LDI DIGISONDE 4D - Page 29

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DIGISONDE-4D
SYSTEM MANUAL
VERSION 1.2.11
1-10 SECTION 1 - GENERAL SYSTEM DESCRIPTION
RF Output
Frequency Scan
0.5 - 30 MHz, start, stop, and step size selectable to 1 kHz
Restriction of Transmission
Programmable list of frequencies without RF transmission
Ionogram Scan Time
Standard VIS ionogram 2 - 200 sec
(varies with programmable settings)
Frequency Synthesis
Fully digital (frequency switching time < 1μs)
Pulse Repetition Rate
100 and 200 pps
Pulse Width
533μs (16 chips of 33 μs) waveform with 30 kHz signal bandwidth
Peak Pulse Power
2 channels @ 150 W each
Output Impedance
50 Ω
Transmitter Type
Dual RF MOSFET Amplifiers for polarized transmission using turn-
stile transmit antenna
Lightning Protection
In-line spark gap discharge devices
User Interface
Unattended Operation
Controlled by 128 measurement programs, 128 schedules,
automatic schedule switch rules, and preprogrammed campaign events
Remote Access & Control
Network TCP/IP) interface for Input/Output access to schedules,
measurement data, diagnostic data, and operating software. Standard
Remote Control Interface uses Microsoft Remote Desktop over Inter-
net or LAN.
Time Setting
Integrated GPS receiver keeps time to +/-25μs
Built-in-Test (BIT)
Full diagnostics to isolate failures to line replaceable units runs auto-
matically, remotely accessible
Self Calibration
Built-in internal cal automatically updates phase/ amplitude adjust-
ment tables. Remotely accessible results.
Signal Processing
Processors
Two Embedded Intel Core 2 Duo Dual Core processor SBCs
(Control and Data Platforms)
Number of Range Bins
Selectable: 256 or 512
Height Range
0-1200 km (0 km used for self-calibration)
Height Resolution
2.5 km sample spacing.
500 m using differential phase technique
RF Interference Mitigation
RFIM reduces coherent interference up to 35 dB
Waveform Processing
Pulse compression of 16-chip phase code provides 15 dB signal pro-
cessing gain
Doppler Processing
4 to 128 integrations can provide up to 21 dB signal processing gain
Doppler Range
+/-3 Hz to +/-50 Hz
Doppler Resolution
.0125 to 12.5 Hz
Amplitude Resolution
< 0.01 dB
Wave Polarization
Alternating transmission with O and X, synchronized receive antenna
polarizations (doubles reliability of O/X identification by ARTIST).
Linear polarization on request.