Overview2-9
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.
BT100 Installation and Operation Manual
