You need to test, we're here to help.

You need to test, we're here to help.

01 October 2015

Taking Best Advantage of Oscilloscopes' Long Memory

Figure 1: Maintaining the maximum sample rate over more
timebase settings is possible with long memory
Two very important considerations when choosing a digital oscilloscope are the length of the acquisition memory and the amount of RAM available for processing of the raw data. Note that acquisition memory and RAM are not the same things, but they are still both important. The amount of acquisition memory often determines the fidelity with which an oscilloscope can record a signal. But that's only the first step; it's the instrument's processing horsepower is the key to finding signal abnormalities and characterizing circuit performance.

11 September 2015

For UART Debugging, Triggering is Key

A typical screen capture of UART serial decode/trigger software
Figure 1: A typical screen capture of UART
serial decode/trigger software
In our survey of how modern oscilloscopes and trigger/decode software (Figure 1) can ease the task of debugging embedded systems, we've covered the I2C and SPI protocols. Now we'll turn to the UART format, where triggering capabilities are of particular importance.

03 September 2015

Shaking Bugs Out of SPI Buses

Figure 1: Debugging of SPI on a Teledyne LeCroy
WaveSurfer 3000 oscilloscope
In the first post of this series, we considered some of the challenges of debugging embedded systems in general and I2C buses in particular. Modern digital oscilloscopes equipped with powerful trigger/decode software for the serial protocol in play go a long way toward easing the path to a properly functioning embedded system. Now we'll consider the particularities of the Serial Peripheral Interface and how the proper tools can make debugging SPI buses easier.

12 August 2015

Test Challenges for PAM4 Signals

The major test challenges posed by PAM4 signals
PAM4 encoding offers the advantage of doubling the bit rate in a serial data channel, doing so by increasing the number of voltage levels from two to four. It's a fairly complex modulation scheme, so it should be no surprise that it presents some test and measurement challenges.

06 August 2015

Why High Sampling Rates Matter

Figure 1: Here is an example of aliasing that results from
sampling a signal at less than the Nyquist rate of 2fmax
A key to accurate measurements with an oscilloscope is to ensure that the instrument maintains a high sampling rate. This applies to most measurements; conversely, for many measurements, accuracy may suffer as sample rate decreases. In the worst case, some signal components may be "aliased," meaning that the true signal shape is corrupted by the addition of bogus signal components that arise from undersampling of real signal components.

22 July 2015

Debugging I2C Buses in Embedded Systems

Debugging of I2C on a Teledyne LeCroy WaveSurfer 3000 oscilloscope
Figure 1: Debugging of I2C on a Teledyne LeCroy
WaveSurfer 3000 oscilloscope
Embedded systems became ubiquitous decades ago and are now found in everything from mobile devices to vehicles to the traffic lights that control their movements. These days, they're typically based on microcontrollers and perform some specific task(s) within a larger system, such as controlling your car's ABS system. They may or may not have any sort of user interface, and can range widely in terms of complexity and functionality.

PAM4 Test Setups Vary With Applications

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In an earlier post, we surveyed the basic properties of PAM4 signals. Now, we will examine some of the ways in which PAM4 is finding application in the real world and what test and measurement setups might look like for those applications.