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vramor

Strange behaviour of DVBViewer's Quality Indicator

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vramor

I receives TV signals from two various transmitters, working through similar antennas placed on the same tower on two various frequencies with various power: 10 kW and 300 W (the difference is about 15 dB).

Here are the results of measuring its parameters for the direct connection tuner-antenna and through a TAP 10 dB.

01_2019-10-25_094950.1571991329.png 02_2019-10-25_095058.1571991368.png 03_2019-10-25_094830.1571991403.png 04_2019-10-25_094724.1571991437.png


Meanwhile DVBViewer's indicator (Quality?) shows a rather strange value for the weakest signal. Despite the less level/quality it shows the better value. Here are the screenshots.

i.gif05_2019-10-25_094155.1571991823.png 06_2019-10-25_094251.1571991522.png 07_2019-10-25_094503.1571991559.png 08_2019-10-25_094537.1571991598.png


Maybe there is a bug in the calculation quality algorithm that brings an error for weak signals...

Edited by Griga
title corrected

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haupauge

Hey vramor, this indicator  just shows what the driver reports. So, if you try with another DVB hardware, the results may also differ.

 

Regard's 🤗

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vramor

I use the same hardware with the same driver both with DVBViewer and the analyser soft. So your idea doesn't work in my case.

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HaraldL

Then your driver reports strange values to DVBViewer which simply displays it. There is nothing that DVBViewer can do in this point.

 

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vramor

The driver provides both progs with THE SAME RAW data. Then each program begins to calculate the value of SQI (Signal Quality Indicator) using one's own algorithm to visualize these values as a number and/or color bar. Analyser does this correctly in the whole range of C/N, but DVBViewer begins to make a mistake if the value C/N is too small for it. That is the question.

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