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E NABLIA. Why is HF popular? Refraction of ionosphere allows medium and long-range radio communication (by skywave propagation) Relatively low-cost equipment.

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Presentation on theme: "E NABLIA. Why is HF popular? Refraction of ionosphere allows medium and long-range radio communication (by skywave propagation) Relatively low-cost equipment."— Presentation transcript:


2 Why is HF popular? Refraction of ionosphere allows medium and long-range radio communication (by skywave propagation) Relatively low-cost equipment Who uses HF? International shortwave broadcasting, amateur radio, CB radios, safety (humanitarian aims), security (law enforcement), aviation (compulsory for all trans-oceanic flights), marine, military forces and for diplomatic interests (even as a back up of satellite links), but also terrorist organizations Who surveys HF? Radio amateurs (DXers) Environmental protection agencies (electromagnetic pollution) National radio frequency agencies (detecting interfering or illegal electromagnetic emissions) Security (national) agencies and foreign intelligence agencies E NABLIA

3 Spectrum analyzer or scanner NB Receiver SW Decoder (PC) HW Decoder Audio Recorder Audio matrix E NABLIA

4 USB Acquisition receiver Personal Computer HW DDC (WB) BUFFER ADC FFT Panoramic Spectrum FFT WB Spectrum Realtime Operation SW Decoder SW DDC (NB) SW Decoder VAC HW DDC (Digital Down Converter) as a dedicated chipset or FPGA core Recording on mass storage device Interface by Virtual Audio Cable E NABLIA

5 SW Decoder SW DDC (NB) SW Decoder Personal Computer FFT WB Spectrum Offline Operation VAC Archive replay E NABLIA

6 Maximum number of NB channels significantly limited by CPU SW implementation of DDCs is computationally expensive (especially for WB channels with large bandwidths) Decoding /NB recording practically limited to about three channels in parallel Spectral zoom strongly impacts CPU Smallest resolution bandwidths require large size FFTs, rising CPU load considerably (FFT bins outside the displayed frequency span are discarded) Performance not independent on frequency span Just one WB channel Need for partitioning of acquisition bandwidth (into more WB channels), to survey more spectral portions in parallel E NABLIA

7 USB TITAN RECEIVER Personal Computer 4X Filters Bank ADC FFT Panoramic Spectrum FFT Spectrum Assembler BUFFER 40X NB Reconstructor SW Decoder VAC SW Decoder Each NB Reconstructor aggregates adjacent subchannels Then it performs retuning, filtering and resampling of aggregate Filters Banks instead of Digital Down Converters Adjacent subchannels are transferred over the USB interface

8 Filters Banks on FPGA instead of WB DDCs WB channels are provided to PC as a collection of subchannels Filters Banks perform pass-band filtering AND decimation, which both downconverts and preserves throughput over the USB interface Spectrum assembler WB Spectrum is obtained by composing individual subchannels spectra (exploiting the power complementarity feature of filters responses) While zooming, just needed subchannels spectra are evaluated, thus saving CPU NB Reconstructors instead of NB DDCs NB channels are obtained by aggregating subchannels, retuning (digital rotation), filtering and resampling Processing is at low sampling rates, resulting in a reduced impact on CPU (with respect to SW DDCs ) and allowing for many parallel NB channels E NABLIA

9 16 Preselectors Unbal/Balanced, amplification and noise rejection filtering Anti-aliasing lowpass AD Converter (16 bit, 80 Msps) FPGA (Xilinx Spartan 3ADSP) USB controller E NABLIA

10 Wideband Channels Narrowband Channels of WB3 NB1 of WB3 WB3

11 List of NB Channels Output to VACs (Virtual Audio Cables) or additonal audio cards Tuning frequencyDemodulation modesAudio card outputChannel Bandwidth Output by LAN to software decoders WAV file recording status

12 Each spectrum scope can be closed (x button), for better view of the others. Typically the Panoramic Scope is closed after tuning of WB channels:

13 Frequency Range 100 kHz – 32 MHz (up to 40 MHz by IF Input) Noise Figure 100 KHz MHz NF = 15.25dB 1.5 MHz – 32 MHz NF = 14.2dB Preselectors (16) Low Pass: MHz Band Pass ( MHz): , , , , , , , , , , , , , , Attenuation 0dB, 10dB, 20dB, 30dB Clipping -8dBm 0dB Attenuation) Wideband Channels Number of Channels: 4 Bandwidths (kHz): 312.5, 625, 937.5, 1250, , 1875, Maximum Total Bandwidth (kHz): , 1875, and 1250 for 1, 2, 3 and 4 Wideband Channels, respectively Narrowband Channels 16 (Basic), 40 (Extended) or unlimited (only constrained by PC hardware), independently tunable within Wideband Channels E NABLIA

14 Panoramic Scope 0 Hz ÷32 or 40 MHz, 5kHz RBW Wideband Scope ÷ kHz, min RBW Hz (Spectrum & Waterfall) Narrowband Scope RF: kHz, min RBW Hz (Spectrum & Waterfall) Audio: ÷22050 Hz, RBW 5.4 ÷ 21.5 Hz (Spectrum & Waterfall) Modes SSB, AM, NBFM, CW, eSSB, FSK, DRM (Dream or DRM Software Radio supported) Selectivity 100 dB (Stop Band Attenuation) Sensitivity -116 dBm (0.34 µV) SSB at S+N/N=10dB, 15MHz, 2.4 kHz BW Recording One Wideband Channel (proprietary file format) All Narrowband Channels (.wav files) Interface to SW Decoders By VAC (Virtual Audio Cable) By LAN (support for Hoka Electronic software decoders) E NABLIA

15 A/D Conversion 16 bit, 80 Msps Image Rejection 90 dB typ. IIP3 >37 dBm SFDR >108 dB Alias Rejection 115 dB Antenna Input 50 Ohm BNC IF input 50 Ohm SMA - Bandwidth: 0.1÷ 40MHz PC Interface USB 2.0 Operating Temperature 0° - 40° (°Celsius) Supply Voltage 9VDC +/-1V Supply Current 2.5Amp Dimensions 243mm x 52mm x 145mm (WxHxL) E NABLIA

16 Automatic detection of emissions Wideband spectra, though useful in locating time continuous emissions, are of little or no help in detecting pulsed emissions, which occur at unknown frequencies Some aid would be highly appreciated in locating emissions when they occur, especially in offline operation, when lengthy acquisitions have to be scanned for activities Each subchannel could be monitored on FPGA by a corresponding detector and activities could be notified to the user and possibly recorded for later consultation Data compression As a consequence of detection, recording of WB channels could regard only subchannels within which some activity is being revealed, thus dramatically reducing storage requirements (even in terms of HD write speed) E NABLIA

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