TABLE OF CONTENTS
Page
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Cover
GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
INPUT MATCHING NETWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
CRYSTAL FILTERS, IF AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
OSCILLATOR/MIXER/DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
AUDIO AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SQUELCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
Buffer Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
High Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
Noise Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
DC Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
Schmitt Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
FAULT DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
VOLTAGE REGULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
RECOMMENDED TEST EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
ALIGNMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
OUTLINE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
PRODUCTION CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
IC DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
MAINTENANCE MANUAL FOR
25kHz RECEIVER IF MODULE
19D902783G1
DESCRIPTION
The MASTR III Receiver IF Module provides ampli-
fication and demodulation of the 21.4 MHz Intermediate
Frequency signal. The IF Module also includes the re-
ceiver squelch circuitry. However, it does not include de-
emphasis or squelch audio gating circuits. Figure 1 is a
block diagram showing the functional operation of the
IF Module.
The IF Module circuitry contains the following:
•
A 50 ohm input impedance matching network and
IF Amplifier
•
A chain of two crystal filters and two integrated
circuit IF amplifiers
•
An integrated circuit containing a crystal
oscillator, mixer, limiter, and quadrature detector
•
A variable gain AF amplifier
•
A squelch circuit
•
A fault detector circuit
•
An integrated circuit voltage regulator
LBI-38643C
ericssonz
Ericsson Inc.
Private Radio Systems
Mountain View Road
Lynchburg, Virginia 24502
1-800-528-7711 (Outside USA, 804-592-7711)
Printed in U.S.A.
Summary of Contents for 19D902783G1
Page 6: ...SCHEMATIC DIAGRAM RECEIVER IF MODULE 19D902494G1 19D902504 Sh 1 Rev 6 LBI 38643C 5...
Page 7: ...SCHEMATIC DIAGRAM RECEIVER IF MODULE 19D902494G1 19D902504 Sh 2 Rev 6 LBI 38643C 6...
Page 42: ...RECEIVER FRONT END BOARD 19D902490G4 G7 OUTLINE DIAGRAM 19D902490 Sh 4 Rev 6A LBI 38673F 5...
Page 43: ...ASSEMBLY DIAGRAM RECEIVER FRONT END MODULE 19D902782G3 19D902782 Sh 1 Rev 6 LBI 38673F 6...
Page 44: ...ASSEMBLY DIAGRAM RECEIVER FRONT END MODULE 19D902782G4 G7 19D902782 Sh 2 Rev 6 LBI 38673F 7...
Page 45: ...SCHEMATIC DIAGRAM RECEIVER FRONT END MODULE 19D902782G4 G7 19D904768 Sh 1 Rev 6 LBI 38673F 8...
Page 47: ...SCHEMATIC DIAGRAM RECEIVER FRONT END MODULE 19D902782G3 19D903498 Rev 7 LBI 38673F 10...
Page 48: ...This page intentionally left blank LBI 38673F 11...
Page 56: ...ASSEMBLY DIAGRAMS LOW PASS FILTER MODULE 19D902856G3 19D902856 Sh 1 Rev 0 LBI 38674F 7...
Page 71: ...ACCESSORIES ANTENNA SWITCH 19B235897P2 LBI 38675E 9...
Page 80: ...SCHEMATIC DIAGRAM RECEIVER IF MODULE 19D902494G7 G11 193D1065 Sh 1 Rev 3 LBI 39123E 7...
Page 81: ...SCHEMATIC DIAGRAM RECEIVER IF MODULE 19D902494G7 G11 193D1065 Sh 2 Rev 3 LBI 39123E 8...
Page 82: ...SCHEMATIC DIAGRAM RECEIVER IF MODULE 19D902494G7 G11 193D1065 Sh 3 Rev 3 LBI 39123E 9...
