A frequency-selective, digitally implemented disturbed-channel simulator

The dispersive channel simulator (DCS), which was developed to evaluate the performance of adaptive-equalizer-based receiving equipment and mission data processing software in the presence of frequency-selective or flat ionospheric scintillation, is presented. It operates on digital input data to produce scintillated outputs on three independent channels. The time-varying channel effects consist of linear filtering, total-electron-content (TEC) envelope delay, TEC carrier frequency modulation, signal absorption loss, and additive noise including sky noise temperature. Parameters for a 1-h scenario are read from a cartridge tape. The channel convolvers contain 96 complex taps per diversity channel with a sample rate of 10 Msamples/s. Modulation is binary or quadrature phase-shift keying with selectable convolutional encoding. The simulator hardware is housed in a 15.75-in chassis and is controlled by a personal computer