fafo/k8ik-stm
15
0
Fork 0
Code Issues Pull requests Projects Activity Actions

Laser-Wobble: Show amplitude spectral density instead

Browse source
This commit is contained in:
Rahix 2025-09-08 02:14:28 +02:00
parent 3bc3984375
commit 1906e71696
3 changed files with 35 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

20
Calculations/Laser-Wobble/Laser-Wobble.md
View file

@ -87,7 +87,7 @@ print(f"Video processing took {processing_time:.2f} seconds ({processing_time /
Snapshot capture of frame 2331 at 77.70s: Intensity 12.612
Snapshot capture of frame 2664 at 88.80s: Intensity 12.257
Snapshot capture of frame 2997 at 99.90s: Intensity 12.728
Video processing took 251.50 seconds (0.084 seconds per frame).
Video processing took 257.32 seconds (0.086 seconds per frame).
@ -202,8 +202,11 @@ pass
```python
from scipy import signal
fx, psd_x = signal.periodogram(np.nan_to_num(laser_position[:, 1]), frame_rate)
fy, psd_y = signal.periodogram(np.nan_to_num(laser_position[:, 0]), frame_rate)
frequency_x, power_spectral_density_x = signal.periodogram(np.nan_to_num(laser_position[:, 1]), frame_rate)
frequency_y, power_spectral_density_y = signal.periodogram(np.nan_to_num(laser_position[:, 0]), frame_rate)
amplitude_spectral_density_x = np.sqrt(power_spectral_density_x)
amplitude_spectral_density_y = np.sqrt(power_spectral_density_y)
```
## Spectral Analysis
@ -214,15 +217,16 @@ The following figure looks at the spectral density in the displacement along X a
fig, ax = plt.subplots(2, 1, figsize=(16, 8))
ax[1].axvline(x=2.822, color="red")
ax[1].annotate(" theoretical spring resonance", xy=(2.822, 2e5))
ax[1].annotate(" theoretical spring resonance", xy=(2.822, 1080 / 2 - 150))
ax[0].loglog(frequency_x, amplitude_spectral_density_x, label="X axis")
ax[1].loglog(frequency_y, amplitude_spectral_density_y, label="Y axis")
ax[0].loglog(fx, psd_x, label="X axis")
ax[1].loglog(fy, psd_y, label="Y axis")
for a in ax:
a.set_xlabel("frequency / Hz")
a.set_ylabel("spectral density")
a.set_ylabel("amplitude spectral density")
a.set_xlim(0.5, 15)
a.set_ylim(1, 5e5)
a.set_ylim(1, 1080 / 2)
a.legend()
a.grid(axis="x", which="both")
a.grid(axis="y", which="major")