feat: implement dea module

dea/bode.py

@@ -0,0 +1,26 @@
+import numpy as np
+from scipy import signal
+
+from .config import BODE_MAX_MULTIPLIER, BODE_POINTS
+from .schemas import BodeParams
+from .validation import require_finite, validate_coefficients
+
+
+def calculate_bode_response(params: BodeParams):
+    fs_val = require_finite(params.fs, "fs")
+    b_vals = validate_coefficients(params.b, "b")
+    a_vals = validate_coefficients(params.a, "a")
+    f_min = params.fs / 50000.0
+    f_max = params.fs * BODE_MAX_MULTIPLIER
+    f_eval = np.logspace(np.log10(f_min), np.log10(f_max), BODE_POINTS)
+
+    _, h = signal.freqz(b_vals, a_vals, worN=f_eval, fs=fs_val)
+    mag = 20 * np.log10(np.abs(h) + 1e-12)
+    phase = np.angle(h, deg=True)
+
+    return {
+        "freq": f_eval.tolist(),
+        "mag": mag.tolist(),
+        "phase": phase.tolist(),
+    }
+