Hi all,

i run into trouble using the correlate estimation block. 

As far as i understand this blocks is used to search for a praeamble which is 
modulated and filtered with match filter.
To achieve this i used modulate vector. I used this block like it`s done in the 
corr_est exapmles provided in  /gnuradio/gr-digital/examples/.

Using no UHD but a channel modell everything works fine having clear 
correlation peak. 
Using it with hardware device it doesn`t work anymore, having more peaks 
avaiable.

 My flowgraph is very simple:

Vector_source (using prae+data as vector tagged with tx_sob and tx_eob) -> 
constellation Modulator(default-QPSK-object) -> stream mux with null_source for 
break -> uhd sink(sync = PC_clock)

Uhd source (sync = PC_clock) -> low_pass -> corr_est(modulated_vector, 0.9) -> 
Pll-clock-sync -> Costas Loop -> constellation-demodulator -> float_to_char -> 
qt time sink 


Modulate vector is called with default-qpsk-object as constellation object and 
[1] as filter taps which i think is right.
The praeamble i am using is the one provided in the examples, so it should be 
ok too.

I dont have that much experience in this topic so I hope somebody is able to 
help me.
I am looking forward to hearing from you and thank you in advance.


Sebastian

PS : I am not sure where and how to provide the flowgraph itself but i´ll try 
to do it asap.




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