Television: The Subjective Effects of Filter Ringing Transients

Step signals passed through sharp-cutoff phase-equalized low-pass filters produce symmetrical ringing transients. The subjective effects of the first two symmetrical transients on television displays were investigated. It was found that first transients whose magnitudes ranged from 2% to 22% of the picture signal amplitude enhanced the quality of the picture. A 12% first transient was found to be the subjective optimum for a noiseless television system and provided a subjective bandwidth improvement of about 2:1. For first transients at 6% of the signal amplitude, a statistically significant difference was obtained between a noiseless channel and one with added noise at an SNR of about 40 dB. Although there was considerable tolerance to second transients when associated with first transients of greater magnitude, they always degraded the quality of the picture.