Rainbow Electronics ATA5812 - Manual (Page 57)

57
ATA5811/ATA5812 [Preliminary]
4689B–RKE–04/04
Figure 49. Bit Error (TMODE = 0)
Recommended Lim_min and
Lim_max for Maximum
Sensitivity The sensitivity measurement in the section “Low-IF Receiver” in Table 3 on page 11 and
Table 4 on page 11 have been done with the Lim_min and Lim_max values according to
Table 39. These values are optimized for maximum sensitivity. Note that since these
Limits are optimized for sensitivity the number of checked bit N
Bit-check
has to be at least
6 to prevent the circuit from waking up to a often in polling mode due to noise.
Demod_Out
Byte n-1 Byte n Byte n+1
Start-up mode Receiving mode
Bit error
Bit-check mode Receiving mode
Preburst
Bit check ok
Byte 1
Table 38. RX Modulation Scheme
Mode ASK/_NFSK T_MODE RF
IN
Bit in TX/RX
Data Buffer
Level on Pin
SD0_TMDO
RX
0
0 f
FSK_L
→
f
FSK_H
1 Z
0 f
FSK_H
→
f
FSK_L
0 Z
1 f
FSK_H
- 1
1 f
FSK_L
- 0
1
0 f
ASK
off
→
f
ASK
on 1 Z
0 f
ASK
on
→
f
ASK
off 0 Z
1 f
ASK
on - 1
1 f
ASK
off - 0
Table 39. Recommended Lim_min and Lim_max Values for Different Baud Rates
f
RF
(f
XTAL
)/
MHz
1.0 kBaud
BR_Range_0/XLim = 1
2.4 kBaud
BR_Range_0/XLim = 0
5 kBaud
BR_Range_1/XLim = 0
10 Kbaud
BR_Range_2/XLim = 0
20 kBaud
BR_Range_3/XLim = 0
315.0
(12.73193)
Lim_min = 13 (261 µs)
Lim_max = 38 (744 µs)
Lim_min = 12 (121 µs)
Lim_max = 34 (332 µs)
Lim_min = 11 (55 µs)
Lim_max = 32 (156 µs)
Lim_min = 11 (28 µs)
Lim_max = 32 (78 µs)
Lim_min = 11 (14 µs)
Lim_max = 31 (38 µs)
433.92
(13.25311)
Lim_min = 13 (251 µs)
Lim_max = 38 (715 µs)
Lim_min = 12 (116 µs)
Lim_max = 34 (319 µs)
Lim_min = 11 (53 µs)
Lim_max = 32 (150 µs)
Lim_min = 11 (27 µs)
Lim_max = 32 (75 µs)
Lim_min = 11 (13 µs)
Lim_max = 32 (37 µs)
868.3
(13.41191)
Lim_min = 13 (248 µs)
Lim_max = 38 (706 µs)
Lim_min = 12 (115 µs)
Lim_max = 34 (315 µs)
Lim_min = 11 (52 µs)
Lim_max = 32 (148 µs)
Lim_min = 11 (26 µs)
Lim_max = 32 (74 µs)
Lim_min = 11 (13 µs)
Lim_max = 32 (37 µs)