XR2211 Exar Corporation, XR2211 Datasheet - Page 13

• Manufacturer Part Number: XR2211
• Description: FSK Demodulator/ Tone Decoder
• Manufacturer: Exar Corporation

Design Example:
1200 Baud FSK demodulator with mark and space frequencies of 1200/2200.
Step 1: Calculate f
Step 2: Calculate R
Step 3: Calculate C
Step 4: Calculate R
Step 5: Calculate C
Step 6: Calculate R
Step 7: Calculate R
Step 8: Calculate R
Step 9: Calculate C
Note: All values except R
Rev. 3.01
( a ) f
( b ) R
( c ) C
( d ) R
( e ) C
R
C
O
O
T
1
1
SUM
F
O
0
0
1
1
F
B
SUM :
F :
: from design instructions
1200·2200 =1624
10
20000·1624·2
1250·39 nF
51000·0.5
15000·1624
from design instructions
: R
: from design instructions
(2200 – 1200)
: from design instructions
: R
: R
R
( R
0
SUM
0
F
B
( R
can be rounded to nearest standard value.
=10K with a potentiometer of 10K. (See design instructions (b))
F
should be at least five times R
1
should be at least five times R
· Baud Rate
F
10
0.25
2
R
2
R
1
1
)· R
15 K
R
3.9 nF
B
B
39 nF
)
51, 000
240 K
1 nF
1
F
13
, R
, R
F
B
= 51,000 5 = 255 K
= 255,000 5 = 1.2 M
XR-2211