What is a Gap Filler?
|ITELCO MEX II||Gap Filler / Repeater||10 / 25 W|
|ITELCO IEC||Gap Filler / Repeater||50 / 100 / 200 W|
The main transmitter on the left side is transmitting as normal but the mountain in the middle blocks that signal from being received at the home on the right
Why use Itelco Gap Filler?
The Gap Filler is installed on the top of the mountain, with the receive antenna directed towards the main station, and the transmit antenna toward the home
The two antennas must be isolated as much as possible in order to limit the Echo effect
Echo Cancellation and Complex FIR System
EXTREMELY LOW QUALITY DEGRADATION
Since the Gap Filler is transmitting on the same frequency as it is receiving, there is a tendency for the transmitted signal to overwhelm the main station signal. There is an “Echo” signal from the transmit antenna which can cause deterioration of the received signal.
The Elenos Group (ProTelevision and Itelco) engineers cooperated with Nokia and five full time university professors at the Institute of Applied Mathematics in St. Petersburg, Russia.
We patented a complex FIR system which senses what the Gap Filler transmits, it derives an error correction term and applies it in real-time to the received signal. This extremely reduce the negative echo effect, for a high quality transmission.
How does the echo cancellation work?
The coefficients of this filter are continuously calculated and updated so that the transfer characteristics assemble those of the real physical channel from the transmitting to the receiving antenna.
Max Loop Gain
with Stable Operation
- Input signal level
- Isolation between antennas
- Gap filler output power
The loop gain is the difference between the RF input wanted signal and the “residual part of the echoes”.
Example: If the RF input wanted received signal -50 dBm, in order to transmit 100W (50dBm) it is necessary to have an antenna isolation of 80dB. This value is 30dB higher that the received signal. In order to transmit higher power (ERP) it is necessary to increase the antenna isolation (IS).
Use gap filler in Single Frequency Network (SFN)
Broadcast spectrum is a finite and valuable resource and, for this reason, digital networks are often operated as single frequency networks (SFNs).
But SFNs aren’t perfect in analog systems because analog signals interfere with each other, even if the content is identical and the frequencies are synchronized.
However, in digital systems, overlapping transmitters can share the same frequency, without need to use two frequencies.
The Elenos Group Gap Filler has a very short internal delay which allows you to easily manage Single Frequency Networks.
The Gap Filler can clean and obtain a pure output spectrum from multiple Single SFNs (Single Frequency Networks)
The Itelco gap filler uses sophisticated internal algorithms for the predictions of the antenna movement / vibrations, due to winds, to reduce the unwanted Doppler effect.
8 reasons to choose our gap filler
Innovation and Experience
Elenos Group’s Gap Filler is the result of a massive engineering and testing program.
We tested a transmission site with TerraCom in Sweden where we installed the Gap Filler and run it for over a year.
We controlled the behavior of the antennas in the wind so that we could physically model and optimize the system under real-world conditions.
Since long time, a lot of our gapfiller(s) are in service in several government and private networks, domestic or foreign, including Rai Way (Italy) and all our customer are extremely satisfied.
The system was written into firmware on the embedded ProTelevision hardware platform (an RF SuperComputer built on 16 layer printed circuit board with 2,200 electronic components), integrated in each gap filler.
Would you like to learn more? Contact us
The product is used to make signal coverage uniform, so it is perfect for networks that have minimum coverage percentage obligations or small shady areas such as valleys or cities with tall buildings.
MEX and IEC Gap-filler with echo cancelling (option) completes Itelco transmitter lines.
Contact us to connect with our team and receive a Gap Filler solution custom offer.