Thursday, September 5, 2013

For the first time except in time

So, I'm reading up on Chuck Yeager.  During the movie [The Right Stuff], I was thinking that he's arguably the baddest human being who ever lived, but that may have been Sam Shepard's acting.  Anyway, there is video in his wiki page documenting his 1947 flight breaking the sound barrier.  And it has a line that is kinda frying my noodle .. "For the first time except in time a man has flown an airplane faster than the speed of sound."  The video is embedded in the wiki page, but this is the direct link.

What does that mean "for the first time except in time"?  

Accordingto Google, it's the only instance of that phrase on the internet (one result is the transcript of that video and the other two are actually "except in time of war").  Maybe someday Google will return this post, too.

Wednesday, May 8, 2013

Last For Now

Last for now.  No padding vs. One Second Padding.

Paddington Goes To Town

No pad, one second pad, two second pad.   Note the already high granularity (goes from 1/190 Hz, to 1/191, to 1/192, ie. roughly 190 samples per HZ).  Note the sinc characteristics.

Tuesday, May 7, 2013

Zero Padding Examples

First, a 190 second window, sampled at 100 Hz, 1.9Hz and 5.2Hz sine.  Note the near-zero values in the spectrum

Now a ONE second zero padding addition to the same.  Note the sinc convultion in spectrum.  This is clearly not due to change in freq-domain granularity increasing from 1/190 sec to 1/191 sec.

 Now lets remove that one second pad by filling in the second w/ real data.  Poof, the sinc convolution is gone, yet we are at the same (1/191sec) granularity as the zero-padded.  I think that this spectrum differs qualitative from the first b/c we are no longer at exact multiples of the fundamental freq

Now the 191 sec window w/ a one second zero pad:  

Here's the same as above, w/ noise added.  Note the persistence of the sinc convolution.

Finally, let's add a bunch more padding and zoom in around one of the fundamentals.