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This article is to share with you about how to use the Limit function in Ripple, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

We normally set the Limit Line when setting the test specification line, and control the actual product waveform by adding frequency points and coordinate values.

However, we found that under the measurement and analysis menu, there is also a [Trace Ripple Limit] called ripple test function, which may not be commonly used. The official definition of this function is that Keysight can not rely on limit testing, but can set fluctuation limits to assess whether the measurement results are qualified or unqualified. This function is called ripple testing.

What does it mean: the ordinary Trace Limit Line is to set one or more limit values or multiple limit lines to control the product waveform, no matter how the product waveform changes in the actual testing process, the set specification line is fixed and will not have any displacement.

But the ripple test is different. The Chinese translation of Ripple is ripple, ripple and fine wave, which means that the actual waveform of some products will not be very smooth or stable, some active devices may change with power or ambient temperature, and the actual test waveform will have a slight drift in a certain range. So how do we define the amount of drift or ripple (or ripple) at this time?

For example, a pool of stagnant water, which is fixed there without anyone to stir the water surface is very smooth, but when there is a pebble or artificial stirring, the water surface will produce water ripples and some water droplets will splash. this phenomenon corresponds to the instrument setting can be understood as a ripple phenomenon, then the splashing range of water droplets is how much, corresponding to the instrument setting is the Max Ripple specified fluctuation limit.

More officially, Ripple refers to the maximum and minimum on the curve, how far is the average or midline offset, and if the curve drifts as a whole, the average or midline also drifts, so you can see the movement of the specification line, and the limit line itself is the spurious range we specify.

If the ripple value specified using the fluctuation limit is not exceeded by any measurement point on the trace, the ripple test will determine that the measurement is Pass, otherwise it will be determined to be Fail. For the measurement points in the excitation range where the fluctuation limit is not specified, the test will determine that the measurement is Pass.

When you open the Ripple Line settings page, you will first find that [Ripple Value] needs to choose Absolute Value or Margin. Aabsolute Value displays absolute values, that is, the difference between the maximum and minimum values in the frequency band. Margin shows the margin, that is, the difference between the absolute value of the ripple and the fluctuation limit.

After setting up, turn on the [Ripple Test] function, and then you can edit the specification line.

For example, when I set up a ripple limit line, the frequency range I specify is 2~4GHz, and the amplitude fluctuation range is 5dB. The wobble amplitude of the measured waveform of the product does not exceed the limit of 5dB, and the test result is Pass.

When I artificially change the position of the waveform (the actual waveform has shifted down), I will find that the control line also moves (but the frequency does not change), and the control line moves within the specified range of 5dB.

If the fluctuation range exceeds the set value, the result will be Fail.

Anli's VNA also provides the function of saving and calling specification lines. Different types of machines set different specification lines, and the files of specification lines can be saved to the PC with the name of the machine, and then directly called during production, which is very convenient for users to operate for some machines that control many Line.

The above is how to use the Limit function in Ripple. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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