Change remove_coarse_band setting when reading derippled MWA data

CHANGELOG.md

@@ -2,6 +2,11 @@
 All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
+### Changed
+- When reading MWAX correlator files , `remove_coarse_band` now defaults to
+`False` if DERIPPLE is on. Otherwise it defaults to `True`.
+- If the user has set `remove_coarse_band=True` when DERIPPLE is on, a warning is
+raised, and no pfb shape is removed.
 
 ### Added
 - A NotImplementedError to `mwa_corr_fits.py` that is thrown when trying to read

src/pyuvdata/uvdata/mwa_corr_fits.py

@@ -1513,7 +1513,7 @@ def read_mwa_corr_fits(
         keep_all_metadata=True,
         use_aoflagger_flags=None,
         remove_dig_gains=True,
-        remove_coarse_band=True,
+        remove_coarse_band=None,
         correct_cable_len=True,
         correct_van_vleck=False,
         cheby_approx=True,
@@ -1745,6 +1745,29 @@ def read_mwa_corr_fits(
                 if key not in self.extra_keywords:
                     self.extra_keywords[key] = value
 
+        if remove_coarse_band is None:
+            if (
+                "DERIPPLE" in self.extra_keywords
+                and self.extra_keywords["DERIPPLE"] == 1
+            ):
+                remove_coarse_band = False
+            else:
+                remove_coarse_band = True
+        elif (
+            remove_coarse_band is True
+            and "DERIPPLE" in self.extra_keywords
+            and self.extra_keywords["DERIPPLE"] == 1
+        ):
+            # turn off pfb correction if it was corrected in the correlator
+            warnings.warn(
+                "No coarse band shape will be removed from this data "
+                "because DERIPPLE is on.",
+                stacklevel=2,
+            )
+            remove_coarse_band = False
+        else:
+            pass
+
         # set parameters from other parameters
         self.telescope.Nants = len(self.telescope.antenna_numbers)
         self.Nants_data = len(self.telescope.antenna_numbers)

tests/uvdata/test_mwa_corr_fits.py

@@ -1711,3 +1711,43 @@ def test_fringe_stopping_error(tmp_path):
         NotImplementedError, match="This data has had fringe stopping applied. "
     ):
         UVData.from_file([test_metafits, fetch_data("mwax_2021_raw_gpubox")])
+
+
+@pytest.mark.filterwarnings("ignore:some coarse channel files were not submitted")
+@pytest.mark.filterwarnings("ignore:Fixing auto-correlations to be be real-only")
+def test_deripple_on_warns_and_passes(tmp_path):
+    test_metafits = str(tmp_path / "1131733552_dr.metafits")
+    with fits.open(fetch_data("mwax_2021_metafits")) as meta:
+        meta[0].header["DERIPPLE"] = 1
+        meta.writeto(test_metafits)
+    with pytest.warns(UserWarning, match="No coarse band shape will be removed"):
+        uvd = UVData.from_file(
+            [test_metafits, fetch_data("mwax_2021_raw_gpubox")], remove_coarse_band=True
+        )
+    assert "Divided out pfb coarse channel bandpass" not in uvd.history
+
+
+@pytest.mark.filterwarnings("ignore:some coarse channel files were not submitted")
+@pytest.mark.filterwarnings("ignore:Fixing auto-correlations to be be real-only")
+def test_deripple_remove_coarse_band_none(tmp_path):
+    test_metafits = str(tmp_path / "1131733551_dr.metafits")
+    with fits.open(fetch_data("mwax_2021_metafits")) as meta:
+        meta[0].header["DERIPPLE"] = 1
+        meta.writeto(test_metafits)
+    uvd = UVData.from_file(
+        [test_metafits, fetch_data("mwax_2021_raw_gpubox")], remove_coarse_band=None
+    )
+    assert "Divided out pfb coarse channel bandpass" not in uvd.history
+
+
+@pytest.mark.filterwarnings("ignore:some coarse channel files were not submitted")
+@pytest.mark.filterwarnings("ignore:Fixing auto-correlations to be be real-only")
+def test_deripple_off_does_nothing(tmp_path):
+    test_metafits = str(tmp_path / "1131733550_dr.metafits")
+    with fits.open(fetch_data("mwax_2021_metafits")) as meta:
+        meta[0].header["DERIPPLE"] = 0
+        meta.writeto(test_metafits)
+    uvd = UVData.from_file(
+        [test_metafits, fetch_data("mwax_2021_raw_gpubox")], remove_coarse_band=True
+    )
+    assert "Divided out pfb coarse channel bandpass" in uvd.history