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v0.3.1 — ANAN sim: real I/Q handedness

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@nigelfenton nigelfenton released this 16 Sep 22:01
v0.3.1
a054153
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A correctness fix for the ANAN-G2 / openHPSDR Protocol 2 simulator. Anyone using anan_sim.py from v0.3.0 should update.

About the binaries below: they are the Flex radio sim, rebuilt with only a version bump. The ANAN / Protocol 2 tools run from source.

The fix

  • The sim's I/Q handedness was mirrored. On the first run against AetherSDR's ANAN-G2 backend (aethersdr/AetherSDR#5143), the "+1 kHz" test tone was drawn 1 kHz below the dial and was audible only in LSB. AetherSDR's polarity had been measured on a real G2 against WWV and cross-checked with an RSP1B running SDR++, so the sim was the one in error: the real HPSDR wire is the conjugate of the textbook convention. A correct client now shows the tone just above the dial and hears it in USB (#8).
  • Why it matters: a mirrored sim would push a correct client towards a "fix" that breaks it on real hardware.
  • Caught by a test now. tests/test_anan_p2.py asserts the tone's signed frequency; nothing checked it before, because every frame was the right size.

Also

  • High Priority frequencies are decoded as phase words (Hz = word × 122.88 MHz / 2³²), so a client tuned to 10.000 MHz is no longer logged as "349.525333 MHz". Discovery advertises it (byte 21 = 1).
  • The README's "not yet run against AetherSDR's ANAN backend" warning is retired — it now has been, end to end.
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