Scope bandwidth: trickier than you think!

edn.com 16 Jul '12, 7pm

Scope bandwidth: trickier than you think!

I’ve been working on some materials for students recently, and this forced me to think about the way bandwidth is specified on oscilloscopes. At first glance, a specification such as bandwidth seems like a fundamental concept. Bandwidth tells you the highest frequency you can measure, right? Well, yes and no. Interpreting the bandwidth of the scope as a maximum allowable frequency is a trap most of us have fallen into at one time or another. Let’s start with a definition of bandwidth. Oscilloscope bandwidth is the frequency at which a sinusoidal input signal is attenuated by 3 dB, which is 70.7% of the signal’s true amplitude. This means that at its specified bandwidth, the instrument can show as little as 70.7% of the actual amplitude of the signal. In other words, the amplitude you see on the display can be as much as 29.3% low. So looking at signals with frequencies at ...

Full article: http://www.edn.com/electronics-blogs/scope-guru-on-signal...

Tweets

@ScopeJunction » 03 Aug '12, 11am
More BW: [link]
@kj6onk » 18 Jul '12, 5am
Scope bandwidth: trickier than you think!: [link] via @ednmagazine. Great summary of frequently misunderstood parameter. Thx
@RSC_Roadmap » 16 Jul '12, 8pm
Hugely useful. Would have saved me weeks last yr MT@CambridgeNano Scope bandwidth-trickier than you think! [link] @ednmagazine
@CambridgeNano » 16 Jul '12, 8pm
Scope bandwidth: trickier than you think!: [link] via @ednmagazine
@goingforwards » 16 Jul '12, 7pm
Scope bandwidth: trickier than you think! - [link] (blog): [link] (blog)Scope bandwidt... [link]
@dgou » 16 Jul '12, 7pm
RT @EDNmagazine: Scope bandwidth: trickier than you think! [link]
@EDNcom » 16 Jul '12, 7pm
Scope bandwidth: trickier than you think! [link]