Gnuradio 64 qam 200 mhz


#1

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


#2

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


#3

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 B. 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