Design of analog to digital converter for SDR (Software Defined Radio)

Software defined radio (SDR) is a potential low cost future-proofed solution to the growing number of incompatible wireless standards operating in different frequency bands and different geographical zones. The attractiveness of the concept is that the same hardware platform can be reprogrammed to operate on many different standards. This paper is aimed at designing an 8 bit Analog to Digital Converter for SDR. An analog-to-digital converter is an electronic integrated circuit, which converts an input analog voltage to a digital number. The digital output may be obtained using different coding schemes, such as binary, Gray code or two´s complement binary. Based on the response, ADC is classified into Linear and Non-linear ADCs. Among the various types of ADC our contribution towards this project is the design of direct conversion ADC (flash ADC). The above mentioned ADC type has been implemented using CMOS logic style in Cadence IC 5.1.41 tool (Composer Schematic) and the results have been compared with SAR ADC type in terms of speed and area efficiency. The individual modules are designed using 1.2 micron and 0.25 micron TSMC process technologies.