Abstract: An apparatus includes a stacked patch radiator having (i) a lower patch and (ii) an upper patch located above and separated from the lower patch. The upper patch includes first and second conductive patches that are separated from one another. The apparatus also includes a heating circuit integrated in the stacked patch radiator. At least a portion of the heating circuit is positioned between the first and second conductive patches of the upper patch. The stacked patch radiator can be configured to radiate at a specified frequency band and can have a thickness that is less than one tenth of wavelengths within the specified frequency band. The upper patch can include conductive vias electrically connecting the conductive patches. The conductive patches and the conductive vias can form an isolation cage configured to reduce a signal loss associated with a presence of at least the portion of the heating circuit between the conductive patches.

Abstract: Method and apparatus for determining a clock frequency for an electronic processor are provided. One embodiment provides a clock generator for determining a clock frequency for an electronic processor and providing a clock signal to the electronic processor. The clock generator includes a crystal oscillator producing a reference signal and a phase locked loop receiving the reference signal and configured to generate the clock signal based on the reference signal. The clock generator also includes a tuning logic controller electrically coupled to the phase locked loop. The tuning logic controller is configured to program the phase locked loop to a first frequency and determine an integrated circuit process corner of the electronic processor. The tuning logic controller is also configured to determine a second frequency based on the integrated circuit process corner and program the phase locked loop to the second frequency.

Abstract: An apparatus includes a stacked patch radiator having (i) a lower patch and (ii) an upper patch located above and separated from the lower patch. The upper patch includes first and second conductive patches that are separated from one another. The apparatus also includes a heating circuit integrated in the stacked patch radiator. At least a portion of the heating circuit is positioned between the first and second conductive patches of the upper patch. The stacked patch radiator can be configured to radiate at a specified frequency band and can have a thickness that is less than one tenth of wavelengths within the specified frequency band. The upper patch can include conductive vias electrically connecting the conductive patches. The conductive patches and the conductive vias can form an isolation cage configured to reduce a signal loss associated with a presence of at least the portion of the heating circuit between the conductive patches.

Abstract: Method and apparatus for determining a clock frequency for an electronic processor are provided. One embodiment provides a clock generator for determining a clock frequency for an electronic processor and providing a clock signal to the electronic processor. The clock generator includes a crystal oscillator producing a reference signal and a phase locked loop receiving the reference signal and configured to generate the clock signal based on the reference signal. The clock generator also includes a tuning logic controller electrically coupled to the phase locked loop. The tuning logic controller is configured to program the phase locked loop to a first frequency and determine an integrated circuit process corner of the electronic processor. The tuning logic controller is also configured to determine a second frequency based on the integrated circuit process corner and program the phase locked loop to the second frequency.

Abstract: A method and apparatus for mitigating electromagnetic noise in an electronic device. The method includes generating a trigger clock signal at a first frequency, and generating a second clock signal at a second frequency. The second frequency is higher than the first frequency. The method also includes receiving an input signal with a converter circuit, detecting an event based on the trigger clock signal, and predicting a time for a conversion of the input signal based on the detected event. The method further includes blanking the second clock signal for a predetermined period based on the predicted time for a conversion.

Abstract: A method and device for generating a multi-rate clock signal using a ring voltage-controlled oscillator based phase-locked loop is provided. The device includes a delay line having a length extending beyond a predetermined length required for operation of the phase-locked loop. The device further includes a tap tuning logic circuit coupled to the delay line. The delay line receives an input signal and a tuning voltage from the phase frequency detector, charge pump and loop filter circuits and generates a plurality of tapped output signals. The plurality of tapped output signals is received by the integrated digital multi-rate clock generator configured to create a plurality of clock signals.

Abstract: A method for transmitting a communication generated by an originating device to a target device using a repeating device is provided. In the method the communication is transmitted from the originating device and received at the repeating device. A repeater request sequence is transmitted from the originating device and retransmitted from the first repeating device to the target device before the repeater request sequence is received at the first repeating device.

Abstract: A radio system for locating a radio transceiver configured to exchange voice or data with a plurality of base stations on a narrowband channel is described. The system includes the radio transceiver that exchanges voice or data on the narrowband channel with a base station of the plurality of base stations and also to periodically transmit a chirp signal to the plurality of base stations. The radio system also includes the plurality of base stations each with a matched filter configured to receive the periodically transmitted chirp signal and to triangulate a location of the radio transceiver using the received chirp signal.

Abstract: An apparatus and method for demodulating an FM RF signal is presented. An Adaptive Differentiate Cross Multiply (ADCM) system in which the energy estimate of the desired on-channel RF is generated using adaptive filtering. The adaptive filter includes low pass filtering of the instantaneous energy estimate. The bandwidth of the LPF is adjusted in real time based on the received signal strength energy estimate, the periodicity of any changes in the energy estimate, AGC setting for the receiver, and/or the type of sub-audible signaling applied to the RF signal if known. After the bandwidth is set, the optimum filtered energy estimate is applied to the system to demodulate the received information free from distortion artifacts associated with IQ imbalance. A normalized signal in the ADCM system is clipped by a limiter whose clipping threshold is equal to a maximum gain of differentiators in the ADCM system.

Abstract: Methods of enabling late entry into an on-going spread spectrum call are described. A late join frame replaces, and has the same size as, a traffic frame. A late join slot in the late join frame contains sufficient information in preamble and sync subframes to permit a target to join the call. The traffic slots in the late join frame replicate data such that call quality of the call is substantially unaffected if one of the remaining traffic frames is not received. The preamble and sync subframes frequencies may be the same as, or different from, preamble and sync frames frequencies during a call establishment phase of the call. If different, the preamble and sync subframes frequencies are selected from one or more frequencies. Use of the preamble and sync subframes frequencies is compensated for when selecting the traffic slot frequencies to obtain uniform utilization of the spectrum.

