NGT—Technical description (2011/2012)
NGT Transceiver System Technical Service Manual 127
Audio & Interconnect PCB (2011)/Audio Interconnect & Data I/O PCB (2012)
Under instruction from the Application Processor Handset I/F 3 V PCB
(2011)/Application Processor Handset & Data I/F PCB (2012), the microprocessor IC9
controls the audio routing via the analog switches, the RF unit diagnostic LED H1, and
the power off control. It also provides status information about the integrity of the
protected A rail voltage back to the Application Processor Handset I/F 3 V PCB
(2011)/Application Processor Handset & Data I/F PCB (2012).
The microprocessor is in Sleep mode when no data is present. When data is received
from the Application Processor Handset I/F 3 V PCB (2011)/Application Processor
Handset & Data I/F PCB (2012) over the 2-wire serial communications, the RC
oscillator starts to run and ‘wakes up’ IC9.
IrDA (2012 only)
IC22 is an IrDA transceiver that passes data to the application processor UART IC2.
RF/IF PCB
IC408 is in Sleep mode when no data is present. When data is received from Application
Processor IC4, the RC oscillator starts to run and ‘wakes up’ IC408.
IC408 then programs the phase lock loop and the DDS ICs depending on the channel
frequency required. It also controls the transmit/receive switching functions, filter select,
AGC time constants and other ancillary functions.
Filter and Control PCB
IC2 is in Sleep mode when no data is present. When data is received from Application
Processor IC4, the RC oscillator starts to run and ‘wakes up’ IC2.
IC2 then selects the correct filter for the channel in use, the PTT switching, high/low
power switching, fast/slow ALC time constant, average ALC on/off and fan control.
Also, in conjunction with R19, IC2 forms a DAC that produces the reference ALC
voltage. This is used to control the power versus frequency output level.
2011: Drawing 04-03425
2012: Drawings 04-03499 (sheet 1) and 04-03499 (sheet 2)
Drawings 04-03499 (sheet 1) and 04-03499 (sheet 2)
Drawing 04-03378 (sheet 3)
NOTE If the PCB issue status is -06 or earlier, see drawing 04-03378 (sheet 3).
Drawing 04-03369, or
Drawing 04-03542
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