Richard wrote:
Hmmm, out of interest, how many more should there be.
I am definitely not the right person to answer to that, but: UHJ decoders with better directional "resolution" used to have four 10-pole phase shifters. The three AD7 shifters are eight pole (if I remember right, would need to check the schematics.)
Also a question, I thought on only X& Y were phase shifted +90 degrees during encoding, am I wrong in this thinking?
AFAIK it is difficult to design phase shifters with so "low" shifts. It is the relative phase difference between the phase shifters inside the decoder that counts. The W shifter has a certain phase shift and the other shifter outputs are leading or lacking the W in phase. A further difficulty is that the relative phase difference between the component signals should be the same on all frequencies. Again - as far as I have understood, this is difficult to solve in analog phase shifters. As the encoders also were made with analog phase shifters, errors in both of them added up as directional distortion. This is the way a sound designer sees it, other people on the list may be able to give you a more scientific explanation. Eero _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
