Wideband characterization of LCD baseband noise modulation for RF interference in mobile phones

Chulsoon Hwang, Takashi Enomoto, Junji Maeshima, Kenji Araki, David Pommerenke, Jun Fan

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

Abstract

A wideband measurement technique to characterize radio frequency (RF) interference caused by a liquid crystal display (LCD) baseband noise modulation is proposed. The LCD noise in baseband frequency range modulated with the Tx carrier signal of cellular communication interferes with the Rx signal, resulting in a RF receiver desensitization problem. Since the frequency offset between the Tx and Rx bands is small (several tens of MHz), a high Tx band rejection filter is essential to characterize the relatively small modulation noise with small frequency offset along with the strong Tx carrier signal. A typical solution is to use a duplexer, which only works for the dedicated communication band and, thus, a narrow band. The proposed measurement technique utilizes a 180° hybrid coupler and reflection cancellation to obtain high Tx band rejection without any frequency limited components. In addition, another reflection cancellation method is demonstrated for a large offset frequency case.

Original languageEnglish
Title of host publication2017 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMCSI 2017 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers
Pages130-134
Number of pages5
ISBN (Electronic)9781538622308
DOIs
Publication statusPublished - 20 Oct 2017
Externally publishedYes
Event2017 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMCSI 2017 - Washington, United States
Duration: 7 Aug 201711 Aug 2017

Publication series

NameIEEE International Symposium on Electromagnetic Compatibility
ISSN (Print)1077-4076
ISSN (Electronic)2158-1118

Conference

Conference2017 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMCSI 2017
CountryUnited States
CityWashington
Period7/08/1711/08/17

Keywords

  • LCD
  • modulation
  • radio frequency interference
  • reflection cancellation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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  • Cite this

    Hwang, C., Enomoto, T., Maeshima, J., Araki, K., Pommerenke, D., & Fan, J. (2017). Wideband characterization of LCD baseband noise modulation for RF interference in mobile phones. In 2017 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMCSI 2017 - Proceedings (pp. 130-134). [8077854] (IEEE International Symposium on Electromagnetic Compatibility). Institute of Electrical and Electronics Engineers. https://doi.org/10.1109/ISEMC.2017.8077854