Fix some math to account for leaky bins

[fronzbot]

• Add option to change xscaling (kHz, MHz, etc)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 50.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 66.47%. Comparing base (cd2fa4b) to head (cd89138).
Report is 10 commits behind head on dev.

Files with missing lines	Patch %	Lines
adc_eval/spectrum.py	50.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev      #76      +/-   ##
==========================================
- Coverage   68.26%   66.47%   -1.79%     
==========================================
  Files           4        4              
  Lines         167      173       +6     
==========================================
+ Hits          114      115       +1     
- Misses         53       58       +5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.