[linrad] Linrad-02.30 short-lived.

[Leif Asbrink <sm5bsz.com; leif@xxxxxxxxxxxxxxxx>]

Hi All,

I have received bug reports on Linrad-02.30 that will
make me upload 02-31 (and remove 02-30) pretty soon.


1) Calibration. The zero point of the main spectrum will
grow in proportion to the number of points behind each
pixel. This does not matter at all for the processing, but
it may be inconvenient.

The reason is that I have changed the way the waterfall
is computed when fft2 is not enabled. There is a difference 
only when fft1 is big enough to have more than one bin
behind each pixel on the screen. Old versions use the
average power from all pixels, but 02-29 and onwards use
the strongest bin within each group. This way the sensitivity
of the waterfall is improved by up to 6 dB depending on
averaging.

When I changed the scale factor for the waterfall to no longer
divide by the number of bins that will be summed, I unintendedly
changed the zero point for the main spectrum the same way and
therefore the main spectrum will shift vertically when 
the number of bins behind each pixel is changed.

The correction to this error is trivial and will be done
in 02-31.


2) This is a serious error. In case the parameters for fft1
are selected in a way that causes a long processing time for
fft1, feeding in numerical values after clicking on a parameter
box does not work well - or does not work at all.

I do not (yet) know what the cause might be, 02-27 does not have
this problem although the response might become a bit slow
when very slow transforms are computed.

In case you have mouse problems with linrad-02.30, set a larger
bandwidth for fft1 and use the second fft in case you want good 
sensitivity in the waterfall.

                               


73

Leif / SM5BSZ






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