new fft

tests/test_processing.py

@@ -14,6 +14,7 @@ from rfg_adc_plotter.processing.calibration import (
     save_calib_envelope,
 )
 from rfg_adc_plotter.processing.fft import (
+    build_positive_only_centered_ifft_spectrum,
     build_symmetric_ifft_spectrum,
     compute_distance_axis,
     compute_fft_mag_row,
@@ -127,6 +128,19 @@ class ProcessingTests(unittest.TestCase):
         self.assertTrue(np.allclose(spectrum[zero_mask], 0.0))
         self.assertTrue(np.allclose(spectrum[neg_idx], spectrum[pos_idx][::-1]))
 
+    def test_positive_only_centered_spectrum_keeps_zeros_until_positive_min(self):
+        sweep = np.linspace(1.0, 2.0, 128, dtype=np.float32)
+        freqs = np.linspace(SWEEP_FREQ_MIN_GHZ, SWEEP_FREQ_MAX_GHZ, 128, dtype=np.float64)
+        spectrum = build_positive_only_centered_ifft_spectrum(sweep, freqs, fft_len=FFT_LEN)
+
+        self.assertIsNotNone(spectrum)
+        freq_axis = np.linspace(-SWEEP_FREQ_MAX_GHZ, SWEEP_FREQ_MAX_GHZ, FFT_LEN, dtype=np.float64)
+        zero_mask = freq_axis < SWEEP_FREQ_MIN_GHZ
+        pos_idx = np.flatnonzero(freq_axis >= SWEEP_FREQ_MIN_GHZ)
+
+        self.assertTrue(np.allclose(spectrum[zero_mask], 0.0))
+        self.assertTrue(np.any(np.abs(spectrum[pos_idx]) > 0.0))
+
     def test_peak_helpers_find_reference_and_peak_boxes(self):
         xs = np.linspace(0.0, 10.0, 200)
         ys = np.exp(-((xs - 5.0) ** 2) / 0.4) * 10.0 + 1.0

tests/test_ring_buffer.py

@@ -56,6 +56,20 @@ class RingBufferTests(unittest.TestCase):
         self.assertFalse(np.allclose(ring.last_fft_db, fft_before))
         self.assertFalse(np.allclose(ring.distance_axis, axis_before))
 
+    def test_ring_buffer_can_switch_to_positive_only_fft_mode(self):
+        ring = RingBuffer(max_sweeps=2)
+        sweep = np.linspace(0.0, 1.0, 64, dtype=np.float32)
+        freqs = np.linspace(3.3, 14.3, 64, dtype=np.float64)
+        ring.push(sweep, freqs)
+
+        changed = ring.set_fft_mode("positive_only")
+
+        self.assertTrue(changed)
+        self.assertEqual(ring.fft_mode, "positive_only")
+        self.assertIsNotNone(ring.last_fft_db)
+        self.assertEqual(ring.last_fft_db.shape, (ring.fft_bins,))
+        self.assertIsNotNone(ring.distance_axis)
+
 
 if __name__ == "__main__":
     unittest.main()