Codan Interconnect Bus Transmit Path; Rf Unit-Audio Interface Pcb Transmit Path - Codan NGT 2010 RF Technical & Service Manual

Codan Interconnect Bus transmit path

The CIB is an 8-wire bus that connects all the units in the system together:
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RF unit—Audio Interface PCB transmit path
Drawing
The Transmit TDM SYS audio from the CIB goes to IC7/B. IC7/B then converts the
push-pull audio to single-ended audio so that the correct audio channel is sampled by
IC6/D.
C21 is the hold capacitor, and IC7/A, IC8/A and IC8/B form a 5-pole Chebyshev
reconstruction filter with a nominal cutoff frequency of 3 kHz. The filtered audio then
goes to the Application Processor PCB via ADC AUX IN.
NGT Transceiver System Technical Service Manual
SYS AUDIO+/–: The audio is TDM balanced, as described in the previous section.
SYS DATA+/–: The data uses CAN protocol. This protocol has good error-detection
capabilities and performs well in high-noise environments. The data rate on the CIB
is 125 kbps.
STBY: Standby power is a 100 mA, 6 V DC continuous supply. This is used to
backlight the key at night.
A PROTECTED: The Protected A rail is an unregulated battery supply that is used
to supply power to all the units in the transceiver system. The maximum current that
this can supply is 2 A. If very long runs of the CIB cabling are required, an external
supply may be connected to the junction box to supply power locally.
PWR ON: The power on line is used to switch on the transceiver when the line is
grounded (see page 70, Power
GND: Ground is the supply return wire and is connected to the negative terminal of
the battery.
04-03109
on).
NGT—Technical description (2010)
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