The 10 Best Digital Oscilloscopes

Whether you're an automotive engineer measuring the vibrations of an internal combustion engine to diagnose operational and design problems, a hospital worker, a television repair technician, or you're simply trying to maintain your electronic equipment, a digital oscilloscope will be a valuable and necessary tool to keep on hand. Also referred to as a digital storage oscilloscope, the digital oscilloscope is an electronic device comprised of various software and hardware modules working together to capture, process, display, and store data about varying voltages over time.

This data can include measurements of sound, vibration, and other electrical signals displayed as a visual graph showing how a specific signal has changed and what that means in terms of a needed repair or action. The vertical Y-axis of the device's graph represents the specific voltage recorded, while the horizontal X-axis represents time, both of which form a shape (or waveform) that is measured against a calibrated scale. The waveform is used to read the status of a signal in order to determine how it has changed or stayed the same within a given time frame. A change in waveform height signifies a change in voltage, whereas a flat, horizontal line means there has been little to no change at all. The use of waveforms as a diagnostic tool makes possible the diagnosis of electrical anomalies that would otherwise go unnoticed by the naked eye due to the speed at which they may occur. Furthermore, waveforms can be analyzed on the device for frequency, wavelength, amplitude, and distortion.

A digital oscilloscope has several components and uses a series of micro-controllers designed to sample an input signal at varying points in time. This is accomplished with an analog-to-digital converter. The resulting voltage readings at these points are converted to digital values called sample points. Additional elements include a CRT or LCD monitor, for visualizing voltage readings; a vertical input amplifier, used to find the device's gain and frequency bandwidth response; a horizontal system, consisting of a sample clock that calculates how often the analog-to-digital converter takes a sample (i.e. a sample rate); a digital memory, responsible for storing, accumulating, and reassembling the sample points into a complete waveform record on the display; and finally, a trigger system, which determines the starting and stopping points of the waveform record.

Various types of oscilloscope (aside from the digital storage variety) include the digital phosphor, sampling, and mixed signal devices. The digital phosphor oscilloscope delivers a higher level of signal visualization than that of the digital storage variety, making it easier to see and capture transient events such as glitches or signal transition errors. Equipped with both analog and digital input channels for analyzing a signal, the mixed signal oscilloscope offers the distinct advantage of efficiently determining the root cause of an issue by leveraging its superior triggering and high-resolution capabilities, making it the device of choice for debugging digital circuits, for example. The unique operating architecture of the digital sampling oscilloscope is such that a signal is sampled before any attenuation or amplification occurs. Having already been converted to a low frequency, this device uses its combination of a lower-bandwidth amplifier and its ability to process multiple waveforms simultaneously to provide a high-frequency function. This means the digital sampling oscilloscope can accurately capture signals whose frequency components are much higher than the oscilloscope’s typical sample rate.