Then,
input level = 10log(# actual channel's) - mfg. rec. level
I hope that this helps. Also remember that whenever you use half (50%) of the maximum channel loading (100%), you have a 3dB difference in overall input. This means you could increase the input by 3dB.
EXAMPLE: You have a DFB laser with a maximum input 15dBmV with 80 NTSC channels per the manufacturer spec's.
In reality, you only have 40 active NTSC channels. Since you have half channel loading (50%), you should increase input by 3dB to 18dBmV for better c/n performance.
If you have 20 channels, ditto. Another 3dB difference to 21dBmV input.
Just like a 2-way splitter. You split the input in half, you lose 3.01dB in theory. Reality you lose 3.4 - 4.0dB depending on the quality and frequency of the splitter. In optical input power, you are much closer to that 3.01dB theory number than with coaxial splitters.
Good luck!
> Help! What is the formula for figuring a power level based on channel loading,e.g. I am allowed a maximum RF input level of +60dBmV on a device based on 1 NTSC channel loading and have 118 analog channels, what is my maximum allowable input level? THIS IS JUST AN EXAMPLE, I AM LOOKING FOR FORMULA.
> Thanks for your help.
