The logic analyser captures, records and displays digital signals from a circuit.
It also displays the captured signals in the form of a timing diagram or tabular data on either a built-in display or via a host PC (USB instrument).
The recording of digital signals can be triggered by a specific event, such as a particular data pattern occurring. The data is then captured on the rising or falling edge of a clock signal. The clock can be another signal being analysed or derived from an internal variable frequency oscillator.
Logic analysers are used to identify specific data faults. If these faults arise at apparently random times then it may be necessary to capture very large amounts of data and analyse it after the event. This can be very time consuming and may not prove fruitful.
To simplify the task of analysing the captured data a combination of setting the trigger point to be as close as possible to the faulty data and choosing only to capture relevant data. This can be achieved by filtering the data captured. Obviously, this does require some knowledge of the nature of the faulty data.
Mixed Signal Analysers
Mixed Signal Analysers allow both analog and digital signals to be displayed together on the same timing diagram.
Some logic analysers
, for example the ZeroPlus
range, also offer a range of decoders so that bus and interface signals can be displayed in a high-level data format (determined by the protocol being decoded). This capability can save a lot of time when analysing signals.