Installation Guide Part 3

NGL FX Installation Manual Rev. *

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C H A P T E R

NGL TUNING

Introduction

This chapter describes the procedures required to properly tune a pulse-listen EAS system with the

TR4215 board. The TR4215 is the replacement for the TR4024 and is called Next Generation

Liberty (NGL). Many of the adjustments are pre-tuned during the manufacturing test process;

therefore adjustments required in the field have been minimized.

Adjustments such as center frequency and bandwidth are preset for Standard 8.2 MHz operations.

If the system is required to detect a different frequency tag, the bandwidth select range will need to

be readjusted by the installer.

Once properly configured, if poor performance is found, the CSE should direct their efforts toward

finding the source of the interference in the environment. The primary diagnostic display is

available via the Field Service Diagnostic Manager Software (DMS) application that runs on a PC.

The diagnostics provided allow the CSE to identify and measure ambient noise levels, resonances

and other sources of environmental interference.

The DSP (digital signal processor) system automatically subtracts stationary resonances seen by

the antennas. The system offers flexibility to adjust for these circumstances. However,

environmental problems are best solved by correcting the environment instead of adjusting the

system. The system may be adjusted to accommodate environmental problems both in the analog

and digital realm. The analog solutions include: reducing power on the transmit antennas (TX1

and/or TX2); reducing the baseband gain during software processing (RX1 and/or RX2); reducing

the hardware gain (RX1 Hardware/RX2 Hardware); and adjusting the receiver sampling hold off.

Digitally, the reader is self-adapting and requires no adjustments. However, different points within

the signal processing chain can be displayed, and are available through the use of the Set Filter

Parameter Selection. Unlike the TR4024, the Set Filter Parameter Selection is only a passive

setting. These tools should only be used after the CSE has attempted to correct the environment.

For extreme cases where a sweeper or other external noise sources are very close to the pedestal

and the RX1 and RX2 adjustments do not lower the emission seen in the “C” view (Set Filter

Parameter Selection), a reduction of front end gain (RF section) must be applied. For the TR4215

(NGL) board there is a RX1 and RX2 Hardware gain adjustment which allows a variable setting of

the front end gain replacing the gain jumper. There is also a soft LED for each receiver, RX1 and

RX2, to indicate saturation in the front end. Between the RX Hardware gain adjustment and the

soft LED the user can find the point of saturation. The same technique as the TR4200 and TR4210

will be used for adjusting the software RX1 and RX2 gain setting.

There are also internal noise problems caused by reader board and antenna matching issues, which

may need to be handled. Some of these problems are seen as high noise in the form of ringing.

These problems are more dominant with reader board/pedestal mismatching and pedestals with