fix range

rfg_vna_viewer.py

@@ -265,13 +265,15 @@ def make_update(reader, parser, assembler, curves, plots):
         if n < 2:
             return
 
-        freqs_ghz = np.linspace(F_START_HZ / 1e9, F_STOP_HZ / 1e9, n)
-        freqs_hz = freqs_ghz * 1e9
-
         ref_amp, ref_phase = process_reference(
             sweep["ref_ch1"], sweep["ref_ch2"]
         )
 
+        # Compute frequency axis from reference signal phase (linear phase-freq model)
+        phi0, phi1 = ref_phase[0], ref_phase[-1]
+        freqs_ghz = (F_START_HZ / 1e9) + (ref_phase - phi0) / (phi1 - phi0) * (BW_HZ / 1e9)
+        freqs_hz = freqs_ghz * 1e9
+
         # Fix reference phase from the first sweep
         if state["ref_phase_first"] is None:
             state["ref_phase_first"] = ref_phase[0]