XE1203 Ver la hoja de datos (PDF) - Unspecified

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Fabricante

XE1203

433MHz / 868MHz / 915MHz Low-power, integrated UHF transceiver

Unspecified 

Data Sheet

XE1203

4.1.8 High sensitivity vs. high linearity: A-mode, B-mode

The receiver can be operated in two different modes that provide the highest sensitivity or the highest linearity. Two

operating mode is selectable via the registers “SWParam_Rmode1” or “SWParam_Rmode2” (see the Configuration

register section). In A-mode, the receiver has the highest sensitivity (see RFS parameter) and in B-mode, the

receiver has the highest linearity (see IIP3 parameter)

4.1.9 RSSI

This function provides a Received Signal Strength Indication based on the signal level at the output of the base-

band filter. To activate this function, the bit “RTParam_RSSI” (see the Configuration register section) must be set to

“1”. When activated, the 2-bits status information is stored in register “DataOut_RSSI” and can be read through the

serial control interface. The meaning of this status information is given in the table below, where VRFFIL is the

differential amplitude of the equivalent input RF signal when the receiver is operated in A-mode. The thresholds

VTHRi are the thresholds at the output of the base-band filter divided by the gain between the input of the receiver

and this output.

DataOut_RSSI

00

01

10

11

Description

VRFFIL ≤ VTHR1

VTHR1 < VRFFIL ≤ VTHR2

VTHR2 < VRFFIL ≤ VTHR3

VTHR3 < VRFFIL

Table 1 RSSI status description

The operating range of RSSI measurement can be changed by programming RTParam_RSSIR register, this way

two ranges with three VTHRi values can be selected. The time diagram of an RSSI measurement is given in the

next figure. When the RSSI function has been activated the signal strength is periodically measured and the result

is stored in the register “DataOut_RSSI” each time “DataOut_RSSI” is read via the 3 wires interface. TS_RS is the

wake-up time required after the function has been activated to get a valid result.

RTParam_Rssi

en

rssi_out

saout_rssi

dataout_rssi

13

TS_RSSI

xxx

val1

val2

val3

val4

val5 0

xxx

val1

Figure 6. RSSI measurement timing diagram

val4

D0308-214

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