Fix divide by zero error

Steps to recreate:

import datetime as dt

from orcasound_noise.pipeline.pipeline import NoiseAnalysisPipeline
from orcasound_noise.utils import Hydrophone

pipeline = NoiseAnalysisPipeline(Hydrophone.ORCASOUND_LAB, pqt_folder='pqt', delta_f=10, bands=3, delta_t=1)
psd_path, broadband_path = pipeline.generate_parquet_file(dt.datetime(2023, 2, 1, 9), dt.datetime(2023, 2, 1, 10), upload_to_s3=False)

Error Message:

fmpeg version 6.1.1 Copyright (c) 2000-2023 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.1.0.2.5)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/6.1.1_2 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
  libavutil      58. 29.100 / 58. 29.100
  libavcodec     60. 31.102 / 60. 31.102
  libavformat    60. 16.100 / 60. 16.100
  libavdevice    60.  3.100 / 60.  3.100
  libavfilter     9. 12.100 /  9. 12.100
  libswscale      7.  5.100 /  7.  5.100
  libswresample   4. 12.100 /  4. 12.100
  libpostproc    57.  3.100 / 57.  3.100
Input #0, mpegts, from '/var/folders/7l/7tynfbss6zx6wlvqs5gs9bnh0000gn/T/tmpe32r9ewz/rpi-orcasound-lab_2023_02_01_09_50_00.ts':
  Duration: 00:09:59.92, start: 11981.411522, bitrate: 87 kb/s
  Program 1 
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
  Stream #0:0[0x100]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, mono, fltp, 72 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (aac (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, wav, to '/var/folders/7l/7tynfbss6zx6wlvqs5gs9bnh0000gn/T/tmp6eelqxuy/rpi-orcasound-lab_2023_02_01_09_50_00.wav':
  Metadata:
    ISFT            : Lavf60.16.100
  Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, mono, s16, 768 kb/s
    Metadata:
      encoder         : Lavc60.31.102 pcm_s16le
[out#0/wav @ 0x600003c60240] video:0kB audio:56250kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000135%
size=   56250kB time=00:09:59.98 bitrate= 768.0kbits/s speed=1.33e+03x    
/Users/vmehrotra/miniconda3/envs/ambient-sound-analysis/lib/python3.9/site-packages/orcasound_noise/pipeline/acoustic_util.py:255: RuntimeWarning: divide by zero encountered in true_divide
  d = np.subtract(np.divide(f,fm),np.divide(fm,f))

orcasound / ambient-sound-analysis

Fix divide by zero error #35