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
人妻丰满熟妇一区二区三| 国产欧美日韩精品一区二区三区蜜桃不卡| 亚洲美女高潮久久久久| 国产av熟女一区二区三区| 精品国产AⅤ无码一区二区| 国产美女自为喷水视频| 夜添久久精品亚洲精品第一国产综合高清| 亚洲国产成人高清在线观看| 国产真实videos灌满| 人妻少妇精品系列| 精品无码午夜福利理论片| 东京热人妻欧美一区2区3区| 高中小鲜肉自慰GAY免费| 亚洲区欧美区综合区自拍区| 美女视频一区二区三区在线教室内污辱女教师在线播放| 亚洲精品第一国产综合精品| 午夜毛片不卡免费观看视频| 97久久超碰色中文字幕| 国产特黄A级三级三级三级| 新精品国偷自产在线| 一级特黄录像免费播放中文版| 亚洲男人的天堂久久无在线观看免费黄视频| 97在线观看视频资源| 亚洲国产日韩欧美一区二区三区| 国产乱子伦视频在线观看| 欧美亚洲一区二区三区| 2020国产精品视频免费| 男人的天堂欧美网站免费观看欧美日韩ay在线观看| 久久久久国产一区二区三区| 丁香色婷婷国产精品视频| 久久人人爽人人爽人人片AV麻烦| 一级特黄高清aaaa大片| 欧美一进一出抽搐大尺度视频| 天天视频一区二区三区| 国产精品无码一级免费看A级毛激情| 亚洲国产成人精品无码区在线观看| 在线播放国产一区二区三区| 国产高清亚洲免费片| 国产亚洲精品a等一页| 男生下面伸进女人下面的视频| 久久发布国产伦子伦精品|