Abstract
The overview and design of fully-digital transmitters based on pulse-width modulation (PWM) are clarified. By employing the parallel architecture with quadrature intermediate-frequency (IF) PWM and pre-corrected polar carrier-frequency (CF) PWM, a fully-digital transmitter is proposed and designed in 180 nm CMOS, with wide CF and high modulation resolution. The presented PWMs are based on delay lines and multiplexers with the unit delay automatically calibrated. Inductive differential power combination with 2-level quadrature operation is proposed to accomplish the equivalent 3-level up-conversion for IF PWM. Piecewise-linearization correction technique is presented to ensure the envelope-modulation fidelity for CF PWM. For 8PSK based EDGE baseband signals, the proposed transmitter achieves a wide CF range of 2 M–1.5 GHz and a low error vector magnitude less than 3 %, with 20 dB spectrum optimized and higher modulation resolution in comparison to the existing designs. Excluding the power amplifiers, the presented implementation dissipates 120 μW from a 1.8 V power supply under the data rate of 270.833 kS/s or 812.5 kb/s, thus achieves the figure of merit of 0.44 nJ/S or 0.15 nJ/bit.
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References
Chen, J., et al. (2012). The design of all-digital polar transmitter based on ADPLL and phase synchronized ∆Σ modulator. IEEE Journal of Solid-State Circuits, 47(5), 1154–1164.
Kim, W.-Y., et al. (2008). 1-bit and multi-bit envelope delta-sigma modulators for CDMA polar transmitters. In Microwave Conference, 2008, APMC 2007, Asia-Pacific, (pp. 1–4), December 16–20, 2008.
Nuyts, P., et al. (2012). A fully digital delay line based GHz range multimode transmitter front-end in 65-nm CMOS. IEEE Journal of Solid-State Circuits, 47(7), 1681–1692.
Nuyts, P., et al. (2012). A CMOS burst-mode transmitter with watt-level RF PA and flexible fully digital front-end. IEEE Transactions on Circuits and Systems II: Express Briefs, 59(10), 613–617.
Midya, P., et al. (2002). Quadrature integral noise shaping for generation of modulated RF signals. In Midwest Symposium on Circuits and Systems, 2002, MWCAS 2002, (pp. II-537–II-540), August 4–7, 2002.
Nielsen, M., & Larsen, T. (2007). An RF pulse width modulator for switch-mode power amplification of varying envelope signals. In Silicon Monolithic Integrated Circuits, 2007, SMIC 2007, (pp. 277–280), January 10–12, 2007.
Lopelli, E., et al. (2009). Minimum power-consumption estimation in ROM-based DDFS for frequency-hopping ultralow-power transmitters. IEEE Transactions on Circuits and Systems I: Regular Papers, 56(1), 256–267.
Kim, K.-W. (2009). A fully-integrated all-digital outphasing transmitter for wireless communications, [PHD dissertation]. Atlanta, USA: Georgia Institute of Technology.
Zhou, B., et al. (2013). Reconfigurable fully digital transmitter with carrier-frequency pulse-width modulation. Electronics Letters, 49(19), 1244–1246.
Zhou, B., et al. (2013). Parallel PWMs based fully digital transmitter with wide carrier frequency range. The Scientific World Journal. doi:10.1155/2013/373429.
Henzler, S., et al. (2007). Variation tolerant high resolution and low latency time-to-digital converter. In 33rd European Solid State Circuits Conference, 2007, ESSCIRC 2007, (pp. 194–197), September 11–13, 2007.
Acknowledgments
The authors would like to thank the National Natural Science Foundation of China (61306037), Beijing Natural Science Foundation (4153063) and Basic Research Foundation of Beijing Institute of Technology (20130542009) for the financial support. This work is also supported by the China Scholarship Council (201406035016).
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Zhang, K., Zhou, B. Pulse-width modulation based fully-digital transmitter with wide CF and high resolution. Analog Integr Circ Sig Process 84, 293–302 (2015). https://doi.org/10.1007/s10470-015-0545-8
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DOI: https://doi.org/10.1007/s10470-015-0545-8