Abstract: A linear power control loop for a power amplifier is disclosed. Embodiments of the invention linearly control the power amplifier output, prevent the power amplifier from failure induced by excessive supply current by reducing power amplifier bias current, and provide a mechanism to detect whether the power amplifier is operating in a saturation condition.

Abstract: A single continuous closed-loop power control feedback system provides seamless power control/for a power amplifier and also enables an AM signal to be injected into the power amplifier through the power amplifiers' control port. The AM signal is developed by an I/Q modulator and supplied to a comparator located in the power control loop.

Abstract: A closed power control feedback loop system allows a single portable transceiver architecture to be used for systems in which a transmit signal including both a phase modulated (PM) component and an amplitude modulated (AM) component are supplied to a power amplifier and in systems in which the transmit signal has only a PM component supplied to a power amplifier. By injecting the inverse of the AM portion of the desired transmit signal into the closed power control feedback loop, the feedback loop will not cancel the AM portion of the signal, thus allowing a system where both a PM component and an AM component of the transmit signal are present at the output of the power amplifier to function using a closed power control feedback loop.

Abstract: A translation loop modulator and power amplifier in a phase and amplitude modulated transmission environment includes a translation loop having a phase locked loop and that is configured to receive a first modulated signal (PM) and that is also configured to provide a frequency specific modulated signal. The invention also includes a power amplifier configured to receive the frequency specific modulated signal, a variable gain element configured to provide a second modulated signal (AM) to the power amplifier and a switching element configured to receive a portion of an output of the translation loop and a portion of an output power of the power amplifier.

Abstract: A software defined transmit architecture includes a plurality of individually selectable components that can be selectively enabled to transmit a data signal that complies with any of a plurality of transmission standards. The software defined transmit architecture comprises components that can be enabled by associated logic to transmit, for example, communications signals that comply with the global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), which employs TDMA, and wide band code division multiple access (WCDMA) transmission standards. A single transmit architecture supports multiple transmission standards, thus minimizing the number of components in a multi-band, multi-mode portable transceiver, while reducing the number of active components.

Abstract: A system for a fast, closed power control loop that quickly adjusts the output power of a power amplifier in a non-constant amplitude modulation format. Embodiments of the invention allow fast and precise closed loop power control in a communication system that has a transmit signal that includes a phase modulated component and an amplitude modulated signal component. By detecting the level of the transmit signal before and after the power amplifier, the invention ignores changes in the amplitude of the transmit signal, resulting in an accurate measure of the power amplifier gain. The difference between the level of the transmit signal before and after the power amplifier provides a signal that represents the gain of the power amplifier. The gain signal is compared with a reference signal to develop an error signal. The error signal is used to control the output of the power amplifier.

Abstract: A translation loop signal upconverter is disclosed. Embodiments of the invention minimize nth order harmonics and spurious tones in the radio frequency output spectrum of a portable transceiver. In one embodiment, the invention is a signal upconverter, comprising a modulator configured to develop a modulated intermediate frequency (IF) signal at a fundamental frequency, the modulated IF signal also including a plurality of nth order components, a synchronous oscillator configured to receive the modulated IF signal, the synchronous oscillator also configured to operate at the fundamental frequency of the modulated IF signal, thereby providing an IF signal substantially free of the nth order components, and a translation loop having a phase locked loop, the translation loop configured to receive the IF signal output of the synchronous oscillator, and supply a radio frequency (RF) output signal to a power amplifier.

Abstract: A mirror translation loop upconverter that is capable of upconverting both constant envelope and non-constant envelope modulation formats is disclosed. Embodiments of the invention provide the ability to upconvert a transmit signal that includes only a phase-modulated component, only an amplitude-modulated component, or both a phase-modulated component and an amplitude-modulated component. If the transmit signal includes both a phase-modulated signal component and an amplitude-modulated signal component, the phase-modulated signal component and the amplitude-modulated signal component are supplied to a pair of phase shifters. The phase shifters alter the phase of the phase-modulated signal by an amount related to the amplitude of the amplitude-modulated signal. The phase shifters oppositely alter the phase of the phase-modulated signal, and therefore supply complementary phase versions of the phase-modulated signal.

Abstract: A system for a closed power control feedback loop allows for the use of a non-linear amplifier for amplifying a phase modulated (PM) signal while introducing an inverse version of the desired amplitude modulated (AM) signal into the feedback loop using a variable gain element. By introducing an inverse version of the desired AM portion of the signal into the power control feedback loop, the non-linear, and highly efficient, power amplifier may be used to amplify only the PM portion of the signal, while the AM portion is introduced by the power control feedback loop. In another aspect of the invention, an inverse version of the AM portion of the desired transmit signal is introduced into the power control feedback loop of an amplifier that is amplifying both a phase modulated signal and an amplitude modulated signal.

