Motorola BT100 - Manual (Page 20)

Overview 2-9
BT100 Installation and Operation Manual
The factory provides 20-ampere fuses to power additional amplifiers. Figure 2-9 illustrates the
location of these fuses. Power to each output port is also provided through 20-ampere fuses. You
can remove the fuses to eliminate power at any of the ports.
Figure 2-9
Fuse locations
Forward Path
The forward path of the amplifier provides an operational gain of 42 dB. The operating gain
includes provisions for the insertion loss of the input cable equalizer and required reserve gain
to operate the Bode equalizer in the middle of its range.
The standard four output forward path’s electronics consist of four parallel three-stage paths
consisting of: (1) pre-amplifier (input hybrid), (2) intermediate amplifier (midstage hybrid), and
(3) power-doubling output hybrid. The first two stages are common to both paths. The
pre-amplifier stage provides a low noise figure while the output stage contributes the preferred
power at low distortion. The amplifier input provides a facility to install a cable equalizer and a
socket for a model JXP-*B attenuator. The attenuator and equalizer are customer installed
options.
Several circuits comprise the mid-stage amplifier. The Bode equalizer is a voltage-controlled
device that receives its input from the manual gain control, the automatic drive unit (ADU-*),
the QAM automatic drive unit (QADU-*), or the thermal drive unit (TDU). Following the Bode
board, the BDR controls response flatness and provides equalization and a JXP pad facility
adjusts the RF level into the mid-stage hybrid amplifier. Because these losses are located
interstage, the noise figure is only significantly impacted by the insertion loss of the forward
cable equalizer or a broadband cable simulator.
To increase tilt after the midstage amplifier, there is a mid-stage equalizer, model MEQ-100-*.
Following this MEQ-100-* and various splitters, there are JXP-*B pad sockets leading into the
power-doubling output stage. The number of pads depends on the number of outputs configured.