## Re: [SpectrumLabUsers] Plotting "selektivity"

Expand Messages
• Hi Sven, Yes, the numeric expression is ok.. ... The selectivity depends on the FFT resolution. It can be increased to ridiculous levels if necessary, but
Message 1 of 3 , Sep 1, 2013
• 0 Attachment
Hi Sven,

Yes, the numeric expression is ok..

I want to measure (plot) Schumann resonance #3 amplitude at 20 Hz (18 Hz to 22 Hz). But I have a spurios at 20Hz. Can this formula work?

max(peak_a(18,19.9),peak_a(20.1,22))

I asume that the spurios is sinus and stabil.

How selective is the measurement plot? Can I go further, for example, the lower limit 19.999 and higer limit 20.001?

The selectivity depends on the FFT resolution. It can be increased to 'ridiculous levels' if necessary, but for the expense of time-resolution. In other words, the longer the FFT, the better the frequency resolution, the worse the time resolution. This is explained to some detail in the manual.

All the best,
Wolf .

• Thank you Wolf /Sven --- In spectrumlabusers@yahoogroups.com, wrote: Hi Sven, Yes, the numeric expression is ok.. I want to measure (plot)
Message 2 of 3 , Sep 1, 2013
• 0 Attachment

Thank you Wolf
/Sven
--- In spectrumlabusers@yahoogroups.com, <dl4yhf@...> wrote:

Hi Sven,

Yes, the numeric expression is ok..

I want to measure (plot) Schumann resonance #3 amplitude at 20 Hz (18 Hz to 22 Hz). But I have a spurios at 20Hz. Can this formula work?

max(peak_a(18,19.9),peak_a(20.1,22))

I asume that the spurios is sinus and stabil.

How selective is the measurement plot? Can I go further, for example, the lower limit 19.999 and higer limit 20.001?

The selectivity depends on the FFT resolution. It can be increased to 'ridiculous levels' if necessary, but for the expense of time-resolution. In other words, the longer the FFT, the better the frequency resolution, the worse the time resolution. This is explained to some detail in the manual.

All the best,
Wolf .

Your message has been successfully submitted and would be delivered to recipients shortly.