Analog oscilloscope provides engineering and technical personnel with the waveform of seeing is believing, which can be tested with confidence in the specified bandwidth.The visual nerves in our five senses are so sensitive that the screen waveform is instantly reflected to the brain for judgment, allowing subtle changes to be felt. Therefore, analog oscilloscope was very popular among users at that time.With the emergence of digital oscilloscope, it has begun to replace analog oscilloscope in some cases. Whether to choose analog oscilloscope or digital oscilloscope as measuring tool completely depends on the work to be measured and the signal to be measured.In some cases, the advantages of digital oscilloscope are obvious, while in other cases, analog oscilloscope is better than existing digital oscilloscope.
Simple repetitive signals are often well observed using analog oscilloscopes (ART) and digital oscilloscopes (DSO).But both have their advantages and limitations.For analog oscilloscope, because of the short afterglow time of CRT, it is difficult to display the signal with low frequency.Since the sweep brightness on the oscillograph tube is inversely proportional to the scan speed, it is difficult to see the low repetition rate signal with fast rise and fall time.However, the sweep brightness and scanning speed of DSO are independent of the signal repetition rate.Depending on the situation of the signal being measured, this may be an advantage or a disadvantage.There is little difference between the performance of a DSO and an analog oscilloscope for a fast edge showing a repetitive signal with a sufficient repetition rate.Both kinds of oscilloscopes can be used to observe the signal waveform very well.
When measuring signal parameters, DSO has the advantage of automatic measurement.When using the analog oscilloscope, the user must set the cursor and analyze and understand the waveform to get the measurement results.If you want to adjust the work, then the general best use of analog oscilloscope.This is because the real-time display capability of the analog oscilloscope enables it to display the input voltage at every moment.The wave update rate (the number of times a trace is drawn on the screen per second) is high.At high scanning speeds it can perform well over 100,000 scans per second.So any change in the signal is immediately apparent. And some of the signal changes on the display screen in the form of waveform brightness changes.In contrast to the analog oscilloscope, DSO displays the waveform reconstructed from the collected waveform data.The waveform is collected much less than 100 times per second.On some oscilloscopes, no more than five times.The result is a significant time delay between when the signal changes and when the changed signal appears on the screen.This is a major drawback to using DSO when tweaking your system.
The simple repetitive signals described above can be found in many fields of electronics and are often used as carriers of information.Therefore, it can take many forms, such as sine wave, pulse, oblique wave or step wave.Moreover, multiple modulation signals and multiple modulation modes are often used simultaneously. A common example of a complex analog signal is an all-tv signal.The signal is composed of components of different frequencies and amplitudes.It includes both pulses and square waves, plus additional sinusoidal waves that are phase shifted to represent color information.For such cases, analog oscilloscopes and DSO have their own special advantages, each of which can make the best observation of different parts of the signal.
For example, the analog oscilloscope has infinite resolution and high scanning times per second, which can show the distribution of waveform in time.The brightness change on the waveform scan is proportional to the duration of the signal at a particular level.This shows the color modulation very well.Because the oscilloscope has a high waveform update rate, it can immediately show the effect of adjusting the system.When using DSO, due to its limited number of sampling points and no change in brightness, many waveform details cannot be displayed.Although some DSO may have two or more brightness levels, this is only a relative difference and the oscilloscope's limited display resolution makes it unable to reproduce the effect of the simulation display.
If you want to display only a small portion of a line of video signals, such as TV in a particular line sending test signals, teletext data, or color pulses on a particular line, it is best to use DSO.If an analog oscilloscope is used, the relatively low signal repetition rate, coupled with the short time of the signal part to be observed, will easily lead to the display of the picture is too dark to see. However, DSO has the same brightness regardless of the repetition rate of signal, so it can display this signal at a very high brightness.If the repetitive waveform also contains sharp peaks or burrs of very narrow width, then it is not possible to see these spikes or burrs by observing the entire waveform with an analog oscilloscope.With DSO, these spikes can be displayed using peak detection.
The main difference between analog oscilloscope and DSO is that DSO can store waveform information.This makes DSO especially valuable in the study of non-repetitive signals and transients.Nonrepetitive signals and transients can be seen in many systems. For example, to measure the impulse current of an electrical system, to measure the parameters in a destructive experiment, only one measurement can be made in a destructive experiment.Although many analog oscilloscopes also often have a single measurement capability, that is, can produce a single time base scan.
Before DSO, nonrepetitive signals and transients were difficult and costly to observe, so such work was often abandoned.At the time, observing such signals required expensive analog storage oscilloscopes, cameras, and long afterglow oscilloscopes.
If an event occurs only once, then the analog oscilloscope is usually unable to cope.This is an opportunity for DSO to demonstrate its ability to capture this rare one-off event and display it for as long as it wants.This rare event may even be the result of interference.By triggering with the interference itself, the DSO has the ability to show pre-triggering, including the cause of the interference.