Nautel NV30LT-N, Руководство по эксплуатации и техническому обслуживанию

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NV30LT-N OPERATIONS & MAINTENANCE MANUAL DESCRIPTION
VERSION 0.1 2015-03-01 PAGE 3.1.7
20 kW Combiner
The 20 kW combiner (A25) accepts the RF outputs from two of the three 10 kW combiner/filters (A12
and A24) and uses a 3 dB hybrid coupler to provide a single RF output. The combined (up to 20 kW)
output is applied to the final 30 kW combiner (A26).
Any amplitude or phase imbalances between the 3 dB hybrid coupler inputs cause a proportional signal
to be applied to the 2-input reject load assembly (A13). The amplitude of the
20 kW Rej Ld Pwr (1-8)
signal (via J1 of the 20 kW combiner) represents imbalance between the 20 kW combiner inputs.
30 kW Combiner
The 30 kW combiner (A26) accepts the RF outputs from the 20 kW combiner/filter (A25) and the 10 kW
combiner/filter (A40) and uses a 4.77 dB hybrid coupler to provide a single, final RF output. The
combined output is applied to the transmitter’s RF output, via the output power probe (A15).
Any amplitude or phase imbalances between the 4.77 dB hybrid coupler inputs cause a proportional
signal to be applied to the 2-input reject load assembly (A13). The amplitude of the
Final Rej Ld Pwr
(1-12)
signal (via J1 of the 30 kW combiner) represents imbalance between the 20 kW and 10 kW
combiner inputs.
4-Input, 5 kW Reject Load Assemblies
The 4-input, 5 kW reject load assembly (A29) provides a means to dissipate reject power from eight of
the 12 (5 through 12)
5kW Rej Ld Pwr
outputs of the 10 kW combiner/filters’ 3 dB hybrid couplers. Each
assembly contains power resistors to dissipate reject power. Cooling air for the reject load assembly is
provided by fans B9, B10 and B11. The control/monitor stage monitors the speed of the cooling fans
and regulates the voltage being applied to them accordingly.
Reject power generated by the first (5 kW) combining stage of the 10 kW combiner/filters is dissipated
by resistors in the 4-input 5 kW reject load assemblies. Micro-strip transmission lines (on 4-input reject
load PWB A29A1) in close proximity to the reject load signals induce true RF sample voltages of the
associated reject power. These samples are peak detected and applied to the control/monitor stage via
the reject load/splitter interface assembly (A30). The reject load/splitter interface assembly provides an
interface between the ac-dc power stage’s Rej Fan Volts supply and the cooling fans. It also acts as the
interface between the cooling fans’ Rej Fan Tach signals and the control/monitor stage.