Removing the DC level of a signal.

Thread Starter

kahafeez

Joined Dec 2, 2008
150
Hello Folks, i got this wave from a VCO which is operated at +5V and GND.....

the frequency is 16.6Mega Hertz

i need to remove the DC component of the signal..... meaning i need to bring the signals GND at DC gnd so that it waves about the DC 0V level....

i thought a simple capacitor would do it bt it didnt really do it.... i used a 220uF capacitor as i didnt know what value to choose.... are there any rules for choosing the Capacitor's value..... plz state them.... or suggest a way to remove the dc level.... thanks....
 

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SgtWookie

Joined Jul 17, 2007
22,230
220uF is much too large. A capacitor of that size will have lots of parasitics at that frequency.

Try a 0.1uF or 10nF ceramic capacitor, with a 10k resistor to ground on the output side.
 

DickCappels

Joined Aug 21, 2008
10,661
AND...add a resistor to ground so the signal will be around ground. When you look with a scope probe, the resistance of the scope probe to ground (usually 1 Meg Ohm or 10 Meg Ohm) will establish a ground reference. But when you remove the probe, the DC level for the signal will float to that of whatever you happen to connect it to.

Try something like 100k for starters.
 
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