Ionospheric research with help of doppler goniometric complex Spektr'

1
Ionospheric research with help of doppler
goniometric complex Spektr.
R. R. Latypov, V. V. Bochkarev, I. R. Petrova
Kazan State University
Work was supported by RFBR ?05-05-64651
Prague - 2007
2
Doppler goniometric complex (DGC) Spektr block
scheme
A
2 IF
Receiver
Amp.
Exit of 2-nd heterodyne
??
1-st heterodyne
QG
geobase.ksu.ru
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DGC antennas systems
4
Calibration device block scheme
Antenna
PC
USB interface FT245
DDS AD9851
Controlled preamplifier
RF amplifier
DAC AD5327
USB communication block
Inner registers block
Interface
Interface
Amplifier OP747
Control device
Interface
Amp. in ??
Receiver ?-339
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Control device scheme
USB interface
Register
DDS interface
A3..0 D3..0 Rst
A3..0 D3..0
Q39..0 Upd Rst
Q39..0
Control device
Reset device
DAC interface
Upd_DDS Upd_DAC Upd_Amp Rst_DDS Rst_DAC Rst_Amp
Q15..0 Upd Rst
A3..0
Rst
A3..0 D3..0 Rst
Amplifier interface
Q8..0 Upd Rst
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Receiving signal with calibration system signal
spectra.
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Digital receiver block scheme
FPGA
sin
Filter
Decimator
??
16 bit
PC interface
Quadrature separation block
2 IF 215 ?Hz
8 bit
DAC
Port
16 bit
Filter
Decimator
cos
Sampling rate 1MSps
USB
PC
FTDI 245
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Doppler goniometric complex (DGC) Spektr block
scheme after modernization
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Signal from Katran second intermediate
frequency spectra, sampling rate 5 KSps, signal
band 300 Hz
Noise spectra in frequency band from 1 to 2500Hz.
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• New antennas system was build. Itll allow us to
  reconstruct polarization ellipse of receiving
  radio wave.
• Calibration system was modernized, after
  modernization we can remove calibration of phase
  from measurement cycle.
• New digital receiver was build. We can increase
  receiving frequency band up to 500 kHz. Also we
  can receive waves from 1 to 1000000 Hz using
  necessary band-pass filters and antennas.