I have just tried the latest version (1.02) of the Upsampling algorithm with SigmaStudio 4.6 and an ADAU1452.
I am running at 96kHz sample rate and downsampling 16x, then Upsampling, with no filtering and insertion set to zero order hold.
What I get looks like the instertion is set to Zero Insertion instead.
when I set it to zero insertion I get no output.
When I revert it to 1.01 (with the LPF switched off), zero order hold looks as expected, and there is output of the expected nature when set to zero insertion.
added more tags
[edited by: alexsconway at 4:14 PM (GMT -4) on 23 Apr 2021]