FPGA-based analog functional measurements for adaptive control in mixed-signal systems

A field-programmable-gate-array (FPGA)-based built-in self-test (BIST) approach that is used for adaptive control in mixed-signal systems is presented. It provides the capability to perform accurate analog functional measurements of critical parameters such as the third-order intercept point, frequency amplitude and phase responses, and noise figure. The results of these measurements can then be used to adaptively control the analog circuitry for calibration and compensation. The BIST circuitry consists of a direct digital synthesizer-based test pattern generator and a multiplier/accumulator-based output response analyzer. The BIST approach has been implemented in an FPGA-based mixed-signal system and used for actual analog functional measurements. The BIST measurements agree quite well with the results obtained with the. traditional analog test equipment. The proposed BIST circuitry provides a unique means for high-performance adaptive control in mixed-signal systems.