1. Design and Realization of HF Station Prototype
James Baskaradas#,
Anna Lisa Saverino*,
Amerigo Capria*.
#INGV, Roma
*RaSS - CNIT, Pisa

2. Overview of the presentation
Introduction
Technology Overview
Tx/Rx Antenna System
Transmitter Architecture
Receiver Architecture
Chirp experiment
PSK experiment
Conclusion
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SWING Final Meeting | CNIT - Pisa, Italy

3. Design and Development of a Robust HF (shortwave) radio link.
Aim
Design and Development of a Robust HF (shortwave) radio link.
Full transceiver;
Low power;
Remote controlled;
Modular and Reconfigurable
Main critical
aspects
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Analog
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ASIC/SOC
High resolution TDC
25 ps binning
~5 man years design
~2 man years test and design fix
Total design price: ~1 million $
Production cost: 10$/chip
Production volume: ~50k chips
Total production cost: 500k$
Image from presentation of Dr.,Jorgen Christiansen,CERN
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Hybrid
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Tx/RX Antenna System
Gain(dBi)
Frequency(MHz)
< -13
1-2
-13 2 -6 3 -3 5 1
7.5 10 20 -1
>20
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8. Transmitter Architecture
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9. Transmitter Architecture:USRP
Dual 100MS/s, 14-bit ADC;
Dual 400MS/s, 16-bit DAC;
DDC/DUC with 25mHz resolution;
Up to 50MS/s Gigabit Ethernet streaming;
Gigabit Ethernet interface to host;
Fully coherent MIMO capability.
USRP N210 features
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10. Transmitter Architecture:USRP
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11. Transmitter Architecture: HPA
Type
Class AB MOSFET
Frequency
100kHz-30MHz
Rated power
500W
Cooling
 Forced air, front to rear
Mains power
V,50-60Hz,single phase,
500VA/750VA/1.5kVA max
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12. Receiver Architecture
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13. Receiver Architecture: BPF
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14. Receiver Architecture:LNA
Model: ZFL-1000LN+
Company: Mini-Circuits
Low Noise Amplifier (LNA)
Operative Band
0.1 MHz – 1000 MHz
Noise Figure
2.9 dB
Gain
20dB
Output power versus frequency
Gain versus frequency
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15. Tx/Rx Synchronization
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SWING Node locations
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Chirp Experiment : why ?
wide band of usable frequency from ionospheric prediction
disturbed link channel (ionosphere)
Single reconfigurable hardware for :
probing the ionosphere (including non-reciprocity* of channel)
HF communication terminal
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Chirp Experiment : How ?
Fine frequency step (0,001Hz) to avoid unwanted noise in the output spectrum
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19. Chirp Experiment : Transmitter
Transmitter station
Frequency sweep
1 MHz – 30MHz
Frequency step
0,001Hz
scan rate
<= 100kHz
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20. Chirp Experiment : Receiver -1
Spectrum monitor receiver
Chirp receiver
Receiver station
User Interface of the Spectrum monitor Receiver
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21. Chirp Experiment : Receiver -2
User interface of the Chirp Receiver
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22. Chirp Experiment : Results -1/2
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23. Chirp Experiment : Results -1/2
Transmitter Power
20W
Received signal power
-95,67dBm
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24. Chirp Experiment : Results -2/2
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PSK Experiment
Aim
Design and Development of a demonstrator for data transmission over HF radio links.
Extreme space and time-varying propagation channel;
External interference (congestion of the HF band);
High background noise level.
Experiment
Issues
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PSK Experiment
Connection type: point-to-point;
Carrier frequency : single;
Modulation type: PSK.
Simulated
Scenario
Simulation equipment
USRP Hardware;
LabVIEW programming language.
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27. Transmitter functions
PSK Experiment
Transmitter functions
Receiver functions
Convert the message to bits;
Rearrange the bit-stream in packets;
Apply modulation;
Write to USRP for the transmission.
Apply demodulation;
Check for valid packets and organization in the correct order;
Full text reconstruction.
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28. PSK Experiment Transmitter/Receiver User Interface Received Message
Raw Received Signal
USRP IP Address
I/Q rate:
Specifies the sample rate of the baseband I/Q data for Tx or Rx in samples per second (S/s);
Carrier :
Carrier frequency in Hz of the RF signal;
Gain:
Specifies the gain, in dB, applied to the RF signal for Rx and Tx;.
TX/RX antenna:
Refers to the connectors on the device front panel;
Actual TX/RX Parameters
Refers to a Tx/Rx values supported by the device.
Tx/RX Constellation Graph
Specifies the detected symbol locations and the transitions between those symbols;
Eb/N0
Specifies the desired Eb/N0 of the output complex waveform in dB;
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29. PSK Experiment Transmitter/Receiver Modulation Interface
Sets the type of modulation and parameters for a pulse shaping filter.
Modulation Type
Spectrum with noise
Spectrum of transmitted base-band complex waveform with noise
Pulse shaping and matched Filters
This filter is applied to each symbol to:
Reduce the amplitude and phase transition of modulated signal;
Reduce Inter-Symbol Interference (ISI);
Maximize the SNR
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SWING Final Meeting | CNIT - Pisa, Italy

30. PSK Experiment Transmitter Packet Interface Guard Band: Sync Seq:
Protects against the filter effect;
Sync Seq:
Is the sequence for the carrier and clock recovery;
Packet Number:
Is used to reorder the packets and to detect missing packets;
Data :
Represents the length of the useful data;
Pad Data:
Represents the number of the samples appended at the end of the signal in order to have a constant packet size;
Constellation Graph:
Shows how the detected symbol locations and the transitions between those symbols are modified by the presence of the noise.
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31. PSK Experiment Receiver Debug Interface Error out Correct Packet Rx
Represents error information
Correct Packet Rx
Represents the number of the correct received packets
Sync Found
Checks for valid packet
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32. Design and Development of the
Conclusion
Design and Development of the
SWING demonstrator
Simulation equipment
USRP:
SDR implementation;
Low cost and extremely flexible solution;
LabVIEW:
General purpose software for data processing and instruments control.
USRP and HF band
Good candidate for the implementation of HF communication because it can directly sample the entire HF band.
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Conclusion
Main activities
Frequency selection in order to establish the HF link (Chirp experiment):
Ionospheric channel;
External noise level;
Design and Development of a demonstrator for data transmission over HF radio links (PSK experiment):
Modulation type: PSK;
Single carrier;
The functionality of the system has been experimentally demonstrated in a closed-loop configuration. Moreover the effect of additive white Gaussian noise has been evaluated by using a set of different signal to noise ratios.
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Conclusion
Future Developments
PSK and Chirp demonstrators : Integration
PSK and HF link : Experimental validation
Realization of a Fully Automated System:
Spectral sensing (low noise, HF band occupancy);
Ionospheric monitoring;
Optimal frequency selection (chirp system);
Data transmission over HF link (PSK system)
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THE END
Thank you for your attention!
Questions?
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