Voice Band Inverter

5

MX014

© 1997 MX•COM, INC.

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Doc. # 20480013.006

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3. External Components

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

XTAL

XTAL

PTT

PTT

PTL

PTL

RXAUDEN

RXAUDEN

PRIVEN

RXOUT

TXOUT

V

V

V

V

V

V

BPFOUT

RXBIN

DEMPOUT

TXBIN

BIAS

FILTR

BALMOD

RXIN

RXFB

TXIN

TXFB

X1

C4

C3

C2

C1

R3

R1

R4

R2

RX Channel

TX Channel

MX014

R5

R7

R6

R8

Bias

Bias

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

XTAL

XTAL

PTT

PTT

PTL

PTL

RXAUDEN

RXAUDEN

PRIVEN

RXOUT

TXOUT

BPFOUT

RXBIN

DEMPOUT

TXBIN

BIAS

FILTR

BALMOD

RXIN

RXFB

TXIN

TXFB

X1

C4

C3

C2

C1

R3

R1

R4

R2

RX Channel

TX Channel

MX014

R9

R11

R10

R12

Bias

Bias

Configuration for Radios with

Existing Pre- and De-emphasis.

For Use in Radios without

Pre- and De-emphasis.

SS

SS

DD

DD

DD

DD

Figure 2: External Components Connections

TX Attenuation

R8

R7

R8

For a gain of 1, R8

, R7

0

=

+

=∞

=

TX Attenuation

R10

R9 R10

For a gain of 1, R9

0, R10

=

+

== ∞

RX Attenuation

R6

R5 R6

For a gain of 1, R6

, R5

0

=

+

=∞

=

RX Attenuation

R12

R11 R12

For a gain of 1, R11

0, R12

=

+

== ∞

Table 2: Gain and Attentuation Calculations

Recommended External Component Notes:

1.

Component Values: C1- C3 = 0.1 µF, C4 = 1.0 µF, X1 = 4 MHz crystal

2.

R1 to R12 values will depend on the configuration and the gain or attenuation required. However R1, R3, R5, R7,

and R11 should be 100 k

Ω or greater. To add gain or attenuate, use R5-R12 as shown. See pin descriptions for

more information.

3.

For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at least 40% of

VDD, peak to peak. Tuning fork crystals generally cannot meet this requirement. To obtain crystal oscillator

design assistance, consult your crystal manufacturer.