The Rexton counterpart is “BiCore”. If you compare the marketing buzz you’ll note that both the BiCore and the AX describe separating the signal between speech and noise, processing each independently, and then recombining the signal.
I tried to find the tech specs of the Rexton for comparison, but could not find anything. What was glaring however is that Rexton in toto devotes only one or two sentences to this feature of the BiCore with no supporting details other than the inference in the name “Bi” core, while Signia’s entire marketing campaign is built around the AX as a platform with two processors and even shows an illustration having two chips.
Perhaps this is a marketing strategy to ensure that the Rexton is not placed on the same level as the AX, or perhaps the implementation in hardware is indeed fundamentally different. No idea which.