Fix integer out of bounds issue

[TERMSTRAANGE]

Convert data to int16 type during operation. As an alternative, data could be initially loaded as int16 as opposed to default uint8 as defined by np.memmap which is used to load the samples.

[Copilot]

Pull request overview

This PR fixes an integer out of bounds issue when processing SDR (Software Defined Radio) data by explicitly converting uint8 data to int16 before performing arithmetic operations with a negative ADC offset.

Key Changes:

• Explicit type conversion to int16 added before arithmetic operations with the ADC offset (-127)
• Prevents potential integer underflow when adding negative offset to unsigned uint8 data
• Applied consistently to both IQ (in-phase and quadrature) components in complex data construction

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
calibratesdr/utils.py	Added astype(np.int16) conversion in get_fft function for both real and imaginary data slices before adding adc_offset
calibratesdr/dabplus/dab.py	Added astype(np.int16) conversion in get_ppm function for IQ data components before adding adc_offset

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.