摘要:
A method determines the signal usability of an adjacent channel in a multi-cell communication system without the aid of synchronization symbols. In general, a three step search is used to arrive at the adjacent channel signal quality. The first step is a coarse timing phase search. This is accomplished through a signal quality estimates (606). The second step arrives at the optimum time phase by first interpolating (608) the received signal around the time phase selected in the first step to generate additional samples. After the interpolation (608), signal quality estimates are calculated (610) for the time phases immediately surrounding the time phase found in the first step. The optimum time phase corresponds to the maximum of these quality estimates. Finally, in the third step, the signal quality estimate is calculated for the optimum time phase. This provides the adjacent channel signal quality estimate desired.
摘要:
A method and apparatus for providing vibration physiotherapy includes a vibration accessory that can produce vibrations over a range of frequencies, and is controlled by a communication device. The communication device executes a physiotherapy application program via which a user can select various operating modes to control vibration of the vibration accessory. The vibrations can be selected to be a constant frequency or the vibrations can be controlled to vary over time.
摘要:
A hybrid energy management method and system which provides a main power supply and a secondary power supply. The main power supply is electrically coupled to the utility power grid, while the secondary power supply is electrically isolatable from the utility power grid. A switch is provided to selectably power the appliance through the main alternating current power supply when the utility is not in a reduced demand operating mode and to selectably power the appliance through the secondary alternating current power supply when the utility is in a reduced demand mode.
摘要:
A communication unit (10) can have at least a first receiver (11) and a second receiver (12). The latter typically consumes more power than the former during ordinary operation. Pursuant to one embodiment a communication unit can use the lower-power receiver to detect energy on a monitored channel while the second receiver is retained in a reduced power mode of operation. Upon detecting an absence of channel activity the second receiver can be restored to normal operability to effect such activities as are then presently required.
摘要:
A transceiver (100) is provided for transmitting during the transmission bursts (12) of a frame and receiving during the receiving time-slot windows (14). The transceiver (100) includes a receiver (320) for receiving a repeating radio frequency data (16) signal at any time within the receiving time-slot window (14) and for demodulating the repeating radio frequency data signal down to a baseband data signal. A data detector and clock recovery device (330) recovers the valid data (CHMP) from the baseband data signal. For controlling the receiver (320) and data detector and clock recovery device (330), a control circuit (400) modifies the receiving time-slot windows (14) to only receive and detect when valid data is expected (52).
摘要:
A communication device (16) comprises first and second transceivers and apparatus for determining when the communication device (16) is in an on-site area (11) and when the communication device (16) is in an off-site area. The first transceiver transmits and receives signals on a first communication medium (17), when the communication device (16) is in a first area (11); whereas, second transceiver transmits and receives signals on a second communication medium (28), when the communication device (16) is in a second area.
摘要:
A radio communication device, having a receive mode and a transmit mode, includes a receiver portion, a transmitter portion, and multiple oscillators for providing reference waveforms for the radio communication device. During the receive mode, the receiver portion receives signals having a selected frequency, converts received signals to at least a first intermediate frequency (IF), and a transmitter oscillator produces a first waveform having a frequency equal to a multiple of the first intermediate frequency during the receive mode. During the transmit mode, the transmitter portion requires a reference waveform having an offset frequency equivalent to the first IF frequency to produce a radio frequency signal. Thus, the radio communication device also comprises a divider coupled to the transmitter oscillator for dividing the frequency of the first waveform to the required offset frequency in the transmit mode.
摘要:
A centralized communication system controller (102) measures and stores a historical record of each subscriber unit's communication activity. By examining this historical record, the controller predicts the subscriber unit's communication activity over a future time interval. A code based upon this prediction is transmitted to the subscriber unit (110), which causes the subscriber unit to enter an energy saving mode and deactivate (208) non-essential circuits for a time period represented by the code. In this way, the duration of the "sleep" interval may be optimally varied based upon the subscriber unit's communication history. In another aspect of the invention, unexpected messages for a subscriber unit in the energy saving mode are stored (114) electronically until the conclusion of the "sleep" interval. This message storing function enhances system efficiency when the subscriber unit's communication history does not correlate with actual commuication traffic.
摘要:
A frequency synthesized transceiver capable of tuning to a plurality of communication channels is disclosed. The transceiver includes a receiver and a transmitter section which are coupled to the synthesizer which generates the appropriate injection signals to achieve tuning. A battery saving circuit generates a battery saving signal having a predetermined duty cycle and period and is responsive to the phase detector in the synthesizer to disrupt power to the synthesizer while maintaining precise tuning. The battery saver circuit is also responsive to the transceiver. In a normal receive operation, a battery saving circuit synchronizes its battery saving signal with the hold condition of the phase detector to disrupt power to selected modules in the synthesizer without altering the injection frequency of the receiver. In a standby mode, power is disrupted to all modules in the receiver, the selected modules in the phase locked loop and the voltage controlled oscillator. During a transmit mode all battery saving is terminated.
摘要:
A sample and hold phase detector for a phase locked loop includes a digital detector for detecting the frequency and phase difference between the reference signal and the voltage controlled oscillator (VCO) signal. In a first mode of operation, the digital detector generates a first signal relating the difference in frequency and in a second mode of operation generates a second signal relating the difference in phase. A capacitor stores the first or second signal depending on the operational mode of the digital detector. The capacitor is selectively discharged in response to a discharge signal produced by the digital detector when either the VCO frequency is higher than the reference frequency or following each detection of a phase difference. A first amplifier is used to bypass a portion of the loop filter to effect rapid changes in VCO frequency in the first mode while a second amplifier couples the control voltage to the VCO via the loop filter to maintain proper VCO frequency in the second mode.