Objective: To gain an understanding of PLL Building Blocks. Includes counters, phase detector, charge pump, VCO, and loop filter.
Length: 60 minutes
Published Date: Jul 30, 04
Step(s) to complete
- Complete the suggested assignments
- Complete the online test to receive a certificate from Bob Pease
About the Instructor: Dean Banerjee is a Senior Wireless Applications Engineer with National Semiconductor's Wireless Products division and is the author of "PLL Performance, Simulation, and Design". During this time, he has assisted in the development and support of various PLL synthesizer chips.
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Reading Assignment:
Additional Resources:
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Research Assignment:
From the PLL Building Blocks
Match the correct PLL Blocks name with the correct definition.
(Reference are throughout the PLL Building Blocks Presentation and slide notes)
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PLL Blocks Name
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Definitions
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| 1 |
VCO Output Frequency (Fout) |
a |
This can be thought of as the tuning resolution, for an integer PLL. As N is changed by 1, the output changes in increments of Fcomp
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| 2 |
Crystal Reference Frequency (Fosc) |
b |
This divides the fixed crystal reference frequency by R to get the comparison frequency. R is usually fixed for a given application |
| 3 |
Comparison Frequency (Fcomp) |
c |
This is the output of the whole system, which is controlled by the PLL |
| 4 |
R Counter Value |
d |
It detects differences in input signals, phase error between 2 input signals, frequency error between 2 input signals and outputs a voltage to the charge pump.
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| 5 |
N Counter Value |
e |
This multiplies the comparison frequency in order to get the output frequency. |
| 6 |
Phase/Frequency Detector |
f |
- Voltage to frequency converter
- Often Not Integrated with the rest of the PLL
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| 7 |
Loop Filter |
g |
It is a Low Pass Filter |
| 8 |
Voltage Controlled Oscillator (VCO) |
h |
This is a fixed frequency. It can be provided by a TCXO (Temperature Compensated Crystal Oscillator) or a crystal |
CHECK ALL ANSWERS HERE
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