FX919B Datasheet, PDF (20/47 Pages) CML Microcircuits – Excellent Radio Fading Performance

4-Level FSK Modem Data Pump
Task Timings
Data to Data Block Buffer
Task to Command Register
IBEMPTY bit
BFREE bit
Symbols to
RRC filter
Modem Tx output
1
1
2
3
2
3
t4
t4
t4
t2
t1
t3
from task #1
t2
t3
from task #2
t2
t3
from task #3
Figure 10 Transmit Task Timing Diagram
FX919B
t1 Modem in idle state. Time from writing first
task to application of first transmit bit to Tx
RRC filter
t2 Time from application of first symbol of the
task to the Tx RRC filter until BFREE goes
to a logic '1' (high).
t3 Time to transmit all symbols of the task
t4 Max time allowed from BFREE going to a
logic '1' (high) for next task (and data) to
be written to modem
Task
Any
T24S
THB/TIB/TLB
T4S
T24S
THB/TIB/TLB
T4S
T24S
THB/TIB/TLB
T4S
Time
(symbol times)
1 to 2
5
16
0
24
66
4
18
49
3
© 1997 Consumer Microcircuits Limited
20
D/919B/1