FM Receiver in GNU Radio

8/9/2019 FM Receiver in GNU Radio

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#9/3,Shree Lakshmi complex,2ndFloor,Opp,To Vivekananda Park,Girinagar,Bangalore-560085.www.tenettech.com

2015

Author: Rakesh

Email id: [email protected]

FM Receiver

Using

GNU Radio and USRP


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What is GNU Radio?

GNU Radio is a software library, which can be used to develop complete applications

What is Universal Software Radio Peripherial(USRP)?

The USRP is an integrated board which incorporates analog-to-digital converters(ADC) and digital-to-analog converters (DAC), some forms of RF front end, and an FPGA

which does some important but computationally expensive pre-processing of the input

signal.

GNU Radio along with the USRP makes the complete Software Defined Radio

Introduction to Universal Software Radio Peripheral

The Universal Software Radio Peripheral (USRP) enables engineers to rapidly design

and implement powerful, flexible software radio systems. The intuitive USRP design helpsyou to get your software radio up and running quickly.

Simply download GNU Radio, a complete open source software radio and signal processing

package, and the USRP is ready to use. Once you install the software and plug the USRP into

a host computer, it is ready to transmit and receive a virtually limitless variety of signals .

Features of USRP

Four 64MS/s 12-bit analog to digital Converters

Four128MS/s 14-bit digital to analog Converters

Four digital downconverters with programmable decimation rates

Two digital upconverters with programmable interpolation rates

High-speed USB 2.0interface (480Mb/s)

Capable of processing signals up to 16MHz wide

Modular architecture supports wide variety of RF daughterboards


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Auxiliary analog and digital I/O support complex radio controls such as RSSI

and AGC

Blocks for building FM receiver

The USRP Source block initiates the flow graph in the GRadio that allows the interfacing with the hardware (USRP).important parameter to be noticed is the output port whichblue in color, which means that signals are received in comp(16bit) format and there are other parameters to be mentionin the block like shown in the figure

The band pass filter is used to filter out the unwanted hfrequency components and to tune to all the FM statiavailable. The band pass filter has a decimation factor in orto reduce the incoming samples.

The wideband FM receiver is used to demodulate the receisignal. The Quadrature rate parameter indicates, at what rthe demodulated signals are passed out. The input receivedcomplex and the output is in float format.


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The Rational Resampler block is meant for resampling signals. In other way, it performs both interpolation adecimation process in order to adjust the sampling rate tha

suitable to the output sink.

Ratio = (input sampling rate*interpolation)/decimation

The audio sink block terminates the flow graph in GNU Radiois used to listen to the tuned FM stations at 96kilo samples/se

The FFT sink is used to view frequency domain representatioof the output.


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The final flow graph of the FM receiver

USRP SETUP


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Connect the usb2.0 cable to communicate with the host PC.

The wbx daughter board is mounted at the given slot on the motherboard

which is capable of receiving the signal from50MHZto 2.2GHZ.

Connect the vert200antenna for the reception of the FM

Finally supply the power to switch on the board .

FM Receiver in GNU Radio

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