Title :
An analog-digital adaptive image-reject technique for quadrature receivers
Author :
Hajirostam, Mohammad ; Martin, Ken
Author_Institution :
Dept. of Electr. & Comput. Eng., Toronto Univ., Ont., Canada
fDate :
28 Aug.-2 Sept. 2005
Abstract :
In this paper, an analog-digital adaptive image-reject (IR) technique for quadrature receivers is presented. In these receivers, I/Q mismatches degrade the image rejection performance. To compensate the mismatches, a complex error signal is generated digitally of which the real and imaginary parts are proportional to the I/Q amplitude and phase mismatches. This error signal is applied to Digitally-Controlled Multiplier-Adder (DCMA) blocks to correct the phase and amplitude mismatches. Simulations show that the Image-rejection ratio is improved to more than 57 dB for a low-W cable modem receiver. This performance is independent of the synchronization and equalization of the receiver.
Keywords :
adders; analogue-digital conversion; modems; multiplying circuits; optical receivers; synchronisation; I/Q amplitude; I/Q mismatches; analog-digital adaptive image-reject; complex error signal; digitally-controlled multiplier-adder block; equalization; image degradation; image rejection; low-W cable modem receiver; mismatch compensation; phase mismatch; quadrature receiver; synchronization; Analog-digital conversion; Degradation; Equations; Error correction; Filtering; Frequency; Image converters; Image retrieval; Interference; Signal generators;
Conference_Titel :
Circuit Theory and Design, 2005. Proceedings of the 2005 European Conference on
Print_ISBN :
0-7803-9066-0
DOI :
10.1109/ECCTD.2005.1523115
