This paper analyses the difficulty in potentiometers' Contact Resistance Variation (CRV) test, and introduces an effective test method-Qarsi-Envelope test method (QETM).

本文分析了电位器接触电阻变化率(CRV)测量的难点，提出了一种行之有效的方法——准包络测量法。

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Many visioneers champion free markets, less government, fewer regulations and profits for those who test the technological envelope.

CNN: A pioneer in space and on Earth

So far, the company has built a one-eighth-size prototype to test its design, which consists of a carbon-fibre keel, an envelope made from modern composite materials, half-a-dozen engines, a passenger compartment, and a specially lightened crane.

ECONOMIST: Pushing the envelope