Just about everything about Red Pitaya
- Posts: 7
- Joined: Mon Oct 13, 2014 4:50 pm
- Location: Munich, Germany
On the wiki, here:
http://wiki.redpitaya.com/index.php?tit ... de#Example
there is an example on how to modify the acquire application.
Could someone explain where the constant 1.079 that is used for the calibration of the front end results comes from?
This seems to give a weighting per bit of 131.73uV, whereas I was working with 122uV per bit. 131uV results in conversions to the correct voltage, but I don't understand where this value came from.
Thanks in advance, Stuart
- Posts: 10
- Joined: Wed Oct 22, 2014 5:46 am
As a quick check, 2^14 (14-bit ADC) * 131.73uV = 2.158V.
The input is rated at +/- 1V.
So I'm assuming the input "protection" kicks in before the ADC has reached its full range.
I have to guess, because this is the kind of thing you'd verify by checking the schematic. Which I have not yet found.
Anyway... since full scale voltage is slightly higher, the step size is also slightly higher.
Hence the correction factor.
Now you've got me wondering what the ADC chip is...
- Posts: 1441
- Joined: Sat Jun 07, 2014 12:49 pm
- Location: Königswinter
jadalnie klasyczne ekskluzywne meble wypoczynkowe do salonu ekskluzywne meble tapicerowane ekskluzywne meble do sypialni ekskluzywne meble włoskie
Who is online
Users browsing this forum: Bing [Bot] and 5 guests