On Tue, Sep 10, 2013 at 09:58:16PM +0000, Monahan-Mitchell, Tim wrote:
GR 3.7.1
gr-digital/examples/ofdm/rx_ofdm.grc
- The OFDM Frame Equalizer block that is downstream from the Header Stream
Virtual Source block has the Length Tag Key field set to length_tag_name, yet all
other blocks on the diagram with that field are set to length_tag_key (which is
the ID of a Variable block at the top of the diagram). Is that a mistake? If
someone will confirm, I can file the bug.
Hm. You make me look like a total scrub.
It seems you’re right. However, on my machine, length_tag_name doesn’t
throw an error. I just can’t see why. GRC itself should figure this is a
problem.
- When I try to run this flowgraph, modified for my target’s custom source
block, I get this error:
FATAL: Missing a required length tag on port 0 at item #0
thread[thread-per-block[21]: <block ofdm_frame_equalizer_vcvc (22)>]: Missing
length tag.
That’s good, actually – it means your block is getting input, which
means it’s receiving headers.
To be honest, the {rx,tx}_ofdm.grc files were more of an illustration of
how the OFDM chain works. I know I’ve used them successfully sometime in
the past, but I’ve changed some stuff in between.
Using the ofdm_tx and ofdm_rx hier blocks should, however, work. Can you
try those?
My main issues when transmitting OFDM is getting a clean spectrum. OFDM
doesn’t like distortions at all.
MB
Which led me to question (1) above. However, changing that block to match the
others does not correct the runtime error.
I found a couple of instances of the same error listed in (2) above in the
mailing list, but no one replied to them.
–
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)
Dipl.-Ing. Martin B.
Research Associate
Kaiserstraße 12
Building 05.01
76131 Karlsruhe
Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu
KIT – University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association