Len_tag_key

GNU Radio
1

Dear all ,
I use a flowgraph containing : File source , OFDM TX ,throttle, File
sink
(I will replace then the file sink by UHD sink to try with USRP)
I got this error message

FATAL: Missing a required length tag on port 0 at item #0
thread[thread-per-block[1]: <block crc32_bb (14)>]: Missing length tag.

I tried to solve this problem but I failed :
in TX in the field called length tag name ,
I tried to write same input to this field as in the loopback :
I wrote in this field : len_tag_key
Then I put a variable block with ID :len_tag_key , with value :
“packet_len”
Then I put another variable block with ID: packet_len , with value:87

Also I tried to write in this field : packet_len & put only one variable
block with ID packet_len & value:87 … I got the same error !!
What is must be written in this field ?!!!

Thanks.

2

On 06/29/2014 10:49 AM, GP 2014 wrote:

I tried to write same input to this field as in the loopback :
I wrote in this field : len_tag_key
Then I put a variable block with ID :len_tag_key , with value : “packet_len”
Then I put another variable block with ID: packet_len , with value:87

Also I tried to write in this field : packet_len & put only one variable
block with ID packet_len & value:87 … I got the same error !!
What is must be written in this field ?!!!

You must provide a key for the tagged stream tags. Read
http://gnuradio.org/doc/doxygen/page_tagged_stream_blocks.html and the
OFDM examples.

M