[Elecraft] Spectrogram - Linear or Log scale?

[Alexandru Csete]

Keith,

I am not familiar with this particular case, but usually people only
want to use log scales when the data range spans over many decades. If
you take the logarithm of your data the decades become equidistant, in
other words, the "distance" between 1, 10, 100, 1000, ... will be the
same. Therfore, I don't see any reason why someone would want to have
log scale on the X axis in a signal strength vs. frequency graph. Your
frequency range spans 2 decades or so, if it is AF.

You may, on the other hand, want to try logarithmic scale on the Y
axis. The signal strength can indeed span several decades.

Taking the above into consideration I would also expect the passband
of a filter to be symmetric if you use linear X axis and skewed if you
use logarithmic X axis.

73
Alex OZ9AEC

On 3/10/06, Darwin, Keith <Keith.Darwin at goodrich.com> wrote:
> I've read through the instructions for aligning filters using Spectrogram.  IIRC, they say to set the X axis to linear.  Shouldn't it be set to log?  I think the difference will be using Linear, you'll have your passband skewed a bit to the low side.
>
> - Keith KD1E -