Connecting the output from a function generator through a BNC cable to the input

Thread Starter

John Manuel

Joined Jun 6, 2018
17
I am trying to work with the signals generated by a function generator using Raspberry Pi. Since Raspberry Pi does not have an inbuilt ADC, I used pcf8591. Now, I do not know how to feed the signal generated by the function generator into the input pins of pcf8591. Please help.
 

danadak

Joined Mar 10, 2018
4,057
Typically the f() generator has a bipolar 50 ohm output.

But ADC has single ended input.

So you need to offset the f() generator output to drive the ADC
within its CM range. Look at its datasheet for those values.
Typically thats Vdd >= Vin >= Vss of ADC chip.

If you drive outside that range you can hose the ADC chip. Simple
preventative measure while getting setup is use a series R to limit
current, say 1 mA, when f() generator exceeds Vdd >= Vin >= Vss
Once setup remove series R. Note if operating at higher frequencies
terminate the ADC input to 50 ohms. Mhz area of frequencies.

Regards, Dana.
 
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