Multipath explained !!


The reception of digital TV signals has several minor issues that are now being addressed by the broadcast industry. The first issue that effects digital TV signals is a phenomenon known as multi-path signals, which are more commonly referred to as ghost signals. The effects of ghost signals in analog broadcasting were shadows, or multiple images on the screen. Ghost signals are basically just signals that take a longer path to your antenna than the main signal by reflecting off of a distant object, and arriving at your antenna slightly lagging in time when compared to the direct path signal.

This timing difference between the direct path and the ghost signals is the main cause of the reception problems we are seeing for digital TV receivers, as it actually causes them to become confused since they cannot determine which is the main or direct path signal, so viewers see the dreaded “No Signal” logo on their screens.

The “No Signal” indicator is actually misleading to viewers, as it is not always a “No Signal” issue that is causing the problem, but is actually a ghost or multi path signal that causes most of the reception problems that we are seeing.

The chipset makers should have went a little further with the on screen messages with an additional message that actually stated "No Signal" when a true no signal situation was encountered, and and an additional message that should read "Data corruption or Data loss", for that is much more accurate than simply stating "No Signal" See simple multi path illustration attached.


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