slight power cal improvement

charon_vna/vna.py

@@ -189,22 +189,20 @@ class Charon:
         )
 
     def set_output_power(self, power: float):
-        # FIXME: this is a hack because I don't want to go through re-calibration
-        if power == 5:
-            tx_gain = -1
-        elif power == 0:
-            tx_gain = -7
-        elif power == -5:
-            tx_gain = -12
-        elif power == -10:
-            tx_gain = -17
-        elif power == -15:
-            tx_gain = -22
-        else:
-            raise NotImplementedError()
-            # # TODO: correct over frequency
-            # tx_gain_idx = np.abs(pout.sel(tx_channel=0) - power).argmin(dim="tx_gain")
-            # tx_gain = pout.coords["tx_gain"][tx_gain_idx]
+        pout = xr.DataArray(
+            [-15, -10, -5, 0, 5],
+            dims=["tx_gain"],
+            coords=dict(
+                # TODO: correct over frequency
+                frequency=1e9,  # FIXME: I'm not sure at what frequency I generated this table
+                tx_channel=0,
+                tx_gain=[-22, -17, -12, -7, -1],
+            ),
+        )
+
+        tx_gain_idx = np.abs(pout - power).argmin(dim="tx_gain")
+        tx_gain = pout.coords["tx_gain"][tx_gain_idx]
+
         self.sdr.tx_hardwaregain_chan0 = float(tx_gain)
 
     def set_output(self, frequency: float, power: float):