TX is one of the most challenging (and rewarding) block in RFIC design, and ACLR is one of the key TX design spec. ACLR is a measure of out-of-band distortion (and noise) that leaks to the neighboring band. While IM3 is a great test for distortion, it leaves a lot to be desired since it is based on two-tone excitation. When a TX is excited with the desired modulated waveform that it is going to actually transmit, ACLR may come out pretty bad given what you might have predicted from IM3. That is why we need to decompose ACLR into different metrics to understand what factors contribute to it, and thereby optimize/debug it with proper insights.
Date Published: 04 Jan 2023
Last Edit: 02 Feb 2023