Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: A multi-wall ceramic core for casting an airfoil with one or more internal cooling passages is made by preforming at least one fugitive core insert, then forming at least one core insert in-situ adjacent and fused to the at least one preformed core insert by introducing fluid fugitive pattern material into a composite core insert mold whereby the fugitive core inserts are integrally connected as a single composite core insert that includes features to form internal passage surfaces in the core when the composite core insert is removed. The composite core insert is placed in a core molding die cavity, and a fluid ceramic material is introduced into the die cavity to form the ceramic core body incorporating the fugitive composite core insert therein.

Abstract: A multi-wall ceramic core for casting an airfoil with one or more internal cooling passages is made by preforming at least one fugitive core insert, then forming at least one core insert in-situ adjacent and fused to the at least one preformed core insert by introducing fluid fugitive pattern material into a composite core insert mold whereby the fugitive core inserts are integrally connected as a single composite core insert that includes features to form internal passage surfaces in the core when the composite core insert is removed. The composite core insert is placed in a core molding die cavity, and a fluid ceramic material is introduced into the die cavity to form the ceramic core body incorporating the fugitive composite core insert therein.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: A multi-wall ceramic core for casting an airfoil with one or more internal cooling passages is made by preforming at least one fugitive core insert, then forming at least one core insert in-situ adjacent and fused to the at least one preformed core insert by introducing fluid fugitive pattern material into a composite core insert mold whereby the fugitive core inserts are integrally connected as a single composite core insert that includes features to form internal passage surfaces in the core when the composite core insert is removed. The composite core insert is placed in a core molding die cavity, and a fluid ceramic material is introduced into the die cavity to form the ceramic core body incorporating the fugitive composite core insert therein.

Abstract: A multi-wall ceramic core for casting an airfoil with one or more internal cooling passages is made by preforming at least one fugitive core insert, then forming at least one core insert in-situ adjacent and fused to the at least one preformed core insert by introducing fluid fugitive pattern material into a composite core insert mold whereby the fugitive core inserts are integrally connected as a single composite core insert that includes features to form internal passage surfaces in the core when the composite core insert is removed. The composite core insert is placed in a core molding die cavity, and a fluid ceramic material is introduced into the die cavity to form the ceramic core body incorporating the fugitive composite core insert therein.

Abstract: Coal-based cellular products that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.

Abstract: Coal-based cellular products that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.

Abstract: A tenant LAN controller includes an association of an MAC address with a geographic location in a first memory; a router connecting a WAN to a plurality of individual computers and a processor. The processor is configured to turn off an individual computer's internet access upon the individual computer being associated with a triggering event, where the individual computer is identified by the association of a geographic location with an MAC address in the first memory. The processor is further configured to throttle bandwidth according to instructions received via said WAN from a web page and is further configured to send messages to a particular MAC address according to the association of geographic locations with the MAC addresses; and is configured to log acknowledgements. The acknowledgements are stored in a second memory, and are associated in the second memory with a MAC address.

Abstract: According to the present invention there is provided coal-based cellular or porous products, also referred to herein as “carbon foams”, having a density of preferably between about 0.1 g/cm3 and about 0.8 g/cm3 and most preferably between about 0.3 and about 0.4 g/cm3 that are produced by the controlled heating of coal particulate preferably up to ¼ inch in diameter in a “mold” and under a non-oxidizing atmosphere. The coal-based cellular or porous products of the present invention have ash contents typically greater than about 1%. More typically these coal-based cellular or porous products have ash contents greater than about 3%, with ash contents in the range of about 7% to 15% being most typical. The ash residue remaining after essentially complete combustion/oxidation of these coal-based cellular or porous products is predominately composed of oxides of aluminum and silicon. Additionally, the cellular coal-based products of the present invention have relatively low overall B.E.T. surface areas.

Abstract: Coal-based cellular products that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.

Abstract: Coal-based cellular products that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.