Abstract: A multi-band transceiver having a receiver portion and a transmitter portion, wherein the receiver portion includes a direct conversion receiver system for directly downconverting a signal to baseband frequencies. The direct conversion receiver system includes a frequency translator having first and second inputs and an output. A first signal at a first frequency is applied to the first input. A second signal having a second frequency is applied to the second input. The first frequency is preferably an nth order subharmonic of the second frequency, wherein n is an integer greater than 1. A low pass filter is integral with or inherent to the first input, and a high pass filter is integral with or inherent to the second input. The corner frequencies of both the low pass and high pass filters is above the first frequency and below the second frequency.

Abstract: A system for controlling a power amplifier using a dual feedback translation loop uses the output of the translation loop during a first time period where a power amplifier has insufficient power to lock the loop and uses the output of the power amplifier to lock the translation loop only after the power amplifier provides sufficient power. By using a first feedback loop taken from the output of the translation loop and a second feedback loop taken from the output of the power amplifier, the translation loop can lock to the output of the translation loop until the power output of the power amplifier is sufficient to lock the translation loop. A pair of phase detectors and corresponding charge pumps associated with each of the feedback loops provides a smooth switching function while transitioning from the first loop to the second loop.

Abstract: A low noise transmitting device is disclosed. The transmitting device receives a modulated signal having a modulation bandwidth and an intermediate center frequency and generates a modulated transmit band signal at a carrier frequency. The transmitting device includes a first filter that receives the modulated signal and passes frequencies within the modulation bandwidth, producing a low noise filtered modulated signal, and a low noise frequency source that generates a low noise main synthesizer frequency. The filtered modulated signal and the main synthesizer frequency are then fed into a mixer that mixes the two signals (produces either the sum or difference). The output is a low noise modulated transmit band signal that may be amplified to transmit power levels without the need for power-inefficient post-amplification filtering.

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: This invention provides a charge pump biasing circuit that varies the bias when the phase lock loop changes frequency to improve the settling time of the phase lock loop. During a frequency change, the charge pump output current taper off as the phase lock loop approaches the desired frequency. The charge pump biasing circuit allows the phase lock loop to change frequencies faster and minimizes spurious sideband noise once the loop has settled.

Abstract: A closed loop power amplifier control system is provided. A self-adapting driver circuit is used to drive the power amplifier in accordance with the feed back error signal. The driver circuit compensates for non-linearities of the power amplifier.

Abstract: A system and method for minimizing power dissipation in a battery-operated mobile unit by adaptively controlling a voltage converter to provide a variable power supply voltage to a transmitter. In the preferred embodiment, the voltage converter is coupled to receive a source voltage from a battery, and is coupled to provide operating power to the transmitter or the power amplifier. The voltage converter is also coupled to receive a control signal from a controller, which adaptively activates the voltage converter to transform the source voltage to a converted voltage, or deactivates the voltage converter so as to directly apply the source voltage to the transmitter. Power dissipation is therefore minimized when conversion functions of the voltage converter are deactivated when voltage conversion is unnecessary.

Abstract: A direct conversion receiver system is provided in which a first input signal at a first frequency is applied to a first input port of a multiplier, a second input signal at a second frequency equal to about {fraction (1/n)} times the first frequency, wherein n is an integer, is applied to a second input port of the multiplier. A first filter coupled to the first input port is configured to substantially filter out any leakage at the second frequency which may be present. A second filter coupled to the second input port is configured to substantially filter out any leakage at the first frequency which may be present. The multiplier is configured to produce a signal at an output port thereof which is derived from the product of the first and second signals. In one embodiment, the output is representative of the product of the filtered first signal and a multiplication factor which switches at n times the second frequency. The output of the multiplier is coupled to a third filter.

Abstract: A differential oscillator based on a first Colpitts oscillator and a mirror image Colpitts oscillator that is coupled to the first Colpitts oscillator. This differential oscillator outputs differential voltage signals that are about 180 degrees out of phase. The differential oscillator may also be adapted to form a voltage controlled oscillator (VCO) such that the differential voltage signals output by the VCO can be varied. A transceiver for telecommunication devices such as cellular phones may use differential oscillators to generate a carrier signal on which a voice or data signal is modulated and the same differential oscillators to assist isolation of the voice or data signal from received signals.

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.