Latest Posts

Example-phase-noise-plot
TIMING
Timing 201 #10: The Case of the Really Slow Jitter – Part 2

Oct. 10, 2022

I realized it is best to first understand what led to the predecessor metric Allan Deviation (ADEV). So, that is the topic I will focus on today.

wander vs jitter
TIMING
Timing 201 #9: The Case of the Really Slow Jitter – Part 1

Oct. 09, 2022

What’s different about wander as opposed to jitter and why do we care? From the perspective of someone who takes a lot of phase noise plots, I consider this the case of the really slow jitter. It’s both slow in terms of phase modulation and in how long it takes to measure.

resulting plot
TIMING
Timing 201 #8: The Case of the Dueling PLLs – Part 2

Oct. 08, 2022

I will discuss in more detail how to calculate the phase noise of both these dual-loop PLL approaches.

Nested Dual-Loop PLL Architecture
TIMING
Timing 201 #7: The Case of the Dueling PLLs – Part 1

Oct. 07, 2022

One consideration is the necessary bandwidth relationship between the inner and outer loops. This topic leads to the play on words in the main title of this blog post, The Case of the Dueling PLLs.

start-up behavior - When the device fails, the 3.3 V supply starts oscillating straight away.
TIMING
Timing 201 #6: The Case of the Autonomously Resetting Clock Generator

Oct. 06, 2022

It turned out that an overlooked spec for a passive component located elsewhere on the board was causing large consequences for the customer’s application. The lessons learned are generally applicable and the subject of this blog article, The Case of the Autonomously Resetting Clock Generator.

PLL Injection Sensitivity – Measuring ILBW via Synchronous Injection
TIMING
Timing 201 #5: The Case of the Parasitic PLL - Part 3

Oct. 05, 2022

I will discuss the topic of measuring injection sensitivity, and what one can do with that information.

multiple frequency plan solutions that output the same clock frequency
TIMING
Timing 201 #4: The Case of the Parasitic PLL - Part 2

Oct. 04, 2022

In this post, I will discuss how to minimize injection sensitivity generally. Part 3, to come later, will cover the topic of measuring injection sensitivity.

Basic Injection Theory
TIMING
Timing 201 #3: The Case of the Parasitic PLL - Part 1

Oct. 03, 2022

In this post, I will review the basic theory and modeling for this phenomenon. My interest is not in walking through the derivations but rather noting the highlights of the results.

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