User Manual

Analyzing a wave

form

An example of using a math waveform is

to calculate instantaneous power (current

times voltage

) by multiplying a voltage

waveform and a current waveform.

Math waveform tips

Math waveforms get their horizontal scale and position from the sources channels. Adjusting these controls for the

source wav

eforms also adjusts the math waveform.

Adding or

subtracting waveforms with different units sets the math waveform units to “?”.

You can ta

ke automatic measurements on math waveforms similarly as on channel waveforms. Just select the Math

side menu in the Measure screen and select the measurements to apply.

You can save a math w aveform to a reference memory or to a ﬁle on a USB drive. You can also recall (load) math

waveforms into reference m emory. (See page 72, Recalling waveform data.)

You can zoom in on math waveforms using the Navigation controls (Zoom button and Multipurpo se knob).

Using F

FT to see signal frequency information

There are many signals that have some sort of distortion or unwanted characteristics. Sometimes these distortions do not

affect how that signal works i n the circuit. But often system clock pulses, signals induced from a nearby printed circuit path,

or noise from a power supply or other source can affect a signal and prevent it from operating correctly. The FFT function is a

powerful tool to help you ﬁnd the frequencies of unwanted signals that are embedded in your main signal.

The FFT function uses Fast Fourier Transformation (FFT) mathematical calculations on the waveform data to determine the

component frequencies in the signal. The resulting w aveform shows a series of ‘spikes’ along a horizontal axis, w here each

spike represents a frequency component of the waveform and its amplitude. In other words, an FFT is a basic spectrum

analyzer function to analyze frequency components of a waveform.

1. Acquire and display several cycles of the

waveform.

NOTE. You can only display FFT waveforms for

2000 and 20K point record length waveforms.

2. Push F (FFT) button.

TBS2000 Series User Manual 59