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 method to authorize, facilitate, and mediate transfer of DRM protected files from one portable multimedia player (1050) to another portable multimedia player (1080), while ensuring appropriate royalty payments are made to appropriate Copyright Owners A source i2i device includes a file transfer counting mechanism for monitoring and disabling the transfer of digital files between portable digital media devices, and further includes hardware for providing a secure Internet interface (1020) capable of connecting the source device a Credit Vendor server (1040) via a network-connected computer (1070) A Credit Vendor (1000) pays a fee to a DRM File Source Company (1010) to obtain virtual credits for transferring DRM files The user connects the source i2i device to the Credit Vendor server (1040) via a global computer network and downloads virtual credits, which authorize and enable the transfer of content between the source i2i device and a target i2i device The Credit Vendor (1000) then pays appropriate royalties to the Copyright holders.
摘要:
An AM/FM/SW receiver coupled with an FM transmitter for personal multimedia players for both listening and recording uses innovative antenna and shielding design and placement to raise the signal-to-noise ratio of the intended broadcast content to a level which is acceptable to the listener.
摘要翻译:与用于个人多媒体播放器的FM发射机耦合的AM / FM / SW接收机用于收听和记录使用创新的天线和屏蔽设计和布局来将预期广播内容的信噪比提高到可接受的水平 听众。
摘要:
A headphone receiver apparatus for use with low power transmitters includes a pair of headphone speaker enclosures connected by a headband. An antenna element in the form of a spring steel band or a plastic cable/antenna band where one of the conductors is utilized as the antenna is configured generally concentric with but offset from the headband and the user's head by at least 0.5 inches over at least some length of the antenna. Low-noise performance is improved by a low noise amplifier incorporated before the receiver IC, and a bandpass filter interposed between the low noise amplifier and the receiver IC. A base-loading inductor is used to tune the antenna element to resonance, with or without capacative end-loading. Lumped inductors, ferrite beads, or a parallel resonant LC circuit may be used to isolate the shield conductor at RF frequencies, and/or to reduce the loading of the other conductors.
摘要:
A circuit and method for providing an auto-off capability for a wireless transmitter, of a type having an audio plug which mates with the output jack of an audio source. The portable transmitter modulates signals from a baseband signal source onto a carrier and transmits the RF carrier to a receiver. The auto-off capability is provided to prolong battery life and eliminate the transmission of unmodulated RF carriers. The auto-off capability comprises turning power off to the transmitter circuit when baseband input signal is absent for more than a predetermined amount of time, and immediately turning on the transmitter circuit when baseband signal is present.
摘要:
A circuit (FIGS. 2A-2D) and method of providing an auto-on and/or auto-off capability for an audio device, of a type having an audio plug (14) which mates with the output jack of an audio source. The portable transmitter (10) 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 (Q2) 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 (C29) 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 (Q2) to supply power to the regulator.
摘要:
The invention is a circuit and method for providing an auto-off capability for a wireless transmitter, 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-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 an input to a comparator below a pre-determined threshold limit when presented with an audio peak and wherein the drop in value causes the comparator output to discharge the capacitor and causing the FET to supply power to the regulator.
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:
A circuit and method for providing an auto-off capability for a wireless transmitter, of a type having an audio plug which mates with the output jack of an audio source. The portable transmitter modulates signals from a baseband signal source onto a carrier and transmits the RF carrier to a receiver. The auto-off capability is provided to prolong battery life and eliminate the transmission of unmodulated RF carriers. The auto-off capability comprises turning power off to the transmitter circuit when baseband input signal is absent for more than a predetermined amount of time, and immediately turning on the transmitter circuit when baseband signal is present.