[Discuss-gnuradio] Read file metadata

[Yan Huang]

Hi all,

 

I’m using Message Strobe to control UHD: USRP Source to receive signal with specified frequency(2.4GHz), but I find flow graph start running before Message Strobe set the frequency as 2.4 GHz.

 

Message Strobe -> UHD: USRP Source ->File Sink

 

So I want to use stream tag to know the time of first item with 2.4GHz. I think I can change File Sink to File Meta Sink to receive the ‘rx_time’ stored in ‘tag_sense1.hdr’ file(attached), and I use the existing program called ‘gr_read_file_metadata’ to read out the header information, but it comes out an error:

 

File "tag_sense1.hdr", line 1

SyntaxError: Non-ASCII character '\xb5' in file tag_sense1.hdr on line 2, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details

 

I have checked the link, but I don’t understand what’s the encoding information of the python source file. Do need to add # -*- coding: <encoding name> -*- to the source file?

 

I problems are:

 

1.       How can I read the’ .hdr’ file?

2.       Am I right to use file meta sink to get the start receiving time?

3.       Do I need to add stream tag and then read it out using other blocks in this scenario?

 

Any advice will be appreciated. Many thanks in advance.

 

Best Regards,

 

Yan

 

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tag_sense1.hdr
Description: tag_sense1.hdr

gr_read_file_metadata
Description: gr_read_file_metadata