An Expanded Scale Ohmmeter

Probably no instrument is used more than the laboratory ohmmeter. Perhaps because of the appearance of sensitive meter movements with large scales and the addition of electronic amplification, no instrument has seen less development in its basic design and none is more deserving of reappraisal. One of the basic defects in all existing ohmmeters is the scale-crowding which naturally occurs when a range of zero to infinity is adopted. This report describes a circuit modification which results in a considerable expansion of the ohmmeter scale, thereby making it possible to read resistance values more accurately.     

Simple, Stable and Reliable Transistorized DC Amplifiers

A transistor dc feedback voltage amplifier using a differential input stage followed by a single common emitter stage is analyzed to obtain the gain and drift rate dependence on temperature. It is found that under typical restraints on allowable input terminal current, the open loop gain of such an amplifier is restricted to a value only somewhat greater than twenty (q/2kT) times the voltage across the collector load of the common emitter stage. The drift rate is found to depend on the common emitter stage transistor and on the signal source resistance as well as on the differential stage. A conservative design philosophy which limits each of the factors contributing to drift rate is found to be necessary if predictable, parameter independent performance is to be obtained.     

A Transistorized Cathode-Ray Phase-Sensitive Null Detector

A tuned cathode-ray null detector developed for use with a current transformer test set is described. Apart from the cathode ray tube, the detector is completely transistorized and has been designed to detect signals as low as 20 ?V at frequencies of 50, 60, and 400 c/s. The third harmonic is down at least 40 dB from the fundamental.     

Analog Linear-Scale Ohmmeter

This paper describes a new solid state circuit for resistance measurement in the range 1-108 ?. The advantages of this circuit include: reliability, simplicity of design and use, low cost, and the fact that resistance scale is linear. The accuracy of measurement is around ±2 percent of reading at full-scale value in the range 1-106 ? and ±6 percent of reading at 10 M? and 100 Mg. This circuit is temperature-compensated and exhibits good operational stability. The constructional cost of the instrument is about $41.00.     

Transistorized quartz clocks

Measurement Techniques -     

Transistorized regenerative frequency divider

Summary Regenerative transistorized frequency dividers have a highly-stable phase characteristic with the supply voltage and ambient temperature varying over wide ranges. The above divider is not inferior in its phase stability to highly stable tube frequency dividers.The use of transistors and miniature components makes it possible to produce economical, reliable and small frequency dividers for quartz clocks. The lower power consumption of transistorized dividers makes it possible to feed them from storage batteries of a relatively small capacity.In transistorized circuits it is advisable to use inductive phase shifters for varying the quartz-clock readings.     

一种基于数学形态学尺度空间的线性条带挖掘方法

提出了一种线性条带挖掘方法L_MSCMO。方法可分为两个主要部分：首先，利用作者提出的基于数学形态学尺度空间的聚类算法MSCMO寻找到最合适的图像重分割尺度；其次，对此尺度下的分割结果进一步分割得到线性条带。L_MSCMO是一种对“非纯粹直线”与噪声具鲁棒性的线性条带提取方法。对地震带这种线性条带的有效挖掘验证了该观点。