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UM2268 Rev 6 41/68
UM2268 Reader Settings
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4.1.5 Carrier Sense panel
If enabled the reader detects if the next transmit frequency channel is free or already
occupied by another reader.
Figure 38. Carrier sense panel
Where:
•
RSSI threshold : If the signal strength of the sensed carrier is below this threshold, the
slot is considered free, and therefore is used by the reader. The RSSI threshold can be
entered from -40 dBm down to - 77 dBm.
• Listen time : Carrier Sense duration. During this time, the RSSI is measured
repeatedly. The maximum value is then checked for threshold crossing.
•
Idle time : Wait time between transmit frequency channel switch and performing Carrier
Sense.
4.1.6 Rx Options panel
• Initial Receive Gain : The receive gain slider adjusts the receive gain and/or receive
attenuation of the reader. The slider affects register 0x0A.
•
Adaptive RX Gain : This section allows to activate adaptive receive gain/attenuation
change. The basic procedure to automatically adapt RX gain is to count slot events and
change the sensitivity when the counter hit upper and lower threshold values. The
counter start with zero and is reset to zero with any sensitivity change. Every slot event
has its own increment value, which can either be positive or negative. The sum is of
these increments is cumulated with every slot event and is stored in an internal event
counter. As soon the event counter reaches either the lower or the upper threshold the
sensitivity is adopted.