Abstract: A system for reducing internal interference in a radio-frequency (RF) receiver includes providing a plurality of time slots within a frame where the receiver is configured to receive external RF signals during a receive time slot within the frame. Data is collected during a receive time slot of a frame, and a receive data value is calculated corresponding to the collected data. A predetermined portion of the data collected is inspected, and a bias data value is calculated. The bias value is attributable to interference signals caused by the internal interference. The bias data value is added to an accumulator, and over time, a running average of the bias data values is determined. A portion of the running average is subtracted from the sample stream of data to provide output data corresponding to the external RF signals absent the internal interference.

Abstract: This invention relates to an oscillator that includes first and second switching elements that each have a control terminal, and first and second conduction terminals. The control terminal of the second switching element is coupled to the first conduction terminal of the first switching element, and the control terminal of the first switching element is coupled to the first conduction terminal of the second switching element. The oscillator also may include first and second capacitive elements, first and second inductive elements, and a resistive element. The first capacitive element may be coupled between the control terminal of the first switching element and a first reference node, and the second capacitive element may be coupled between the control terminal of the second switching element and the first reference node.

Abstract: A system for amplifying a transmitted signal is provided. The system includes a receiver that receives the transmitted signal and generates a conducted signal from the transmitted signal. A non-linear oscillator, such as a synchronous oscillator that is operating in a borderline stable condition, is connected to the receiver. The non-linear oscillator receives the transmitted signal from the receiver and amplifies the transmitted signal without modifying the frequency of the transmitted signal, or its relative phase. The amplification by a non-linear oscillator causes the signal to be amplified relative to the noise, thus improving the signal-to-noise ratio.

Abstract: A filter system comprising three or more filters, each having different passbands, and an impedance adjusting network coupled between a filter system ports and each of the ports of at least two of the filters to adjust the port impedances of the filters coupled to the network. The adjusted port impedance of each filter at a frequency representative of at least one of the other filters coupled to the network is at a non-loading level. In one embodiment, the filter system is configured for use in a wireless communication receiver and/or handset.

Abstract: An apparatus for controlling the power level of an output signal from the output of an electronic amplifier. The electronic amplifier has a control signal input for receiving an amplifier control signal and has a power input for receiving current from a power supply. The apparatus comprises an amplifier output power detector, coupled to the output of the amplifier, used for generating a power measurement signal representing the output power of the amplifier. The apparatus contains a current detector arranged to detect the current received by the amplifier from the power supply and to provide a current measurement signal dependent on the amount of current received from the power supply. The apparatus contains a digital signal processor which receives the current measurement signal and provides a reference signal dependant on the current measurement signal.

Abstract: A method and system for efficiently transmitting RF energy from a RF device is disclosed. The method and system comprises a multi-stage power amplifier having a plurality of power amplifier stages arranged in parallel with associated switches for selectively switching on or off the plurality of power amplifier stages to produce a desired power level. By selectively switching on or off each individual power amplifier's associated switches at predetermined operating point's produces the desired power level for maximum efficiency. Additionally, more than one connected multi-stage power amplifiers each having a plurality of power amplifier stages arranged in parallel with associated switches for selectively switching on or off the plurality of power amplifier stages may be used to produce a desired power level.

Abstract: A method and system for efficiently transmitting RF energy from a RF device is disclosed. The method and system comprises a multi-stage power amplifier having a plurality of power amplifier stages arranged in parallel with associated switches for selectively switching on or off the plurality of power amplifier stages to produce a desired power level. By selectively switching on or off each individual power amplifier's associated switches at predetermined operating point's produces the desired power level for maximum efficiency. Additionally, more than one connected multi-stage power amplifiers each having a plurality of power amplifier stages arranged in parallel with associated switches for selectively switching on or off the plurality of power amplifier stages may be used to produce a desired power level.

