Assessment of potential noise immunity of stroboscopic converter of periodic pulse signals by numerical simulations

The paper considers a simplified linear mathematical model of a stroboscopic converter, which allows recording broadband signals and consists of a multiplicative element multiplying the input and strobing signals and a low-frequency filter that highlights one of the products of spectral conversion. Statistical calculations of the error in reproducing a pulse signal by stroboscopic converter under the action of normal noise (additive interference) and a violation synchronization of strobing pulses (multiplicative interference) were performed using numerical modeling methods. Rectangular, triangular and bipolar signals, as well as radio signals with rectangular and Gaussian envelopes, were selected as input signals. Low-frequency filtering of stroboscopic samples was carried out using the FFT algorithm. During stroboscopic processing of radio signals in the converter model, the low-pass filter (LPF) was replaced by a bandpass filter that highlights spectral components at the mixer output in the vicinity of the carrier frequency difference. As a result of numerical experiments conducted under conditions of additive and multiplicative interference, it is shown that a violation of synchronization of the studied and gating signals has a greater effect on the accuracy of reproduction of input signals compared with additive noise. Analysis of the effect of additive interference on video signals has shown that the error value weakly depends on their shape. The results obtained in the simulation process allow us to estimate the permissible level of interference during stroboscopic processing of broadband pulsed radio signals at the design stage of radio engineering systems.