XE1205SKC868XE1 Semtech, XE1205SKC868XE1 Datasheet - Page 22

• Manufacturer Part Number: XE1205SKC868XE1
• Description: KIT STARTER FOR XE1205 868MHZ
• Manufacturer: Semtech
• Series: TrueRF™r
• Type: Transceiver, ISMr

Specifications of XE1205SKC868XE1

• Frequency: 868MHz
• For Use With/related Products: XE1205 (868MHz)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

6
XE1205 is able to sustain other bit rates between 152.34 kbit/s and 304.7 kbit/s using OSR_minus_1 register as
described in section 5.2.3.2. It is recommended whenever possible to use a modulation index (β=2Δf/BR) ≥2
whenever possible. For the highest bit rates the receiver filter bandwidth will limit the maximal usuable β. Lower
modulation indexes should be used then. In this chapter we provide the example of the highest bit rate.
In order to operate at 304.7 kbit/s the following settings should be used:
Please note that exact bitrate value is 304.6875 kbit/s.
6.1.1
At 304.7 kbit/s, a modulation index close to 1 is compulsory because of the limited bandwidth of the Rx filter.
Frequency deviation will be set to 160 kHz to also take benefit from the Tx filter available (Cf Table 11).
Consequently, following settings should be programmed:
6.1.2
For a correct behavior we recommend to have an Rx filter bandwidth of minimum fdev + (BR/2).
Consequently, following settings should be programmed:
6.1.3
Tx filter is also available at 304.7 kbit/s operation and although not compulsory, its use is recommended to reduce
spectrum bandwidth. Contrary to the other bitrates, an additional specific bit must be set.
Consequently, following settings should be programmed:
© Semtech 2008
6.1
HIGHEST BIT RATES: EXAMPLE OF 304.7 KBIT/S OPERATION
REGISTERS SETTINGS
Bitrate (BR) and frequency deviation (fdev)
Rx filter
Tx filter
TParam_Code_BW(8:0)
TParam_Low_BW
304 kbit/s_filter
Freq_dev(8:0)
Chg_OSR
OSR (7:0)
Max_BW
BW(1:0)
Br(6:0)
Name
Name
Name
Filter
Table 12: common registers settings for 304.7 kbit/s
Table 13: Rx registers settings for 304.7 kbit/s
Table 14: Tx registers settings for 304.7 kbit/s
Address
Address
Address
27
28
19
21
22
18
0
1
2
8
8
7
22
Bits
Bits
Bits
7-0
6-0
7-0
6-5
6-0
7-6
0
4
4
2
4
3
Value (d)
Value (d)
Value (d)
320
15
87
0
1
3
0
1
1
1
…=>304.68 kbit/s
152.34 kbit/s…
…=>320 kHz
160.36 kHz
200 kHz…
Note
Note
Note
XE1205
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