Frame Synchronization

GNU Radio
1

Hello,

I’m trying to detect the start of a frame after demodulation. To do
this,
I’m using the ‘correlate access code - tag’ block. I want a tag to be
placed at the end of the prbs used to frame sync so subsequent blocks
can
process the packet.

I’m attaching a screenshot of a test I’m doing with the block. I can’t
get
it to work. In the screenshot, I am appending a 32 bit long sync frame
to
320 bits of data for the correlate block to detect. When I make the data
all 0’s, the correlate block detects nothing adding no tags to the
stream.
If I make the data random, tags are added at points in the stream which
are
not equal to the access code.

What am I doing wrong or how do I use this block correctly?

Thanks,
Rich

2

This is strange, I agree, but the frame detect sequence is passed into
the
Correlate Access Code block as a string, like: “1010101010”. It is this
way
for historical reasons.

–n

On Wed, Mar 11, 2015 at 12:26 PM, Richard B. [email protected]

3

Thank you Nick. That’s what I was doing wrong. Really appreciate that.

Rich