Abstract: A system for reducing internal interference in a radio-frequency (RF) receiver includes providing a plurality of time slots within a frame where the receiver is configured to receive external RF signals during a receive time slot within the frame. External RF signals are the prevented from reaching a front-end portion of the receiver and the receiver is activated, and a predetermined period of time is permitted to elapse to permit the receiver to settle. An interference data collection is performed during a period of time prior to a predetermined receive time slot where the data collected represents internally generated interference signals. The data collected during the interference data collection is processed to determine a bias value corresponding to the interference signals, and the receiver is then permitted to receive external RF signals during the predetermined receive time slot so that data is collected during the predetermined receive time slot.

Abstract: A method and apparatus for improving the sensitivity of a radio frequency (RF) receiver at certain frequencies suffering from co-channel interference. In the preferred embodiment, when a reference frequency, FREF, generates significant harmonics for a received RF signal in a selected channel, the reference frequency is varied or offset by a small amount, &Dgr;F. The harmonics of the offset reference frequency, F′REF=FREF±&Dgr;F, are thereby shifted away from the frequency of the received RF signal, thus reducing co-channel interference. The offset amount &Dgr;F is chosen such that the same injection frequency synthesized from FREF can still be synthesized from FREF±&Dgr;F by shifting N by an integer amount, preferably to N+1 or N−1. However, the invention encompasses shifting N by other integer amounts.

Abstract: A switch circuit for a cellular radiotelephone operable in a TDMA communication scheme. The switch circuit is disposed upon a plurality of tandemly-positioned ceramic substrates having transmission lines disposed upon one of the ceramic substrates. The switch circuit alternately connects transmitter circuitry to an antenna or receiver circuitry to the antenna, thereby alternately to permit transmission or reception of signals generated by, or received by the radiotelephone. Because circuits disposed upon ceramic materials are of low insertion losses, the switch circuit is advantageously utilized to form a portion of the radiotelephone.

Abstract: A filter duplexer, such as a filter duplexer for a radio transceiver, of minimum dimensions is disclosed. First and second filter portions of the duplexer each include a plurality of transmission lines. Cross sections of the plurality of transmission lines of each filter portion are of at least two different geometries. The amount of coupling between adjacent ones of the resonators, as well as the loading capacitances of such resonators, is controlled by the relative geometric configuration of the adjacent ones of the resonators. Because the amount of coupling between the resonators and the loading capacitances of the resonators is determinative of the filter characteristics of the filter duplexer, desired filter characteristics may be effectuated by careful selection of the geometric configurations of the resonators of each filter portion.

Abstract: A dielectric filter having at least two adjacently-positioned resonators extended therethrough. The two adjacently-positioned resonators are of trapezoidal cross-sections to form thereby trapezoidal resonators. By suitable selection of the configurations of such resonators, the amount of coupling between such adjacent resonators may be controlled. For instance, a minor base side of the first trapezoidal resonator may be positioned adjacent to a corresponding minor base side of the adjacent trapezoidal resonator, or a major base side of the first trapezoidal resonator may be positioned adjacent to a major base side of the adjacent trapezoidal resonator, or a minor base side of the first trapezoidal resonator may be positioned adjacent to a major base side of the second trapezoidal resonator. Such electromagnetic coupling between the adjacent resonators is controlled by the relative configurations of such resonators rather than by increasing the spacings between such adjacent resonators.

Abstract: A filter assembly comprised of a dielectric filter and a shield positioned about the dielectric filter. The dielectric filter may be surface-mounted upon a circuit board and includes at least one notch formed to extend along a side face surface thereof. The shield is integrally formed of two sheets of an electromagnetic wave-absorptive material interconnected by a shoulder forming a right angle to fit about two sides of the dielectric filter. At least one projecting prong, corresponding in number and position with the at least one notch of the dielectric filter, extends beyond an end surface of one of the sheets of the shield to interfittingly engage with a corresponding notch formed on the filter. The shield is positioned about the dielectric filter prior to tuning of the filter, and openings are formed to extend through the shield to permit access to the dielectric filter to permit tuning thereof once the shield is positioned thereabout.

