Global Features; Transceivers And Isolation Transformers; Time Tags; Local Timer - DDC Total-AceXtreme MIL-STD-1553 Design Manual

4

GLOBAL FEATURES

4.1

Transceivers and Isolation Transformers

The transceivers in Total-AceXtreme® series terminals require only +3.3 power. The
transmitter sections satisfy the MIL-STD-1760 requirement for a minimum of 20 volts
peak-to-peak, transformer coupled output. The transceivers are very low power, and
dissipate less than 0.5 Watts Max when transmitting.
The receiver sections of the Total-AceXtreme are fully compliant with MIL-STD-
1553B Notice 2 in terms of front end overvoltage protection, threshold, common-
mode rejection, and word error rate.
The Total-AceXtreme integrates two isolation transformers from Beta Transformer
Technology Corporation.
As an alternative to using the internal transceivers and transformers, it is possible to
operate the Total-AceXtreme with external electrical or fiber optic transceivers. For
information about this, refer to section 8.2.
4.2

Time Tags

In BC, Multi-RT, and MT modes, the Total-AceXtreme stores time tags associated
with all processed MIL-STD-1553 messages. The Total-AceXtreme provides two
sources for the relative time tags: a local timer with hardware support for the 1553
Synchronize mode codes, along with a digital IRIG-B input. The IRIG-B input
supports applications where accurate synchronization with other devices is required.
4.3

Local Timer

The Local Timer is a free-running 48-bit binary counter that is maintained locally by
the Total-AceXtreme. It can optionally be modified under full host control or be set
up to automatically update in response to "Synchronize" and "Synchronize with data"
messages received from the 1553 bus. In BC mode, "Synchronize with data"
messages can be configured to send the lower 16 bits of the current value of the time
tag as the data word. Timer resolution and overflow frequency can also be
programmed. Refer to the AceXtreme Architectural Manual for a full description on
how to use the Local Timer.
4.3.1 IRIG-B Timer
The Total-AceXtreme includes a digital IRIG-B input that can be used to synchronize
the time tags used by the 1553 interface with external devices. The IRIG-B input will
receive and synchronize to a new time-code once per second.
Data Device Corporation
www.ddc-web.com
22 DS-BU-67301B-G
1/14