The decibel (dB), named for Alexander Graham Bell, spent much of its life as a ratio of two signal powers for describing audio and RF levels. Now it is commonly used in signal integrity to characterize signal losses and reflections in transmission channels that carry digital signals.
As a result, digital designers -- the ones who attend DesignCon -- have had to learn about this analog concept.
All of this week's questions come from "dB or not dB? Everything You Ever Wanted to Know About Decibels But Were Afraid to Ask," an application note from Rohde & Schwarz (registration required). As usual, the answers appear on the last page. Following the answers, you'll find links to relevant articles, including "How to think in dB" by Eric Bogatin. Sorry, but you'll have to go to the last page for the link. You didn't think I'd let you off that easily, did you?
Good luck, and may you have the power to get a perfect score. If not, then follow the link above, but beware: You'll have to browse through all 35 pages to find what you seek. I did.
1. A voltage level of 120 dBµV has a voltage of:
- 1 nV
- 1 µV
- 1 mV
- 100 mV
- 1 V
- 1.2 V
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