Ett-p Rdjournal Â€ " a Hewlett-packard Journal Contents: April 1983 Volume 34 Â€¢ Number 4 Noise Figure Meter Sets Records for Accuracy, Repeatability, and Convenience, a New Microcomputer-controlled Laser Dimensional Measurement and Analysis System Dimensional Metrology Software Eases Calibration S
A New and Laser Dimensional Measurement and Analysis System, by Robert C. Quenelle and Lawrence J. Wuerz It's more compact, more powerful, and less expensive than previous systems. Dimensional Metrology Software Eases Calibration, by Lawrence J. Wuerz and Chris topher time An HP-85 Computer automates complex laser calibrations to save time and reduce errors. Automatic Compensation, by Deane A. Gardner Sensors help the laser measurement system compensate for atmospheric conditions and material temperature. Laser Optical Components for Machine Tool and Other Calibrations, by Richard R. Bald component Larry E. Truhe, and David C. Woodruff Each optical component is designed to mea sure a particular degree of freedom of a machine tool. Manufacturing the Laser Tube, by Richard H. Grote Custom-designed machines auto mate the process to control quality at every step. Mechanical Design Features of the Laser Head, by Charles R. Steinmetz Low manu facturing cost and ease of repair are designed in. Measurements that used to be tedious or inaccurate or both are now neither. Laboratory Notebook â€ " Mass Storage Unit Exerciser The problem was how to provide built-in diagnostics for a flexible disc drive that didn't come with them. In this Issue: In this surface, world of ours, there's no such thing as a straight edge, a flat surface, or parallel lines. Those who inhabit the world of precision machining are constantly reminded of these newest as designers demand tolerances just a little tighter than the newest and best Â» machine a can deliver. In this environment, it's essential to know just how imperfect a machine tool is. Many machine tools are computer controlled and can be programmed to compensate for errors if accurate calibration data is available. Because today's machine tools are very, very precise, it takes a super-precise measuring tool 22, Laser them. The subject of the articles on page 3 to 22, the HP 5528A Laser Measurement System, is such a tool. The LMS consists of a laser head, precision optical components, and a microcomputer-based measurement and display unit, optionally augmented with an HP-85 Computer. The cover photo shows it doing its job. The LMS is used periodically or as needed to check a machine's accuracy, to provide data for computer error compensation, to detect wear, and to diagnose problems. Back described as 1 970, HP's first laser measurement system was described in these pages as "a two-hundred-foot LMS with graduations every microinch." The …
Noise of a Self‐Sustaining Avalanche Discharge in Silicon: Studies at Microwave Frequencies
The studies of avalanche noise reported by Haitz are extended to frequencies up to and above the avalanche frequency ωa. It is found that the open‐circuit spectral voltage density is flat within ±5% from less than 100 Hz up to frequencies approaching ωa. Near ωa the open‐circuit spectral voltage density increases with frequency, goes through a maximum at ωa and then decreases rapidly. The spectral power density is similarly flat but fails to exhibit an expected maximum at ωa. For ω≫ωa the spectral power density decreases with ω−4. The experimental results are in good agreement with Hines' theory of avalanche noise for ω≪ωa and ω≫ωa. The discrepancies observed near ωa are thought to be caused by an oversimplification in Hines' theory which neglects internal diode losses. Compared with conventional noise sources such as temperature‐limited diodes or gas discharge tubes, avalanche diodes have several advantages: larger noise output, larger bandwidth, lower 1/f noise, low power consumption, small size, and lo...
"Flying Triangulation" - a new optical 3D sensor enabling the acquisition of surfaces by freehand motion
In order to obtain complete 3D surface information of an object it is often necessary to acquire many partial 3D views. For this purpose, the sensor has to be moved (e.g. for the acquisition of sculptures or rooms). Further, in many cases a motion of the object relative to the sensor is unintended but inevitable (e.g. for medical applications such as intraoral measurements of teeth). Nearly all existing optical 3D sensors either lack an easy handling or require a standstill during the acquisition of a single partial 3D view, since usually multiple camera shots have to be taken for this purpose. This makes such measurements elaborate or even impossible.