Abstract: A method of detecting an on-channel signal and synchronizing signal detection with correcting for DC offset errors in a direct conversion receiver is presented. A received signal is digitized, and a state machine operates to detect the presence of an on-channel signal. If the signal is not detected, a mixed mode training sequence is initiated in which the DC offset errors in both an analog and digital received signal path are corrected. While training, processing of the digitized samples by a digital signal processor and a host controller is suspended (while they are put into battery save mode) and the gain provided to subsequently received signals is minimized. The DC offset correction circuitry is bypassed and put into battery save mode at predetermined periods when DC offset correction is not performed.

Abstract: A method for transmitting a communication generated by an originating device to a target device using a repeating device is provided. In the method the communication is transmitted from the originating device and received at the repeating device. A repeater request sequence is transmitted from the originating device and retransmitted from the first repeating device to the target device before the repeater request sequence is received at the first repeating device.

Abstract: Methods of enabling late entry into an on-going spread spectrum call are described. A late join frame replaces, and has the same size as, a traffic frame. A late join slot in the late join frame contains sufficient information in preamble and sync subframes to permit a target to join the call. The traffic slots in the late join frame replicate data such that call quality of the call is substantially unaffected if one of the remaining traffic frames is not received. The preamble and sync subframes frequencies may be the same as, or different from, preamble and sync frames frequencies during a call establishment phase of the call. If different, the preamble and sync subframes frequencies are selected from one or more frequencies. Use of the preamble and sync subframes frequencies is compensated for when selecting the traffic slot frequencies to obtain uniform utilization of the spectrum.

Abstract: An apparatus and method for demodulating an FM RF signal is presented. An Adaptive Differentiate Cross Multiply (ADCM) system in which the energy estimate of the desired on-channel RF is generated using adaptive filtering. The adaptive filter includes low pass filtering of the instantaneous energy estimate. The bandwidth of the LPF is adjusted in real time based on the received signal strength energy estimate, the periodicity of any changes in the energy estimate, AGC setting for the receiver, and/or the type of sub-audible signaling applied to the RF signal if known. After the bandwidth is set, the optimum filtered energy estimate is applied to the system to demodulate the received information free from distortion artifacts associated with IQ imbalance. A normalized signal in the ADCM system is clipped by a limiter whose clipping threshold is equal to a maximum gain of differentiators in the ADCM system.

Abstract: A method of detecting an on-channel signal and synchronizing signal detection with correcting for DC offset errors in a direct conversion receiver is presented. A received signal is digitized, and a state machine operates to detect the presence of an on-channel signal. If the signal is not detected, a mixed mode training sequence is initiated in which the DC offset errors in both an analog and digital received signal path are corrected. While training, processing of the digitized samples by a digital signal processor and a host controller is suspended (while they are put into battery save mode) and the gain provided to subsequently received signals is minimized. The DC offset correction circuitry is bypassed and put into battery save mode at predetermined periods when DC offset correction is not performed.

Abstract: A method for correcting I/Q imbalance in a received signal is disclosed. The method includes the steps of grouping (202) the received signal into a predetermined number of clusters, and determining (204) at least one coefficient value by feeding the predetermined number of clusters into a nested loop. The method further includes computing (206) a compensation value based on the at least one coefficient value, and correcting (208) the I/Q imbalance in the received signal by using the compensation value.

Abstract: An adaptive dc compensation technique (100) eliminates dc error for both digital and constant envelope modulation protocols (108). For analog modulation, a dc averaging technique utilizes piece-wise continuous dc averaging (110) that calculates discrete dc error values over a variable number of samples (112) and updates the dc compensation value as a fixed value for a specified sample length (114). The piece-wise “update-and-hold” technique (110) results in a pseudo high pass filter response with an equivalent corner. For digital modulation, a continuous high pass filter section of the receiver is enabled (120).

Abstract: A public/private communication system is provided which includes a public communication device 100, a private communication device (102) and a radio accessory extension (RAE) 200 coupled therebetween. The RAE (200) of the present invention provides audio and/or display capability which allows the public communication device to operate as a private communication accessory. Methods (300, 400 500) provide for the configuration and prioritization of private and public calls through the three devices to ensure that private calls will take priority and public calls will be received on the public communication device and handled appropriately.

Abstract: A modulator (102) modulates a plurality of symbols to create a modulated signal. A transmitter is coupled to the modulator (102). The transmitter transmits the modulated signal if the modulated signal is above a threshold. A minima enlarger (104) is coupled to the modulator (102). The minima enlarger (104) computes an adjustment to the plurality of symbols if the modulated signal is below the threshold. A summer (106) is coupled to the modulator (102) and the minima enlarger (104). The summer (106) adds the adjustment to the plurality of symbols if the modulated signal is below the threshold.

Abstract: A modulator (102) modulates a plurality of symbols to create a modulated signal. A transmitter is coupled to the modulator (102). The transmitter transmits the modulated signal if the modulated signal is above a threshold. A minima enlarger (104) is coupled to the modulator (102). The minima enlarger (104) computes an adjustment to the plurality of symbols if the modulated signal is below the threshold. A summer (106) is coupled to the modulator (102) and the minima enlarger (104). The summer (106) adds the adjustment to the plurality of symbols if the modulated signal is below the threshold.