TIC TR-220 - Page 17

Rev E TR-220 90 008 088-1
1-8
MODE S A secondary radar system where transponders can be individually
interrogated or selected (the “S” in MODE S) so that in a crowded air
traffic area, the amount of interference or garble can be reduced to a
minimum.
MHz Megahertz
nmi. Nautical mile
ns Nanosecond
PAM Pulse Amplitude Modulation
PDME Precision Distance Measuring Equipment
PMCS Preventative Maintenance Checks and Services
PPM Pulses per Minute
PRF Pulse Repetition Frequency
PW Pulse Width
PWR Power
RA Resolution Advisories
Receiver Efficiency The Test Set’s Measurement of valid replies received. Displayed as a
Percentage.
Reply Codes A transmitted response, from the airborne transponder, to an
interrogation. Commercial transponders responses are designated as
either ATCRBS/A where the reply includes the pilot selected 4096 ID
code, or ATCRBS/C, where the reply includes the aircraft pressure
altitude. These same responses for military transponders are designated
as MODE 3A and MODE 3C. See Mode S for further information.
RF Radio Frequency
RMS Root Mean Square
R/T Receiver Transmitter
SIF Selective Identification Feature
SLS Side Lobe Suppression. A pulse transmitted from an omni-directional
antenna used as a reference level to prevent replies to interrogations
received from the secondary radar antenna side lobes.
Squitter The self-generated transmissions made by a MODE S transponder, not in
reply to an interrogation, for the use of the collision avoidance system.
And ADS-B Receivers and Transmitters.
SSR Secondary Surveillance Radar
Surveillance Altitude An interrogation that causes only the addressed MODE S transponder to
reply.
Surveillance ID An interrogation that causes only the addressed MODE S transponder to
reply to its “4096” code.
TA Traffic Advisories
TACAN Tactical Air Navigation
TCAS Traffic Alert and Collision Avoidance System
TIS Traffic Information System
TX Transmitter
UF Uplink Format. The format in a MODE S interrogation that indicates the
type of reply expected.
VORTAC VOR and TACAN (co-located)
VOR VHF Omni-Directional Range
VSWR Voltage Standing Wave Ratio
WOW Weight On Wheels
UUT Unit Under Test
XPDR Transponder
XPDR UT Transponder Under Test
4096 Code This refers to the octal number dialed into either an ATCRBS MODE A or
MODE S transponder by the pilot. This is to be distinguished from the
address of the MODE S transponder, which cannot be changed.