I know it is some sort of wide question, but nowday I usually only see digital oscilloscopes around. I want to know if their digital nature will affect the accuracy of measurements? (Something like digitization error in sampling signals). Or asking other way are they any specific applications which accurate measurement requires using only analog ones in current time? I guess flexibility of digital oscilloscope grows trend to using this type of oscilloscopes, but I will be happy if you correct me.
Electronic – Which one is more accurate: Digital oscilloscope or Analog oscilloscope
analogmeasurementoscilloscope
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Best Answer
The modern digital oscilloscopes are sophisticated analog beasts!
Most of the modern day high speed digital and analog equipment, such as computer interfaces (USB, SATA, Gigabit Ethernet) are tested, designed and refined using digital oscilloscopes. Even many SoCs containing complex analog and digital peripherals are validated using digital oscilloscopes. For example USB 3.0 can have speeds up to 5Gig bits per second. The interfaces are literally probed by digital oscilloscope inputs and careful test setups are built around them.
Even high speed analog blocks such as ADCs, Amplifiers, Filters and Oscillators are tested using DSOs.
However from a purchase point of view, these are very expensive oscilloscopes. For the highest analog bandwidth available, the boxes from companies such as LeCroy (part of Teledyne now), Keysight (Changed from Agilent's T&M division), Rhode & Schwartz and Tektronix, may cost a Ferrari!
But for most of hobby use, student laboratory or even a decent embedded testing there are value-for-money oscilloscopes from above companies and many other from around the world. There are also PC based USB oscilloscope products (BitScope, Picoscope or USBee).
Digital oscilloscopes exists because they work! And engineers use them! I use them!
Most of the time, we expect more from a box and potentially use an unsuitable signal for analysis. A high speed square pulse stream on a lesser bandwidth oscilloscope will look smoothed out! Or even as a sine-wave! Because all the higher frequency part of the signal is filtered out on channel.
These are few questions you may want to ask yourself before choosing an equipment.
Ideally every signal is of infinite bandwidth. Only that the higher harmonics are very feeble. So choose the "Analog bandwidth" of the scope based on your signal.
Try to use the full dynamic range of the scope (Full bit resolution vs. full scale). If your interest is about superimposed parts of a signal, like that sharp glitch on a sinewave output of a switched power supply, go for higher ADC resolution scopes.
If the signal is small, the scope will amplify it. If the signal is large the scope will attenuate it to suite the full swing of the internal ADC. Some times you may want to use the auto-scale feature of the scope.
If the signal is too small amplitude, then amplifying it will also amplify some noise. If the signal has large glitch, then attenuating it will reduce its details.
We should also look into the merits of Digital Vs. Analog scopes
However if you admire pure analog signals, directly imposing themselves on a phosphor screen, nothing wrong with that too!