2320 results about "Transmission loss" patented technology

A microwave tunable filter having some advantages as follows: a) the integration of MEMS tunable filter and MMIC; b) the very low signal transmission loss and low dispersion; and c) the drastic variation and linear characteristic of frequency by means of MEMS capacitor and an external control signal. The microwave tunable MEMS filter includes a plurality of unit resonant cells, each unit resonant cell being formed by various serial and parallel combination of an inductor, a capacitor, a transmission line, and a variable MEMS capacitor, whereby capacitance variation of the variable MEMS capacitor in the unit resonant cell converts a resonant frequency of the unit resonant cell to thereby convert a center frequency of the filter.

The present invention relates to a wavelength-division multiplexed passive optical network. In particular, it relates to a technology for minimizing the optical loss at a wavelength-division multiplexed passive optical network based on wavelength-locked light source Thereby it improves the transmission quality and increases the transmission distance. A 4-port optical path setting device of the present invention increases the amount of light injected into an optical transmitter and thereby improves the wavelength-locking characteristic of a light source. In addition, it can decrease the optical transmission loss in an optical transmission path, and by an optical amplifier being inserted therein; it can also compensate the optical loss in an optical transmission path. In the present invention, a 4-port optical path setting device having the characteristics described above and a method for fault recovery without an additional optical loss are presented.

Included among the many structures described herein are photonic bandgap fibers designed to provide a desired dispersion spectrum. Additionally, designs for achieving wide transmission bands and lower transmission loss are also discussed. For example, in some fiber designs, smaller dimensions of high index material in the cladding and large core size provide small flat dispersion over a wide spectral range. In other examples, the thickness of the high index ring-shaped region closest to the core has sufficiently large dimensions to provide negative dispersion or zero dispersion at a desired wavelength. Additionally, low index cladding features distributed along concentric rings or circles may be used for achieving wide bandgaps.

A transmission power control device is provided that includes: a transmission loss calculator that calculates a transmission loss in the electric wave transmission path between a mobile station and each base station; and a transmission power control information determiner that determines which transmission power control information is to be used in a transmission power control operation at the mobile station, based on transmission power control information transmitted from each base station to the mobile station and the transmission loss in the transmission path between the mobile station and each base station calculated by the transmission loss calculator. This transmission power control device may further include an autonomous controller that increases transmission power from a current value in accordance with predetermined characteristics, regardless of transmission power control information from another communication device, when reception signal quality has become lower than a predetermined quality level. With this structure, after synchronization with a signal from the base station is established at the mobile station, the transmission power is controlled to increase from the initial value in accordance with the predetermined characteristics, regardless of the transmission power control information transmitted from the base station.

A high efficiency photovoltaic DC-DC converter achieves solar power conversion from high voltage, highly varying photovoltaic power sources to harvest maximum power from a solar source or strings of panels for DC or AC use, perhaps for transfer to a power grid at high power levels with coordinated control possible for various elements. Photovoltaic DC-DC converters can achieve efficiencies in conversion that are extraordinarily high compared to traditional through substantially power isomorphic photovoltaic DC-DC power conversion capability that can achieve 97%, 98%, 99.2% efficiency, or even only wire transmission losses. Switchmode impedance or voltage conversion circuit embodiments may have pairs of photovoltaic power interrupt switch elements and pairs of photovoltaic power shunt switch elements to first increase voltage and then decrease voltage as part of the desired photovoltaic DC-DC power conversion.

The present invention provides a sound-transmitting membrane for a microphone, to be disposed to a sound-collecting opening of the microphone so as to allow sound to transmit through the membrane while preventing a foreign matter from entering into the microphone through the opening. This membrane for a microphone prevents the entry of a foreign matter, such as fine dust and water vapor, that is difficult for conventional sound-transmitting membranes to block, and ensures the microphone performance. This membrane for a microphone is composed of a nonporous film or a multilayer membrane including a nonporous film, has a surface density of 30 g/m² or less, and has a sound transmission loss of less than 3 dB in a frequency range of 300 to 4000 Hz.