What does ADC sample rate mean and how it affects oscilloscope performance?

[umer_366]

what is meant by this sample rate and how it effects it my oscilloscope performane if i am using microblaze processor to take data from signal generator through ADC while my ADc is LTC 1407 and what it limits for????

 

[sweethomela8]

Re: ADC sample rate???

Whatever the highest frequency signal your signal generator will output, you will have to have the ADC be sampled / clocked at ATLEAST twice that frequency (what they call the nyquist frequency), in practice, we usually sample higher than 2 the highest frequency. You do this to avoid aliasing of the signal. Aliasing is when higher frequency signals will looks like lower frequency signals after the ADC samples it because it is not being sampled fast enough.

ex. signal gen produces 10 Mhz. ADC needs to sample > or equal to 5Mhz.

 

[umer_366]

Re: ADC sample rate???

thanks fro replying
ex. signal gen produces 10 Mhz. ADC needs to sample > or equal to 5Mhz

what else i have got from your message that it should be like

x. signal gen produces 10 Mhz. ADC needs to sample > or equal to 20Mhz

as u said that ADC should sample more quickly to avoid aliasing...
please correct me in the statement as i got it problem in understanding

so nice of u

 

[amraldo]

Re: ADC sample rate???

Sampling frequency should be greater than double the max frequency of your input.
--
Amr

 

[sweethomela8]

Re: ADC sample rate???

My mistake, yes, sig gen = 10Mhz, you must sample >= 20Mhz.

 

[umer_366]

Re: ADC sample rate???

hi
ok.i got it.
my ADC has max sample rate of 1.5 MHz and my maximum frequency should not increase above .75 MHz..
but it is mentioned over there that there are two ADC's over there with two preprogrammed Amplifier..
can i go for my max frequency of 1.5 at my signal generator..
so nice of u.
and if u know some thing about EDK then tell me that in which form i can store data in microblaze processor for further processing like implementing FFT core on data..
while my kit is sparten 3E.and EDK is 10.1...
thanks