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Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD
From: |
Marcus Müller |
Subject: |
Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD |
Date: |
Thu, 25 Jun 2015 15:07:44 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
Hi Gabriele,
have you tried adding more gain on the TX side?
Also, you will need to increase sampling rate. Right now, you're using
100kHz, which is 1/1000 of the master clock rate of the N200. If I'm not
mistaken, the maximum decimation for the N200 is 512, and hence the
minimum rate would be 100MHz/512 = 195.3125kHz. You probably just want
to use 200kHz or something similarly practical.
I hope that helps!
Best regards,
Marcus
On 06/25/2015 02:23 PM, Gabriele Galiero wrote:
> Hello, I was interested to test tx_ofdm.grc and rx_ofdm.grc from
> gr-digital, at the same time using USRP N200 devices.
>
> TX OFDM:
>
> The changes that I did were, removing throttle block and adding an UHD
> Sink instead, with center frequency 430 MHz, which is the frequency band
> for which my department has license to transmit.
>
> RX OFDM:
>
> In this case I removed all blocks before throttle (included), and placed
> there an UHD Source at the same center frequency.
>
> Flow graphs attached in the files.
>
> I monitored the output signal and the received signal. I also used a
> spectrum analyzer to check the actual signal that is being transmitted.
> Pics are attached.
>
> In the tx signal measured by a spectrum analyzer, we can see that the
> spectrum is not that we desire. I would like to ask if I am doing
> something wrong with the configuration. Before transmission there was no
> signal at that frequency and tx and rx antennas are suitable for the
> carrier frequency.
>
> In addition I tried to transmit a file instead of just random bits. In
> reception I was not receiving the file. The config was just adding a
> file sink at the end of the rx block and a file source at the beginning
> of the tx block. Could you please help me with some tip?
>
> Attachments:
> http://www.ruby-forum.com/attachment/10886/tx_ofdm.jpg
> http://www.ruby-forum.com/attachment/10887/rx_ofdm.png
> http://www.ruby-forum.com/attachment/10888/tx_signal.jpg
> http://www.ruby-forum.com/attachment/10889/rx_signal.jpg
> http://www.ruby-forum.com/attachment/10890/tx_sig_spectrum.jpg
>
>
- [Discuss-gnuradio] OFDM example from gr-digital with UHD, Gabriele Galiero, 2015/06/25
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD,
Marcus Müller <=
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Gabriele Galiero, 2015/06/26
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Marcus Müller, 2015/06/26
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Jose Perez, 2015/06/29
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Marcus Müller, 2015/06/29
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Jose Perez, 2015/06/30
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Martin Braun, 2015/06/30
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Jose Perez, 2015/06/30
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Martin Braun, 2015/06/30
- Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD, Jose Perez, 2015/06/30