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

3 Citations (Scopus)
151 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 publicationIEEE International Symposium on Circuits and Systems
Place of PublicationUNITED STATES
Number of pages5
ISBN (Electronic)978-1-5386-4881-0
ISBN (Print)978-1-5386-4882-7
Publication statusPublished - 4 May 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
ISSN (Electronic)2379-447X


ConferenceIEEE International Symposium on Circuits and Systems
Abbreviated titleISCAS
Internet address


  • radio frequency
  • radio transmitters
  • power combiners
  • bandwidth
  • baseband
  • quantization (signal)


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