|Feb4-08, 06:25 PM||#1|
Removing DC Offset
1. The problem statement, all variables and given/known data
I need to remove a DC offset as apart of my research project I'm doing for my CS professor and his research group.
This signal is a sine wave, 10 Hz, riding on a +1V DC offset.
2. Relevant equations
I'm utilizing a high-pass filter using a series RC.
f = 1 / 2*pi*R*C - this is the cutoff frequency (ideal). I realize that practical filters do not cutoff exactly at this frequency, rather over a range of frequency.
3. The attempt at a solution
Input = 10sin(10t) + 1V = x(t)
So, I know that DC is 0 Hz.
Through my research, it seems that choosing the proper R and C values (close to the standard element values that you can buy from an electronics store), it would make sense that to block a 0 Hz signal, you "ideally" need to design the filter so the cutoff frequency is > 0 Hz. However, for practical and lab purposes, what frequency should I select as the 'cutoff frequency'? Do I select a random frequency above 0 Hz, with some room for leeway? I know that it will block it, but is there some sort of "rule" I must follow as to choosing the proper cutoff frequency?
As of now, I could say f = 1 / 2 * pi * R * C.
f = 5 Hz (Ill choose this)
C = 0.1uF
therefore, R = 318kOhm. The closest standard R value is 31.6kOhm.
Is this a good approach?
Also, is there a difference in using a simple series RC circuit or a differentiator high pass circuit? I know the gain is modified (inverted), but if I take care of that, is there any *real* advantage of using one?
My connections would be:
Vin -- C -- R -- Inverting Input
GND -- Noninverting Input
Output feedback --- Resistor --- Inverting Pin
and power supply for the OpAmp.
|Feb5-08, 11:18 AM||#2|
By the way, you should use rd/s instead of Hz in specifying your signal. It should be:
Input = 10sin(2\pi\times10t) + 1V = x(t)
and not as you wrote.
|Similar Threads for: Removing DC Offset|
|Two Offset Slits||Advanced Physics Homework||2|
|Two Offset Slits (help really appreciated)||Introductory Physics Homework||0|
|DC Offset||Electrical Engineering||2|
|don't print the crazy offset!||Computing & Technology||1|
|[ASM] Instruction Offset||Computing & Technology||2|