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Products => Test Equipment => Topic started by: Sharp on December 11, 2021, 07:47:56 pm

Title: MSO5000 FFT question
Post by: Sharp on December 11, 2021, 07:47:56 pm

Hi guys

I have a MSO5000 and are now looking into the FFT functionality and have a question for your guys.

If you take a look at the attached MSO5000 screen dumps, I use a 10kHz sine wave 1 volt PP on the FFT 1 screen dump and a 10kHz triangular wave 1 volt PP on the FFT 2.
The FFT setup is dBV and the waveform generator and the MSO is 50 ohm terminated.

My question is on the FFT 1 screen dump – the 1 volt sine wave – The FFT analysis shows the first fundamental to -9.5 dBV – If I want to find the voltage from the FFT analysis I get:  Voltage = 10^(-9.5/20)  = 335mV  - why is it not 1 Volt – what is wrong here ???
     

Title: Re: MSO5000 FFT question
Post by: mawyatt on December 11, 2021, 08:20:54 pm

Likely because 1Vpp is 0.3536Vrms for a sine wave.

Best

Title: Re: MSO5000 FFT question
Post by: Sharp on December 11, 2021, 09:13:11 pm

 |O Of cause I’m stupid

@mawyatt  Thank you  ^-^
 

Title: Re: MSO5000 FFT question
Post by: Wallace Gasiewicz on December 12, 2021, 12:43:46 am

Me Too!