Keysight Technologies DSO-X 2014A, User Manual

Page: 81 / 378

Math Waveforms
4
Keysight InfiniiVision 2000 X-Series Oscilloscopes User's Guide 81
3 To make cursor measurements, press the [Cursors] key and set the Source
softkey to Math: f(t) .
Use the X1 and X2 cursors to measure frequency values and difference between
two frequency values (
Δ
X). Use the Y1 and Y2 cursors to measure amplitude in
dB and difference in amplitude (
Δ
Y).
4 To make other measurements, press the [Meas] key and set the Source softkey to
Math: f(t) .
You can make peak-to-peak, maximum, minimum, and average dB
measurements on the FFT waveform. You can also find the frequency value at
the first occurrence of the waveform maximum by using the X at Max Y
measurement.
The following FFT spectrum was obtained by connecting a 4 V, 75 kHz square
wave to channel 1. Set the horizontal scale to 50 µs/div, vertical sensitivity to
1 V/div, Units/div to 20 dBV, Offset to -60.0 dBV, Center frequency to 250 kHz,
frequency Span to 500 kHz, and window to Hanning.
NOTE
Scale and offset considerations
If you do not manually change the FFT scale or offset settings, when you turn the horizontal
scale knob, the span and center frequency settings will automatically change to allow
optimum viewing of the full spectrum.
If you do manually set scale or offset, turning the horizontal scale knob will not change the
span or center frequency settings, allowing you see better detail around a specific frequency.
Pressing the FFT
Auto Setup softkey will automatically rescale the waveform and span and
center will again automatically track the horizontal scale setting.