Signal Processing using Pluto-SDR

1. Signal Processing using
Pluto-SDR
Bhavna Singh, 15116012 Lab Based Project
Rohit Raushan, 14116058 B.Tech. 3rd yr, ECE
Under the supervision of : Dr. Meenakshi Rawat

2. Abstract
● Here we represent the basic idea about the Software Defined Radio (SDR) and
have demonstrated the fundamental digital modulation schemes.
● SDR is a technique which can be used to replace the current hardware.
● Implementation of simple modulation schemes like AM,FM and tested
different modulation circuits to test our Pluto-SDR connectivity with GNU
Radio signals and IIO-Oscilloscope..
Software Used: GNU Radio Companion,
IIO-Oscilloscope.

3. Presentation Flow:
1) Software Defined Radio
2) Hardware Platform( Pluto-SDR)
3) GNU Radio Companion
4) IIO-Oscilloscope
5) SDR Working Model
A) Transmit Test
B) FFT & Waterfall Sink Test
C) IIO Oscilloscope
6) GRC Implementation
A) Cyclic Sine Wave
B) Amplitude Modulation
C) FM Receiver
7) Conclusion & Reference

4. Software Defined Radio
● A complete software implementation of hardware processes.
● Hardware like filters, amplifiers, modulators etc are implemented in
embedding devices.
● Hardware complexity is widely reduced.

5. Software Defined Radio
● Dynamic nature of modifying the system parameters without changing the
hardware part.
● Effective solution to the very high cost and limited flexibility of hardware based
radios.
● Hardware Platforms: Adalm Pluto-SDR, RTL-SDR, FPGA Board.

6. ADALM-PLUTO SDR
Active device features independent receive and transmit channels that can
be operated in full duplex.
FEATURES:
➢ Portable self-contained RF learning module
➢ Cost-effective experimentation platform
➢ RF coverage from 325 MHz to 3.8 GHz

7. FEATURES:
➢ Flexible rate, 12-bit ADC and DAC
➢ Small sized enough to put in a pocket
➢ GNU Radio sink and source blocks
➢ Up to 20 MHz of instantaneous bandwidth (complex I/Q)
➢ Two antennas (824 MHz to ~894 MHz/ 1710 MHz to ~2170 MHz)

8. Pluto-SDR-Hardware (AD9363)

9. GNU Radio Companion
● GNU Radio is a free & open-source software development toolkit.
● Provides signal processing blocks to implement software radios.
● It can be used with readily-available low-cost external RF hardware
to create software-defined radios, or without hardware in a
simulation-like environment.
● It’s a graphical tool for creating signal flow graphs and generating
flow-graph source code.

10. II0 Oscilloscope
● IIO Oscilloscope is a product from Analog Devices, Inc. that uses libiio to
interface with Linux IIO devices.
● It is a great tool not only for demonstrating capabilities of Analog Devices'
products but also for testing, debugging and fine-tuning an RF system.

11. SDR Working Model
● In SDR, signal is captured by an antenna which is further converted into
digital samples with regular intervals.
● These digital values are then processed in software.
● The resulting output can be then converted back into audio, video or required
form.

12. Testing on PlutoSDR
1) Transmit test
Next we tried adapting a simple transmit test by creating a
flowgraph sending and receiving signal via Pluto-SDR.
Transmit Performance:
★ Output Power (how far can I transmit)
★ Output Fidelity (how accurate is the transmission)

13. Transmit Test

14. 2) FFT & Waterfall sink
● We tested a simple FFT and Waterfall sink using the Pluto SDR source.
● We set the sample rate to the maximum of 61.44 MSPS, and the RF
bandwidth to 60M. we were able to see the 900 MHz GSM band.
● It seemed the max sample rate is not used as the output is only 30 MHz, or
perhaps it’s only one ADC.

15. FFT & Waterfall Sink

16. IIO-OSCILLOSCOPE
We tested using the PlutoSDR IIO-OSCILLOSCOPE software and were able to
generate a FFT spectrum of the GSM band

17. Cyclic Sine Wave
Block Diagram Constellation Plot

18. Cyclic Sine Wave Output Plots:
FFT PLOT Waterfall Plot

19. Amplitude modulation
The modulation of a wave by varying its amplitude, used especially as a means of
broadcasting an audio signal by combining it with a radio carrier wave.

20. Amplitude Modulation Plots:

21. FM Receiver Plot with GRC Block Diagram

22. CONCLUSION
● We have implemented simple modulation schemes and tested different
modulation circuits to test our Pluto-SDR connectivity with GNU Radio signals
and IIO-Oscilloscope.
● This concept of SDR using GNU Radio helps us to learn the concepts
practically.
● Our work is to get familiar with GRC open source software tool. The basic
demonstrations are done using the basic theories of communication
systems.
● One single Universal Software Radio Peripheral (USRP) can implement all the
modulations and multiplexing techniques in real time.

23. REFERENCE
1. https://www.mouser.in/new/Analog-Devices/adi-adalm-pluto/
2. http://www.csun.edu/~skatz/katzpage/sdr_project/sdr/grc_tutorial.pdf
3. https://www.sciencedirect.com/science/article/pii/S187770581200985X
4. http://oz9aec.net/radios/gnu-radio/grc-examples
5. Analog and Digital Modulation Toolkit for Software Defined Radio-paper
published by R.Gandhiraja , Ranjini Ramb , K.P.Somanb
6. Bard, John and Kovarik, Vincent, “Software Defined Radio: The Software
Communications Architecture,” Wiley Series in Software Radio, 2007

24. Thank You