摘要:
A selective call radio (300) includes receiver (200). The receiver in turn includes an antenna (202) for receiving a radio signal having a first operating frequency, an amplifier(204) coupled thereto for generating an amplified signal; and a frequency translation circuit (208). The frequency translation circuit includes a selectivity filter (212) and an integrated frequency conversion circuit (216). The selectivity is coupled to the amplified signal for generating a filtered signal. The integrated frequency conversion circuit is coupled to the filtered signal and is incorporated into at least one IC (integrated circuit). The integrated frequency conversion circuit includes an oscillator (220), a divider (224), and a mixer (218). A first input of the mixer is coupled to the filtered signal generated by the selectivity filter. The divider is coupled to the oscillator and its output is coupled to a second input of the mixer. The mixer generates an output signal having a second operating frequency, the second operating frequency having a frequency value different from the frequency value of the first operating frequency of the radio signal.
摘要:
A method (500) and system for compensation of frequency offset between a first transceiver (102) and a second transceiver (104) in wireless communication are disclosed. The compensation of the frequency offset between two or more transceivers (102, 104) is achieved using frequency synchronization bursts. These bursts contain information about the frequency offset. The frequency synchronization bursts are transmitted by the first transceiver at a range of frequencies above and below its carrier frequency (502). A second transceiver that receives at least one of these bursts (504) determines the frequency offset (504), and adjusts its frequency to match the frequency of the first transceiver (508). Thereafter, the second transceiver may enter a low power sleep mode (510) in order to reduce its power consumption. The second transceiver returns to active mode (512) just before the start of the transmission of the data packets (514).
摘要:
The present invention provides a multimode receiver design for mitigation of frequency offset by selective demodulation of an input modulated signal. The receiver (103) comprises a plurality of demodulators (207). Each of the plurality of demodulators (207) has the same functionality but different receiver sensitivity versus frequency-offset mitigation characteristics. Each of these demodulators incorporates a different demodulation technique. A suitable demodulator is selected to demodulate the received signal. The choice of a suitable demodulator is based on the value of the frequency offset (305, 307).
摘要:
A receiver (100) for receiving an input signal and generating an output signal therefrom has a switchable gain circuit (104) with a stepwise variable gain control (118), a local oscillator (106) and an automatic gain control (AGC) detector (114) with a response for detecting a level of the output signal and generating an AGC signal indicative of the level of the output signal and a state machine (116) being responsive to the AGC signal generating a control signal at the stepwise variable gain control to increase or decrease a gain of the switchable gain circuit in discrete stepwise steps.
摘要:
A communication access protocol improves the accessibility of devices operating on an asynchronous network (100), while supporting reduced power consumption. The network (100) includes a mediation device (130) for facilitating communications among network devices. Generally, each network device periodically transmits beacon signals to advertise its presence, and listens for communication signals targeted at the network device (532, 534). A device initiating communication with another operates in one of at least two operating modes in order to establish communications (536, 537, 538). In one mode, the initiating device communicates with the mediation device in order to derive timing information for the other device (537). In another mode, the initiating device listens to receive beacon signals directly from the target device in order to synchronize communications with the device (538). The selection of one of the two operating modes depends on a control parameter established for the initiating device, which in one embodiment is dependent on the urgency of communication, a maximum number of retries for using the mediation device, or the like.
摘要:
An amplifier circuit (20) uses a series transistor (38) to couple the output of an amplifier (26) to a tuned circuit load (40) and to act as a variable resistance. In one embodiment for a multi-band receiver, multiple series transistors (38, 42) are switched for connecting different tuned circuits (40, 44) to the amplifier's output, and an activated one of the series transistors receives a gate voltage that varies its resistance so as to achieve gain control. An activated series transistors can also provide a resistance that stabilizes the amplifier (26).
摘要:
A selective call receiver (100) operating from a battery (102), includes a battery monitor (114), a radio receiver (108), a regulator (104), a capacitor (105) coupled to the regulator and the radio receiver, and a processor (116) for controlling the foregoing elements. The processor is adapted to determine from the battery monitor an energy level of the battery, configure the regulator to supply a first limited current to the radio receiver and the capacitor for a first predetermined time when the energy level is above a predetermined threshold, or configure the regulator to supply a second limited current to the radio receiver and the capacitor for a second predetermined time when the energy level is at or below the predetermined threshold. After configuring the regulator, the processor is then adapted to enable the regulator to charge the capacitor and to power the radio receiver.
摘要:
A communication device (100) having a receiver circuit (110), signal processor circuit (120), controller circuit (130), either embodied by integrated circuits or on a single integrated circuit. The transfer of signals between the circuits is timed so as to minimize the effects of noise introduced into any one of the circuits, particularly the receiver circuit (110). The center of a symbol of a received RF symbol is detected and, through hardware control or software control, the transfer of a data signal generated by the signal processor circuit (120), for example, is permitted to occur only during a period(s) of time determined to have minimal effects on the sampling of a symbol in a received signal by the receiver circuit (110).
摘要:
Mediation devices in an asynchronous network of low power consumption communication devices are leveraged through the use of new protocols (2500) that analyze relevant QoS parameters (2520) in order to provide a better than best effort service in the network. These protocols invoke adaptive quality of service (QoS) mechanisms to capitalize on the strength and flexibility provided to the network by the presence of one or more MDs, as described above. Expanded functionality of the MD includes control information messaging and service differentiation for the purpose of improving QoS of the network.
摘要:
A transmission line (218) is formed to have a characteristic impedance which increases at a first substantially exponential rate with respect to a distance from the input (202). A plurality of resonators (206-214) are coupled to the transmission line and positioned at a plurality of locations along the transmission line. The plurality of resonators has resonant frequencies that decrease at a second substantially exponential rate with respect to the distance from the input. An output signal (810, 812) is obtained at a point in the filter that produces a filter response having a corner frequency.