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Noise Blanker Effectiveness

February 5th Fact-of-the-Day

A noise blanker blocks signal processing in a receiver for the duration of each noise pulse that exceeds a user-adjustable amplitude-threshold. That process provides highly-effective suppression of narrow noise pulses, such as ignition noise pulses, if the blanking is done prior to highly-selective IF filtering. However, a noise blanker is much less effective and often even degrades the quality of received signals if blanking is done after highly-selective IF filtering. The reason is that all highly-selective IF filters ring after being excited by each noise pulse. The ringing widens each noise pulse, causing a noise blanker to block receiver signal processing for longer periods of time than the durations of the input pulses. ©2005 Martek International All rights reserved.


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