Forum: GNU Radio GNURADIO 64 QAM 200 MHZ

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2f52e10363978033f326e76630d62602?d=identicon&s=25 didem colak (Guest)
on 2009-01-27 12:00
(Received via mailing list)
Hi all,

I want to configure USRP with Basic TX and Basic RX daughter boards
using GNU Radio.

I am not sure their capabilities are convenient for VHF 200 MHz and 64
QAM transmission.

If they are suitable , which python or C++ programs can I use as
examples for writing new program?

also I tried to run some examples from gnu radio on USRP.

Regards,
Didem
745d8202ef5a58c1058d0e5395a78f9c?d=identicon&s=25 Eric Blossom (Guest)
on 2009-01-28 22:58
(Received via mailing list)
On Tue, Jan 27, 2009 at 02:57:04AM -0800, didem colak wrote:
> Hi all,
>
> I want to configure USRP with Basic TX and Basic RX daughter boards using GNU Radio.
>
> I am not sure their capabilities are convenient for VHF 200 MHz and 64 QAM transmission.

The DACs run at 128MS/s, thus there's a "fold" at 64MHz.  There's an
image in the 4rd Nyquist zone that you might be able to use, but 200 MHz
is pretty close to 3fs/2 (192MHz).  If you're a bit above 200M you
this can probably be made to work.  You'd need a bandpass filter to
suppress the other images.  If you've got access to a spectrum
analyzer, just fire it up and see what you get.

> If they are suitable , which python or C++ programs can I use as examples for writing 
new program?

There's python code in
gnuradio-core/src/python/gnuradio/blks2impl/qam*.py that's probably
usable for a transmitter.

Eric
5510b005b7054da5b0486bf653873198?d=identicon&s=25 Michael Matrakis (manoli07)
on 2009-08-01 13:00
Hi Eric,

Could you explain how you add the QAM modulations like the 16-QAM
function which is also in blks2impl? I am have un commented the code at
the bottom of these python files but they still do not come up in the
modulation options for benchmark_tx/rx...I am assuming there is some
other code I must change?...

Cheers,
Michael



Eric Blossom wrote:
> On Tue, Jan 27, 2009 at 02:57:04AM -0800, didem colak wrote:
>> Hi all,
>>
>> I want to configure USRP with Basic TX and Basic RX daughter boards using GNU Radio.
>>
>> I am not sure their capabilities are convenient for VHF 200 MHz and 64 QAM 
transmission.
>
> The DACs run at 128MS/s, thus there's a "fold" at 64MHz.  There's an
> image in the 4rd Nyquist zone that you might be able to use, but 200 MHz
> is pretty close to 3fs/2 (192MHz).  If you're a bit above 200M you
> this can probably be made to work.  You'd need a bandpass filter to
> suppress the other images.  If you've got access to a spectrum
> analyzer, just fire it up and see what you get.
>
>> If they are suitable , which python or C++ programs can I use�as examples for writing 
new program?
>
> There's python code in
> gnuradio-core/src/python/gnuradio/blks2impl/qam*.py that's probably
> usable for a transmitter.
>
> Eric
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