Can anyone help with the question below?

Thanks,
Vipin

> On May 4, 2018, at 12:35 AM, Vipin Sharma <[email protected]> wrote:
> 
> Hi,
> 
> I have a question about the Rx section of the flow graph here: 
> http://aaronscher.com/GNU_Radio_Companion_Collection/Audio_Modem_loop_back_test_FSK.html
>  
> <http://aaronscher.com/GNU_Radio_Companion_Collection/Audio_Modem_loop_back_test_FSK.html>.
> 
> The Rx section has a Binary Slicer block which feeds the Correlate Access 
> Code - Tag Stream block. If I understand correctly, once the predetermined 
> access code is detected in the data stream, the Correlate Access Code - Tag 
> Stream tags the Payload start with len_key2 tag so that downstream blocks now 
> only operate on Payload packet. 
> 
> My application needs a similar functionality but I would like the Payload to 
> be the input of the Binary Slicer block (as opposed to the output of the 
> Binary Slicer block in the link above). 
> 
> I basically don't want the sliced payload but the non-sliced version. But if 
> I don't slice the output of Polyphase Clock Sync block in Rx section, then 
> there isn't a binary (soft decision) value for Correlate Access Code - Tag 
> Stream to work with? What happens if I change the IO type of Correlate Access 
> Code - Tag Stream block to "float" type? Would it still be able to match the 
> access code?
> 
> My application basically has some preamble, header and payload information. I 
> simply want to implement some form of basic frame synchronization mechanism 
> so that I can precisely define where the payload (or the frame) starts. 
> Without frame synchronization I am unable to do frame based (or packet based) 
> processing. However, note that, I want the raw I/Q samples (in float value) 
> to be extracted for the payload instead of the soft decision outputs as 
> described in the flow graph of Rx in the link above.
> 
> How do I achieve this?
> 
> Vipin

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