Teledyne LeCroy Company Profile
Teledyne LeCroy is a leading manufacturer of advanced test instruments that measure, analyze, and verify complex electronic signals. The Company offers high-performance oscilloscopes and protocol test solutions used by electronic design engineers in a wide range of application and end markets. Teledyne LeCroy is based in Chestnut Ridge, N.Y. For more information, visit Teledyne LeCroy's website.
Measuring Current and Current Sharing of DC-DC Converters
The measurement of current in power converters, especially in switching DC-DC converters, is a very important task. This paper will establish a practical range for the time constants that we need to cover and will illustrate the effectiveness of DSP-based corrections for a few selected time-constant values. It will be shown and illustrated that even though the voltage across the capacitor of the RC element rides on the ‘quiet’ output voltage, for multiple reasons the common-mode voltage range and common-mode rejection of the measurement circuit is still very important. This paper analyzes the noise floor, dynamic range, confidence level and measurement speed of the impedance measurement solution.
The Gap Between Eye “Mark” Compliance, BER and BER Contours
Various methodologies existed over recent decades for treatment of eye diagrams. These coexist and in some ways collide. One such example is “mask compliance”. From the 1950s through the early 1980s, mask testing consisted of a grease-pencil shape drawn on the reticule of an analog oscilloscope … and instructions to be sure the oscilloscope trace stayed inside or outside of the shape. With the advent of digital oscilloscopes, methods appeared that approximated this kind of test in a more precise fashion. The grease pencil was abandoned. The mask was more precisely specified and drawn. The matter of detecting and recording a mask violation became more objective. Fast-forward 20-25 years and we have notions of Bit Error Ratio (BER) and contours of constant BER based on statistical analysis of digitized waveforms and eye diagrams. Mask tests are still around … but few seem to know precisely what they mean; just that they seem prudent. Here, we examine the meaning of Eye diagram mask testing, BER contours, BER and the relationships between them.
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