Comparison of Downconversion Techniques for Software Radio

Software radio is an enabling technology for future radio transceivers, allowing the realisation of multimode, multiband, and reconfigurable base stations and terminals. This paper describes work comparing two suitable methods of downconverting RF signals to baseband, which may be used in software radios. These are direct conversion and bandpass sampling. The performance of each method is evaluated and the effects of the specifications of the front end bandpass filter on the receiver performance are analysed, in terms of bit error rate.