Baud band selection, Channel selection – Linx Technologies TRM-xxx-NT User Manual
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19
Power Level vs. Resistor Value
Power
Level
P
O
(dBm)
1%
Resistor
Value
Power
Level
P
O
(dBm)
1%
Resistor
Value
Power
Level
P
O
(dBm)
1%
Resistor
value
57
12.22
Open
38
3.49
154k
19
−5.47
44.2k
56
12.12
750k
37
3.11
143k
18
−5.78
41.2k
55
12.14
649k
36
2.77
133k
17
−6.12
37.4k
54
11.86
576k
35
2.12
127k
16
−6.72
34.8k
53
11.85
510k
34
1.65
118k
15
−7.09
32.4k
52
9.58
453k
33
1.16
111k
14
−7.52
29.4k
51
9.78
412k
32
0.81
105k
13
−7.91
26.7k
50
8.94
347k
31
0.38
97.6k
12
−8.36
24.3k
49
8.33
340k
30
−0.18
91k
11
−8.83
22k
48
8.02
316k
29
−0.66
86.6k
10
−9.39
19.6k
47
7.42
287k
28
−0.93
80.6k
9
−9.13
17.4k
46
6.99
267k
27
−1.46
76.8k
8
−9.68
15.4k
45
6.72
243k
26
−1.84
71.5k
7
−10.23
13.3k
44
6.33
226k
25
−2.39
66.5k
6
−10.86
11.3k
43
5.80
210k
24
−2.83
62k
5
−11.50
9.53k
42
5.38
200k
23
−3.27
57.6k
4
−12.23
7.5k
41
4.83
182k
22
−3.79
54.9k
3
−13.04
5.76k
40
4.33
174k
21
−4.30
51k
2
−13.98
4.02k
39
4.05
165k
20
−4.85
47k
1
−14.59
2.32k
0
−15.78
750
Channel Selection
The transceiver allows for setting the channel frequency with the
CHN_SEL0, CHN_SEL1 and CHN_SEL2 lines in a parallel manner. The
logic states of the three lines select from among eight channels. This allows
the channel to be set by DIP switches, microcontroller lines or hardwired.
The 868MHz channels are shown in Figure 25 and the 900MHz channels
are shown in Figure 26.
Baud Band Selection
Baud Band BAUD1 BAUD0
Baud Rate
(kbps)
IF Bandwidth
(kHz)
Receiver Sensitivity
(dBm)
1
0
0
1 to 19.2
100
−113
2
0
1
19.2 to 80
150
−110
3
1
0
80 to 160
200
−106
4
1
1
160 to 300
300
−102
Figure 23: NT Series Transceiver Power Level vs. Resistor Value
Figure 24: NT Series Transceiver Baud Band Selection
Baud Band Selection
There are two baud select lines (BAUD0 and BAUD1) that configure the
transceiver for the desired over-the-air data rate. The two baud select lines
choose among four baud bands, or ranges of data rate and IF bandwidth,
as shown in Figure 24.
Setting the baud band appropriately for the desired baud rate configures
the internal filters and circuitry for optimal performance at that rate. Data
can be sent in at a lower rate than specified for the band, but the sensitivity,
and therefore range, will not be as good as in a lower setting. Data can
also be sent in faster than specified by the band, but the internal filters will
cause distortion of the data stream and range will be significantly reduced.
868MHz Channel Selection
CHN_SEL2
CHN_SEL1
CHN_SEL0
CHANNEL
FREQUENCY
0
0
0
0
863.15
0
0
1
10
864.15
0
1
0
20
865.15
0
1
1
30
866.15
1
0
0
52
868.35
1
0
1
58
868.95
1
1
0
64
869.55
1
1
1
67
869.85
Figure 25: NT Series Transceiver 868MHz Channel Selection