Design Information

This information is a guide for approximating the value of

external components for the CD4046B in a phase-locked-

loop system The selected external components must be

In addition to the given design information refer to

Figure 5

for R1 R2 and C1 component selections

Using Phase Comparator I

Using Phase Comparator II

Characteristics

VCO Without Offset

VCO With Offset

VCO Without Offset

VCO With Offset

VCO Frequency

For No Signal Input

VCO in PLL system will adjust

VCO in PLL system will adjust to

Frequency Lock

Frequency Capture

1

q

Loop Filter

Component

Selection

Phase Angle Between

Always 0 in lock

Single and Comparator

Locks on Harmonics

Yes

No

of Center Frequency

Signal Input Noise

High

Low

Rejection

VCO Component

Selection

Figure 5a to

from the equation

the equation

Figure 5b to

determine R1

determine R2 and C1

and C1

2

Calculate

to determine R2 and C1

determine R1 and C1

Use

with

Figure 5c

Calculate

to determine ratio

from the equation

R2R1 to obtain R1

e

Use

with

Figure 5c

to determine ratio R2

R1 to obtain R1

TLF5968 – 7

TLF5968 – 9

TLF5968 – 10

TLF5968 – 8

TLF5968 – 11

TLF5968 – 12

References

GS Moschytz ‘‘Miniaturized RC Filters Using Phase-Locked Loop’’ BSTJ May 1965

Floyd Gardner ‘‘Phaselock Techniques’’ John Wiley

Sons 1966

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