XE1205I074TRLF データシートの表示（PDF） - Semtech Corporation

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XE1205I074TRLF

180 MHz – 1GHz Low-Power, High Link Budget Integrated UHF Transceiver

Semtech Corporation 

XE1205

5.2.5.2 Bit synchronizer in buffered mode

In buffered mode the bit synchronizer is automatically enabled (DCLK is not externally available).

5.2.5.3 Pattern recognition block in buffered mode

In buffered mode the pattern recognition block is automatically enabled. The PATTERN signal may be mapped to pin

IRQ_0. Please refer to section 5.2.2 for further details.

5.2.5.4 RSSI in buffered mode

In buffered mode the Received Signal Strength Indication operates the same way as in continuous mode. In buffered

mode, however, RSSI_irq may be mapped to IRQ_1 (please refer to section 5.2.2) instead of to IRQ_0 in continuous

mode.

5.2.5.5 Frequency Error Indicator in buffered mode – FEI

In buffered mode the Frequency Error Indication operates the same way as in continuous mode. Please refer to section

5.2.3.5 for more details.

5.2.6 Additional narrowband filter bandwidths

The lowest bandwidth for the base-band filter which can be selected by changing only a 2-bit word in the configuration

register is 10 kHz. However, as described in section 7.2.8, additional register settings allow this bandwidth to be further

reduced. This option allows the user to improve the selectivity of the receiver for very narrow-band applications.

Activating this option is advised for bit rates and frequency deviations not higher than 4.8 kbit/s and 5 kHz and if the LO

frequency of the receiver is well controlled, for instance by means of a very accurate crystal or the activation of an AFC.

The table below gives the sensitivity and the adjacent channel rejection for BR = 4.8 kbit/s and Δf = 5 kHz for different

bandwidths.

Bandwidth

SSB

10 kHz

9 kHz

8 kHz

7 kHz

TParam_Low _BW TParam_Code_BW(8:0)

0

X

1

139

1

160

1

185

Sensitivity

RFS

(BER=0.1%)

-116 dBm

-116 dBm

-115.5 dBm

-115 dBm

Adjacent Channel Rejection

ACR

(25 kHz offset single tone)

20 dBc

25 dBc

30 dBc

35 dBc

Table 8: Performances of the receiver for very narrow bandwidths and 4.8 kbit/s

Table 9 below gives the sensitivity and the adjacent channel rejection for BR = 1.2 kbit/s and Δf = 2 kHz.

Bandwidth

SSB

TParam_Low _BW TParam_Code_BW(8:0)

10 kHz

0

X

9 kHz

1

139

8 kHz

1

160

7 kHz

1

185

Sensitivity

RFS

(BER=0.1%)

-117.5 dBm

-118 dBm

-119 dBm

-119.5 dBm

Adjacent Channel Rejection

ACR

(25 kHz offset single tone)

18 dBc

23 dBc

28 dBc

33 dBc

Table 9: Performances of the receiver for very narrow bandwidths and 1.2 kbit/s

It can be seen from table 9 that this option also allows the sensitivity to be improved for very low bit rates and frequency

deviations.

© Semtech 2008

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