COFDM reception Low Noise Preamplifier
LNA –Low-Noise Amplifier
MANUAL V5
1Description
The very low noise preamplifier for COFDM signals offers its best
performance with COFDM digital links. Also, it can be used with analogue
links. This LNA is very useful for Broadcast applications and air links.
This equipment expands the possibilities of existing COFDM digital links,
because with it, the noise figure of the receivers is improved. The selectivity
is also increased and it compensates the attenuation caused by the coaxial
cable between the antenna and the receiver.
It has two radiofrequency filters: one selective at the input with 5 poles,
which enables it to work in the most adverse radiofrequency environments
and other between the amplifier’s stages.
The COFDM low noise preamplifier uses PHEMT technology and 90º hybrid
couplers to ensure excellent linearity. The third order intermodulation
products (IP3) are +33 dBm, which means they have no problem working
with strong COFDM signals modulated in 64QAM.
The LNA preamplifier for COFDM signals has an excellent noise figure and
so, link sensitivity is increased, thus improving coverage and reliability.
It has a good input adaptation, eliminating undesired self-oscillations.
The LNA is powered through the output coax. For it, a bias insertion tee
(BIAS-TEE) can be used.