USRP from Ettus

Hello,

I this entry I will write about USRP (Universal Serial Radio Peripheral) from the company Ettus Research. The intention of talking about USRP is due it is the hardware I am working with at this moment, it is not a commercial entry. USRP is only one of many recommended hardware peripherals by GNU Radio. Specifically I will write about USRP N210 kit. The basic idea of this kind of hardware it to be the front-end of our baseband signal processing waveforms in order to be transmitted over the air.

There are basically three series of USRP hardware:

1. Networked Series.
2. Serial Series.
3. Embedded Series.

The Networked Series connects the peripheral with its host computer using an Gigabit Ethernet interface. On its side, the Serial Series uses USB 2.0 and USB 3.0 as interface between host computer and the radio hardware. The Embedded Series is not intended to be used with a host computer but for stand-alone operation applications.

Next few months I will be working with a couple of USRP N210 kits, this hardware has a Spartan 3A-DSP 3400 FPGA as its main feature. It also has dual 14-bit ADC (analog-to-digital converter) with a capacity of 100 MS/s (mega-samples per second) and 400 MS/s 16-bit DAC (digital-to-analog converter). The next figure shows the basic architecture of the USRP N210.

USRP N210 Architecture. Source.

It is very interesting to compare the architecture of this hardware (and any other hardware of its kind) to a basic SDR reference architecture as the one shown in the next figure.

Ideal SDR architecture. Kenington, P. B. (2005). RF and baseband techniques for software defined

radio (p. 177). Norwood: Artech House.

In a future entry, I will write about how to connect and use USRP with GNU Radio for a complete radio solution.