A Fractional-N Frequency Synthesizer with a Sigma-Delta Modulator for Polar Transmitter
| Autor: | Kuo-Hao Chao, 趙國豪 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 In 2.5G or 3G communication system, the envelope of the modulation signal is non-constant, so it is a trade-off between the linearity and the efficiency of a power amplifier in the transmitter. Polar transmission techniques offer the capability of multi-standard and the potential for significant efficiency gains over solutions based on I/Q modulation. A main component of a polar transmitter is the phase modulator. In the work, we setup a complete behavior model of phase modulator in Simulink environment. The EVM and the power spectrum are estimated, and the effect of delay mismatch between the phase and envelope signal is also discussed. Finally, we use a Σ-Δ fractional-N frequency synthesizer to implement partial RF circuit of the phase modulator. A phase frequency detector, a charge pump and a multi-modulus divider are fabricated with 0.35μm 2p4m CMOS technology and are operated over 1 GHz. The Σ-Δ modulator is implemented by FPGA. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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