Technical description of -300 Symbol Generator

[mxmxmx]

I had a discussion about the functioning of the Symbol Generator (SG) for the EFIS (EADI and EHSI) of the 737-300, so I'm looking for a technical description of it. What's written in the flight manual is not detailed enough.

Anyone willing to share his information with me? The more detailed the better.

Thanks in advance,
Chris

[Boeing 737-Fan]

Hello Chris,
i have some informations from my Training Letters. I hope thät helps you

Have a nice day
Manuel

General
The EFIS symbol generator receives data from the EFIS control panel and the
airplane’s navigation and guidance systems. The symbol generator then processes
the data and provides video signals for display on the EADI and EHSI.
The input data is received on ARINC 429 low speed and high speed data
buses, as well as ARINC 453 weather radar high speed buses, and discrete
inputs.
A symbol generator can supply all display units. However, in this case captain’s
displayed data and FO’s displayed data are the same.

Most of the parameters displayed on the EADI and EHSI utilize signals that
originate from various systems on the airplane. However, the display of a number
of parameters requires computations based on inputs from several systems.
The computations for these parameters are performed by the symbol
generator.
The symbol generator computed displays are as follows:

Airspeed trend vector

DH alert

Altitude alert

Curved trend vector

NAV/IRU position difference

Range disagreemement message

Course deviation and TO/FROM indication