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rprodrigues
Joined: 18 Nov 2006
Posts: 53
Helped: 1
Location: Itajubá MG Brazil
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 03 Nov 2007 23:10 differences of digital and analog oscilloscope |
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Hi, all.
I am sure I don't have enough knowledge over both digital and analog eletronics areas to make a decision about which oscilloscope I should buy.
I know it's not difficult to realize that, when treating with µC (microcontroller) circuits, a digital oscilloscope (logic analyzers) may be a better choice than an analog one, but I think that the analogs may have better overall characteristics.
Then, the questions I'd like to let to you are:
When the usage of an analog oscilloscope should be considered instead the usage of a digital one?
When the usage of an digital oscilloscope should be considered instead the usage of an analog one?
Considering two oscilloscopes with the same BW, which one is better: analog or digital?
Thank you.
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zeeshanzia84
Joined: 29 May 2006
Posts: 202
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Location: Pakistan / Germany
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04 Nov 2007 2:38 analog oscilloscope vs digital oscilloscope |
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well i guess by digital oscilloscope, companies don´t only mean that it samples and digitizes the input signal.....usually it will also have a digital display...and a built-in microprocessor to control everything....which means that they definitely will be placing some extra functions like displaying the frequency, mean, pk-pk, etc values.... which is really great....provided u´re comparing two equal BW instruments (of course i guess the cost is going to be greater)
on the other hand....the analog oscilloscope IMO, will not only be analog in the sense that it doesn´t digitize the signal (using ADC)...but also that it has an analog display....and no microprocessor....so no direct Frequency, Mean Voltage, Pk-Pk voltage display....which is definitely an inconvenience....but i think it will be at a lower cost for the same BW instrument.
hope this helps.
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04 Nov 2007 2:38 Ads |
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Old Nick
Joined: 14 Sep 2007
Posts: 445
Helped: 49
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04 Nov 2007 2:56 oscilloscope digital pk-pk |
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Your question has no answer.
If one was better than the other only one would exist.
A logic analyser and an Oscilloscpe are different instruments used for different purposes.
Tektronix make a few combined logic analyser/oscilloscope you may want to check out.
But in deciding which of the two is better, you have to understand what it is you want to measure, the one which is 'better' depends on what you want to measure/observe.
Added after 10 minutes:
| zeeshanzia84 wrote: |
well i guess by digital oscilloscope, companies don´t only mean that it samples and digitizes the input signal.....usually it will also have a digital display...and a built-in microprocessor to control everything....which means that they definitely will be placing some extra functions like displaying the frequency, mean, pk-pk, etc values.... which is really great....provided u´re comparing two equal BW instruments (of course i guess the cost is going to be greater)
on the other hand....the analog oscilloscope IMO, will not only be analog in the sense that it doesn´t digitize the signal (using ADC)...but also that it has an analog display....and no microprocessor....so no direct Frequency, Mean Voltage, Pk-Pk voltage display....which is definitely an inconvenience....but i think it will be at a lower cost for the same BW instrument.
hope this helps. |
Most (if not all) analog scopes display pk-pk, frequency information etc. And loads of them have math's functions to plot average values, FFT's, A+B etc. A logic analyser will not tell you this, it will giver you the transition times, but not voltage information. To look at analogue waveforms a Oscilloscope is the tool to use (of course Scopes are all digital, but they display an analogue response).
I'm not sure what you mean about an Oscilloscope not having a voltage display, that is what they do!!
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rprodrigues
Joined: 18 Nov 2006
Posts: 53
Helped: 1
Location: Itajubá MG Brazil
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04 Nov 2007 3:50 which analog oscilloscope to buy |
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| Old Nick wrote: |
Your question has no answer.
If one was better than the other only one would exist.
A logic analyser and an Oscilloscpe are different instruments used for different purposes.
Tektronix make a few combined logic analyser/oscilloscope you may want to check out.
But in deciding which of the two is better, you have to understand what it is you want to measure, the one which is 'better' depends on what you want to measure/observe.
Added after 10 minutes:
| zeeshanzia84 wrote: |
well i guess by digital oscilloscope, companies don´t only mean that it samples and digitizes the input signal.....usually it will also have a digital display...and a built-in microprocessor to control everything....which means that they definitely will be placing some extra functions like displaying the frequency, mean, pk-pk, etc values.... which is really great....provided u´re comparing two equal BW instruments (of course i guess the cost is going to be greater)
on the other hand....the analog oscilloscope IMO, will not only be analog in the sense that it doesn´t digitize the signal (using ADC)...but also that it has an analog display....and no microprocessor....so no direct Frequency, Mean Voltage, Pk-Pk voltage display....which is definitely an inconvenience....but i think it will be at a lower cost for the same BW instrument.
hope this helps. |
Most (if not all) analog scopes display pk-pk, frequency information etc. And loads of them have math's functions to plot average values, FFT's, A+B etc. A logic analyser will not tell you this, it will giver you the transition times, but not voltage information. To look at analogue waveforms a Oscilloscope is the tool to use (of course Scopes are all digital, but they display an analogue response).
I'm not sure what you mean about an Oscilloscope not having a voltage display, that is what they do!! |
Old Nick,
You are right. My question is a little bit difficult to answer. It was not a good one.
Trying to clarify the ideas, I'd like to let you another question:
Is a digital oscilloscope capable of doing anything that a analog one does (both with the same BW) ?
Thank you
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Old Nick
Joined: 14 Sep 2007
Posts: 445
Helped: 49
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04 Nov 2007 14:38 analog oscilloscope digital oscilloscope |
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The benefit of logic analyzers is that you can display many channels 16+ usually, so you can watch transitions (between 1 and 0, not voltage information) times etc over a multitude of paths. Analog scopes will show you the voltages over the same period, but you'll only be able to monitor 2-4 traces.
You must realize though that a digital oscilloscope is not a logic analyser. A digital oscilloscope is (I assume) what you are refering to as an analogue scope.
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kevpat
Joined: 26 Nov 2006
Posts: 47
Helped: 7
Location: Scotland
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04 Nov 2007 18:53 phase shift analogue oscilloscope |
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rprodrigues,
As you probably realise analog and digital scopes both have their uses and it would be ideal if you can have both an analog and digital scope in your lab. However if you can only have one I would recommend a digital scope as it has so many additional features that an anog scope does not have. The maths functions are very useful in digital scope and can be used to carry out FFT's, histogramming etc on a signal. One problem with digital scopes you will have to be careful with however is aliasing (look it up) and this will be a bigger problem if you purchase a relativley cheap low sample rate scope.
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ddkrishna
Joined: 09 Aug 2005
Posts: 73
Helped: 4
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06 Nov 2007 1:04 analogue or digital oscilloscope |
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Analog oscilloscope will certainly give you better results in cases like phase shift measurement.
Digital oscilloscopes on the other hand will have auxiliary functions like file saving, image saving etc
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