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2.1
Operating Principle
2.2
Charge-Up of the Transponder
2.3
Transponder Orientation
Chapter 2
SCBU025 – November 1996
How the System Works
The antenna has two tasks in the TIRIS system:
1. Send an energizing signal to the transponder.
2. Receive the resulting ID signal from the transponder.
When the transponder passes through the magnetic field created by the transmitting antenna, a capacitor
in the transponder is charged up to a certain voltage. The energy thus created in the capacitor is used to
transmit an ID code back to the readout antenna. For proper functioning, the transponder needs a
minimum voltage of 5 V on its capacitor.
Because the charge-up takes place in a fixed time, the magnetic field strength of the charging signal is
relevant to the maximum readout range (see
The 'readout diagram' of a transponder depends on the orientation of the transponder with respect to the
reader antenna. The magnetic field lines of the reader antenna must incident (cross) the antenna of the
transponder, and vice versa, in order to achieve a proper reception.
through
show
the affect that orientation has on the readout diagram. They show, respectively, the diagrams for
orientations of 0
°
, 30
°
, 60
°
, and 90
°
.
See
for an explanation of how these definitions of orientation are derived.
SCBU025 – November 1996
How the System Works
9
Summary of Contents for TIRIS SCBU025
Page 1: ...Antenna Reference Guide November 1996 SCBU025...
Page 2: ...Antenna Reference Guide Literature Number SCBU025 November 1996...
Page 6: ...www ti com 6 SCBU025 November 1996 Submit Documentation Feedback...
Page 20: ...www ti com Noise Characteristics 20 SCBU025 November 1996 Submit Documentation Feedback...
Page 30: ...www ti com Mechanical Characteristics 30 SCBU025 November 1996 Submit Documentation Feedback...
Page 34: ...www ti com Theory of Coupled Inductors 34 SCBU025 November 1996 Submit Documentation Feedback...