[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] attribute/control stream question
From: |
Eric A. Cottrell |
Subject: |
Re: [Discuss-gnuradio] attribute/control stream question |
Date: |
Wed, 13 Jun 2007 21:53:11 -0400 |
User-agent: |
Thunderbird 1.5.0.8 (X11/20060911) |
Tom Rondeau wrote:
> Matt Ettus wrote:
>> Eric A. Cottrell wrote:
>>
>>> Hello,
>>>
>>> The processing of pulses into data requires me to keep track of valid
>>> pulses (following samples are above threshold) and leading edges (sample
>>> is 6 dB or more than previous sample and following sample is 6 dB or
>>> less than current sample). I also want to indicate preamble start and
>>> pass timestamps along. I have thought of three methods to do this but
>>> do not know which would be the best one.
>>>
>>>
>>
>> You can do this, or you may be able to break things up into chunks of
>> samples and process them as vectors. See the ofdm_sync code for an
>> example of how we do that.
>
> Also, off the top of my head, you might find the peak_detector and
> sample_and_hold blocks useful for what you're doing. If these won't do
> what you need, that at least the S/H block illustrates the use of
> different streams where input stream 0 is some data type (float,
> gr_complex, bytes, ints) and input stream 1 is a byte stream
> (sizeof_char) as the control line.
>
> Tom
Hello,
Thanks for the suggestions and observations. I will look at the OFDM
code and other blocks.
This is getting to be a big project. PPM is so simple but there are
some interesting enhanced receiving techniques to squeeze the last drop
of performance. I took a text description and turned it into code so no
doubt there are other functions I can use to optimize the current code.
I want to add capability to time stamp the frames and get signal levels
so I am modifying the code again. I also want to comment it so others
can figure out what is going on. Sorry it is taking some time to get
the code ready but I want the code structure to be set before check-in.
I am still figuring out GNURadio and Python so I looked at the cfile
example and used it to improve my log program. I noticed that I may be
able to use a higher sample rate if I go with the 4rx0tx USRP file. A
future enhancement may be to put the AM detector in the USRP and just
send shorts over the USB bus. I want to try 10 or 16 MSPS rate to see
if performance improves.
I want to try the OFDM code anyway and see if I get any data off the
BPSK carriers of IBOC AM stations used for station information.
73 Eric