Stereophonic Frequency Modulation using MATLAB: An Undergraduate Research Project

Frequency modulation (FM) is used worldwide for high-fidelity broadcast radio communication. This paper presents a MATLAB implementation of a stereophonic FM transmitter and receiver. Simulations are performed to measure the performance of the stereophonic FM receiver in the presence of additive white Gaussian noise (AWGN). A stereophonic FM signal with pre-detection SNR values from 0 to 60 dB, in increments of 10 dB, is demodulated using a discriminator. Post-detection SNR values are determined, and performance characteristics are examined for above and below threshold modes of FM operation. The simulations show that the receiver reliably demodulates the message signal for pre-detection SNR values greater than 30 dB. Degradation of the signal occurs at and below 20 dB with a complete loss of signal at 0 dB (below threshold mode). A 15 dB post-detection SNR gain occurs at 60 dB pre-detection SNR.