Ericsson EF738 Service Manual page 147

Technical Description
Logic Design ______________________________________ 24
Audio Design ______________________________________ 27
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GUSTAV ________________________________________________24
Circuit Description ___________________________________________ 24
6303 ____________________________________________________ 24
ROM ___________________________________________________ 24
RAM ___________________________________________________ 24
Bus Interface _____________________________________________ 24
Decoder _________________________________________________ 25
Serial Interface____________________________________________ 25
External Ports_____________________________________________ 25
WatchDog On/Off _________________________________________ 25
IFC _____________________________________________________ 25
BAR ____________________________________________________ 25
Clock Generator___________________________________________ 25
Internal Ports _____________________________________________ 26
Modem __________________________________________________ 26
Baud Clock ______________________________________________ 26
I2C Controller ____________________________________________ 26
FLASH EPROM __________________________________________26
EEPROM ________________________________________________26
Receive Audio Circuit Description ___________________________27
Receive Audio Interface _______________________________________ 27
De-Emphasis Network ________________________________________ 27
RXSENSE Programmable Gain Stage ____________________________ 27
Receive Bandpass Filter _______________________________________ 27
Expandor Gain ______________________________________________ 28
RX HF Attenuation ___________________________________________ 28
RX Volume Control __________________________________________ 28
EARSENS Programmable Gain Stage ____________________________ 28
Externally Programmable Gain Stage_____________________________ 28
Earpiece Driver ______________________________________________ 29
AFMS _____________________________________________________ 29
Transmit Audio Circuit Description __________________________29
ATMS _____________________________________________________ 29
Microphone Input ____________________________________________ 29
Soft Limit __________________________________________________ 30
INPSENSE Programmable Gain Stage____________________________ 30
Transmit Bandpass Filter ______________________________________ 30
TX HF Attenuator ____________________________________________ 30
Compressor _________________________________________________ 30
Pre-emphasis ________________________________________________ 30
Hard Limit__________________________________________________ 31
Transmit Lowpass Filter _______________________________________ 31
AUDIODEV Programmable Gain Stage __________________________ 31
Summing Amplifier __________________________________________ 31
TXSENSE Programmable Gain Stage ____________________________ 31
Low Voltage Detect Circuit _________________________________31