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intergrated curcuits

时间:2021-06-14 00:29:11 来源:网络整理编辑:FerriShield

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Size of faces (or heads) among children vary more dramatically than for adults. Further, the average head size of kids in Japan, for example, is known to be bigger than that of the United States or Europe.

Size of faces (or heads) among children vary more dramatically than for adults. Further, the average head size of kids in Japan, for example, is known to be bigger than that of the United States or Europe.

A number of companies including Nortel Networks, Lucent Technologies and Onix Microsystems are backing silicon micromachining (known as microelectromechanical systems, or MEMS) technologies to emerge as the leader. Silicon MEMS technology uses processing steps derived from the IC fabrication techniques of photolithography, material deposition and chemical etching to produce movable mechanical structures on a silicon chip.

Economical MEMS

intergrated curcuits

Often with integrated microactuators built into them, these MEMS devices are typically addressed using electrical signals to produce controlled motion of the micromechanical structures on the chip. The batch-processed nature of the fabrication procedure means that MEMS devices can be mass-produced on a large scale, which reduces manufacturing costs. In addition, the extremely small physical sizes and masses of these silicon machine parts” often make them more robust and capable of faster operation than conventional macroscopic mechanical devices.

With the close affiliation of its founding members with the University of California at Berkeley (one of the world's leading centers for MEMS research), Onix Microsystems is bringing optical MEMS to the market with a range of optical switching products based on patented micromirror technologies. The key element of its switching engines is a two-dimensional matrix of micromachined mirrors, fabricated in single-crystal silicon, that is used to make reconfigurable optical connections between input and output fiber arrays. One particular Onix approach uses a two-dimensional N x N mirror matrix combined with linear input and output fiber arrays to form an N x N crossbar switch. Control signals applied to the MEMS chip fix the position of each individual mirror to either pass or intersect the input light beams, directing each incoming light signal to the desired output port.

Because the intersecting micromirrors must direct the outgoing light beams into small-diameter fiber cores (typically fewer than 9 microns across), tight control of the mirror angles is vital to minimizing the optical power loss incurred from passing through the switch. Extremely low insertion loss and channel crosstalk can be achieved by this architecture to produce compact, all-optical switch modules with up to 64 input/output ports.

intergrated curcuits

Scalable solutions

These relatively small port-count switches are useful, for example, for network protection and restoration-to allow carriers to quickly reroute data traffic around fault locations in the event of fiber breaks or equipment failures. However, central offices often require larger switches with hundreds and up to thousands of input/output ports. To scale up the channel count beyond 32 x 32 ports, two solutions are available depending on the specific requirements of the end system.

intergrated curcuits

One is to use the smaller switch modules as building blocks, cascading them to form a larger switch. A three-stage network configuration allows one to construct a fully nonblocking cross connect with up to 1,024 x 1,024 channels by linking together 32 x 32 switch modules. Alternatively, instead of using N2 mirrors-each with two controlled positions-to form an N x N switch, one can use 2N mirrors each having N controllable positions to achieve the same functionality. This latter architecture, called the steered beam” configuration (also often referred to as the analog” or 3-D” approach), is used to construct large optical cross-connect switches within a single switch stage. The micromirrors that direct the free-space light paths are even more closely controlled by servo-feedback loop electronics and therefore give a lower insertion loss than the N2 mirror configuration is capable of.

Switching is accomplished by manipulating the free-space propagation paths of the light beams directly. As a result, the MEMS switches are optically transparent. In other words, they can be used in networks with widely varying data rates, modulation formats and signal wavelengths. Moreover, changes in the network properties have no effect on the switch functions. Therefore, no hardware modification is needed when the communication service providers upgrade the other parts of their networks or systems.

The Semicon West rumor mill hinted that AMD may be thinking of a new fab, possibly a 300-mm-wafer plant, with a chip partner. But any yet-to-be-announced AMD fab will certainly trail Intel's awesome capital-spending spree already in full effect.

For sure, the race for the MPU bumper crop goes on, with all the critical tools either at hand or soon to be.

LONDON — Apple Inc. has not said very much about its A4 processor.

However, it is widely supposed that a design team that came from Apple's acquisition of P.A. Semiconductor Inc. — known to have ARM design expertise — was given an architectural ARM license to come up with a best-in-class power efficient microprocessor. It is also supposed that result of this two-year gestation is the A4 inside the iPad computer tablet.

Of course the design team may have ignored that ARM architectural license — how ungrateful to the management would that have been — and gone down a different route. There is at least one observer who believes the PA6T-1682M, a dual-core microprocessor based on IBM's Power Architecture is at the heart of the A4 (see markstechchat.blogspot.com), although he concedes that such a core would require the addition of graphics support. But elsewhere it is widely supposed that Apple stuck with an ARM solution, which can readily support the iPhone operating system and applications, which are also a key part of the iPad functionality.