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【转载】sun_ic 的电路设计漫谈篇

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发表于 2015-1-24 17:37:27 | 显示全部楼层 |阅读模式
本帖最后由 wanghanq 于 2015-1-24 17:42 编辑

[原创]电路设计漫谈1-17 (原创,电路瞎侃)
http://bbs.eetop.cn/thread-296106-1-1.html

陆续在数字/模拟电路设计-讨论交流中发了一些帖子。汇总了前17篇发在这里。到现在断断续续几年来写了70多篇,有兴趣的可以去google一下。宗旨是自由瞎侃,沾不沾边的都撤一撤,别把技术看的太严肃了。别人以唱歌,做生意,种田。。。。为职业,我们以电路设计养家糊口混饭吃。

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做了若干年的电子系统设计。所涉领域有数字通信,数据交换机,模拟电路,芯片设计等等。有些感慨逐渐写出来灌灌水,博大家一笑。宗旨是自由瞎侃,沾不沾边的都撤一撤,别把技术看的太严肃了。别人以唱歌,做生意,种田, ,做帐。。。。为职业赚钱,我们以电路设计养家糊口混饭吃。


电路设计漫谈之一:境界层数

传统的武功都分若干层,好像大多是7-9层吧,呵呵。这电路设计的功力也一样,印象中有dx分过4-9层。俺这也不免俗,根据自己的经验把它分成了5层。

1层:初步入门。做什么都难。大多时间是借鉴前人或能找到的设计。仿制的过程中来理解电路的架构类型。能拿到一个可直接用的电路很兴奋。经常看些2-3流杂志上的实际例子。做些笔记什么的。经常参加各种会议讲座。设计出来的板子一堆飞线。总是疑惑为啥电路图或者逻辑设计一样,怎么出来的性能总比不上原设计。

2层:做了几年后有了感觉。了解了电路设计需要遵循的一些实际原则。开始能独立完成一个系统,即使是新的算法或者协议也能实现。设计一个电路有点随心所欲。觉得这电路设计也就那么会事,什么东西只要有时间都能做出来。但细节的考虑不周(细节这个词可能有误导,其实并不像字面那样简单)。做出的东西长期稳定性和可靠性不见得理想。

3层:觉得做什么都要慎重。再简单的东西设计好了,成为批量生产的可靠产品都不容易。即使做个分频器也要分析半天。不管大小project都先仔细做architecture spec,都想事前先做仿真。注重步骤和过程的严谨。以一种敬畏的态度对待大大小小的设计项目。
知道了RD的不同。明白做个项目主要80%的部分用20%的时间就可完成。而余下的20%要花80%的时间。当别人说这个项目简单花不了多少时间时,也不愿意与其争论。

4
常回过头来看看以前的教科书。比如电磁学上电容的原理。有了些以前不管上学还是应用时没有过的领悟。
注重可重复性设计,测试结果跟仿真的比较。积累仿真与实现一致性的经验。宁要知道为什么不工作的不工作的设计,不要不知道为什么工作的工作的设计。
能准确抓住一个项目的框架结构,明白主要的和需要仔细分析对待的部分。并能分清哪些可以不用花太多时间和精力。知道什么重要是一种能力,知道什么不重要也是一种能力。
开始琢磨一些新的协议或者想独创点什么。

5层:只是一个工具和过程,用它来赚钱养家。跟去养猪种菜一样,是谋生或者用来创业的一个手段。

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【爱好】

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[原创] 电路设计漫谈之25 - 浏览器的使用与IQ  2011-9-23 05:27

不久前据说加拿大的一个心理咨询机构调查表明,人们使用何种浏览器跟其平均智商有关。使用IE的人群其平均智商为70-80. Chrome和firefox的使用者为110. Opera和Camino的使用者竟达到120。分析的原因是可能低智商的人群更趋向于保守和不善于尝试新东西。不知这个结果是否可信。
fangzhh2008 2011-10-3 22:16
不知你当时看最后的结果没有,这是一个愚人节笑话!而且当时还有很多人信了.

据说加拿大的一个心理咨询机构调查表明,人们使用何种浏览器跟其平均智商有关。使用IE的人群其平均智商为70-80. Chrome和firefox的使用者为110. Opera和Camino的使用者竟达到120。分析的原因是可能低智商的人群更趋向于保守和不善于尝试新东西。前一段又有消息说这个是编造的故事。
且不说浏览器的使用到底跟智商有无关系,我倒觉得是否只习惯使用主流或者强势宣传者的工具,不善于尝试新出现的自己不熟悉的东西,跟创造力的培养会有些许关系。比如微软是无处不在的强势集团,使用其office,IE,Windows等产品无可非议。可是在可能的情况下,作为一个工程师你是否应该尝试一下firefox或者chrome,也许习惯后你会觉得他们比IE快多了,也简洁好用多了。至少你会知道原来世界上还有跟IE不一样的东西,人们还可以开发出比已经主宰市场的产品还不一样(或者更好)的特性和产品。Office也是一样,在使用开源软件日益流行的今天,openoffice运行速度快,界面极接近人们熟悉的office,应该下载一个试用一下。对我们电路设计者来说,是不是应该尝试一下protel之外的东西? 切不说更强大的,即使用过orcad之类的原理图和PowerPCB之类的布线工具后,会感觉到跟protel不一样的天地。
现在人们尤其年轻人把使用apple的产品当为一种style了。感觉这样至少能启发大家跳出MS的框架,开发出与习惯了的产品不一样的东西。尝试新东西,跳出习惯的束缚,是培养创新力的重要一环。
俺目前用的笔记本MACPro通过VM整合了XP,这样可以使用两者中自己最喜欢的功能。桌面浏览器比较后发现chrome轻便好用。但在手机上还是选用了更轻便的opera。Office等软件能用开源的时候就不用商用的。比较不喜欢ipad那强制人用itune的同步方式,进了台windows mobile 6.5 的手机,最近把它涮成了Android。因为在现在的潮流中,不用apple也是一种生活style


