2858 results about "Fixed frequency" patented technology

Communication systems and methods are provided allowing a single mode mobile terminal to support mobile assisted signal strength measurement operations in both a fixed frequency reuse based communication network and an adaptive channel allocation based communication network. Candidate base station signal strength measurements are requested by a fixed frequency reuse type network, measured by the mobile terminal and provided to the fixed frequency reuse type network which is seeking to identify a strongest signal for mobile assisted handover operations. In addition, interference signal strength measurements are requested by an adaptive channel allocation type network, measured by the mobile terminal and provided to the adaptive channel allocation type network by the mobile terminal. No redundant circuitry is required in the mobile terminal. Instead, the mobile terminal executes the same operations using the same hardware regardless of whether the requested measurement is of a candidate signal strength or an interference signal.

An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

The present invention is generally directed to systems and device for monitoring remote device with a wireless, dual-mode communication protocol. As such, a representative embodiment is a system for monitoring and controlling remote devices. The system includes a first- and a second remote device; and a first and a second wireless transceiver integrated with the respective remote devices. The wireless transceivers are configured to communicate with at least one of a spread-spectrum communication protocol and a fixed-frequency communication protocol.

An automated meter reading network system to collect utility usage data from multiple utility meters having utility meter sensors is provided. The system includes multiple meter data collectors each in communication with one or more utility meters to collect utility usage data and forming a wireless mesh communications network characterized by having a varying frequency mode of operation. The system also includes a host computer in communication with the meter data collectors either directly or through multiple field host data collectors, which can be connected to the host computer through a wide area network. The system also includes a meter data collector program product at least partially stored in the memory of the host computer adapted to manage the mesh communication network that is adapted to vary the frequency mode of at least portions of the mesh communication network between a fixed frequency mode and a frequency hopping spread spectrum mode to enhance network performance.

Method and apparatus for transmitting messages between communication devices via a communication channel allowing at least voice messages to be transmitted, the messages including data subdivided in a sequence of basic data units, the method including; a) encoding the basic data units as unique signals (us_j) including a predetermined number of basic signals (b_i), each basic signal having a unique fixed frequency (f_i); b) transmitting a sequence of unique signals (us_j) during a sequence of fixed time periods (t1, t2, t3, . . .); c) receiving and decoding the sequence of unique signals (us_j) into the sequence of basic data units; the data being transmitted in superposition over voice.

the invention shows a jamming device having a transmitting system that outputs a signal frequency modulated that inhibits a low power receiving antenna from receiving a fixed frequency such as a cellular telephone.

The jamming device can function as a stand alone device or be incorporated into existing electrical systems whereby energizing said electrical system will cause said jammer to inhibit the use of low power radio transmission/reception devices such as cellular phones.

The present invention facilitates clock and data recovery (330,716/718) for serial data streams (317,715) by providing a mechanism that can be employed to maintain a fixed tracking capability of an interpolator based CDR circuit (300,700) at multiple data rates (e.g., 800). The present invention further provides a wide data rate range CDR circuit (300,700), yet uses an interpolator design optimized for a fixed frequency. The invention employs a rate programmable divider circuit (606,656,706) that operates over a wide range of clock and data rates (e.g., 800) to provide various phase correction step sizes (e.g., 800) at a fixed VCO clock frequency. The divider (606,656,706) and a finite state machine (FSM) (612,662,712) of the exemplary CDR circuit (600,650,700) are manually programmed based on the data rate (614,667). Alternately, the data rate may be detected from a recovered serial data stream (718) during CDR operations (on-the-fly) utilizing a frequency detection circuit (725) to automatically program the divider (706) and FSM (712) to provide CDR circuit operation at the nearest base clock rate (716).

A fixed-frequency current mode converter comprises a power stage to produce an inductor current and an output voltage, an error amplifier to generate an error signal from the difference between the output voltage and a reference voltage varied with the inductor current, a comparator to compare the error signal with a ramp signal varied with the inductor current to generate a comparison signal, and a PWM generator to generate a PWM signal in response to a fixed-frequency clock and the comparison signal to drive the power stage. A second comparator is further comprised to compare the error signal with a second reference voltage varied with the inductor current, and generates a second comparison signal to reset the clock when the error signal is lower than the second reference voltage.

The present invention provides methods and devices for monitoring physiological data such that a health care provider is able to effectively monitor a patient's health status, including, for example, blood flow characteristics, without having to maintain constant visual contact. In one embodiment of the present invention, a physiological data monitoring system measures at least one physiological characteristic wherein the physiological data monitoring system comprises a sensor unit and a monitoring unit in data communication with the sensor unit. The monitoring unit has a sonification module that comprises one programmable sound generator module to produce a plurality of signals indicative of a physiological parameter and a memory module for storing a plurality of control parameters for managing the programmable sound generator module, wherein the plurality of signals produced have a plurality of frequencies modified in accordance with at least one physiological data value. More specifically, the present invention provides a pulse oximetry sonification system that generates fixed frequency singular and/or combined amplitude-adjusted dual audio tones corresponding to predetermined transition and/or intermediate points over a range of SpO₂ measurements.

