When deploying the TRIAX EoC system into an existing Coax network, there could be circumstances where you will have to bypass the controller with the TV signal.
There is typically 2 situations:
1. In different situations it can be desirable to use frequencies in the G.hn range [2-200MHz]:
- TV in the low range, this could be analogue or digital
- Return signaling from VoD or other systems
2. Due to old coax cables and passive components, you would like to use frequencies below 300 MHz for TV signals. This is to reduce further attenuation of the TV signal.
You will then deploy the EoC system "parallel" to the existing Coax installation.
Lets first look at a "normal" installation the system (illustrated below).
- You will connect the TV signal to the EoC Controller - possibly compensating for the insertion loss on the Controller (32/2: ~5dB / 64/4: ~10dB).
- You will have the TV signal in the 300-862MHz range
- You will have the internet (G.hn) in the range from 2-200HMz range.
This setup gives you a 100% separation of the signals. Remember, the endpoints also transmits back to the controller with ~100dBµV !
Now - if you wish to bypass the controller you could introduce issues, if you aren't careful !
- The controller & endpoint transmits with ~100dBµV in the range 2-200MHz !
- TV signals are attenuated through the installation and often not as powerful as the G.hn signal (seen from the EP).
- Tuners in TV / STB has a "TV tuner Input Sensitivity Range" typically between ~43 - ~83dBµV. Signal levels higher than this range may cause inter modulation (bad/no picture quality on the TV / STB).
The EoC notch filter can be configured to clear G.HN signals in that area.
Doing this will pass the TV signals to the endpoint - but please bear in mind ... the EoC endpoint has a build-in filter on the TV output.
This filter is hardware based and cannot be adjusted/changed.
From the data sheet:
In order to use the frequencies below 300 MHz for TV signals, the TV signal must be extracted BEFORE the EoC endpoint.
This can be achieved by using a simple 2 way splitter ( fx. SCS 2 - 2 way splitter ) in front of the EoC endpoint.