摘要:
An electronic device having a unique audio sensing method that senses the event of no audio for a predetermined period of time. The sensed information is used by a microprocessor to bring the device into a low-power mode. The same method may be used to bring a device into active mode from a low-power mode.
摘要:
A low-current transceiver, powered by two small low-voltage batteries, for use in wireless headset/phoneset applications, such as hands-free headsets used with cellular telephones. Re-use of current from at least one circuit to provide power to at least one other power-consuming element of the transceiver, along with interrupt-driven control of the current made available to transmit and receive circuits, enables extended battery life (e.g., 120 hours). The headset/phoneset circuits incorporate a technique that draws an extremely low supply current from two low-voltage batteries while providing clear two-way communication over a range of about 3 meters.
摘要:
A GPS receiver includes a slot antenna having first and second surfaces. The second surface includes a semi-circular portion. The first and second surfaces define a slot within which is disposed dielectric material. The slot antenna is optimized for receiving GPS signals when in proximity to a human body. The relatively compact size of the slot antenna allows for the incorporation of the antenna into a small device that can be worn on or carried in close proximity to the body of a user. This type of antenna is not as sensitive to gain variations when in the proximity of a human body because the design has a wider aperture and thus operates better near the body. Further, this type of antenna is virtually omni-directional, i.e., it is not problematically sensitive to the location of the GPS signal source. Moreover, the design is such that the antenna arrangement can be oriented within a device in a way that maximizes the number of GPS satellites tracked.
摘要:
An antenna assembly (10) for subsurface utility metering equipment includes a disk-shaped radiating element (50) which is connected through a wire (51) having a self-inductance to a capacitor C and then to a ground plane (41) and a connector (31) for a coaxial cable (30) to provide an LC circuit for impedance matching of the antenna assembly (10) to a transmitter.
摘要:
A method and apparatus for streaming and/or transferring data and/or content between a source multimedia player (SMP) having mass storage and at least one destination multimedia player (DPM), including SMP connection means for bringing the inventive apparatus into either wired or wireless communication with the SMP using a selected transfer medium; a user interface and identification and selection software for identifying content on the SMP mass storage for extraction; file extraction software for extracting the content from mass storage on the SMP; input hardware for receiving content data from the SMP; formatting or storage software for formatting the extracted content into a format suitable for transmission to a DMP or for storing the content to internal or external flash memory for later transmission to one or more DMPs; transmission hardware for transmitting the formatted content, or transferring the stored content, to DMPs; and DMP connection means for bringing the inventive apparatus into wired or wireless communication with one or more DMPs.
摘要:
An audio circuit digitizes raw analog input and uses a digital signal processor (DSP) to filter, modulate, and mix the input to produce a multiplex composite signal. The multiplex composite signal is output from the DSP through a digital/analog converter (DAC), and modulates a conventional FM RF stage. In a first preferred, hydrid embodiment, the composite signal is output from the DSP through a digital/analog converter (DAC), and modulates a conventional FM RF stage. In a second preferred, fully digital embodiment, carrier modulation takes place in the DSP, and FM modulated RF is output via a fast DAC for final filtering and radiation.
摘要:
An RC filter pole (R1, C1) for FM transmitters converts an internal 2-pole Bessel-type filter (R1, C1, C2) on a chipset (BH141XS/F) by adding an external filter function to create a 3-pole composite filter with improved roll-off characteristics. The design methodology and specific low cost circuit implementation of the composite filter effectively minimizes the impact of signal degradation on overall link performance.
摘要:
A circuit and method of providing an auto-on and/or auto-off capability for an audio device, of a type having an audio plug which mates with the output jack of an audio source. The portable transmitter modulates audio signals from the audio source onto a carrier and transmits them to a receiver. The auto-on and auto-off capability is provided to prolong battery life and degradation of the transmitter circuit and comprises pinching off a FET when the circuit is in an “off” state. This occurs when a pre-determined threshold in a capacitor is reached by not discharging that capacitor. The capacitor is discharged by dropping a comparator input below a pre-determined threshold limit when presented with an audio peak and wherein the drop in value causes the comparator output to go low, causing the capacitor to discharge and causing the FET to supply power to the regulator.
摘要:
An antenna arrangement for a GPS signal processing device having a circuit board is disclosed. In a preferred embodiment of the invention, the arrangement comprises an antenna member mounted to the circuit board. The antenna member includes a first surface, second surface and a third surface. The third surface adjoins the first and second surfaces. The first, second and third surfaces define a cavity within which is disposed dielectric material. At least one conductive connector comprising first and second ends is in communication with the antenna member first surface. An amplifier is in communication with each conductive connector second end.