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相对系统的参考内容可参 eeworld 中楼主的日志整理
http://home.eeworld.com.cn/home.php?mod=space&uid=355576&do=blog&view=me&from=space&page=1

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 楼主| 发表于 2015-1-24 17:57:43 | 显示全部楼层
本帖最后由 wanghanq 于 2015-1-24 17:58 编辑

google抛弃面试智力测验和脑筋急转弯
sun_ic的个人空间 2013-6-25 14:10 |个人分类:life|

google现在决定在招聘时不再搞那些不靠谱的智力测验脑筋急转弯的东西。原因是若干年统计下来,这些玩意跟之后的工作业绩没毛关系。甚至毕业几年后跟学校时的GPA也没啥相关。这些面试唯一的用处就是证明面试官比求职者聪明。现在他们主张面试时测试求职者做过的东西,并沿着其已有的经验深入探求求职者解决问题的能力。几年前俺也写过一篇博客谈论类似的问题

下边是这个访谈google人事副总的全文。

“We found that brainteasers are a complete waste of time. How many golf balls can you fit into an airplane? How many gas stations in Manhattan? A complete waste of time. They don’t predict anything. They serve primarily to make the interviewer feel smart.”
That was just one of the many fascinating revelations that Laszlo Bock, Google’s senior vice president for people operations, shared with me in an interview that was part of the New York Times’ special section on Big Data published Thursday.
Bock’s insights are particularly valuable because Google focuses its data-centric approach internally, not just on the outside world. It collects and analyzes a tremendous amount of information from employees (people generally participate anonymously or confidentially), and often tackles big questions such as, “What are the qualities of an effective manager?” That was question at the core of its Project Oxygen, which I wrote about for the Times in 2011.
I asked Bock in our recent conversation about other revelations about leadership and management that had emerged from its research.
The full interview is definitely worth your time, but here are some of the highlights:
The ability to hire well is random. “Years ago, we did a study to determine whether anyone at Google is particularly good at hiring,” Bock said. “We looked at tens of thousands of interviews, and everyone who had done the interviews and what they scored the candidate, and how that person ultimately performed in their job. We found zero relationship. It’s a complete random mess, except for one guy who was highly predictive because he only interviewed people for a very specialized area, where he happened to be the world’s leading expert.”
Forget brain-teasers. Focus on behavioral questions in interviews, rather than hypotheticals. Bock said it’s better to use questions like, “Give me an example of a time when you solved an analytically difficult problem.” He added: “The interesting thing about the behavioral interview is that when you ask somebody to speak to their own experience, and you drill into that, you get two kinds of information. One is you get to see how they actually interacted in a real-world situation, and the valuable ‘meta’ information you get about the candidate is a sense of what they consider to be difficult.”
Consistency matters for leaders. “It’s important that people know you are consistent and fair in how you think about making decisions and that there’s an element of predictability. If a leader is consistent, people on their teams experience tremendous freedom, because then they know that within certain parameters, they can do whatever they want. If your manager is all over the place, you’re never going to know what you can do, and you’re going to experience it as very restrictive.
GPAs don’t predict anything about who is going to be a successful employee. “One of the things we’ve seen from all our data crunching is that G.P.A.’s are worthless as a criteria for hiring, and test scores are worthless — no correlation at all except for brand-new college grads, where there’s a slight correlation,” Bock said. “Google famously used to ask everyone for a transcript and G.P.A.’s and test scores, but we don’t anymore, unless you’re just a few years out of school. We found that they don’t predict anything. What’s interesting is the proportion of people without any college education at Google has increased over time as well. So we have teams where you have 14 percent of the team made up of people who’ve never gone to college.”
That was a pretty remarkable insight, and I asked Bock to elaborate.
“After two or three years, your ability to perform at Google is completely unrelated to how you performed when you were in school, because the skills you required in college are very different,” he said. “You’re also fundamentally a different person. You learn and grow, you think about things differently. Another reason is that I think academic environments are artificial environments. People who succeed there are sort of finely trained, they’re conditioned to succeed in that environment. One of my own frustrations when I was in college and grad school is that you knew the professor was looking for a specific answer. You could figure that out, but it’s much more interesting to solve problems where there isn’t an obvious answer. You want people who like figuring out stuff where there is no obvious answer.”
Please share your thoughts on these insights below, and as I’ll be writing frequently on LinkedIn, please hit my FOLLOW button to see future posts.
Adam Bryant has interviewed more than 200 leaders for his \\\"Corner Office\\\" feature that runs every Friday and Sunday in The New York Times. He is the author of the New York Times bestseller, \\\"The Corner Office: Indispensable and Unexpected Lessons from CEOs on How to Lead and Succeed.\\\" His second book,“Quick and Nimble: Creating a Corporate Culture of Innovation,\\\" will be published in January.


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