What are oscilloscopes?
Oscilloscopes, or oscillographs, are devices from the field of electrical engineering that measure voltage changes over a defined time and display their course in the form of curves. Many devices are controlled by electrical signals, which are made visible by means of an oscilloscope.
- the x-axis indicates the time and
- the y-axis the measured signal strength.
In this way, standard voltages, voltage deviations, frequency fluctuations, etc. are visualized.
In the past, only analog oscilloscopes using cathode ray tubes were used. These devices are being replaced more and more by digital devices, where the analog waveform is sampled and stored digitally. The digital devices can capture and display other mathematical functions such as transformations, frequency determinations, frequency anomalies and more.
How do you find the right oscilloscope?
To find the right oscilloscope for your application, you need to define what exactly you want to measure. If only DC voltage signals or a sinusoidal, stable AC voltage is to be measured, a simple multimeter would suffice. If an oscilloscope is required, the question arises whether it should be an analog device with the well-known blurring as well as pure image storage or a more expensive, digital device with a significantly more powerful range of functions for high-frequency signals or a mixed-signal or mixed-domain oscilloscope. In practical terms, it must also be clarified how much space is available or whether it has to be a portable instrument.
As far as technical parameters are concerned, the following requirements in particular must be taken into account
- sampling rate
- memory depth
- input impedance and the
- number of input channels.
What is bandwidth?
The bandwidth is one of the decisive criteria for the selection and price of a scope. It defines the width of the interval in a frequency spectrum, i.e. it determines the maximum signal frequency that the respective oscilloscope can measure with minimum attenuation.
As a standard guideline, an oscilloscope needs a bandwidth that is at least twice as large as the maximum frequency of the analog signal to be measured. The higher the signal frequency, the more bandwidth is needed for the measurements to be meaningful and free of interference.
What is meant by sampling rate?
The sampling rate describes the number of samples of the analog signal per second and is specified in S/s - samples per second. The analog voltages are converted into digital information - so-called samples - using analog-to-digital converters, which is why the term sampling rate or sampling frequency is often used.
Therefore, the faster the sampling rate, the less information of the signal is lost between the individual samples, and consequently the more exactly the curve corresponds to the actual values of the measured signal. Conversely, the minimum sampling rate is particularly valuable for mapping signals that change only slowly over a longer time interval.
A reasonable sampling rate is usually defined as a function of bandwidth. Normally, it is assumed that it must be about five times the oscilloscope bandwidth in order to display as accurate a graph as possible.
What is the memory depth?
The memory depth indicates the maximum number of samples stored. Consequently - the larger the memory capacity, the more samples can be stored. So, when comparing scopes with different memory capacities, for the same unit of time, the instrument with a high memory depth can store significantly more values and display a more accurate trace than an instrument with a lower memory capacity.
Why buy oscilloscopes from LXinstruments?
By buying from us, you are making the right choice, because we are experts in measurement technology. Not only the trade with measurement technology instruments is our business, but at LXinstruments and our sister company bsw TestSystems & Consulting we are also proven specialists for the integration of turnkey test systems up to high performance systems as well as high frequency systems in the terahertz range.