Hewlett-packard Company

Hewlett-packard Development Company, L.p.

Agilent Technologies, Inc.

George D Zuras, Jr

Storrs Townsend Hoen

Leslie Ann Field

Phillip W Barth

David J Waller

William H McAllister

Paul P Merchant

Channing R Robertson

Alexander J Neudeck

A cyclic SEC-DED-PEC code is provided and circuitry therefor which has the characteristics of two different distance codes. When w&lsqb;i&rsqb; and w&lsqb;j&rsqb; are two different code words in the code, then distance(w&lsqb;i&rsqb;,w&lsqb;j&rsqb;)&gE;4 for all i&ne;j and, when w&lsqb;i&rsqb; and w&lsqb;j&rsqb; differ in both of an adjacent pair of bits, then distance(w&lsqb;i&rsqb;,w&lsqb;j&rsqb;)&gE;6 where distance(w ,w ) is the ordinary Hamming distance. When the code is permuted by a cyclic permutation, the same code results. The code may be thought of in hyperspace as a hypersphere of a certain distance having spikes extending from the center of the hypersphere to the tip of the spike a further distance. This presents a &ldquo;hyper-mace&rdquo;, thus the name &ldquo;Mace Code&rdquo;, having the property that it is a certain distance code generally and a further distance code in the direction of the spikes. The circuitry further provides for a code that is only slightly more complex than an ordinary distance-4 code but which can correct more errors that are likely to occur.

Mace code

An exchange switch for an optical switching network utilizes the manipulation of fluid to selectively exchange outputs for two optical transmission paths. That is, when the switch is in a signal-exchange state, first and second transmission paths reciprocally exchange optical signals that are received at input waveguides of the transmission paths. In one embodiment, the exchange switch includes an optical switching arrangement having first and second switching members. The first switching member is positioned to selectively interrupt the continuation of signal propagation along the first transmission path, while the second switching member is positioned to selectively interrupt the continuation of signal propagation along the second transmission path. When fluid resides within the chambers of the two switching members, the exchange switch is in a signal-continuation state. However, by evacuating fluid from the chambers, a signal propagating along one of the transmission paths will be reflected into an exchange waveguide that transfers the optical signal to the other transmission path. In other embodiments, the exchange switch includes at least one fluid-manipulable chamber and a steady-state reflector. The different elements cooperate to enable either signal continuation or signal exchange, depending on the states of the fluid-manipulable chambers.

Optically controlled exchange switches within an optical signal network

A pressure regulator that sets the pressure of a liquid to a predetermined pressure differential below a reference pressure, such as atmospheric pressure. The pressure regulator comprises a liquid delivery channel and a capillary array. The liquid delivery channel includes a liquid input and a liquid output. The liquid flows through the liquid delivery channel from the liquid input to the liquid output. The capillary array is composed of ones of an elongate capillary. The capillary includes a first end in fluid communication with the liquid delivery channel and a second end in pressure communication with a source of the reference pressure. The liquid flows through the first end into the capillary to form a liquid surface in the capillary. The second end is remote from the first end. The capillary has cross-sectional dimensions in relation to the surface tension of the liquid and the angle of contact between the liquid and the capillary such that the pressure drop across the liquid surface in the capillary is equal to the predetermined pressure differential.

Passive pressure regulator for setting the pressure of a liquid to a

A method and circuit allows for generating syndrome bits from a plurality of data bits and a plurality of correction bits. The plurality of data bits are divided into subsets. From each subset of data bits, a plurality of syndrome bit partial products are generated using a logic gate tree, for example of XOR logic gates or XNOR logic gates. Each logic gate tree generates a syndrome bit partial product for each syndrome bit. The syndrome bits are generated from the syndrome bit partial products and from the correction bits, for example using XOR logic gates or XNOR logic gates. Within each logic gate tree, logic gates are arranged in rows. Each row of logic gates is used to generate a syndrome bit partial product for at least one syndrome bit.

Method and circuitry for generating syndrome bits within an error

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San Jose, CA, United States of America

George D Zuras, Jr