Signal Quality of a Wideband SDR Transceiver Under Varying Frequency Deviation

This study examines the quality of an audio signal received via a Software-Defined Radio (SDR) peripheralfor Wideband Frequency Modulation (WBFM). The objective is to evaluate the impact of varying the maximumfrequency deviations of the modulator, through the WBFM transmit block, on audio quality. Tests were conductedin an open space at a fixed distance of 50 meters using a chirp signal and an audio file in .WAV format asmessages. Signal quality was evaluated using the RMAA 6.1.4 Right Mark Audio Analyzer and SDR# spectrumanalyzer, with a 16-bit resolution and a 96 kHz sampling rate. Key performance parameters included: total harmonicdistortion (THD), peak power (Pp), frequency response (RF), and signal-to-noise ratio (SNR). Results indicatehigh-quality reception under specific conditions: THD ≤ 2 %, Pp ≥ 2.7 dBFS, RF at 13 kHz, and SNR ≥ 39 dB. Optimalperformance was observed with a frequency deviation of 75 kHz, highlighting HackRF One’s suitability forWBFM transmission. This work demonstrates SDR’s flexibility in modulating and demodulating signals, providing a low-cost and efficient alternative for audio transmission. The study was funded by the Escuela Colombiana de Ingeniería Julio Garavito under code PRY18, 2018-1.