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
中国国产aa一级毛片| 免费无码专区毛片高潮喷水| 日本日本乱码伦视频在线观看| 在线视频免费观看爽爽爽| 99国产欧美另娄久久久精品| 国模一区二区三区| 久久亚洲精品无码AV| 好男人高清免费观看日本| 国产乱妇无码大片在线观看| 久久亚洲国产综合精品日本| 日韩a片免费无码完整版电影| 欧美 亚洲综合在线一区| 亚洲AV色香蕉一区二区| 欧美乱人伦中文在线观看不卡| 免费99精品国产自在现线观看| 精品国产乱码一区二区三区麻豆| 老熟女老熟女精品视频性色| 一本大道无码人妻精品专区| 亚洲中文久久精品无码浏不卡| 国产欧美综合在线观看| 精品人妻系列无码人妻不卡| 亚洲日韩成人久久Av免费高清| 尹人香蕉99久久综合网站| 人妻无码,无码人妻| 久久久久噜噜噜亚洲| 又大又粗又爽a级毛片免费看| 大屁股av系列在线 哟男哟女视频八区 | 国产免费高清视频在线观看不卡| 爽到高潮无码视频在线观看| 久久精品无码一区二区日韩AV| 精品国产爱在线观看| 永久免费无码日韩视频| 免费国产黄线在线观看| 欧美XXXX色视频在线观看免费| 青春草无码精品视频| av中文字幕一区二区三区久久| 久久亚洲男人第一av网站久久| a级毛片100部免费观看| 欧洲变态另类zozo-av色国产色拍| 好妈妈在线观看完整版| 久久一区三区五月丁香基地|