Saturation detection

June 1, 2006.

The objective of this function is to indicate by means of an icon if the signal that arrives at the TV EXPLORER is saturated. It is a very useful function to determinate the correct adjust of analogue channel amplifiers.

When the gain in the head-end of a SMATV system is too high, it can cause saturation. This function allows the adjustment of the maximum levels of the analogue signals coming from the amplifiers. When the level of a certain analogue channel is over the maximum level, the equipment detects its saturation and the symbol 'detection of saturation' appears in screen.

Saturation icon
Saturation icon

This icon also appears when the burst signal (transporting the information about the color) does not contain information and therefore the images are in black and white.

In summary, this function is very useful, to identify problems related to the distortion or excess of amplification, that can occur in the mast, system or distribution amplifiers.

Safety margin

While carrying out gain adjustments at the antenna amplifiers on analogue channels, the amplifier could be saturating the signal. When this happens, the icon will appear in the left top corner on the screen.

In this case, it is necessary to reduce the gain of the amplifier and to reduce it until the icon disappears completely. Then it is recommendable to take reading of the signal level and to readjust the amplifier 3 dB below the value previously read.

Readjusting an amplifier

This procedure will provide a sufficient safety margin to guarantee the adjustment of each analogue amplifier to avoid saturation. Furthermore, it allows to determine the maximum gain to equalise the installation correctly. In this way, there will be a margin to avoid saturation conditions in case of an unexpected increase in the entrance signal level.

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PROMAX is a leading manufacturer of test and measurement systems, broadcast and TV signal distribution equipment. Our product lines include measuring instruments for cable TV, satellite TV, broadcast, wireless and fibre optics networks, FTTH and GPON analyzers. DVB-T modulators, IP streamers or IP converters (ASI, DVB-T) are among the company’s latest developments.