We have recently developed a programmable composite noise generator (P-CNG) which can easily control noise parameters such as average power, time-based amplitude probability distribution (APD), crossing rate distribution, occurrence frequency distribution and burst duration. Two applications of the P-CNG are demonstrated to show its usefulness. For the first application, Middleton's Class A noise is simulated. A method of setting parameters for Class A noise is demonstrated. The APD of P-CNG output is in good agreement with that of true Class A noise. In the second application, the P-CNG is used for subjective evaluation test (opinion test) of TV picture degradation. Five simple composite noise models with two kinds of APD are used. Other parameters such as average power are kept constant. Experimental results show that the envelope and APD of composite noises do not greatly influence the subjective evaluation. Finally the capabilities of the P-CNG are shown.

The effects of Gaussian electromagnetic noise and non-Gaussian one on TV picture degradation are studied by using a composite noise generator which can control noise parameters. Three kinds of still pictures and four kinds of motion pictures are tested, and the picture degradation is subjectively evaluated with five-grade impairment scale. The tendency of the picture degradation against the every picture is almost the same. But MOS (Mean Opinion Score) between still picture and motion picture degradation is different in some measure when the power of burst noise is small.

A composite noise generator (CNG) is proposed for simulating the actual non-Gaussian noise and its applications are mentioned. Basing upon the actual measured result (APD) of induced noise from electric contact discharge arc, the APD is approximated by partial linearlization and shown that it can be simulated by a combination of plural Gaussian noise sources. Applying the CNG, quasi-peak (Q-P) detector is investigated and shown that the Q-P detector response is different for non-Gaussian noise when its time domain parameter is different even if its original APD is the same. For digital transmission error due to non-Gaussian noise, and for TV picture stained by the non-Gaussian noise, the CNG is applied to evaluate their performances and quality. The results obtained show that the CNG can be used as a standard non-Gaussian generator for several immunity tests for information equipments.