[Scipy-tickets] [SciPy] #1105: Logarithmic chirp frequency sweep incorrect

SciPy Trac scipy-tickets@scipy....
Mon Feb 8 15:38:29 CST 2010


#1105: Logarithmic chirp frequency sweep incorrect
-----------------------------------------+----------------------------------
 Reporter:  johntryan                    |       Owner:  somebody    
     Type:  defect                       |      Status:  needs_review
 Priority:  normal                       |   Milestone:  0.8.0       
Component:  scipy.signal                 |     Version:  0.7.0       
 Keywords:  chirp logarithmic frequency  |  
-----------------------------------------+----------------------------------

Comment(by warren):

 In my patch, 'logarithmic' still computes the sweep using the previous
 formula.  As I mentioned in item 1 of my list of changes, this sweep gives
 f(0) = f0 + 1, and I agree that this is wrong. (Where I said "instance
 frequency" I meant "instantaneous frequency".)

 I implemented the sweep that you and I agree is the preferred one with the
 name 'geometric'.  This sweep is also referred to as 'exponential'; see,
 for example:

     http://en.wikipedia.org/wiki/Chirp

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1105#comment:6>
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