Measurements of digital systems in Gaussian additive noise and interference

A series of experimental measurements are described that examine the performance of the five different digital modems in Gaussian noise and additive interference. These experimental results are then compared with theoretical predictions to determine if the performance of digital systems can be accurately predicted. Some of the modems tested are: frequency-shift keying, phase-shift keying with coherent detection, and differentially encoded phase-shift keying with coherent detection. Also tested are two modems that use bandwidth conservation types of modulation. One of the bandwidth conservation modems uses minimum-shift keying as its basic modulation format. Test results are presented showing the results of interference from both unmodulated, continuous wave interference and modulated interference.