Question: "How do you execute GDDR5 device training during a shmoo run?"

Due to high speeds, GDDR5 devices require adjusting timings through device training steps. These timing adjustment values are dependant on device settings like VDD, frequency etc. When shmooing along such a parameter the device training needs to be executed repetitively during the shmoo run. The shmoo supplied with smartest do not allow this, so how can this be done? PDF, 285 KB.

Question: “What is a best way to measure pulse width of DisplayPort transmitter with PS3600?”

I need to measure a pulse width of a pattern generated by my DisplayPort transmitter as part of transmitter test. What is the best way to perform such a measurement on PS3600?. PDF, 20 KB
 

Question: "What's the best approach to perform basic measurements on a free-running clock?"

I need to perform some basic measurements (frequency, jitter, rise/fall time) on a free-running clock. What’s the best way to do that?

Question: "What is the spectrum shape of the DAC quantization noise?"

In a previous Q&A, it says "The quantization noise of the DAC appears almost like spurious frequencies." Please show the examples. PDF, 294 KB

Question: "What’s the difference between MIPI D-PHY and MIPI M-PHY?"

DigRF v4 is the recently introduced successor of DigRF v3. DigRF v4 uses MIPI M-PHY as physical layer. How does MIPI M-PHY compares to MIPI D-PHY? PDF, 20 KB.

Question: "There are many small spurious frequencies shown in DAC output. What are they?"

When I check the spectrum performance of my DAC output with a spectrum analyzer many small spurious frequencies are shown. They are not the harmonics and they are also seen in a lower frequency range. The distances of each spurious frequency component are the same but this distance is not related to the sampling clock of the DAC. What are they? PDF, 23 KB.

Question: "What are the differences between other functional vector files and special scan vector files?"

Often vectors of scan tests are stored in a different format compared to other functional tests, although basically scan test is like any other functional test: Vector by vector certain values are forced at the inputs and certain values are expected at the outputs. Nevertheless, a special scan test vector format exists – what is the difference? PDF, 28 KB.

Question: "Is there any difference between ADC and DAC linearity?"

A test program is developed for linearity tests of both ADC and DAC devices. Is there any difference in ADC and DAC linearity testing? Can I use the same calculation algorithm for both of ADC and DAC linearity tests? PDF, 19 KB.

Question: "What is the difference between 'Boundary Scan Test' and 'Scan Test'?"

Often devices support both scan test and boundary scan test. What is the difference between 'Boundary Scan Test' and 'Scan Test'?

Question: "What Type of RF Connector Provides the Best Performance?"

There are a couple of different RF connectors available (like SMA or SMP) that I can use for RF projects, but which one provides the best RF performance?

"Why do I see unexpected low signal amplitude in low-power mode during a MIPI D-PHY transmitter test on my ATE?"

When I try to characterize the output transition from high-speed to low-power mode on a data lane of a MIPI device on my ATE, I am measuring different signal voltage levels in low-power mode compared to what I am expecting. Why do I see smaller low-power signal voltage levels compared to the real application?

"Why does my INL/DNL result look bad?"

The INL/DNL result of an ADC is bad. I expected +/- 1 LSB but I am seeing 10 LSBs of error. What is wrong?

"How can I achieve optimal test time for power measurements?"

This seems like a basic question, but it is loaded with a lot of potential benefit. First of all, a lot of people tend to use averaging to acquire good repeatability of their measurements. This habit stems from the use of spectrum analyzers on the bench, where test time is not necessarily of concern and averaging always stabilizes the measured values...

"Why is Random Jitter Always Modeled with a Gaussian Distribution?"

I always read that random jitter is Gaussian and unbounded. But why do we use a Gaussian distribution (and not another type)?

"Why does my Total Harmonic Distortion (THD) result look poor?"

The THD result of an ADC is bad. I expected -58 dB THD of 1 MHz signal at 10 MHz bandwidth but it only has -41 dB. What is wrong?

"How can I improve my inter-modulation distortion (IMD) results?"

Inter-modulation distortion occurs when multiple input frequencies (usually two) to a non-linear device cause additional unwanted signals. To improve the test, it is necessary to minimize the effects of the RF source or the RF measurement sub-system.

"How do I get the expected results when measuring setup and hold time on a DDR interface?"

I need to measure setup and hold time on a high-speed DDR interface. When I look at the results the measured setup and hold times are much smaller than expected. What shall I do?

"Why is my SNR result is so bad?"

The SNR result of an ADC or DAC is bad. I expected 60dB SNR of 1 MHz signal at 10 MHz bandwidth but it only has 45dB. What is wrong?