Re: [Discuss-gnuradio] Schmidl & Cox Detector

[Martin Braun]

Noise shouldn't cause false triggers, but if you increase the gain you
might see more artefacts (e.g. more DC offset), which will cause false
triggers.

You can run the block through simulation and see how it behaves.

Cheers,
Martin

On 01/11/2016 11:50 PM, David Halls wrote:
> Hi guys,
> 
>  
> 
> Happy New Year to everyone.
> 
>  
> 
> We are using a flow graph based on the OFDM example in GR, including the
> Schmidl and Cox detector block. Having spread the USRPs out over our
> test environment we have increased the receiver gain significantly (to
> about 30dB). (N210 XCVR240 @ 1MS/s, 2.4GHz)
> 
>  
> 
> Anything above around 10dB Rx gain, we get a lot of false triggering on
> the S&C block. Presumably the heightened noise causes false peaks in the
> peak detector? The technique doesn’t have a fixed threshold does it? So
> is there a way we can avoid this issue? Not sure how to debug as it’s a
> hierarchical block so not sure how to effectively get intermediate
> debugging output.
> 
>  
> 
> Thanks!
> 
>  
> 
> David
> 
> 
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