Baseband Signal Processor

5

MX829 PRELIMINARY INFORMATION

© 1998 MX

•COM Inc.

www.mxcom.com Tele: 800 638-5577 336 744-5050

Fax: 336 744-5054

Doc. # 20480160.004

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

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3. External Components

MOD1 IN

SUM OUT

V

DD

V

DD

V

SS

V

BIAS

MOD1

AUDIO OUT

MOD2

SERIAL CLOCK

"C-BUS"

INTERFACE

COMMAND DATA

XTAL/CLOCK

MIC

DEMOD IN

R4

R2

R3

R5

R6

R7

Input from

Demodulator

MX829

VOL IN

C4

Mic

Input

C5

C3

C6

C8

C9

C7

REPLY DATA

CARRIER DETECT

CD CAP

DEMOD FB

FILTER OUT

SUM IN

MSK/DTMF OUT

1

2

3

4

5

6

8

9

10

11

12

13

14

7

24

23

22

21

20

19

18

17

16

15

XTAL/CLOCK

C1

C2

X1

R1

XTAL

XTAL

CS

IRQ

V

DD

Figure 2: Recommended External Components

C1

22pF

±20%

R1

1M

Ω

±5%

C2

22pF

±20%

R2

Note 1

±10%

C3

68pF

±20%

R3

Note 1

±10%

C4

0.1µF

±20%

R4

100k

Ω

±10%

C5

0.1µF

±10%

R5

100k

Ω

±10%

C6

100pF

±20%

R6

Note 2

±10%

C7

0.1µF

±20%

R7

22k

Ω

±10%

C8

Note 2

±20%

C9

5.6nF

±20%

X1

Note 3

4.032MHz

±100ppm

External Component Notes:

1. R2, R3, R4 and C3 form the gain components for the Summing Amplifier (AMP2).

R2 and R3 should be chosen as required from the system specification, using the following formula:

Audio Gain = -

R4

R3

DTMF Gain = -

R4

R2