2.7 R3 REGISTER

The R3 register contains the IF_R, IF_CPP, IF_CPG, IF_CPT, and IF_RST control words, in addition to two of the four bits that

compose the MUX control word. The detailed descriptions and programming information for each control word is discussed in the

following sections.

Reg

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9876543210

DATA[20:0] FIELD

ADDRESS

[2:0]

FIELD

R3

MUX[1:0]

IF_

RST

IF_

CPT

IF_

CPG

IF_

CPP

IF_R[14:0]

0

1

1

2.7.1 IF_R[14:0] - IF Synthesizer Programmable Reference Divider (R Counter) (R3[17:3])

The IF reference divider (IF_R) can be programmed to support divide ratios from 3 to 32767. Divide ratios less than 3 are

prohibited.

Divide Ratio

IF_R[14:0]

14

13

12

11

10

987654321

0

3

00000000000001

1

4

00000000000010

0

•

••••••••••••••

•

32767

11111111111111

1

2.7.2 IF_CPP - IF Synthesizer Phase Detector Polarity (R3[18])

The IF_CPP bit is used to control the IF synthesizer’s phase/ frequency detector polarity based on the VCO tuning characteristics.

Control Bit

Register Location

Description

Function

01

IF_CPP

R3[18]

IF Phase/ Frequency

Detector Polarity

IF VCO Negative

Tuning

Characteristics

IF VCO Positive

Tuning

Characteristics

IF VCO Characteristics

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