WBX daughterboard

Revision as of 09:47, 25 February 2010

This is a recent USRP transceiver daughterboard, released in January 2010. It can cover frequencies from 50MHz to 2.2GHz for reception or transmission (max announced power ~100mWatts).

This makes it the ideal board to cover broadcast frequencies. It was used successfully to generate DAB or FM signals.

Introduction

We immediately purchased several units and try them ! The main feature of this board is the wide coverage, from 50 MHz until 2.2 GHz ! It include 2 RF ports One for RX and TX the second for RX only. The card provide filter, LNA...

Using the updated version of the CRC-Dwap player (frequency offset etc.) we achieved to get a clean signal up to 10 mW on the band 3. Playing with the gain allow us to trim from 1 uW (g = 0) to 10 mW (g = 20)

Pay attention that you need to run the branch 3 of GNU Radio (we run 3.3.x) to use this board otherwise it will not be recognized on your system.

Test with DAB modulator

The measurement is done under the same condition as for the Basic TX and modified RFX400. The output = 8 mW

The WBX output without any additional filtering, the picture show the spectrum from 0 Hz until 3 GHz : We clearly see the upper harmonics...

Then the same with one filter cell :

Looks good !

Now a closer look on the OFDM group : No LO Leak and image frequency.

With this board and external filter feeding the amplifier we achieve a good linear 15 Watt output.