A switched-capacitor image rejection filter, for complex IF receivers

Author

Pun, Kong-Pang ; Franca, José E. ; Azeredo-Leme, C.

Author_Institution

Centre for Microsyst., Inst. Superior Tecnico, Lisbon, Portugal

fYear

2000

fDate

2000

Firstpage

140

Lastpage

143

Abstract

This paper presents a switched-capacitor (SC) image rejection filter to solve the image problem in complex IF receivers, caused by mismatches between the in-phase (I) and quadrature (Q) paths. The proposed filter is actually a complex FIR Hilbert transformer with a notch frequency at +¼f_s, (f_s is the sampling frequency). An SC realization, as a part of the sampling units of the analog-to-digital convertor (ADC), is proposed. As demonstrated by circuit simulations, over 70 dB of image rejection can be achieved in the presence of 1% capacitance mismatch

Keywords

FIR filters; Hilbert transforms; analogue-digital conversion; circuit simulation; digital radio; radio receivers; switched capacitor filters; SC realization; analog-to-digital convertor; capacitance mismatch; circuit simulations; complex FIR Hilbert transformer; complex IF receivers; mismatches; notch frequency; sampling frequency; sampling units; switched-capacitor image rejection filter; 1f noise; Circuit simulation; Costs; Digital communication; Finite impulse response filter; Frequency; Image converters; Image sampling; Local oscillators; Receivers;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2000. IEEE APCCAS 2000. The 2000 IEEE Asia-Pacific Conference on

Conference_Location

Tianjin

Print_ISBN

0-7803-6253-5

Type

conf

DOI

10.1109/APCCAS.2000.913426

Filename

913426