Spectral Effects of Discrete-Time Amplitude Levels in Digital-Intensive Wideband Radio Transmitters

Mikko Martelius, Kari Stadius, Jerry Lemberg, Enrico Roverato, Marko Kosunen, Jussi Ryynänen, Lauri Anttila, Mikko Valkama

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

    2 Citations (Scopus)
    7 Downloads (Pure)


    This paper examines one source of spectral degradation in polar and multilevel outphasing transmitters. The degradation is caused by the amplitude signal appearing at the transmitter output as a baseband component, in addition to the desired RF signal. This baseband component contains sampling images and quantization noise across the spectrum. Thus, it adds noise at the signal band where it cannot be filtered and limits the achievable ACLR, particularly in wideband LTE and 5G systems. We analyze the origin of this phenomenon and related effects of system and signal parameters, and propose three design solutions for eliminating or alleviating the problem. Our analysis and simulations demonstrate that using a voltage-subtracting power combiner cancels the described degradation, potentially leading to significant improvement in spectral performance.

    Original languageEnglish
    Title of host publication2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018
    ISBN (Electronic)9781538648810
    Publication statusPublished - 26 Apr 2018
    Publication typeA4 Article in conference proceedings
    EventIEEE International Symposium on Circuits and Systems - Florence, Italy
    Duration: 27 May 201830 May 2018

    Publication series

    ISSN (Electronic)2379-447X


    ConferenceIEEE International Symposium on Circuits and Systems

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering


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