Analyzing RADAR Signals with Demodulation

Figure 1: An example of a radar
signal with 1-GHz RF carrier

In the electronic warfare milieu, one of the most common RF applications is that of radar systems. Radar, which uses RF energy to determine the range, angle, and/or velocity of objects, can be used for detection of aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain, among other things. An oscilloscope's demodulation math function is very helpful in analysis of radar signals, so let's look at a couple of examples of how to approach such measurements.

Video: The Many Varieties of Oscilloscope Probes

Got a minute (OK, a minute and a half)? Take a look at this quick tutorial video that takes you through the four basic types of probes and what they're used for:

If this little thumbnail sketch whetted your appetite for more info on oscilloscope probes, we've got you covered with a series of popular blog posts on the topic:

The Realities of Oscilloscope Probes

Back to Basics: Probes (Part I)

Back to Basics: Probes (Part II)

Back to Basics: Probes (Part III)

Back to Basics: Probes (Part IV)

Understanding Probe Calibration Methods

Understanding Probe Calibration Methods (Part II)

The Effects of Passive Probe Ground Leads

Analyzing Pulse-Width Modulation Signals

Figure 1: Persistence display provides
a quick-and-dirty view of a PWM signal

Pulse-width modulation (PWM), a favorite technique for achieving analog ends through digital means, finds application in all kinds of end systems. Motor control might be the number-one application, but PWM turns up in telecommunications, audio systems and amplifiers, and any number of other uses. Armed with a capable oscilloscope, one can thoroughly analyze and understand the behavior of PWM circuits.

Determining an RF Burst's Envelope

Figure 1: Demodulation is one method
of determining the envelope of an RF burst

There aren't many wireless environments more complex than that of the electronic-warfare arena. Spread-spectrum clocking, frequency hopping, jamming, you name it: It's an RF jungle out there, and signals intended for electronic-warfare applications demand precision instrumentation and skilled hands for test and measurement purposes.

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.

For UART Debugging, Triggering is Key

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.

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.