Abstract: Circuit techniques are disclosed for improving the SFDR of a DAC. In an embodiment, a DAC includes a resistor ladder network operably coupled to input logic circuitry and an output. The input logic circuitry receives a multi-bit input signal and effectively creates a plurality of processed input signals therefrom. The resistor ladder network is configured to receive the plurality of processed input signals and includes a corresponding plurality of current paths. Each current path includes: a current switch operably controlled by one of the processed input signals; a first resistor in series with the current switch; a second resistor in series with the first resistor; and a feedforward capacitor in parallel with the second resistor. The output is operably coupled to each of the plurality of current paths and is configured to output an analog output signal that corresponds to the multi-bit input signal.

Abstract: A zero knowledge communications protocol is provided that can unconditionally secure communications sent through a communications network by encrypting all messages, continuously sending noise messages through the network, and routing all network activity through an anonymity network. This combination of components prevent an eavesdropper on the network from garnering any information about when a communication is sent, the contents and statistics of a communication, the sender, or the intended recipient of the communication.

Abstract: Frequency divider techniques are disclosed which can be used to address two problems: when an incorrect division occurs if the modulus control changes before the divide cycle is complete, and when an incorrect division occurs due to a boundary crossing (e.g., power-of-2 boundary crossing in a fractional-N PLL application). In one embodiment, a frequency divider is provided comprising a plurality of flip-flops operatively coupled to carry out division of an input frequency, and configured to generate a modulus output and receive a divided clock signal of a previous cell. An additional flip-flop is selectively clocked off one of the modulus output or the divided clock of the previous stage, depending at least in part on a Skip control signal applied to a data input of the additional flip-flop, and is further configured to selectively reset the plurality of flip-flops to a state that will result in a correct divide ratio.

Abstract: Techniques are disclosed for fabricating optical instrumentation. The techniques can be used, for instance, to populate an optical bench with several optics that can be simultaneously bonded and simultaneously verified to precise assembly, and without the use of adjustable mounts or active alignment. The techniques may be embodied, for instance, in a jig designed for operatively coupling to a given optical bench. The jig includes cut-outs that identify placement locations for the various optical components on the underlying optical bench. Thus, once the jig is secured to the optical bench, precise placement of the optical components is simplified. In some such embodiments, the jig further includes a clamping assembly for each cut-out, so that once an optical component is placed on the optical bench via that cutout, the clamping assembly can be engaged to hold that optical component in place while a deposited bonding agent is cured.

Abstract: A method for fabricating a thermal optical heating element capable of adjusting refractive index of an optical waveguide is disclosed. A silicon block is initially formed on a cladding layer on a silicon substrate. The silicon block is located in close proximity to an optical waveguide. A cobalt layer is deposited on the silicon block. The silicon block is then annealed to cause the cobalt layer to react with the silicon block to form a cobalt silicide layer. The silicon block is again annealed to cause the cobalt silicide layer to transform into a cobalt di-silicide layer.

Abstract: A method is disclosed to detect a broad class of signals in Gaussian noise using higher order statistics. The method detects a number of different signal types. The signals may be in the base-band or the pass-band, single-carrier or multi-carrier, frequency hopping or non-hopping, broad-pulse or narrow-pulse etc. In a typical setting this method provides an error rate of 3% at a signal to noise ratio of 0 dB. This method gives the time frequency detection ratio which may be used to determine if the detected signal falls in Class Single-Carrier of Class Multi-Carrier. Additionally, this method may be used for a number of different applications such as multiple signal identification, finding the basis functions of the received signal.

Abstract: Whether or not the CW radar is utilized for through-the-wall detection, additional one or more sensors are used with the CW radar to confirm the motion detection result or to in fact turn on the CW radar once motion or the physical presence of an individual has been sensed, thereby to provide confirmation of a less-reliable sensor with the use of the more reliable CW radar. Thus, the addition of other sensors provides lower power consumption, lower false alarm rates and better discrimination and classification of moving objects.

Abstract: A method for early detection of faulty antenna arrays comprising the step of treating said detection as a special case of target recognition; wherein targets of interest are all previous examples of defective antenna arrays.