Title :
Mixer linearisation for software defined radio applications
Author :
Nesimoglu, T. ; Beach, M.A. ; MacLeod, J.R. ; Warr, P.A.
Author_Institution :
Centre for Commun. Res., Bristol Univ., UK
Abstract :
The inherent non-linearity of mixers is particularly acute in broadband receiver design for software defined radio (SDR) applications. Here, the receiver frontend ´sees´ not only the wanted channel, but also a number of nearby signals. A conventional mixer will downconvert all of these received channels to IF, thus adding inband interband interference to the wanted channel. In this paper, known mixer linearisation schemes are explained and a new technique using frequency retranslation within a linearised mixer architecture is presented. Two-tone-test results from a prototype offered 33 dB reduction in the distortion products and 22 dB suppression of adjacent channel interference (ACI) for a π/4-DQPSK modulated carrier. A theoretical analysis is also carried out to demonstrate the amplitude and phase matching requirements of the technique.
Keywords :
adjacent channel interference; differential phase shift keying; interference suppression; intermodulation distortion; linearisation techniques; mixers (circuits); quadrature phase shift keying; radio receivers; software radio; π/4-DQPSK modulated carrier; IF; adjacent channel interference suppression; amplitude matching; broadband receiver design; distortion products; frequency retranslation; inband interband interference; linearised mixer architecture; mixer linearisation; phase matching; receiver frontend; software defined radio applications; two-tone-test results; Application software; Baseband; Communication systems; Filtering; High definition video; Interchannel interference; RF signals; Radio frequency; Receivers; Software radio;
Conference_Titel :
Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th
Print_ISBN :
0-7803-7467-3
DOI :
10.1109/VETECF.2002.1040401