Logic Analyzers

Logic analyzers are tools for measuring the performance of signals on a digital bus and for debugging digital systems. Essentially, they make digital measurements instead of analog measurements unlike a signal analyzer or oscilloscope. A logic analyzer can show data in terms of timing diagrams, or it can decode the received data into the protocol or state machine information for easier debugging.

Selecting the right logic analyzer depends on several features tailored to your specific requirements. Considerations such as the channel count, sampling rate / mode, protocol support, memory depth, and software compatibility play pivotal roles in determining the ideal fit for your tasks. Additionally, assessing your threshold needs is crucial. Ensure that you fine tune the logic analyzer and accompanying probes  to the signal levels of your system under test.

Synchronous (state) capture means that the measurement system in the logic analyzer determines the logic value of digital parallel buses or control lines when there is an associated valid clock, such as a rising edge on a probed system clock line.  In contrast, asynchronous (timing) capture means that the measurement system samples the value of a bus or individual digital lines asynchronously from the system under test or not in sync with the system.

Many industries use logic analyzers that require protocol analysis and digital system debugging. Examples include embedded systems development, digital circuit design, and debugging digital protocols like I2C, UART, Ethernet, USB, and DDR memory. By capturing and visualizing the precise sequence of high and low voltage states over time, they unveil critical insights into the synchronization and coordination of digital signals. This capability proves invaluable in debugging communication errors, optimizing data transfer rates, and ensuring protocol compliance —  Keysight tailors logic analyzers and interposers specifically for DDR memory protocol analysis.

For precise logic analysis, Keysight provides high-impedance probes with interposers that fit between the memory chip and the memory controller. This process enables you to make signal quality or protocol measurements with minimal effect on the system under test. These robust probes and interposers ensure solid connections in varied conditions, while their noise-resistant design protects against electromagnetic interference for clean, accurate data capture. Paired with Keysight logic analyzers' front-end circuitry, these probes optimize performance, guaranteeing precise measurements at specified clock rates.

Oscilloscopes measure and visualize the analog signals in a system, while logic analyzers limit themselves to discrete digital signals. Logic analyzers generally support more channels than an oscilloscope, which can be important when testing systems with multiple serial or parallel bus channels. Oscilloscopes can measure digital signals; however, analog measurements of digital signals are primarily concerned with rise time, eye height, and other signal integrity measurements rather than studying the logic levels and timing of a digital signal. Mixed-signal oscilloscopes feature digital logic analysis capabilities by supporting digital channel inputs as well as analog ports, although rarely as many channels as a dedicated logic analyzer.