer architecture, since it is combined with the Gaussian data filter. Matching between the transmit [ilter and the synthesizer closed-loop response is not an issue since the loop parameters are digitaily defined and are therefore predictable. An experimental GSM modulator operating at ?GHz was developed to validate the suitability of the architecture for use in wireless communication systems. It makes use of a custom BiCMOS AX frequency discriminator chip that is a key component in the modulator architecture.
doi:10.22215/etd/2000-04402 fatcat:3sugfcarjrfxtd5kta4lq4332u