DC blocking in DSP

[Dr. Dhiman Kakati]

Hello Everyone,
I am trying to understand the internal structure and algorithm associated, In the preprocessing step of the DSP block there are 3 steps among the I am not getting as following.

The DC blocking is applied to offset any imperfectly biased voltages in the modulator. So how it has managed to offset i.e. the mechanism related with it. it says that imperfectly biased is that mean that while giving the bias voltages at the modulator properties we have done mistake. If we could know the mechanism of how the DSP is managing to solve the problem.

and in the normalization step of 16-QAM DSP there is “the received signal is normalized to the 16-QAM grid [-3 -1 1 3]” I am not getting what is 16-QAM grid [-3 -1 1 3].
Thanking you in advance.

Regards,
Dhiman Kakati

[Dr. Dhiman Kakati]

I am not getting any kind of response in most of the query, While I am trying my best to solve the issues in the forum. I can expect some response.

Regards,
Dhiman

[Rajguru M. Mohan]

Hi,
The removal of a dc bias (a constant-amplitude component)
from a signal is a common requirement in signal
processing systems. Thus, a good dc blocking algorithm is a desirable
tool to have in one’s bag of signal processing tricks.
I don’t know which technique if DC blocking is used in DSP of optisystem. But generally, we have nonlinear phase fixed-point dc
blocker (using a noise-shaping trick that
eliminates a signal’s dc bias using fixed point arithmetic) and a general linearphase
dc blocker network that may prove useful in various DSP appllications.
FIXED-POINT DC BLOCKER
Simple fixed-point implementations of a
dc blocker algorithm have a vexing quantization
problem that can create more dc
bias than they block.

Thanks,
I will try to find out solution of your problems

[Author]

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