Design and implementation of noise simulation circuit for a noncoherent spread-spectrum system IF signal simulator

The noise simulation circuit of noncoherent spread-spectrum system intermediate frequency (IF) signal simulator is designed based on FPGA and DSP. This circuit generates white Gaussian noise (WGN), calculates coefficients of signal-to-noise ratio (SNR) refer to the specified SNR of each channel and according to these coefficients to generate spread-spectrum IF signal for transmitting to simulate the actual receive signal of responder beacon (RSP). It has been verified that the result of test meets the requests of system.