DVBS2 TX

Hello everybody ,

Iam trying to build a TX DVBS2 ,QPSK,in GNUradio , and iam getting after the decimating cosine filter  on the constellation sink a 4 dots plus a dot in zero x,y .

What is expecting a clean constellation with the 4 dots only , but keep getting an additional one in zero x,y ....is there an explanation for this ? what i need to do to get a clean 4 dots only four

 Dots on the constellation sink? If anybody can guide me plz.

I tried to add a dc block,delay before or after interpolation rrc filter . but no change .

I did attached a screenshot for the constellation sink and blocks .

Thanks in advance .

Best regards,

othman

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