MODULE 4 MIXED SIGNAL

Question 1

What is a Phase Locked Loop (PLL)

Used to act as a ______ to stabilize the output of the VCO

Answer 1

frequency controller

Question 2

What is a Phase Locked Loop (PLL)

Used as ____ , ______ , _____

Answer 2

clock clean up circuits
frequency synthesizer
FM demodulator

Question 3

When the comparison is in steady state, and the output frequency and phase are matched to the incoming frequency and phase of the error detector

Answer 3

PLL LOCK

Question 4

Phase Shift is constant if the 2 signals have ____ frequencies

Answer 4

similar

Question 5

Phase shift changes if the 2 signals have _____ frequencies

Answer 5

different

Question 6

Used to compare the phases of the signal input with the reference input. The comparison is an error signal that is proportional to the phase difference of the input signals

Answer 6

Phase Detector

Question 7

a type of phase detector that is sensitive to both the phase and frequency difference between two input signals

Answer 7

Phase Frequency Detector (PFD)

Question 8

The loop filter is technically a _____

Answer 8

Low Pass Filter

Question 9

The loop filter is used to convert (average) the PFD output thereby giving a

Answer 9

DC voltage proportional to phase shift

Question 10

Output frequency changes with change in input voltage

Answer 10

Voltage Controlled Oscillator

Question 11

Allows the PLL to generate output frequencies that is a multiple of the input frequency

Answer 11

Feedback Divider

Question 12

A time deviation of a signal transition from its ideal position in time.

Answer 12

Jitter

Question 13

Measured in Unit Intervals and measured using eye diagrams

Answer 13

Jitter

Question 14

Type of jitter that is ever present phenomenon that cannot always be predicted

Answer 14

Random Jitter

Question 15

Type of jitter that is not bounded and described by a Gaussian probability distribution

Answer 15

Random Jitter

Question 16

Random jitter is a combination of these factors:

Answer 16

• Thermal noise
• Trace width variations
• Shot noise
• Flicker (pink noise)

Question 17

Bounded jitter with a non-Gaussian probability density function

Answer 17

Deterministic Jitter

Question 18

Jitter that is repetitious at one or more frequencies

Answer 18

Deterministic Jitter

Question 19

Types of Deterministic Jitter

Answer 19

1. Data-dependent – ISI(inter symbol interference), duty-cycle distortion
2. Periodic

Question 20

Tool used to analyze signal/data quality

Answer 20

Eye Diagram

Question 21

In an eye diagram, what are fluctuations in signal amplitude

Answer 21

Vertical closing

Question 22

In an eye diagram, this indicates timing issues (jitter)

Answer 22

Horizontal narrowing

Question 23

Maximum difference between any two adjacent clock periods

Answer 23

Cycle-to-cycle Jitter

Question 24

Jitter that is the difference in a clocks period from one cycle to the next

Answer 24

Cycle-to-cycle Jitter

Question 25

Jitter whose maximum deviation of any clock period from its mean clock period

Answer 25

Period Jitter

Question 26

In period jitter, change in a clocks output transition from its _____ over some number of cycles

Answer 26

ideal position

Question 27

____ jitter ensures that the clock does not drift across time

Answer 27

Period

Question 28

A type of jitter where the difference between observed clock edge time and expected clock edge time for each clock edge present

Answer 28

Time Interval Error Jitter

Question 29

Time Interval Error Jitter formula

Answer 29

Measured by subtracting the actual clock edge from the ideal clock edge

Question 30

Deviation in edge location with respect to mean edge location

Answer 30

Phase jitter

Question 31

The skew between a stable input clock and the output clock after the PLL has acquired locked

Answer 31

Phase jitter