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

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Research units

  • Tampere University of Technology


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.


Original languageEnglish
Title of host publication2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Proceedings
Publication statusPublished - 26 Apr 2018
MoE publication typeA4 Article in a conference publication
EventIEEE International Symposium on Circuits and Systems - Florence, Italy
Duration: 27 May 201830 May 2018

Publication series

NameIEEE International Symposium on Circuits and Systems proceedings
ISSN (Electronic)2158-1525


ConferenceIEEE International Symposium on Circuits and Systems
Abbreviated titleISCAS
Internet address

    Research areas

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

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