成人小说亚洲一区二区三区,亚洲国产精品一区二区三区,国产精品成人精品久久久,久久综合一区二区三区,精品无码av一区二区,国产一级a毛一级a看免费视频,欧洲uv免费在线区一二区,亚洲国产欧美中日韩成人综合视频,国产熟女一区二区三区五月婷小说,亚洲一区波多野结衣在线

立即打開
How bad is the iPhone 4's signal loss?

How bad is the iPhone 4's signal loss?

Philip Elmer-DeWitt 2010年07月05日
Pretty bad, say engineers who have measured the effect of the "death grip." But it's not fatal.

????The lower left-hand corner gap. Photo: Apple Inc.

????It's been nearly a week since Steve Jobs famously told a new iPhone owner with reception issues to "stay tuned," but Apple (AAPL) still hasn't solved the new device's Death Grip problem -- its tendency to lose signal strength rapidly when gripped across the gap on the left-hand corner where its two external antennas meet.

????But thanks to some clever work by a pair of engineers at Anandtech, we now have a pretty good idea what's going on when those signal indicator bars start to disappear.

????The report, signed by Brian Klug and Anand Shimpi, the tech site's founder, includes a quantitative analysis of the so-called attenuation -- or signal loss -- that occurs when the device is held four different ways: cupped tightly (the worst), held comfortably in the hand, resting atop a flat open palm and held naturally inside a case.

????The results -- with comparisons to the iPhone 3GS and Google's (GOOG) HTC Nexus One -- are shown in the chart below.

????Source: Anandtech

????As the chart says, small numbers are better; big numbers are worse. But to understand the significance of these results, you need a second Anandtech chart that assigns numerical values in decibels to the bars on an iPhone's display. See below:

Source: Anandtech???

????Since decibels are logarithms, a small drop in dB can mean a huge drop in signal strength. -51 dB is the best signal you can get on a 3G network; go beyond -113 and you lose contact entirely. According to Anantech, anything above -107 is usually perfectly fine for voice and data. But even a full five bars can be wiped out by the 24.6 attenuation you get from gripping an iPhone 4.

????"The results are pretty self explanatory," Klug writes about the attenuation chart. "Inside a case, the iPhone 4 performs slightly better than the Nexus One. However, attenuation gets measurably worse depending how you hold the phone. Squeezing it really tightly, you can drop as much as 24 dBm. Holding it naturally, I measured an average of 20 dBm.

????The drop in signal from cupping the device with a case on is purely a function of us being "ugly bags of mostly water." A material which happens to be pretty good at attenuating RF - thus increasing path loss between the handset and cellular base station. There's nothing Apple nor anyone else can do to get around physics, plain and simple. It's something which demonstrably affects every phone's cellular reception.

????But there's a silver lining. The stainless steel band that surrounds the iPhone 4 and serves as its antenna, Klug writes, is better than other cell phones', even with all the attenuation. And when he protected it with a case like Apple's $29 Bumper, he writes,

????"I felt like I was going places no iPhone had ever gone before. There's no doubt in my mind this iPhone gets the best cellular reception yet."

????Given all this, it's surprising that Apple has made it clear in instructions it issued to its telephone reps (and leaked to The Boy Genius Report) that it has no intention of offering free Bumpers to customers who complain about their iPhone 4's signal loss.

????Worse still, for an iPhone 4 owner like myself willing to spend $30 to solve the problem, there are no Bumpers to be had in New York City, not even for ready money.

掃碼打開財(cái)富Plus App
国产美女被遭强高潮免费网站| 国产蜜桃一区二区三区在线观看 -| 久久99r66热这里有精品| 久久国产精品二国产精品| 丝袜老师办公室里做好紧好爽| 国产又大又粗又长硬又紧又爽| 丝袜老师办公室里做好紧好爽| 久久国产劲爆AV内射—百度| 西西大胆午夜人体视频| 无码少妇一区二区| 中文字幕人妻丝袜二区| 日本丰满妇人成熟免费中文字幕| 国产韩国精品一区二区三区| 国产色无码精品视频国产| A级毛片无码久久精品免费| 操无毛小嫩逼就是过瘾| 精品亚洲a∨无码专区毛片| 久久99精品久久久久久齐齐| 97天天做天天爱夜夜爽| 亚洲六月丁香六月婷婷花| 国产欧美综合在线观看| 无码精品A∨在线观看十八禁| 国产69tv精品久久久久99| 九九99久久精品在免费线bt国内精品伊人久久久久| 黄色网页在线播放| 香蕉乱码成人久久天堂爱免费| 色又黄又爽网站在线无码看| 日韩国产欧美二区高清| 亚洲AV无码之国产精品网址| 国产成人综合久久亚洲精品| 日韩精品中文字幕无码一区| 久久精品亚洲日韩AV| 欧美久久久久久免费国产精品中文字幕| 国产成人影院一区二区三区| 国产成人91亚洲精品无码| 亚洲精品国产精华液怎么样亚洲 | 中文字幕精品一二三四五六七八| 免费A级毛片无码无遮挡| 国产精品一区二区在线播放观看| 91精品啪在线观看国产电影| 精品久久久久久无码中文字幕一区|