OOK Modulation

Hello,

I am working on creating a OOK Modulation block. I have created a block
using the bpsk.py file as an example. I changed the constellation points
such that 1+0j and 0+0j. I am now trying to change the waveform that is
outputted from the USRP. I would like to transmit a square wave for 1
and
nothing for 0. I am not sure how I can do these. I would greatly
appreciate
any help or advise that any one could give me. Thank you for your time
and
help.


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On Fri, Oct 12, 2012 at 5:43 PM, sibar002 [email protected] wrote:

Hello,

I am working on creating a OOK Modulation block. I have created a block
using the bpsk.py file as an example. I changed the constellation points
such that 1+0j and 0+0j. I am now trying to change the waveform that is
outputted from the USRP. I would like to transmit a square wave for 1 and
nothing for 0. I am not sure how I can do these. I would greatly appreciate
any help or advise that any one could give me. Thank you for your time and
help.

What are you seeing when you change the bpsk.py file for your new
constellation? That should be close. The bpsk modulator uses a root
raised cosine pulse shaping filter, is that what your problem is? If
you really want to transmit a square wave (but remember, doing that is
going to throw a lot of signal into the spectrum; also your
transmitter, receiver, and channel are all going to filter this signal
in their own way to distort it), you can change this to a LPF filter
with a wide enough passband to pass the square wave. The filter also
interpolates the signal, which you’ll want to do, too.

Tom