Abstract: A dielectric filter construction having at least two resonating cavities extending longitudinally through a block of dielectric material. At least one of the resonating cavities is of a cross-sectional area which is elongated in a transverse direction, and at least one notch is formed to extend longitudinally along at least one of the surfaces of the block of dielectric material between adjacent ones of the resonating cavities. By appropriate selection of the amount of elongation of the cross-section of the resonating cavity, and the location and dimension of the notch formed along the surface of the block, the component values of the component elements comprising the filter may be selected over an increased range without altering the physical size of the filter.

Abstract: A low pass filter circuit for a radiotelephone which filters harmonic, spectral components of a modulated signal generated by the radiotelephone. The filter circuit is comprised of inductors and capacitors wherein each inductor and each capacitor of the filter is comprised of a distributed-element portion and a discrete-element portion. The distributed element portions of each inductor and each capacitor of the filter attenuate higher-frequency, spectral components of a signal applied thereto. The discrete element components of each inductor and each capacitor of the filter attenuate lower-frequency, spectral components of the signal applied thereto.

Abstract: A voltage controlled oscillator and buffer amplifier circuit (211) is disclosed. The circuit is in a stacked configuration, whereby, the current from the power supply (361) is used by the buffer amplifier circuit and reused by the VCO circuit. The VCO circuit includes two transistors (333, 325). The transistors are set-up in a mirrored configuration, so that one of the transistors (325) controls the bias current in the other transistor (333). Both of the transistors are integrated into a semiconductor circuit die (365), thus, matching the thermal characteristics of the transistors (333, 325) and improving control of the bias current. The die (365) is bonded to a ceramic substrate (601). The substrate (601) has connectivity paths for connecting components in the circuit die to components external to the circuit die. Some of the connectivity paths are made of a material and length to form passive circuit elements.

Abstract: A dielectric filter assembly and mounting therefor. The mounting bracket forms a support surface and includes integrally formed strip members for interconnecting electrodes formed upon a face surface of the dielectric filter and a circuit disposed upon an electrical circuit board. Once interconnected, reflow solder connections are formed between the strip members and the electrodes and the strip members and the circuit disposed upon the circuit board. The strip member is then severed from the mounting bracket to electrically isolate the electrode disposed upon the face surface of the dielectric filter, while maintaining the electrical connection between the electrodes formed upon the dielectric filter and the circuit disposed upon the circuit board.

Abstract: A dielectric block filter construction having resonating cavities formed therein to form one half wave-wavelength resonators thereby. The resonating cavities span opposing side surfaces of the dielectric block forming the dielectric block filter to define openings at the opposing side surfaces. Outer surfaces of the dielectric block, including the opposing side surfaces having the openings defined thereat, are coated with an electrically-conductive material except for portions of one side surface of the dielectric block about peripheral surfaces of input and output couplers formed on the one surface. Because the opposing outer surfaces are coated with the electrically-conductive material, the opposing outer surfaces of the dielectric block are self-shielding to prevent propagation of electromagnetic radiation through openings defined by the resonating cavities of the dielectric block.

Abstract: A ceramic filter includes a multiple zero bandstop filter function. The ceramic filter has a dielectric block with top and bottom surfaces and at least two holes, including a first hole and a second hole, extending from the top surface toward the bottom surface of the block. The block is selectively covered with a conductive material to provide a transmission line resonator for each of the two holes. The filter also includes an input electrode coupled to the dielectric means at a predetermined distance from the first hole, and an output electrode coupled to the dielectric means at a predetermined distance from the second hole. Finally, conductive plating, in the form of a transmission line, is contiguously disposed on the dielectric means adjacent the two holes and coupled thereto to provide a bandstop filter function with a zero represented at each hole.