From 98dee7a6aec3f061ff534b5bcddd9e24bf823673 Mon Sep 17 00:00:00 2001
From: wendtalexander <wendtalexander@protonmail.com>
Date: Wed, 11 Jan 2023 15:49:07 +0100
Subject: [PATCH] adding simulated chirps

---
 code/chirp_sim.py       | 24 ++++++++++++++++
 code/modules/filters.py | 61 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 code/chirp_sim.py

diff --git a/code/chirp_sim.py b/code/chirp_sim.py
new file mode 100644
index 0000000..fffc8d6
--- /dev/null
+++ b/code/chirp_sim.py
@@ -0,0 +1,24 @@
+from modules.filters import create_chirp, bandpass_filter
+import matplotlib.pyplot as plt 
+from chirpdetection import instantaneos_frequency
+from IPython import embed
+# create chirp
+
+time, signal, ampl, freq = create_chirp(chirptimes=[0.05, 0.2501, 0.38734, 0.48332, 0.73434, 0.823424], )
+
+# filter signal with bandpass_filter 
+
+signal = bandpass_filter(signal, 1/0.00001, 495, 505)
+embed()
+exit()
+fig, axs = plt.subplots(2, 1, figsize=(10, 10))
+axs[0].plot(time, signal)
+
+# plot instatneous frequency
+
+baseline_freq_time, baseline_freq = instantaneos_frequency(signal, 1/0.00001)
+axs[1].plot(baseline_freq_time[1:], baseline_freq[1:])
+
+
+
+plt.show()
diff --git a/code/modules/filters.py b/code/modules/filters.py
index c36fe63..bf311d7 100644
--- a/code/modules/filters.py
+++ b/code/modules/filters.py
@@ -34,3 +34,64 @@ def envelope(data, rate, freq=100):
     sos = butter(2, freq, "lowpass", fs=rate, output="sos")
     envelope = np.sqrt(2) * sosfiltfilt(sos, np.abs(data))
     return envelope
+
+
+def create_chirp(
+    eodf=500,
+    chirpsize=100,
+    chirpduration=0.015,
+    ampl_reduction=0.05,
+    chirptimes=[0.05, 0.2],
+    kurtosis=1.0,
+    duration=1.0,
+    dt=0.00001,
+):
+    """create a fake fish eod that contains chirps at the given times. EOF is a simple sinewave. Chirps are modeled with Gaussian profiles in amplitude reduction and frequency ecxcursion.
+
+    Args:
+        eodf (int, optional): The chriping fish's EOD frequency. Defaults to 500 Hz.
+        chirpsize (int, optional): the size of the chrip's frequency excursion. Defaults to 100 Hz.
+        chirpwidth (float, optional): the duration of the chirp. Defaults to 0.015 s.
+        ampl_reduction (float, optional): Amount of amplitude reduction during the chrips. Defaults to 0.05, i.e. 5\%
+        chirptimes (list, optional): Times of chirp centers. Defaults to [0.05, 0.2].
+        kurtosis (float, optional): The kurtosis of the Gaussian profiles. Defaults to 1.0
+        dt (float, optional): the stepsize of the simulation. Defaults to 0.00001 s.
+
+    Returns:
+        np.ndarray: the time
+        np.ndarray: the eod
+        np.ndarray: the amplitude profile
+        np.adarray: tha frequency profile
+    """
+    p = 0.0
+
+    time = np.arange(0.0, duration, dt)
+    signal = np.zeros_like(time)
+    ampl = np.ones_like(time)
+    freq = np.ones_like(time)
+
+    ck = 0
+    csig = 0.5 * chirpduration / np.power(2.0 * np.log(10.0), 0.5 / kurtosis)
+    #csig = csig*-1
+    for k, t in enumerate(time):
+        a = 1.0
+        f = eodf
+
+        if ck < len(chirptimes):
+            if np.abs(t - chirptimes[ck]) < 2.0 * chirpduration:
+                x = t - chirptimes[ck]
+                gg = np.exp(-0.5 * np.power((x / csig) ** 2, kurtosis))
+                cc = chirpsize * gg
+
+                # g = np.exp( -0.5 * (x/csig)**2 )
+                f = chirpsize * gg + eodf
+                a *= 1.0 - ampl_reduction * gg
+            elif t > chirptimes[ck] + 2.0 * chirpduration:
+                ck += 1
+        freq[k] = f
+        ampl[k] = a
+        p += f * dt
+        signal[k] = -1 * a * np.sin(2 * np.pi * p)
+
+    return time, signal, ampl, freq
+