http://milestek1553.com/blog Just another WordPress weblog Wed, 19 Aug 2009 17:30:13 +0000 http://backend.userland.com/rss092 en Trusting MilesTek to be your provider for Military-Grade cabling requirements and components can easily be justified by the trust placed in us by our vendors and manufacturers.  MilesTek is an approved supplier for many Tier I and Tier II Defense and Aerospace companies, including:   Boeing,  Lockheed Martin, Raytheon, Rockwell Collins, ... http://milestek1553.com/blog/index.php/2009/08/milestek-quality/ In 2009, Trompeter Electronics appointed MilesTek as an authorized distributor.  With more than three decades of Trompeter experience, MilesTek’s expertise is unequal to any other distributor.  The service provided by MilesTek is a compelling reason why customers should choose MilesTek for their Trompeter requirements.  The key attributes are because MilesTek Possesses ... http://milestek1553.com/blog/index.php/2009/07/why-buy-trompeter-products-from-milestek/ The digital data bus MIL-STD-1553 was published in 1973 to replace analog point-to-point wire bundles between electronic instrumentation. Revision A to the standard was issued in 1975 as a tri-service standard.  After two years effort by a SAE task group, Revision B was published as a tri-service/NATO standard in 1978.  ... http://milestek1553.com/blog/index.php/2009/06/what-is-the-legacy-of-the-mil-std-1553/ The MIL-STD-1553B bus has four main elements: (1) a bus controller that manages the information flow; (2) remote terminals that interface one or more simple subsystems to the data bus and respond to commands from the bus controller; (3) the bus monitor that is used for data bus testing; and ... http://milestek1553.com/blog/index.php/2009/06/what-are-the-physical-characteristics-of-mil-std-1553b/ The data bus LAN topology encompasses: • Bus couplers (coupling transformers with fault-isolation resistors) • Bus terminators • Twinax cable (shielded twisted pair) • Concentric twinax connectors (with a center contact and an intermediate cylindrical contact) http://milestek1553.com/blog/index.php/2009/06/what-are-the-integral-hardware-pieces-of-a-typical-data-bus/ If a terminal device has internal isolation resistors and transformers, then direct coupling is possible to the bus cabling without the use of bus couplers. Direct coupling connections must only be used with stub lengths of less than 1 foot.  However, MIL-STD-1553B cautions the employment of direct coupling because a ... http://milestek1553.com/blog/index.php/2009/06/are-bus-couplers-necessary/ Bus couplers are available in various stub configurations including: • Box type (used in lab or vehicle applications) • In-line type (used in vehicles where light weight and small size are important). http://milestek1553.com/blog/index.php/2009/06/what-type-of-bus-couplers-are-available/ According to MIL-STD-1553B, the bus must be terminated at both ends of the cable with resistors equal to the cable characteristic impedance.  The purpose of termination is to minimize the effects of signal reflections that can cause waveform distortion.  If termination is not used, the communications signal can be compromised ... http://milestek1553.com/blog/index.php/2009/06/why-does-the-bus-need-termination/ In a lab application, unused stub ports on the coupler need not be terminated since the stubs have higher impedance than the bus.  A high-impedance terminator (1000 to 3000 ohms) is sometimes used in vehicle applications to simulate a future load from an unspecified device. In both cases, an RFI ... http://milestek1553.com/blog/index.php/2009/06/should-the-stub-ports-be-terminated/ Although MIL-STD-1553B specifies that the data bus should have a characteristic impedance between 70 and 85 ohms, industry has standardized on 78 ohms. http://milestek1553.com/blog/index.php/2009/06/what-is-the-characteristic-impedance-of-the-bus/