USER’S MANUAL, TR7240 TX/RX
CHECKPOINT SYSTEMS, INC. CONFIDENTIAL AND PROPRIETARY INFORMATION, FOR INTERNAL USE ONLY
Document No.
Rev. 00
Page 6 of 11
1.0
INTRODUCTION
The TR4240/TR7240 transceiver is the electronics PCB system of a pulse-listen Electronic Article
Surveillance (EAS) detection system which utilizes targets that are applied to merchandise.
Compared to TR4240, the primary electronics in this document (TR7240) features advanced
functions including network and serial communication, as well as enhanced connectivity to
peripheral devices such as people counters.
Checkpoint provides targets tuned to different frequencies in the HF ranges; 8.2 MHz, 7.2 MHz,
9.2 MHz, 9.5 MHz, etc… When an article of merchandise is purchased, the target is deactivated
which causes it to no longer resonate. The pulse-listen EAS system monitors one or more detection
zones (typically an area 3 feet on either side of the antenna) in the 7.2 MHz to 9.9 MHz band, and
triggers an alarm when a non-deactivated target is detected.
2.0
1
GENERAL DESCRIPTION
The pulse-listen EAS detection system consists of three main components including the antenna,
the Primary Electronics, and the power supply. The antenna is constructed with two “canceling”
loop designs consisting of a 2-Loop, a 3-Loop, and a single-Loop which is a “shorted turn”
contributing to far-field EM cancellation. The Primary Electronics detects targets in the field of the
primary antenna in which it is mounted.
The TR4240/TR7240 PCB integrates both the processing logic controller, consisting of a Blackfin
DSP and a FPGA, and the analog section, consisting of two class D HF transmitters, a direct sample
HF receiver, an RF selector switch, and an ADC used to digitize a tag signal for the FPGA to
process. The detection method is known as “direct sampling” and addresses environmental noise
by identifying RF saturation in the local environment, and the electronics use DSP to process the
incoming RF signals for better accuracy and certainty of when a tag signal is received (vs. noise).
The external power supply is a switching mode with 24 VDC output voltage. Depending on the
power supply used, it could have 1.5A or 2.1A of output current capability.
3.0
SPECIFICATIONS
3.1
MECHANICAL
PCB Layers:
8
PCB Materials:
FR-4 laminate, Solder Mask over bare copper, Electroless
Nickel/Immersion Gold finish
Dimensions:
29.59 x 12.7cm [11.65 x 5.00in]
3.2
ELECTRICAL
CPU:
300 MHz ADSP-BF536 Embedded DSP processor
System Clock:
100 MHz
Interrupts:
LVCMOS/LVTTL Level input
VCC:
+1.2V @ 150 mA typ.
+2.5V @ 30 mA typ.
+3.3V @ 600 mA typ.
