Ericsson 19D901841G2, Руководство по обслуживанию

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Printed in U.S.A.
MAINTENANCE MANUAL
851-870 MHz, 100 WATT POWER AMPLIFIER
19D901841G2
TABLE OF CONTENTS
Page
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Cover
CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Cover
Power Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Cover
Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
INTERCONNECTION DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
OUTLINE DIAGRAMS
Power Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Power Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SCHEMATIC DIAGRAMS
PowerAmplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Power Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
DESCRIPTION
The 800 MHz power amplifier assembly used in station
applications uses five RF power transistors to provide a
maximum of 100 watts output power. R11 on the Power
Control Board (19D901803G3) provides adjustment of the
output power over a 10 dB range (10W to 100W).
The power amplifier assembly consists of an RF board
with all the amplifier stages and an output detector, a power
control board, and an isolator.
Supply voltage from the system board is connected to
TB1 and decoupled by C6.
CIRCUIT ANALYSIS
POWER AMPLIFIER
The exciter output (65-130 mW) is coupled to the ampli-
fier input connector J1 by a 50 ohm coaxial cable. L1, C1,
C2, and the base microstrip form the input matching circuit
for Q1. Control voltage is applied to Q1 through a collector
feed network consisting of C3, C4, and L3.
Interstage matching between Q1 and Q2 is provided by
L4, L5, C6, C8, C9, and C10. Control voltage is applied to
Q2 through a collector feed network consisting of Z1, C11-
C13, and L7. The output of Q2 is matched to the input of Q3
by L8, L9, C30, C15, and the base microstrip.
Supply voltage for Q3 is applied through collector feed
network Z2, C16-C18, and L11. The output of Q3 is matched
to 50 ohms by microstrip W2. This output is applied to a
Wilkinson divider consisting of microstrips W4 and W5. R1
provides isolation between the signal paths.
Input matching for Q4 and Q5 is provided by microstrips
W8 and W9. Supply voltage is applied to Q4 and Q5 by
collector feed networks Z3, Z4, C20-C25, L12, and L13.
Microstrips W12 and W13 provide output matching.
The outputs of Q4 and Q5 are summed by a Wilkinson
combiner consisting of W16, W17, and R3. The output of the
combiner is connected to pin 1 of circulator U1.
LBI-38134C