Datasheet
ST7540 Functional description
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6.3 Mark and space frequencies
Mark and Space Communication Frequencies are defined by the following formula:
F ("0") = FCarrier + [∆F]/2
F ("1") = FCarrier - [∆F]/2
∆F is the Frequency Deviation.
With Deviation = “0.5” the difference in terms of frequency between the mark and space
tones is half the Baudrate value (∆F=0.5*BAudrate). When the Deviation = “1” the difference
is the Baudrate itself (∆F= Baudrate). The minimal Frequency Deviation is 600Hz.
Table 8. ST7540 synthesized frequencies
Carrier
frequency
(KHz)
Baud
rate
Deviation
Exact frequency
[Hz]
(Clock=16MHz)
Carrier
frequency
(KHz)
Baud
rate
Deviation
Exact frequency
[Hz]
(Clock=16MHz)
“1” “0” “1” “0”
60
600
--
82.05
600
--
1 59733 60221 1 81706 82357
1200
0.5 59733 60221
1200
0.5 81706 82357
1 59408 60547 1 81380 82682
2400
0.5 59408 60547
2400
0.5 81380 82682
1 58757 61198 1 80892 83171
4800
0.5 58757 61198
4800
0.5 80892 83171
1 57617 62337 1 79590 84473
66
600
--
86
600
--
1 65755 66243 1 85775 86263
1200
0.5 65755 66243
1200
0.5 85775 86263
1 65430 66569 1 85449 86589
2400
0.5 65430 66569
2400
0.5 85449 86589
1 64779 67220 1 84798 87240
4800
0.5 64779 67220
4800
0.5 84798 87240
1 63639 68359 1 83659 88379
72
600
--
110
600
--
1 71777 72266 1 109701 110352
1200
0.5 71777 72266
1200
0.5 109701 110352
1 71452 72591 1 109375 110677
2400
0.5 71452 72591
2400
0.5 109375 110677
1 70801 73242 1 108724 111165
4800
0.5 70801 73242
4800
0.5 108724 111165
1 69661 74382 1 107585 112467