Test loop translator: Difference between revisions

Revision as of 14:13, 8 November 2015

Revision as of 19:35, 8 January 2016

Line 1:

{{Orphan|date=February 2015}}

[[File:TLT.jpg|thumb|upright=1.8|Tampa Microwave Lab, Inc. LTT-03-1RU-107 Test Loop Translator]]

A '''test loop translator''' ('''TLT''') is a type of [[radio frequency]] converter or [[heterodyne]], used to translate between [[Telecommunications link|uplink and downlink]] segments (generally in the same band), to allow for "loop-back" testing and calibration of a satellite [[ground station|ground segment]] without the need to interface with the [[satellite]].<ref name=novella>{{cite web|title=Test Loop Translator|website=http://www.novella.co.uk/test_loop_tech.htm|publisher=Novella Satcoms Ltd.|accessdate=23 February 2015}}</ref><ref name=atlantic>{{cite web|title=Model ASC 710C Test Loop Translator|url=http://atlanticsat.com/ASC710C.htm|publisher=Atlantic Satellite Corporation|accessdate=23 February 2015}}</ref>

The test loop translator is an extremely valuable tool for evaluating the performance of satellite earth stations. It allows the user to carry out analysis, alignment and testing without incurring satellite airtime costs and the risk of interfering with other satellite users. Thus, it has applications during equipment development, qualification, trouble-shooting and in-service routine monitoring.<ref name="Loop Test Translators for Satcom Systems">{{cite web|title=Loop Test Translators for Satcom Systems|url=http://www.atlantecrf.com/pdf_downloads/MJ%20Article%20-%20Loop%20Test%20Translators.pdf|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref>

TLTs generally contain a fixed or preset [[local oscillator]] and a preset [[Gain (electronics)|gain]], though the LO and gain may be adjustable in some models.<ref name=novella/> Most models have a negative gain (i.e., a loss), with -15 [[decibel|dB]] being the most common.<ref name=novella/>