During a homologation activity of the RTN950-V1R1C02, it was necessary to measure the transmission frequency of an ODU. However the equipment does not have the function to suppress the carrier signal using a direct command of the management software’s, due to this, the frequency meter was not able to measure the TX-frequency because the signal is not steady enough to be measured.
In order to achieve this measure, it is necessary to remove from the signal under test the carrier component. Therefore, making an outloop over IF interface we are removing the carrier signal and the signal under tested is just the transmission oscillator clock of the radio. Using this procedure the frequency meter is able to make the measurement properly.
The frequency meter is not able to measure the transmission frequency because the signal under tested is not a perfect wave product just by the oscillator clock of the radio; instead of this the signal is also carrying the carrier and that’s why we cannot measure this parameter.
Procedure to measure the transmission frequency at an ODU:
Set frequency and power parameters of the link
Mute the ODU which is going to be under test
Connect the frequency meter (be sure that the transmission power is not higher than the maximum value accepted for the equipment)
Unmute the ODU
Make an outloop over IF interface
Make the transmission frequency measurement over the ODU under test