ble Logic Controller，可編程邏輯控制器，一種數(shù)字運(yùn)算操作的電子系統(tǒng)，專為在工業(yè)環(huán)境應(yīng)用而設(shè)計(jì)的。它采用一類可編程的存儲(chǔ)器，用于其內(nèi)部存儲(chǔ)程序，執(zhí)行邏輯運(yùn)算，順序控制，定時(shí)，計(jì)數(shù)與算術(shù)操作等面向用戶的指令，并通過數(shù)字或模擬式輸入/輸出控制各種類型的機(jī)械或生產(chǎn)過程。是工業(yè)控制的核心部分。 另外PLC還有以下幾個(gè)名稱： PLC = Power line Communication，電力線通信，即我們俗稱的“電力線上網(wǎng)”。 PLC = Public Listed Co
In recent years, cellular voice networks have transformed into powerful packet-switched
access networks for both voice communication and Internet access. Evolving Universal
Mobile Telecommunication System (UMTS) networks and first Long Term Evolution
(LTE) installations now deliver bandwidths of several megabits per second to individual
users, and mobile access to the Internet from handheld devices and notebooks is no
longer perceived as slower than a Digital Subscriber line (DSL) or cable connection.
Bandwidth and capacity demands, however, keep rising because of the increasing number
of people using the networks and because of bandwidth-intensive applications such as
video streaming. Thus, network manufacturers and network operators need to find ways
to continuously increase the capacity and performance of their cellular networks while
reducing the cost.
Fordecades,microwavelineofsight(LOS)linkshavebeenoneofthebasictechnolo-
gies used to build telephone networks. Until 1980, the fast rollout of high capacity
transport networks and deployment of links in areas with challenging geographic
characteristics could not be understood without this technology.
One of the very first books published on the social impact of the mobile phone
was Timo Kopomaa’s The City in Your Pocket: Birth of the Mobile Information Society.
The book, published in 2000, was based on research that Kopomaa had under-
taken for Nokia and Sonera as part of his doctoral studies in the Centre for Urban
and Regional Studies at the Helsinki University of Technology. The first line he
writes in the book is peculiar: ‘Mobile communication is not a serious matter’. By
this, we assume he is referring to a view of the world that would regard the mobile
phone as little more than an unremarkable fact of everyday life – a simple play-
thing for the young, or a productivity tool for the business executive and busy
parent.
his research aims at creating broadband tunable, fully integrated filters for the application of
cognitive radio and signal classification receivers. The approach under study is the N-path filter
technique which is capable of translating a baseband impedance to a reference frequency creating
a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations,
namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed-
through, and jammer power handling limitations. In the first approach, the fundamental trade-
off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by
a transmission line (T-line) N-path filter technique.
