Motorola Broadband House Amplifier BHA-100K/P-R - Manual (Page 14)

Overview 2-3
BHA-100* Broadband House Amplifier Installation Manual
Forward Amplifier
Figure 2-2 illustrates a functional block diagram of both the forward amplifier and the optional
return amplifier, and applies to all models.
Figure 2-2
BHA-100* functional block diagram
RF
output
Preamp
Postamp
Gain
Slope
Attenuator
(plug in)
Attenuator
(plug in)
Attenuator
(plug in)
Equalizer
(plug in)
Equalizer
(plug in)
-20dB
test point
+24Vdc
test point
-20dB
test point
-20dB
test point
Return amplifier
(plug in)
Switching
power
supply
+24Vdc
90-240Vac
2.5A/250V
5A/125V
H
L
H
L
RF
input
-20dB
test point
The forward amplifier consists of a low noise pre-amplifier followed by a power-doubled output
stage to achieve low distortion. Between the two stages there are gain and slope controls for
level adjustment.
The input signal level to the pre-amplifier is controlled by a vari-losser with a range of 6 dB.
The vari-losser is controlled by the GAIN potentiometer. A JXP-*B socket is also incorporated in
the signal path to further reduce input signal amplitude. SFE-100-* cable equalizers can be
installed in the socket to supplement the slope control network.
A –20 dB directional coupler test point at the amplifier input monitors forward input signal
levels. Directional coupler test points are also available to measure forward amplifier output,
return input, and return output signal levels.