Design and Implementation of a Wideband Digital Interpolating Phase Modulator RF Front-End

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A4 Artikkeli konferenssijulkaisussa

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2018-04-26

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en

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2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Proceedings, Volume 2018-May, IEEE International Symposium on Circuits and Systems proceedings

Abstract

This paper describes implementation details of a digital-intensive phase modulator architecture that does not require a frequency synthesizer to cover a wide carrier frequency range. The phase modulator operation is based on toggling the output accurately during the sample period to generate the phase-modulated signal. The toggling instants within the sample period are calculated by DSP solvers that utilize linear interpolation. The interpolation effectively multiplies the phase signal sample rate by the modulator phase resolution, which enables wider signal bandwidth and a completely digital method of defining the transmitter carrier frequency. The phase modulator concept is verified by implementing it as a part of an outphasing transmitter in 28 nm CMOS. With a constant sample rate of 1.5 GHz and without any predistortion, the transmitter achieves better than -28 dBc ACLR with 100 MHz aggregated LTE downlink signal between 0.8-2.0 GHz carrier frequency.

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Keywords

analogue-digital conversion, CMOS integrated circuits, frequency synthesizers, interpolation, Long Term Evolution, phase modulation, radio transmitters, signal sampling

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Citation

Lemberg, J, Kosunen, M, Nieminen, T, Roverato, E, Martelius, M, Stadius, K, Ryynänen, J, Anttila, L & Valkama, M 2018, Design and Implementation of a Wideband Digital Interpolating Phase Modulator RF Front-End . in 2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Proceedings . vol. 2018-May, 8350977, IEEE International Symposium on Circuits and Systems proceedings, IEEE, IEEE International Symposium on Circuits and Systems, Florence, Italy, 27/05/2018 . https://doi.org/10.1109/ISCAS.2018.8350977