[time-nuts] A simple sampling DMTD

[W7SLS]

Hello,

(It has been a more few years since I designed / developed DSP for spectrum analyzers for a major company, thanks for your patience.)

I recall that:

	sample @ fs -> decimate (toss samples) by a factor of N

is equivalent to

	sample @ fs / N

If we wanted a lower sample rate, we would:

	sample @ fs  -> lowpass filter at (say) 80% of (fs/2) / N -> decimate

Otherwise all of the energy > 50% of (fs / N) gets aliased into your data.

Why not just sample at 100 kHz?

What am I missing ?

Thanks for considering,
Scott W7SLS

> On Nov 3, 2019, at 12:59 PM, Jan-Derk Bakker <jdbakker at gmail.com> wrote:
> 
> Is this not caused by the fact that I'm currently subsampling the ADC
> (conversion rate 10Msps, rate into the microcontroller 100ksps by dropping
> 99 put of 100 samples)?