Front end design Front end like SEQUOIA, except that both signal polarizations combined with ortho-mode transition. Entire signal band down-converted at once to two 18.5 GHz wide IF bands. Four receivers with 8 outputs in total GHz LO 95 GHz LO
Beams separated in azimuth with spacing of 3 HPBW. Receiver has two dual polarized beams with a beamswitch. One beam always on source.
In Out Faraday Rotation Switch Beamswitch developed for this work improves enormously on any previous device. Dual polarized beam is rotated by 45 using a switched magnetic field in a ferrite. Added noise <10K, switching time <10 sec.
Analog autocorrelator vs digital Analog correlation requires no high speed signal sampler-digitizer. Analog requires no signal quantization: Very wide dynamic range. No noise degradation. Analog bandwidth is much larger GHz. High accuracy analog autocorrelation is practical with low cost, ~$10/lag.
Analog Autocorrelator Basics Delay lines Nyquist sampled ( /4) for 8 GHz bandwidth with weak coupling using a resistive tap. Many taps are practical, we use 64 on each line. Tap signals are detected with silicon diodes which act as multipliers.
Correlator board presently in test, everything works. Delay lines with 256 taps, detectors, AC amplifiers, A/D converters, FPGA for digital signal processing all on one board. 31 MHz resolution.