Clearly, the pulse carrier is shifting in a linear fashion across the pulse, from left to right, as designed. Notice that the linear ramp display is not going across the entire width of the RF pulse. This is because the 1,000 measurement limit in the trend calculation has been reached. It is important that a portion of the pulse FM function can be seen, and it is linear. For the frequency measurements across the pulse to have enough precision, it was imperative that the High Resolution acquisition mode was selected. SummaryFFTs in oscilloscopes are a valuable tool to give a frequency-domain view of a signal. This can ultimately be done with very wide bandwidth, enabling measurements not possible with a narrower band vector signal analyzer. Example FFT measurements were able to verify that a linear FM chirp signal was shifting the carrier frequency as it should. There also was a place for other math functions, namely the measurement trend function. In this example, such a calculation allowed for a very simple verification of a linear FM chirp.
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