o A signal generator producing -46dBm at 38.1MHz
o USRP2 + Basic_RX
o GRC flowgraph:
o An FFT filter, reducing the incoming 250KHz bandwidth to 5KHz
o A power detector:
(I**2 + Q**2)--->single-pole-iir-filter o A strip-chart scope display
Using the scope display, I measured the detector output difference
between nothing connected (which on the BASIC_RX means that
the A/D is “seeing” the 50-ohm termination across the input-half of
the balun transformer), and my -46dBm signal connected.
That difference amounted to a 65dB difference in detected output power.
Doing the math, does that mean that a “naked”
USRP2 + Basic_RX is sensitive down to roughly -111dBm, or should I
factor in root(5KHz), which brings it up to -92dBm.
Shirleys Bay Radio Astronomy Consortium