Analog-to-digital converter effects on airborne radar performance

In order to evaluate A/D (analog/digital) converter effects on airborne radar performance, a polynomial A/D converter model based on measured harmonic levels of a 14-bit A/D converter has been developed. The model has been validated by comparing the measured spurious-free dynamic range of the A/D converter at different amplitude levels and frequencies with the simulated data from the model. The comparison shows that the model captures the roll-off in spurious-free dynamic range due to increasing input frequency and causes small ripples across frequency and input power levels. The model has been included in an airborne radar simulation to evaluate the effect of internal noise and nonlinearities of the A/D converter on the radar performance. It is concluded from 50 Monte Carlo simulation runs for two cases-ideal A/D converter and A/D converter with nonlinearities-that the number of false alarms and subclutter visibility are not significantly degraded by nonlinearities for this 14-bit A/D converter for the case of mainbeam land clutter at broadside