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Now I'm trying to prove the Sawtooth Ramp wave output of ADF4159 with tektronix oscilloscope as the below. But as you can see the below image, it's FREQUENCY-TIME graph. So I want to know how to prove the Sawtooth Ramp wave output of ADF4159 with tektronix oscilloscope. Would you please help me? enter image description here

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    \$\begingroup\$ Before even trying, you need to know if your scope works to 12GHz and above. There are a scopes that go that high, but they are expensive. \$\endgroup\$ – JRE Aug 16 '17 at 4:46
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    \$\begingroup\$ Alternately, pre-scale the synthesizer output down to a frequency your scope can handle, and measure that. \$\endgroup\$ – The Photon Aug 16 '17 at 4:54
  • \$\begingroup\$ @JRE here is written such as TDS5054, 500Mhz 5GS/s \$\endgroup\$ – ele_911 Aug 16 '17 at 5:49
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    \$\begingroup\$ @ele_911 So that oscilloscope has a 500 MHz front-end bandwidth, and so won't pass your 12 GHz signal. \$\endgroup\$ – Blair Fonville Aug 16 '17 at 6:00
  • \$\begingroup\$ So, you will have to either follow the suggestion from @ThePhoton, or get a spectrum analyzer that can do waterfall diagrams. \$\endgroup\$ – JRE Aug 16 '17 at 9:30
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Note that your chip isn't going to make a 12 GHz signal on its own. You need to use it with an appropriate VCO, loop filter, and reference clock generator to make a complete synthesizer.

Having done that, you can pre-scale down your 12 GHz synth's output and use it as the REF input to a second PLL (probably optimized for fast tracking rather than low phase noise). Then use your 'scope to monitor the VCO control signal of the 2nd PLL to get the frequency-time graph you're looking for.

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  • \$\begingroup\$ Analog devices offers the full board for the purpose of evaluation, analog.com/en/design-center/evaluation-hardware-and-software/… I guess the question is what Analog Devices engineers are using to generate those nice frequency-time plots and put them into their datasheets. \$\endgroup\$ – Ale..chenski Sep 27 '17 at 7:03
  • \$\begingroup\$ @AliChen, to be honest, the easiest way to make the graph would be 1. First trace out the f-vs-V relationship of the VCO in the PLL circuit. 2. Monitor the VCO control voltage during the test. 3. Calculate frequency from voltage. 4. Plot it. It won't be 100% accurate if the temperature changes, but good enough for a "typical" graph. \$\endgroup\$ – The Photon Sep 27 '17 at 15:44
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You possibly can't without some extra hardware or capabilities. Oscilloscopes aren't typically designed for frequency vs time. If your scope actually has a high enough sample frequency and bandwidth, it probably also has an fft mode in which you can view the signal in the frequency domain. But even then it will show you magnitude vs. freq and not freq vs time (and you would see something like a single rectangular pulse centered at the middle frequency).

Some fancy scopes have Matlab built in. In this case you could demodulate the incoming samples in real time, to extract the frequency component, and then output the freq signal to the oscilloscope viewport. That's how I would do it if I were required to.

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What you're looking to do is plot a measurement trend of a frequency measurement.

This is built into some oscilloscopes (at Keysight, it's the 3000T X-Series oscilloscopes and up), but not others. Often, it's a math channel.

If your scope can't plot that, you're out of luck.

If you need to see a 12 GHz signal, you'll need a very high bandwidth oscilloscope (pronounced "expensive") and it will likely be able to do it.

I'd also point out that if you just need to check the frequency of a sine wave, you could probably get away with a lower bw scope, but the signal will look very attenuated.

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  • \$\begingroup\$ The Keysight 3000T scope operates only up to 1 GHz. The OP doesn't want to see the 12 GHz signal, he wants to see its frequency as a function of time. How do you convert the 12 GHz frequency into voltage then? \$\endgroup\$ – Ale..chenski Sep 27 '17 at 6:34

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