Samsung Electronics
4-5
Circuit Description
4-3 Transmitter Section
POWER AMP MMIC
Power Amp MMIC (U407) amplifies signal to be
sent out to the base station through the antenna.
DRIVER AMP
The driver amp (Q413) allows the input signal to
the power amp MMIC(U407) to be within a
specified level.
UP CONVERTER (MIXER)
The up-converter (U405) receives the first local
signal to generate 1880
°æ
30MHz from the signal
controlled by TX AGC amp (U404). 1880
°æ
30MHz
signal comes out of the mixer output by adding
130.38MHz IF signal to 1749.62
°æ
30MHz first local
signal. The driver amp's reference number is Q413
and up converter's reference number is U405.
IF AUTOMATIC GAIN CONTROLLER AMP
The signal output from BBA (Base Band ASIC)
should be a constant level. The TX IF AGC amp
(U404) controls power to keep the signal at a
desired level. Dynamic range is 85 dB, up gain
+40dB, and down gain -45dB.
POWER SUPPLY REGULATOR
The power supply regulator (U414) generates the
regulated power.
ANTENNA
ANT1 allows signals to send and to receive to
from the base station.
RF BAND PASS FILTER (BPF)
The RF BPFS (F402, F403) accept only a specific
frequency (1880
°æ
30MHz) to send it out to power
amp MMIC. The bandwidth is 60MHz.
POWER SUPPLY SWITCHING
Power supply switching (Q412) turns on TX
POWER when the phone is in traffic mode and
supplies power to the circuits.
ISOLATOR
Isolator (I401) is used to reduce a reflected signal
to protect the power amp MMIC from being
damaged.
POWER SUPPLY REGULATOR
The power supply regulator (U413,U414) supplies
a regulated power to each part of transmitter.
U413 supplies 4.8V to Tx driver (Q413) and Power
Amp MMIC (U407). U414 supplies 4.2V to the
others.
Summary of Contents for SCH-1900
Page 2: ...Samsung Electronics Co Ltd GH68 60620A Printed in Korea ...
Page 27: ...Samsung Electronics 6 1 6 Troubleshooting 6 1 Logic Section 6 1 1 No Power ...
Page 29: ...Samsung Electronics 6 3 Troubleshooting 6 1 3 Abnormal Backlight Operation ...
Page 30: ...Troubleshooting 6 4 Samsung Electronics 6 1 4 Abnormal Key Data Input ...
Page 31: ...Samsung Electronics 6 5 Troubleshooting 6 1 5 Abnormal Keytone ...
Page 32: ...Troubleshooting 6 6 Samsung Electronics 6 1 6 Abnormal Alert Tone ...
Page 33: ...Samsung Electronics 6 7 Troubleshooting 6 2 Transmitter Section ...
Page 34: ...Troubleshooting 6 8 Samsung Electronics ...
Page 35: ...Troubleshooting 6 9 Samsung Electronics 6 3 Receiver Section ...
Page 36: ...Troubleshooting 6 10 Samsung Electronics ...
Page 37: ...Samsung Electronics 6 11 Troubleshooting ...
Page 39: ...Troubleshooting 6 13 Samsung Electronics 6 4 2 No Power HHP PWR 5 8V 13 5V Supply ...
Page 40: ...Samsung Electronics 6 14 Troubleshooting 6 4 3 Hands Free RX Path ...
Page 41: ...Troubleshooting 6 15 Samsung Electronics 6 4 4 Hands Free TX Path ...
Page 42: ...Samsung Electronics 6 16 Troubleshooting 6 5 Desk Top Rapid Charger ...
Page 43: ...Troubleshooting 6 17 Samsung Electronics 6 6 Cigarette Lighter Adapter 6 6 1 Power Fault ...
Page 44: ...Troubleshooting 6 18 Samsung Electronics 6 6 2 LED On Fault ...
Page 45: ...Troubleshooting 6 19 Samsung Electronics 6 6 3 Charge Fault ...
Page 46: ...Troubleshooting 6 20 Samsung Electronics 6 7 Travel Charger ...
Page 48: ...Exploded View and its Parts List 7 2 Samsung Electronics 7 1 Main Set Exploded View ...
Page 50: ...Exploded View and its Parts List 7 4 Samsung Electronics 7 3 Hands Free Kit Exploded View ...
Page 58: ...Exploded View and its Parts List 7 12 Samsung Electronics 7 11 Main Set Packing Layout ...
Page 60: ...7 14 Samsung Electronics Exploded View and its Parts List 7 13 Hands Free Kit Packing Layout ...
Page 62: ...7 16 Samsung Electronics Exploded View and its Parts List ...
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Page 100: ...10 2 Hands Free Kit Block Diagram ...
Page 101: ...10 3 Desk Top Rapid Charger Block Diagram ...
Page 102: ...10 4 Cigarette Lighter Adapter Block Diagram ...
Page 103: ...10 5 Travel Charger Block Diagram ...
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