MSK sequence generator constellation poin

[Dr. Dhiman Kakati]

Hi all,
I am facing some problem again with the constellation point for MSK pulse generator, here i have taken sequence length of 16384 ie, quite high but still not getting the constellation point as expected. so please go through the attached design file and kindly find some solution, Thank you.

Regards

[alistu]

Hi Dhiman,

I cannot find any attachments. I will go through your design as soon as you attach the file.

Regards

[Dr. Dhiman Kakati]

Sorry for the mistake. I have attached here.

Regards

Attachments:

1. MSK-pulse-generator.osd

[Gokul Boro .]

I am also facing such problem. Please do share if you find the solution.

[Dr. Dhiman Kakati]

Dear Gokul, in most of the cases we can eliminate this problem using higher sequence length, but in the file i have attached, increasing the sequence length has no effect in the constellation point. so there may be some other parameter that need to be adjusted. hoping to get the solution soon.

Regards

[alistu]

How many constellation points are you expecting to see in the visualizer? I know it uses PSK, but I don’t know how its bits per symbol parameter is determined in the component, and the number of constellations positions is dependent on it. I simply changed the phase and the constellation in the attached screenshot is obtained.

Attachments:

1. 

   constpoint.jpg
   

[Dr. Dhiman Kakati]

Dear Alistu, in case of MSK the constellation points should come in a circular pattern, i mean when we connect the constellation points it should for a circle theoretically, but neither your’s nor mine we are getting the expected theoretical result. I may be wrong also, please make me correct.

Regards

[alistu]

You’re right! I forgot to mention this as my whole point of attaching the image after I attached it. The additional point in your constellation is always there, as I used just two-bit, four-bit and eight-bit user defined sequences and it was there (not related to any bit pattern) while the other symbols were correctly mapped.

[Dr. Dhiman Kakati]

yes I agree but how can we remove the additional points, or is this the component issue. I think there should be some way to remove the extra constellation point. in these if i get a reply from the official staff it would be helpful.

Regards
Dhiman Kakati

[Author]

Posts