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[Discuss-gnuradio] Questions about gr_block


From: Jens Elsner
Subject: [Discuss-gnuradio] Questions about gr_block
Date: Thu, 20 Jul 2006 12:54:25 +0200
User-agent: Mutt/1.5.9i

Good morning!

I started writing a small signal processing block (OFDM transmitter) and ran 
into some problems. 

My starting point was the well written gr-how-to-write-a-block tutorial. 

I have, let's say, 1536 input samples and want to produce 1800 output 
samples with my block. When I run my code with small values 
(say fft size of 32) I get valid OFDM symbols but a lot of zeros in
between. When I uses higher values either the scheduler quits

(
sched: <gr_block ofdm_tx_vcc (0)> is
requesting more input data
  than we can provide.
)

or even the buffer can't be allocated. This makes me sure that there is 
a programming mistake on my part, but I can't seem to find it.
I would be thankful if somebody could point out my mistake? The main
files are attached, a modified gr-how-to-build-a-block can be found here:
http://www.1c3.de/gr-dab.tar.bz2 .

Yet another question: Can blocks somehow interchange values? I would
like to write two blocks, one that estimates a frequency offset and 
another one that compensates it (simple modulation). Or do I have to 
do that in one block?

Jens

Attachment: ofdm.i
Description: Text document

Attachment: ofdm_tx_cc.cc
Description: Text Data

Attachment: ofdm_tx_cc.h
Description: Text Data

Attachment: qa_ofdm.py
Description: Text Data


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