complex的博客

记得上学期做LNA仿真的时候，发现1dB压缩点和三阶交调点之间有10dB左右的关系。当时没有仔细考虑两者之间的关系，以为没有关系。今天看到某书上写到：1dB压缩点对应的输入功率比三阶教条点对应的输入功率低9.64dB。既然精确到x.xx，那么肯定有一些情况了。于是花了一些时间来推导繁琐的三角函数，果然，两者之间是有9.64dB的差值。不过，这个结论一定是建立在如下这个基本假定：PA的非线性是三阶幂级数近似。实际上，大多数PA用三阶幂级数近似已经可以获得相当精确的模拟。一般情况下，实际PA的1dB压缩点对应输入功率小于三阶交调点对应输...

阅读全文>>

PORTLAND, Ore. — Copper interconnections on CMOS could become a bottleneck as future chips get faster. One solution could be harnessing carbon nanotubes, which have much higher electron mobility. Until now, however, researchers have been unable to perfect a method for coaxing the nanoscale carbon tubes into the correct positions on chips. Now, one group thinks they have the answer. The world's first CMOS circuit using nanotubes as an interconnect was recently designed at Stanford University, in...

阅读全文>>

Mona M. Hella 《RF CMOS Popwer Amplifiers: Theory, Design and Implementation》 Implementing power amplifiers in CMOS technology is considered a major step towards the realization of a complete transceiver on-chip. Modern transceivers require means for adjusting the transmitted power over a finite range to further reduce power consumption and improve channel capacity. A low performance, short-range wireless standard such as the Bluetooth radio requires a high level of integration, and low cost t...

阅读全文>>

Mona M. Hella 《RF CMOS Popwer Amplifiers: Theory, Design and Implementation》 RF PA oscillation problems can be broadly categorized into two kinds; Bias oscillations, and RF oscillations. Bias oscillations occur at low frequencies, in the magahertz to VHF range, and are caused by inappropriate and unintentional terminations at those frequencies by the bias insertion circuitry, such as the addition of a large-value decoupling capacitors. The oscillations have little to do with the detail of the...

阅读全文>>

Mona M. Hella 《RF CMOS Popwer Amplifiers: Theory, Design and Implementation》 The design of power amplifier in CMOS technology is mainly affected by the following factors: 1. Low breakdown voltage of deep sub-micron technologies. This limits the maximum gate-drain voltage since the output voltage at the transistor's drain normally reaches 2 times the supply for Class B, and F, and around 3 times the supply for class E operation. Thus, transistors have to operate at a lower supply voltage, del...

阅读全文>>

Fujitsu looks set to confirm its RF GaN pioneer status by selling WiMAX base stations based on wide-bandgap transistors, beginning in the second quarter of 2008. The BroadOne WX300 outdoor macrocell base station uses the Japanese corporation's GaN HEMTs to provide wide-area transmission over a range of several kilometers. The base station offers world-class efficiency and performance, Fujitsu says, and is the first of a wider series of BroadOne WiMAX transmitters due to be marketed worldwi...

阅读全文>>

SBX：Sea-Based X-Band Radar

阅读全文>>

CTSD: 连续时间Sigma-Delta。与传统的流水线架构相比，CTSD架构的主要优势有： 1. 更低功耗。 2. 集成滤除混叠信号的低通、砖墙式滤波器，可将频带外的信号滤除。 3. 易于驱动，采用纯电阻式输入级，无需外加采样及保持放大器。 4. 集成锁相环路(PLL)和压控振荡器(VCO)，可以执行时钟调节功能，让系统设计工程师可以采用成本经济的时钟电路。 5. 芯片内置实时超载恢复(IOR)电路。即使输入信号超过预设极限，也可在一个时钟周期内从饱和状态下恢复过来。  

阅读全文>>

By Richard Stevenson, from compound semiconductor.net. TriQuint, Anadigics, Skyworks SOlutions and Win Semiconductors have developed different technologies to monolithically integrated an HBT with a pHEMT or a FET. TriQuint says that its BiHEMT process is deisigned to address the needs of internal product designs and foundry customers. As a result, a premium is placed on process flexibility, which measn that E- and D-mode gate pHEMT devices are included in the process. (For applications that do...

阅读全文>>

From: compoundsemiconductor.net TriQuint Semiconductor has united its HBTs and PHEMTs with a BiHEMT process that promises to integrate power amplifiers and antenna switches on the same chip, according to Tim Henderson. At TriQuint Semiconductor we are planning to join a handful of manufacturers offering high-functionality integrated chips with the launch of a BiHEMT manufacturing process in the second half of 2008. This technology, which unites power HBTs and E/D PHEMTs, will target existing app...

阅读全文>>

From: EETChina.com “Wimax被列为全球3G标准”是2007年业内的一件大事。WiMax去年10月成为IMT-2000家族的一名正式成员，与WCDMA、CDMA2000以及我国的TD-SCDMA并列，成为全球第四大3G标准。世界无线通讯大会上，最终议定分配给WiMAX的全球性统一无线电频段：2.3~2.4GHz和3.4~3.6GHz频段都被划分为IMT无线电频率波段。 Wimax被列为全球3G标准被论为“是IT与CT融合成大的ICT行业的一个里程碑事件” 。对于Wimax成为3G标准，爱立信、高通等WCDMA和CDMA2000阵营的核心利益代表者自然持反对意见，而由于Wimax同TD-SCDMA一样均使用了TDD技术，...

阅读全文>>

From Compoundsemiconductor.net. If you asked somebody at random to name a semiconductor company, the chances are most people would say: "Intel". Now, there aren't really any compound semiconductor companies that make for household names (yet), but if you had to pick the "Intel" of the GaAs world, there's a fair chance that you'd say: "RF Micro Devices". These two firms are the kingpins in silicon and GaAs semiconductors. One thing that really characterizes them is their commitment to research ...

阅读全文>>

An antenna from E-Band's E-Link 1000 multi-gigabit capacity wireless communication system, which operates in the 71-76 GHz and 81-86 GHz bands. Wireless Multi-Gigabit Technology: 99.999% Availability 1 to 10 Gigabits per second 1 to 6 Miles Highly Integrated MMIC Chipset based technology Highest performance for lowest cost 这个简直和Gigabeam的东西一样。只不过，Gigabeam采用InP技术，而E-band则是采用Northrop Grumman的GaAs毫米波技术，异曲同工。好东西呀。

阅读全文>>

From chinese.wsj.com 最近一段时间，创新一词成了中国人的口头禅。在国家主席胡锦涛10月15日所作的中共十七大报告中，这个词出现了35次之多。中国追求创新以及沿着价值链向上攀升的内在逻辑是显而易见的。它在扮演世界工厂这一角色方面已几乎做到了极限。中国的空气和水污染正在引发越来越多的社会矛盾和公共健康问题。中国对美和对欧贸易顺差剧增引发了重重贸易摩擦，而人民币升值又势必会降低中国作为低成本生产基地的吸引力。 从理论上说，通讯市场能够起到引领创新潮流的作用。通讯业已经是中国经济中最具活力的领域之一。中国的移动...

阅读全文>>

*** 顺便说一句，终于吃到小郑老师的喜糖了，呵呵。恭喜。

阅读全文>>