ATG429EBPOperationManual
4‐2
June4,2015
Rev.A2
The 429 Generator circuits send TTL level bit stream data to the Analog board, where it is converted to
the correct levels for output. The Generator is loaded and started by the Control circuits. The Generator
consists of the following components:
1. Digital drivers (U9)
2. Serial Register (1/2 U6)
3. Baud Clock/Bit Counter (U5)
4. Driver Enable (1/2 U8)
4.1.3 ANALOG BOARD
The Analog board contains the analog circuitry for the 429EBP. This circuitry has three major sections:
1. Power Circuits
2.
429 Receiver
3.
429 Driver
The Power circuits supply power to the system from one of two sources. If the battery charger is
disconnected, the circuits supply power to the system from the battery pack. The battery voltage is
monitored by the power circuits. Should the voltage drop to an insufficient level it is the power circuits that
will indicate this to the Control circuits. An indication of low power will be seen on the display board
should the afore mentioned conditions exist. If the charger is connected, the power circuits will supply
power to the system from the charger and will also trickle charge the NiCad batteries. The power circuits
consist of the following components:
1. Low Drop Out Regulator (U5)
2.
Voltage converter (U6)
3. Monitor (U7)
The 429 Receiver circuits convert ARINC 429 RZ transmitted signals from 10V levels (between A & B) to
TTL level signals for use by the 429 Receiver Buffer on the Digital board. The 429 receiver circuits consist
of a Comparator and a number of discrete components. The 429 driver circuits convert the TTL level
signal from the digital board into 10V (between A and B) ARINC 429 compatible signal levels.
The 429 Driver circuits consist of the following components:
1. "1" Driver (U2, Q1, Q2)
2. "0" Driver (U3, Q3, Q4)
3. Speed Switch (U1)
The battery Pack supplies power to the system and consists of the following components:
1. Battery Holder
2. Six (6) `AA' NiCad rechargeable batteries.
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