Unknown Signal Detection Using a Digital Total-Power Radiometer with Finite Internal Precision

The influence of fixed-point implementation in the unknown signal detection using a total-power radiometer is studied. The detection is done using a general-purpose receiver structure. The system uses uniform analog-to-digital conversion (ADC) and internal calculations are performed using fixed-point. ADC and the finite internal precision cause the decision variable to be discrete. This leads to difficulties to maintain the constant false alarm rate required by the Neyman-Pearson criterion. Two internal calculation modes are compared. One removes the most significant bits and the other the least significant bits. From a detection point of view the preservation of the least significant bits outperforms the preservation of the most significant bits