1200/2400/4800bps MSK Modem
5
MX469
Signal
P
17
DW
18
D3
15
RX Sync
Type
output
Description
A flywheel squarewave output. This clock will
synchronize to incoming RX MSK data. (See Figure 4
and Figure 6).
A logic ‘1’ on this pin selects the 1200bps option; tone
frequencies are one cycle of 1200Hz represents a logic
‘1’, one-and-a-half cycles of 1800Hz represents a logic
‘0’. A logic ‘0’ on this pin selects the 2400bps option;
tone frequencies are one-half cycle of 1200Hz represents
a logic ‘1’, one cycle of 2400Hz represents a logic ‘0’.
This pin has an internal 1M pull-up resistor.
Operational Data Rate Configurations are illustrated in
Table 3
A logic '1' on this pin combined with a logic '0' on the
1200/2400 BPS Select pin will select the 4800 option
(1M pulldown resistor). Tone frequencies are: one-half
cycle of 2400Hz represents a logic '1', one cycle of
4800Hz represents a logic '0'. This state can only be
achieved using a 4.032MHz Xtal input. Operational Data
Rate Configurations are illustrated in Table 3
A logic input to select and allow the use of either a
1.008MHz or 4.032MHz Xtal/clock. Logic ‘1’ =
4.032MHz, logic ‘0’ = 1.008MHz. This input has an
internal pulldown resistor (1.008MHz).
Part of the carrier detect integration function. The value
of C4 connected to this pin will affect the carrier detect
response time and therefore the noise performance (See
Figure 2, Note 3).
Positive supply. A single 5-volt supply is required.
No Internal Connection.
16
19
16
1200/ 2400 BPS
Select
input
18
20
17
4800 BPS Select
input
MX469P package discontinued
19
21
18
Clock Rate
input
20
23
19
Carrier Detect
Time Constant
output
22
4,
21
24
4, 6,
17,
22
20
V
DD
N/C
power
Table 1: Signal List
RX Enable
1
0
=
=
=
RX Function
Enabled
Powersave
Clock Data Output
Enable
0
Carrier Detect
Enabled
0
Rx Sync Out
Enabled
1 or 0
Table 2: RX Enable Control Functions
XTAL/CLOCK Frequency
Clock Rate pin
1200/2400 Select Pin
4800 Select Pin
Data Rate (bps)
1.008MHz
0
1
0
1200
0
0
0
2400
1
1
0
1200
4.032MHz
1
0
0
2400
1
0
1
4800
Table 3: Operational Data Rate Configuration
1998
MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480081.010
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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