I'm using AD630 as lock in amplifier and it is giving me an offset at the output. I want to remove that offset and I don't know how it gets there.
I will explain my conditions of the circuit.
My input signal is noisy sine wave(it does not contain a dc offset).
-I figured out that if I'm giving an input signal which has offset It will give me amplified offset at the output. So I guess it can not be the problem.
My sync(reference) signal is a 0-5V square wave derived from a sine wave. It should have 50%(closely) duty cycle. It contains no offset.
-I figured out if there is a offset in the ref signal AD630 giving an offset at the output.
I'm wondering what could cause me to have a offset at the out put. Can I adjust a offset from the AD630?.
I followed the circuit diagram of AD630 FIGURE 35.
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