An Introduction to Oscilloscopes

by Andy on January 6, 2012

Oscilloscopes are important pieces of equipment for any electronics expert. However, they can be rather complicated as they have many specifications to keep in mind. Below are a few terms that come up when looking at the specs of an oscilloscope and general things to look for when purchasing one for yourself.

Analog and Digital

Oscilloscope The first terms that come up when describing oscilloscopes are analog and digital. The main difference lies in the circuitry inside the device. Analog oscilloscopes tend to take the signal and display it directly without interpreting or affecting the data. This allows for a near instantaneous display, showing what is happening while it is happening. Digital oscilloscopes take the input, convert it to a digital signal to interpret and analyze it, and then output an analog signal to the display. When digital oscilloscopes first came out, they had a delay in displaying the signal, but now most can display just as fast as their analog counterparts.

Digital oscilloscopes can analyze, record, and transform data more naturally than analog oscilloscopes. This can be very useful if you need to take measurements and refer back to them later. If you just need to monitor a signal in real time it can be beneficial to get an analog oscilloscope. However, the majority of oscilloscopes on the market now are digital, as they are surpassing analog in features and accuracy.


Bandwidth is one of the most important specifications for oscilloscopes. It is measured in hertz and it tells you the frequency range. When measuring a wave, there are many high frequency components known as harmonics. In order for the oscilloscope to give you the most accurate picture of the wave, it has to be able to capture these harmonics; a general suggestion is to have your bandwidth be ten times higher than the fundamental frequencies that you are testing.

Sampling Rate

The sample rate of an oscilloscope is how many points of data it collects. The higher the sampling rate, the more accurate your display will be. Typically your sampling rate should be two to three times higher than your bandwidth to get the best picture of the data.


Oscilloscope 2 Oscilloscopes often reference how many channels they have. Each channel is an independent set of inputs, allowing for multiple signals to be compared at the same time. It also lets the operator have different settings for each channel to make switching tests easier. Most oscilloscopes are dual-channel but you can also get one-channel and multi-channel scopes depending on your needs.

While these are a few items to keep in mind when looking at oscilloscopes, it is only brushing the surface of this technology. If you would like more information, National Instruments has a good article on the specifications of oscilloscopes. Another great resource is the blog Effective Bits. It has a bunch of great articles on oscilloscopes in its backlog, all very informative. Looking to buy an oscilloscope? We are now carrying the new BK Precision 2540B and 2542B digital storage oscilloscopes at www.All-Spec.com, as well as many other digital and analog oscilloscopes.

Are there any other pieces of equipment that you want to know more about? Leave a comment below and we’ll help you out!

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