Analog signal generator for BIST of wideband IF signals bandpass sigma–delta modulator

Abstract

This paper presents improvements in generation of wideband and high dynamic range analog signal for area-efficient MADBIST, especially for the on-chip testing of wireless communication IF digitizing sigma–delta modulator chip. Via increasing the order of the one-bit bandpass sigma–delta modulation algorithm up to 12 and using finite repetitious bitstream approximating scheme, it can achieve great improvements in signal bandwidth instead of purity at the cost of very little hardware overhead. Another contribution in this work is to provide the theoretical analysis of the reconstructed signal degradation due to harmonic distortion and clock jitter. Such on-chip analog stimulus generation scheme is especially fit for IF digitizing bandpass sigma–delta modulator chip's production-time testing and in-the-field diagnostics. The technique can also be extended to mixed-signal communication SoC built-in-self-test.