Installation; Connections; Theory Of Operation - Codan Cascade Operation Manual

36
Cascade Power Amplifier
I N S TA L L ATI ON
One or two power amplifiers can be inserted into the CASCADE subrack. The power amplifier is
fastened with two Phillips screws at the front of the subrack (see Figure 13).
C ON N E C TI ON S
The PA requires DC power from the 48V PSU which is supplied to the front of the PA. The ribbon
cable connector on the bottom front is used to communicate with the other components of the
CASCADE system. The input and sampled output signals are connected to the transceiver units via
short cables with SMA connectors. The output is delivered via a Type-N female connector at the back.
T H E O RY O F OP ER AT ION
The PA is designed to amplify an input signal with modulation characteristics that produce a spectrum
with a 5dB peak to average ratio with high fidelity when operated in a Cartesian loop. A further
requirement is that the output should be variable in 1W steps from 40dBm (10W) to 51dBm (125W)
nominal. This is accomplished by internal variable attenuators in the amplification path as well as in
the sampled output path setting up the appropriate power window for the Cartesian loop controlled
from the transceiver module.
The output voltage standing wave ratio (VSWR) is monitored, as well as the heatsink temperature.
Protective action is taken under severe thermal and VSWR, as well as fault conditions by the control
system.
Cascade System Modules Operation Guide
OG-CASC-SYS-MOD-1-0-0P
FIGURE 13: Power Amplifier Subrack Locations