Glossary
Page 9-2 MDE-3664B TRIND® Start-up, Service, and Parts Manual · June 2013
LF
- Low Frequency - portion of the frequency spectrum from 30kHz to 300kHz.
M
Magnetic Field
- Field of Force to which magnetic materials and permanent or
electromagnets respond. Surrounds any magnet or electric current. May be most easily
visualized as the force exerted by the field on a tiny magnet placed in the path of a radio wave
or moved about within the field of another magnet.
Modulation
- The methods of modulating or altering the carriers in order to carry the encoded
information are quite varied. They include Amplitude Modulation (AM)/ phase modulation
(PM), frequency modulation (FM), Frequency Shift Keyed (FSK), pulse position (PPM), pulse
duration (PDM) and continuous wave (CW). In some cases, different modulating techniques
are used in each direction (to and from the tags).
N
Noise
- Unwanted, usually random, electrical or electromagnetic energy that interferes with
the detection of wanted signals.
O
Orientation
- Alignment of the tag with respect to the scanner, measured in pitch, roll, and
yaw.
P
Passive Tags
- Passive tags contain no internal power source. They are externally powered
and typically derive their power from the carrier signal radiated from the scanner.
R
Resonance
- The condition in a circuit containing inductance and capacitance in which the
inductive reactance is equal and opposite to the capacitive reactance. (XL=XC) This condition
occurs at only one frequency and the circuit in that condition is said to be in resonance or at the
natural frequency.
RFID
- Radio Frequency Identification Systems that read or write data to RF tags that are
present in a radio frequency field projected from RF reading/writing equipment. Data may be
contained in one (1) or more bits for the purpose of providing identification and other
information relevant to the object to which the tag is attached. It incorporates the use of
electromagnetic or electrostatic coupling in the radio frequency portion of the spectrum to
communicate to or from a tag through a variety of modulation and encoding schemes.
S
SMA
- Sub Miniature A.
Speedpass
- An RFID system used for wireless payment in ExxonMobil branded fuel
dispensers. This system has been available as a payment option since 1997 at Mobil branded
stations and since 2001 at Exxon branded stores (www.speedpass.com).