When we launched this blog, we directed you to an article published by Richard Soden Application Engineer who underlined how to interpret quoted specifications in datasheets. As a matter of fact, you should start from there when you need to select an analog-to-digital converter that responds to your signal acquisition and processing requirements. However, the conclusion of this paper was quite straightforward. READ MORE It may be very difficult to choose a digitizer only based on the published specifications because somewhere each manufacturer sets his own testing requirements and rules to provide its specifications. It’s therefore unlikely possible to compare 2 digitizers coming from 2 different manufacturers based on published specifications. Then what can you do?
You may say that most manufacturers give typical values in their datasheet which somewhere may be comparable since there are not warranted but show an average performance value. This is true but to make sure the average value is “solid”, it would may be a good idea to ask a manufacturer on how many tested channels these typical values are set? Are the tests performed on the whole temperature range? How many measurements points are taken during the test phases? Typical values can be aggressive or not. It all depends on the manufacturer testing philosophy and methodology. At Agilent, the philosophy is rather conservative. Typical values should be good for at least 80% of the modules even then there are not warranted as per the specification following model:
As a matter of fact at Agilent a specification will only be warranted after a large number of channels have been tested. To minimize the number of human errors, these tests should be automated. Today, high-speed digitizers are more and more performing which renders the fixation of specifications harder to get. Indeed, the higher the performances are, the most difficult it is to find signal sources that are reliable to test the signal integrity. The source of the test is therefore very important. Nowadays, the signal generators have to have better and better phase noise and be higher and higher in frequency.
As a general result, the only option to make sure you will be ordering the digitizer that is best suited to what you need to do is to contact the manufacturers, explain them what type of signals you want to convert and what type of processing you would like to do with it. Once your needs have been clearly defined, you will need to request a demo unit to be really able to compare 2 similar hardware on the paper. Then once the choice is done and the order is passed don’t forget to require you calibration certificate in order to know the exact performances of your acquired module.Please let us know if you would like to learn more about our testing processes and how we fix our specifications and don’t hesitate to contact us for any other matter related to digitizer technology. Tags: datasheet interpreation share specifications