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

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

18 June 2014

Applying Selective Averaging to Waveform Acquisitions

Figure 1: Using pass/fail testing to average only those
waveforms which are inside the tolerance mask
In the course of using an oscilloscope, there are likely to be times when you'd like to separate pulses based on wave shape or some parametric value and average only those pulses that meet some criteria. Teledyne LeCroy's oscilloscopes, and others, provide pass/fail testing using masks and/or parametric readings to qualify waveforms before they're added into an average or other processing function. Let's take a look at how this works on a Teledyne LeCroy oscilloscope.

09 June 2014

Video: Vertical Controls on the HDO Oscilloscopes

Here's another in our continuing series of tutorial videos. This time, we'll review the use of the vertical controls on a Teledyne LeCroy HDO oscilloscope. These controls facilitate positioning and scaling of waveforms vertically on the oscilloscope's display. Note that although we're demonstrating these controls on an HDO, you'd be rather hard pressed to find an oscilloscope from any manufacturer without a volts/div and vertical offset control. Thus, this video is applicable to whatever oscilloscope you have on your bench.

There are quite a few tutorial videos for a broad range of Teledyne LeCroy products on our YouTube channel. Head on over whenever you need a refresher!

22 May 2014

The Effects of Passive Probe Ground Leads

Teledyne LeCroy's PP108, a representative passive probe
Figure 1: Teledyne LeCroy's PP108,
a representative passive probe
When you open the box containing your shiny new oscilloscope, one of the items you'll likely find inside is a set of basic 10:1 passive probes (Figure 1). Those probes have a ground lead that you'll want to use when you make measurements. Your probe has a bandwidth specification that's probably somewhere between a few hundred megahertz to 1 GHz; that spec was obtained at the factory with a specialized test jig having a specific ground inductance and source impedance. Now, the way in which you connect your ground lead can have a big impact on the real-world bandwidth and response of the probe.

15 May 2014

Back to Basics: S-parameters

S-matrices for one-, two-, and three-port RF networks
Figure 1: S-matrices for one-, two-,
and three-port RF networks
Suppose you have an optical lens of some sort onto which you shine a light with a known photonic output. While most of the incident light passes through the lens, some fraction of the light is reflected and some is absorbed (the behavior is also dependent on the wavelength of the incident light). You'd like to characterize that lens: Exactly how much light was reflected? How much passed through? What is it about the lens that prevented all of the light from passing through?

07 May 2014

VIDEO: Horizontal Controls on the HDO Oscilloscopes

In the first of two posts on how to control the Teledyne LeCroy HDO oscilloscopes, we cover a good deal of ground relative to the front-panel controls. One of the topics is the horizontal controls, which position and scale acquired waveforms horizontally on the instrument's display. In this short video, application engineer Jeff Krauss takes you through the application of the time/div and horizontal delay controls so as to best position your waveforms for optimal viewing.

16 April 2014

Is Your Testbench Mixed-Signal Ready?

A representative block diagram of a mixed-signal embedded system
Figure 1: A representative block diagram of
a mixed-signal embedded system
Mixed-signal design is ubiquitous these days, with hybrids of digital and analog circuitry turning up everywhere. A typical mixed-signal designer may be a hardware or software engineer with specific needs. They may be working with 4-bit, 8-bit, 16-bit, and 32-bit microcontrollers in a single embedded controller or across several embedded systems. They need to capture a host of different signal types and serial-data protocols and understand timing relationships between them. Then there's all the different sensor signals, power-supply signals, and PWM control signals to guarantee embedded system performance and reliability.

09 April 2014

Applying Multi-Stage, Multi-Rate Digital Filtering

63-kHz signal with 60-Hz component
Figure 1: The input signal shows both the desired 63-kHz signal
along with a 60-Hz component. Zoom trace Z1 shows the
60-Hz component in detail.
A while back, we posted some basics on how to apply digital filters to sort out signals with undesirable elements riding on top of them, i.e. a square wave that's being corrupted by a sinusoidal signal creeping in from somewhere in your system design. Now, let's look at how to extend the range of cutoff frequencies for digital filters, allowing them to be used even more effectively.