The invention provides an intelligent controller used for a direct current (DC) frequency-conversion air conditioner compressor and a technical proposal of the control method thereof; the hardware proposal comprises a rectifier filter circuit and a power module which are electrically connected sequentially; the rectifier filter circuit (220) is also electrically connected with a single DSP controller used as a core processing unit by a switch power supply (240); the single DSP controller is also respectively and electrically connected with the power module, a communication isolation circuit which is used for communicating with the indoor machine of the air conditioner, a fan driving circuit (280), and a temperature sampling circuit (270); the control method comprises the steps as follows:the control software is embedded in the DSP controller; by a control type of dual close-ring FOC no-sensor magnetic field vector, the current ring at the internal ring realizes the decoupling controlto the driving current of the permanent magnetic synchronous motor of a compressor and indirectly controls the output torque of the motor; the speed ring at the external ring is used for controlling the working frequency of the compressor, thus not only meeting the stable requirement during fixed frequency but also meeting the dynamic response during the frequency conversion; and the control software comprises a primitive recursive function and a main interrupt function.

A fixed frequency continuously beam-steerable leaky-wave antenna in microstrip is disclosed. The antenna's radiating strips are loaded with identical shunt-mounted variable-reactance elements, resulting in low reverse-bias-voltage requirements. By varying the reverse-bias voltage across the variable-reactance elements, the main beam of the antenna may be scanned continuously at fixed frequency. The antenna may consist of an array of radiating strips, wherein each strip includes a variable-reactance element. Changing the element's reactance value has a similar effect as changing the length of the radiating strips. This is accompanied by a change in the phase velocity of the electromagnetic wave traveling along the antenna, and results in continuous fixed-frequency main-beam steering. Alternatively, the antenna may consist of two long radiating strips separated by a small gap, wherein identical variable-reactance elements are mounted in shunt across the gap at regular intervals. A continuous change in the reactance value has a similar effect as changing continuously the width of the radiating strips. This results in a continuous change in the phase velocity of the electromagnetic wave traveling along the antenna, thereby achieving continuous fixed-frequency main-beam steering.

The invention relates to a series resonance DC/DC converter of a photovoltaic system, which comprises a single-pole converter (40), a series resonance circuit (50), a high-frequency isolation transformer (16) and a rapid uncontrollable rectifier (20), wherein the single-pole converter (40) is used for converting a direct voltage (26) of a photovoltaic array (10) into a single-pole pulse voltage; the series resonance circuit (50) is used for converting the single-pole pulse voltage into a sine voltage with a fixed frequency; the high-frequency isolation transformer (16) is used for boosting and isolating as well as protecting; and the rapid uncontrollable rectifier (20) is used for rectifying the high-frequency sine voltage into a stable direct current voltage (28). The converter (100) is only provided with two switching elements, has the advantages of simple control mode and no switching loss, and can be used for boosting and stabilizing the larger photovoltaic array so as to be convenient for synchronizing through a three-phase converter or charging a storage battery.

A frequency synthesizer is disclosed. The frequency synthesizer comprises a fixed frequency generator configured to generate a fixed frequency signal, a variable frequency generator configured to generate a variable frequency signal, wherein the fixed frequency signal and the variable frequency signal are combined to provide a fast-hopping output signal.

Various embodiments provide a coupling mechanism, method of activation and a square lattice. The coupling mechanism comprises two qubits and a tunable coupling qubit that activates an interaction between the two qubits by modulation of a frequency of the tunable coupling qubit. The tunable coupling qubit capacitively couples the two qubits. The tunable coupling qubit is modulated at a difference frequency of the two qubits. The difference frequency may be significantly larger than an anharmonicity of the two qubits. The tunable coupling qubit may be coupled to the two qubits by two electrodes separated by a superconducting quantum interference device (SQUID) loop having two Josephson junctions or by a single electrode with a SQUID loop coupling to ground. The SQUID loop is controlled by an inductively-coupled flux bias line positioned at the center of the tunable coupling qubit.

The invention provides a control method of a flyback converter. The control method is a control method in a mixed control mode; in other words, the flyback converter works in a non-complementation state under light loads, the clamp switch pipe on time is shortened through down conversion, and light load losses are effectively reduced through down conversion; flyback converter works in a fixed-frequency drive complementation state under heavy loads, and the clamp switch pipe on time is prolonged. Compared with the prior art, the control method has the advantages that the voltage stress of a main switch pipe and a clamp capacitor can be effectively reduced, the main switch pipe off losses can be reduced, the clamp circuit current change slope is decreased, the EMI interference is reduced, the secondary current change slope is decreased, and the longer detection reaction time is provided for synchronous rectification. Meanwhile, the working area of a magnetic core in the third quadrant is enlarged, the maximum flux density is reduced, and the size of the magnetic core is reduced.