Dual polarized MSK

[Dr. Dhiman Kakati]

Hi everyone,

I am presently working on a dual polarized MSK Transmitter and receiver design, at the receiver section the all constellation point are coming nice but the problem is they are all in the the same quadrant, that is both for X and Y polarization. I have attached the snapshot for both X and Y polarization separately in two images. so i want to know where the problem is. please anyone help.

Regards

[Dr. Dhiman Kakati]

Here is the attachment.
please go through the name of the image for understanding.
Thanks

Regards

Attachments:

1. 

   Y-polarized-transmitterleft-and-receiverright.jpg
   

[Dr. Dhiman Kakati]

X polarization

Attachments:

1. 

   X-polarized-transmitterleft-and-receiverright.jpg
   

[Dr. Dhiman Kakati]

Still waiting for your response. Because I am unable go further for this reason. Please help.

Regards

[alistu]

Hi Dhiman,

Could you please attach your simulation osd file here? You have mentioned that all the constellation points in the constellation diagram at the transmitter side are all in one quadrant, while the attached images show the transmitter and receiver constellations are more or less similar, except for the extra point you had discussed in another topic. Can you verify if I am correct?

Regards

[Dr. Dhiman Kakati]

I mean there are two image for X and Y polarization separately and in each image the the left constellation is for transmitter and right one for receiver. at the transmitter the constellation point are distributed in all the quadrants while at the receiver they are at any one of the quadrant (for X-polarization the receiver points are in 4th and for Y polarization in the 2nd quadrant) but according to me as the transmitter constellation points are in all quadrant(ie, 2 point at each quadrant) the receiver constellation points should also be in the distributed in all the quadrant(2 point in each). I need to mention that the receiver points are the same as the transmitter, only the quadrant issue is there which we need to solve. I am unable to guess what may be the problem. I can not upload the design file presently I will upload later on.

you can ignore the extra points that are seen, I asked this issue in another topic in this forum only which is also not solved till now.

Thanks for the co-operation and going through the topic.

Regards

[alistu]

You’re right. I hadn’t paid attention to the quadrant of the received signal. I will take a closer look into it as soon as you upload the osd file.

[Dr. Dhiman Kakati]

Dear Alistu,
Sorry to say that I can not upload the file as we as a team 4 are doing on the same project and they are not allowing me to upload for the same. I uploaded a part of it in my previous question related to MSK, this time they have refused to do so.

Regards

[alistu]

I understand. I don’t upload project related files either and it is sensible. However, I hope you realize it is really difficult to troubleshoot a simulation with such an error without having access to the system design file.

[Dr. Dhiman Kakati]

Yes agree to you. If anyone have faced this problem before please share your experience.

Regards

[Dr. Dhiman Kakati]

One more thing I need to mention here that I got a reply from expert regarding this topic that is “Ideally we can remove, because there is no channel involved where maximum noise are encompassed. Well, in photo-detector some inherent noise cannot that we have to tolerate.
Please try to correct the Direct Current (DC) shift, because of that there is shift in coordinates of constellation.”

I am not getting how to achieve this. Please let me know how to correct the DC shift as mentioned in the above context.

Thanks

Regards

[Author]

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