Specifications

Page 37
WT1231H
Rx startup request
(sequencer or
user)
TS_RE
XO S
tarted and PLL is locked
Analog FE’s
group delay
Channel Filter’s
group delay
DC Cutoff’s
group delay
RSSI
sampling
RSSI
sampling
Reception of Packet
Tana Tcf Tdcc Trssi Trssi
ModeReady
RxRe
ady
Received Packet Preamble may start
Figure
18. Rx Startup - No AGC, no AFC
Rx startup request
(sequencer or user)
TS_RE_AGC
The LNA gain is adjusted by
the AGC, according to the
RSSI result
XO Started and PLL is locked
Analog FE
’s
group delay
Channel Filter’s
group delay
DC Cutoff’s
group delay
RSSI
sampling
RSSI
sampling
Channel Filter’s
group delay
DC Cutoff’s
group delay
RSSI
sampling
Reception of Packet
Tana Tcf Tdcc Trssi Trssi Tcf Tdcc Trssi
ModeReady
RxReady
Received Packet Preamble may
start
Figure 19. Rx Startup - AGC, no AFC
Rx s
tartup request
(sequencer or user)
TS_RE_AGC&AFC
The LNA gain is adjusted by
the AGC, according to the
RSSI result
Carrier Frequency is adjusted
by the AFC
XO Started and
PLL is locked
Analog
FE’s
group delay
Channel Filter’s
group delay
DC Cutoff’s
group delay
RSSI
sampling
RSSI
sampling
Channel Filter’s
group delay
DC Cutoff’s
group delay
RSSI
sampling
AFC
PLL
lock
Channel Filt
er’s
group delay
DC Cutoff’s
group delay
Reception of Packet
Tana Tcf Tdcc Trssi Trssi Tcf Tdcc Trssi Tafc Tpllafc Tcf Tdcc
ModeReady
RxReady
Received Packet Preamble may
start
Figure 20. Rx Startup - AGC and AFC
The dif
ferent timings shown above are as follows:

Group delay of the analog front end: Tana = 20 us

Channel filter’s group delay in FSK mode: Tcf = 21 / (4.RxBw)

Channel filter’s group delay in OOK mode: Tcf = 34 / (4.RxBw)

DC Cutoff’s group delay: Tdcc = max(8 ,
2^(round(log2(8.RxBw.Tbit)+1)) / (4.RxBw)

PLL lock time after AFC adjustment: Tpllafc = 5 / PLLBW (PLLBW = 300 kHz)

AFC sample time: Tafc = 4 x Tbit (also denoted TS_AFC in the general specification)

RSSI sample time: Trssi = 2 x int(4.RxBw.Tbit)/(4.RxBw) (aka TS_RSSI)
Note The above timings represent maximum settling times, and shorter settling times may be observed in real cases