Applications
2.9.2
2.9.3
2.9.4
ABSOLUTE LEVEL OF TRANSMIT TONE
1.
The absolute level coming out of the transceiver and going to the amplifier is not that critical
because the gain of the amplifier is set to give the correct level out of the amplifier. The typical
peak level out of the transceiver is +12.75 dBm @ 50 Ohms.
2.
In a single RF channel system an F6 tone will be at +12.75 dBm @ 50 Ohms at the output of
the transceiver.
3.
The gain of the amplifier is set using pot R83. This must be adjusted to ensure that the
transmitted level will not exceed the maximum output compliance of the amplifier, which is
+47 dBm into 50 ohms or 50 Vrms for a 50 Watt system, for that reason, the peak-to-average
relation of a QAM signal must be considered when setting the amplifier gain.
ABSOLUTE RECEIVE LEVEL
1.
After the hybrid is balanced, the absolute receive level into the transceiver should be adjusted
using R10 on the line board. It should be set so the pilot tone in an 8 KHz system is -20 dBm
@ 50 Ohms.
2.
In order for the Xcvr to properly calculate the receive levels, the remote Xcvr Voice level and
Signaling level must be manually entered into the RF Setup section of the NMS software prior
to a write operation.
3.
The RX AGC set point should be set to -1,5 for a better performance of the teleprotection
function.
ALARM LEVEL SETTING
1.
The current gain should be entered as the nominal gain in the Rx Screen of the RFL 9508D
NMS. It can be in the range of 0 to 75 dB. The current gain value, which can be seen using the
monitor feature, should be reentered as the nominal gain in order to set the alarm threshold.
The low signal alarm will occur when the current gain has exceeded the LOS threshold.
RFL 9508D UCC
RFL Electronics Inc.
July 1, 2007
2-11
(973) 334-3100