RADAR TEST SET
EQUIPMENT DESCRIPTION AND DATA - Continued
The TS-4530/UPM illuminates the green ACCEPT indicator or the red REJECT indicator to indicate the status
of the transponder or interrogator unit under test. This section contains the criteria used by the host processor
in the TS-4530 to make the accept/reject decision. The host processor makes these decisions based on
information from the DSP processor. The DSP processor performs an initial pre-screen of the signals from
the transponder or interrogator unit under test. A gross failure of the unit under test will usually result in an
indication of No Reply that would cause the red REJECT indicator to illuminate. In this case, additional
information about the unit under test (such as reply delay or transmitter frequency) would not be available
since no replay is available to measure.
The following is a list of characteristics of the transponder or interrogator system that are measured by the
Test Set. These measurements are available to the user:
Mode S aircraft address
Mode C altitude
Mode S uplink / downlink type
Refer to Test Set Operating Instructions (WP0006 00) for a more detailed description of accept/reject
decisions made by the user. Refer to the Theory of Operation section for hardware related details.
All measurements are performed on replies from the transponder under test
to 12 interrogations from the TS-4530/UPM at a level 3 dB above measured
MTL. These measurements can be saved in the TS-4530/UPM memory and
recalled for printout via the Bench Utility software (WP0008 00).
SIF MODES (Mode 1, Mode 2, Mode3/A, Mode C)
ISLS Percent Reply
Measurement is an average of the valid responses to twelve interrogations.
Reply Delay measurements are decreased by approximately 2 ns per foot distance from aircraft in radiated tests. (At user distance of
100 ft, limits would be 2.60 us min, 3.80 us max.)