> Floating values could be a function of the PCB, tthe quality of the input signal, the
> connections, the impedance/capacitance of the probe wire, improper
> coupling/grounding...etc.
>
> If you don't have access to a scope, I'd start by filtering the input pin as shown on
> page 7 (below) with a 620 Ohm resistor and a 510pf capacitor to make sure your imput
> is clean.
>
> http://www.national.com/ds/LM/LM1881.pdf
Ok thanks, I'll try filtering the input..but capacitors must be polarized or normal ceramic?
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Re: HELP:Measuring refresh rate of PCBs
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