Go Down

Topic: Measuring unstable input (Read 386 times) previous topic - next topic

swoshie

Hello,

I'm currently trying to read an analog input that is very unstable, it's a signal meter indication that's part of a radio receiver. The DC voltage is good when the signal is strong but really noisy when the signal is weak.

I've tried to use several averaging codes but none seems to be enough, the value of the read is jumping up and down all the time.

The finished project is to make a tone out off the measured value, it has to be linear.

Any advice?

Thanks!

dhenry

Quote
Any advice?


Depending on how "unstable" your "very unstable" signal is, the solution ranges from "no one can do it for the next 2 billion  years" to "piece of cake".

swoshie

I'm sorry. The input is not THAT unstable  :P

Think of it this way:



When the signal is getting weaker, the noise rises and makes the analog read unstable. I need to filter that somehow to get a solid value that is linear with the generated tone.

Thanks!

robtillaart


Quote
I've tried to use several averaging codes but none seems to be enough, the value of the read is jumping up and down all the time.

The finished project is to make a tone out off the measured value, it has to be linear.

Any advice?


1) post the averaging algorithms you have tried

2) check - http://arduino.cc/playground/Main/RunningMedian - and use a size of 9 [or higher] and add 9 [or more] samples and use the middle one.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

Go Up