If you read the DSO nano manual, you will see the microcontroler used in the DSO nano is the STM32F103VBT6 (based on ARM Cortex M3), this one can maximum be clocked at 72MHz (and can reach 90 DMIPS source: STM32 docs, but according to some forumers on a topic, we can´t reach this performance (?!) ). I don´t know the clock frequency used in the DSO nano but according to the reference manual, 1MSPS ADC´s rate can only be achieved with a 56MHz System Clock.
On the ST´s site you can find a DSP library which include an FFT function.
See user´s manual: st.com/stonline/products/lit … /14988.pdf
you can download the DSP library firmware here (in firmware section): st.com/mcu/familiesdocs-110.html
And you can find somes discussions about in the forum…
An other idea which can be interesting is to improve the ADC accuracy by oversampling (for lower frequency signals)… But it depends from other hardware accuracy too…
(I´ve just discovered the DSO nano today and I actually programm on STM32 but not with FFT calculations. I will probably buy one when it will be possible… Do you know when last release will be available?)
PS: Modified Friday 23 Oct. at 10h (GMT+1)