New-Tech Europe Magazine | Q3 2021 | Digital Edition

Automate Measurements with the Digilent Analog Discovery PRO

New-tech Magazine group

Oscilloscopes are the tool of choice for every engineer when it comes to measurements. If the instrument can also work as a waveform generator and can do some mathematical calculations on the signals acquired, or allows automated tests, even better. For many measurement tasks that designers face in their daily work, oscilloscopes are an excellent choice as they offer many ways to achieve good results. But occasionally, it is necessary to document the obtained data or to process the signals further. Just as a simple example: You want to quantify the power of a certain block in your circuitry, and you are also interested in the waveform originating from these calculations, not only in the absolute values. But most oscilloscopes only

measure voltages, the current, and therefore the power cannot be measured directly. So, a shunt resistor must be used to obtain the current passing through the circuit, allowing for the computation of the power consumed (Figure 1). You also have into account that the channels of most oscilloscopes are single ended, and all measurements therefore must be referred to ground. It is not possible to read the voltage drop over the load directly. A second measurement taking the voltage drop over the shunt resistor is necessary. In the end, this means that some computations have to be done to get the power reading. Here oscilloscopes capable of doing the calculations right on the device, like the Analog Discovery Pro (ADP 3450) from Digilent, enter the game. This four-channel oscilloscope (a two-channel version is available as well) with 14 bits of resolution at a

sampling rateof up to0.5GSamples/s is a true mixed-signal measurement device that the meets the needs for professional-level electronic test- benches at the office or at home. Besides the analog inputs, it also provides engineers with 16 digital I/O-channels, two external trigger inputs, and a two-channel arbitrary waveform generator (Figure 2). Analog Discovery Pro is smaller and lighter than a laptop and has no built-in user-interface. It connects to a host computer through one of its four high-speed USB 2.0 ports or through its Ethernet interface, and it is controlled by the free WaveForms software from Digilent running on the host. This software, refined by over 10 years of customer feedback, provides a user experience with the look-and-feel of traditional benchtop applications and is compatible to the macOS, Windows, and Linux operating systems.

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