Simulate Missing Components

Useful article in T&M EETimes

(http://www.tm-eetimes.com/content/create-stimulus-response-system-awg-and-digitizer/page/0/2) 

reminds us that you can easily simulate missing parts by capturing a waveform with an oscilloscope and feeding it to an AWG for repetitive output.

"The lack of a critical component can often delay testing and product development. If, however, you have access to the missing component's response waveform, you can generate it with an AWG. You can capture real-world waveforms with a digitizer or oscilloscope, then import the waveform into the AWG for playback. One such example is a CAN (controller area network) bus, a serial data stream generated by a steering angle sensor (Figure 5). This waveform was acquired using an oscilloscope and transferred to the AWG in ASCII file format.

Figure 5. An AWG can simulate a serial data stream such as those from a CAN bus.

A CAN bus signal is dual-channel waveform that represents the bus' differential (+ and –) components. To generate this signal, you need a two-channel AWG that's set to output the CAN bus waveform as a differential signal.

Once the AWG receives a trigger signal, it can generate the waveform so you can test the system. Additionally, these waveforms can be modified for margin testing of both amplitude and timing.

AWG’s can generate standard function generator waveforms such as sine, square, triangle and ramp signals. They can generate modulated waveforms and serial data patterns. They can even be used to replay real world signals that have been acquired by digitizers and oscilloscopes. AWGs can be paired with an accompanying digitizer and programmed using a manufacturer’s supplied software suite, a commonly available system integration software like MATLAB, or LabVIEW, or custom programmed in the language of your choice through an API (application programming interface).