Abstract: Methods and systems for mitigating interference between different transceivers in a portable communication device. An electronic control circuit is configured to quantify an electromagnetic isolation between a first transceiver of a portable communication and a second transceiver of the portable communication device based on a detected radio frequency power coupled to the first transceiver from radio frequency signals transmitted by the second transceiver. A mitigation action is selected from a plurality of mitigation actions based on a magnitude of the quantified electromagnetic isolation. The selected mitigation action is then applied to the second transceiver to adjust at least one radio frequency characteristic of the second transceiver.

Abstract: A communication_system, apparatus, and method are provided including a portable public safety (PS) radio that scans a portable non public safety (non-PS) communication device having electronic press credentials stored therein. A server temporarily registers the portable non-PS communication device and electronic press credentials. The server monitors movement of the temporarily registered device for boundary violations within a public safety incident scene, and communicates a warning to the temporarily registered device in response to boundary violations. Electronic press scores are saved and used as a basis to determine access to future registration requests at future incident scenes.

Abstract: Methods and systems for mitigating interference between different transceivers in a portable communication device. An electronic control circuit is configured to quantify an electromagnetic isolation between a first transceiver of a portable communication and a second transceiver of the portable communication device based on a detected radio frequency power coupled to the first transceiver from radio frequency signals transmitted by the second transceiver. A mitigation action is selected from a plurality of mitigation actions based on a magnitude of the quantified electromagnetic isolation. The selected mitigation action is then applied to the second transceiver to adjust at least one radio frequency characteristic of the second transceiver.

Abstract: A method and apparatus for single port modulation of a phase locked loop frequency modulator includes a phase locked loop with a voltage controlled oscillator (VCO) and a integer loop for multiplying up the output of the VCO which is divided by a fractional-N modulator and divider in the feedback control. The integer loop enables the use of a high frequency reference oscillator that allows a closed loop response of the phase locked loop having a bandwidth that is wider than the modulation bandwidth.

Abstract: A method and apparatus for single port modulation of a phase locked loop frequency modulator includes a phase locked loop with a voltage controlled oscillator (VCO) and a integer loop for multiplying up the output of the VCO which is divided by a fractional-N modulator and divider in the feedback control. The integer loop enables the use of a high frequency reference oscillator that allows a closed loop response of the phase locked loop having a bandwidth that is wider than the modulation bandwidth.

Abstract: A synthesizer architecture, responsive to a low noise reference signal from a discrete oscillator, provides a continuous periodic output with a period that is a fractional multiple of the low noise reference signal. One exemplary embodiment includes a phase detector providing a control signal to a selected one of a plurality of integrated voltage controlled oscillators (VCO), wherein the phase detector is a sub-harmonic continuous time sampling phase detector. Another exemplary embodiment includes a continuous fractional divider input to the phase detector in response to an output of the selected VCO. Yet another exemplary embodiment comprises an injection locked ring oscillator responsive to the low noise narrow band variable reference signal with a fractional output period.

Abstract: A tunable narrow band radio frequency (RF) filter (200) includes an RF input (225), an RF output (227), a capacitive network (201-209) for coupling the RF input (225) with the RF output (227) and an inductive network (219-223) for resonating the filter at a predetermined center frequency. A number of semiconductor devices such as varactor diodes (215, 217, 229, 233) are used for tuning respective capacitors in the capacitive network (201-209). A single voltage source (Vc) is used for tuning each one of the respective varactor diodes for moving the resonant frequency of the filter over a substantially wide frequency range.

Abstract: A tunable narrow band radio frequency (RF) filter (200) includes an RF input (225), an RF output (227), a capacitive network (201-209) for coupling the RF input (225) with the RF output (227) and an inductive network (219-223) for resonating the filter at a predetermined center frequency. A number of semiconductor devices such as varactor diodes (215, 217, 229, 233) are used for tuning respective capacitors in the capacitive network (201-209). A single voltage source (Vc) is used for tuning each one of the respective varactor diodes for moving the resonant frequency of the filter over a substantially wide frequency range.

Abstract: A bandpass filter (40) includes a first microstrip split-ring resonator (12), having at least a first edge and a second edge, the first edge having a gap (20), and an input The bandpass filter (40) also includes a second microstrip split-ring resonator (14), having at least a first edge and a second edge, the first edge being coupled to the second edge of the first microstrip split-ring resonator electromagnetically (22) and by a central grounding aperture (223), and the second edge of the second microstrip split-ring resonator comprising a gap (26) and a balanced output (30, 32).

Abstract: A radio frequency variable gain amplifier (204) has a plurality of outputs. The amplifier (204) includes a transistor amplifier (330) having a plurality of switchable fixed gain states for amplifying an oscillator signal. The amplifier (204) includes a biasing circuit (302, 306, 312, and 316) for selectively biasing the transistor amplifier (330) to produce the plurality of switchable fixed gain states. The biasing circuit (302, 306, 312, and 316) includes switches (310 and 320) for switching between the switchable fixed gain states of the transistor amplifier (330).

Abstract: An actively biased oscillator (200) includes a set of current sensing components (214,216) for sensing the amount of current flowing into the first terminal of the amplifier; and a differential amplifier (212) responsive to the current sensing components for automatically adjusting the amount of current flowing into the second terminal of the amplifier.

Abstract: An improved frequency modulation apparatus (100) is provided comprising a generator (102), a biasing voltage line (116), and an interface circuit (110). The generator (102) is utilized to generate a carrier signal. A control line input (104) on the generator (102) adjusts the frequency of the carrier signal. The biasing voltage line (116) provides DC power in order to DC bias the generator (102). The interface circuit (110) couples an information signal (114) to the biasing voltage line (116) for altering the biasing of the generator (102) in response to the information signal (114). The alteration of the biasing of the generator (102) results in the carrier signal being frequency modulated by the information signal (114).

Abstract: A shorted component 10 is provided on a module 18 whereby the shorted component 10 is trimmed to either a capacitor 22 or an inductor 30. In the same step, the capacitor or inductor is further trimmed to a predetermined value of reactance.