Forum: GNU Radio Re: Basic USRP transmission

>
> I'm trying the USRP using GNU Radio but I cannot receive successfully. I'm
>> using the following flowgraphs in GRC:
>
>
TX:
Vector Source => Packet Encoder => DPSK Mod => UHD Sink

RX:
UHD Source => DPSK Demod => Packet Decoder => File Sink

I tried using benchmark_tx and benchmark_rx and the packages got through
without errors. However, in my GRC example, nothing gets written to the
file. Why is that? How can I send a simple binary file through the UHD?

Fabin

Are you looping back to the same USRP, or different ones?

What type of daughtercards?

If looping back, are you using an attenuator?


I'm not looping back. I'm using two USRP's, each one with a XCVR2450. 
I'm
transmitting at 5GHz using 200KSps, DBPSK.

On 27 Nov 2012 13:26, Fabián Kozynski wrote:

>>> I'm trying the
USRP using GNU Radio but I cannot receive successfully. I'm using the
following flowgraphs in GRC:
>
>>> TX:
>>> Vector Source => Packet
Encoder => DPSK Mod => UHD Sink
>>>
>>> RX:
>>> UHD Source => DPSK
Demod => Packet Decoder => File Sink
>>>
>>> I tried using
benchmark_tx and benchmark_rx and the packages got through without
errors. However, in my GRC example, nothing gets written to the file.
Why is that? How can I send a simple binary file through the UHD?
>>>

>>> Fabián
>>
>> Are you looping back to the same USRP, or different
ones?
>>
>> What type of daughtercards?
>>
>> If looping back, are
you using an attenuator?
>
> I'm not looping back. I'm using two
USRP's, each one with a XCVR2450. I'm transmitting at 5GHz using
200KSps, DBPSK.

The usual reason is frequency offset between sender and
receiver. The effect is worse when it's narrowband, and is also
dependent on the frequency precision of the master oscillator on the
USRP. Different USRPs have different-quality master oscillators.

This
is pretty normal for radio-based digital communications systems. The RX
side normally has some kind of frequency-offset compensation built in.