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From: | Ben Abbott |
Subject: | Re: outstanding changesets |
Date: | Sun, 01 Feb 2009 14:38:31 -0500 |
On Feb 1, 2009, at 1:56 PM, Daniel J Sebald wrote:
Ben Abbott wrote:On Jan 29, 2009, at 1:50 AM, Søren Hauberg wrote:? ... that is not what I expected. My impression was the Matlab unwrapped the phase in such a way that only positive delays would result. However, in this example, it appears to be opposite.ons, 28 01 2009 kl. 22:13 -0500, skrev John W. Eaton:Does Matlab produce the same result?Matlab produces the attached pdf Søren <matlab_freqz.pdf>Any idea what they are doing?To "unwrap the phase" does not mean disallowing negative, it means to remove any 360 degree jumps from the phase which were created as a consequence of the modular arithmetic of phase angles. Note that if there are 180 degree phase shifts, those stay because they are actual phase jumps.Dan
Hi Dan,What I've inferred is that Matlab's implementation favors unwrapping the phase so that the phase slope is negative (downward sloping), and the delay is positive.
See the examples at the link below. http://hauberg.org/wiki/doku.php?id=freqz Ben
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