108 results about "Polar transmitter" patented technology

Certain aspects of a method and system for a wideband polar transmitter may be disclosed. Aspects of the method may include polar modulating a plurality of signals by generating a plurality of modulated intermediate frequency (IF) signals corresponding to each of a plurality of wireless communication protocols within a transmitter that handles the plurality of wireless communication protocols. The generated plurality of modulated IF signals may be upconverted to a plurality of radio frequency (RF) signals. The plurality of RF signals may be combined and the combined plurality of RF signals may be amplitude modulated.

A test signal comprising a periodic waveform, such as a triangular waveform and sawtooth waveform, is used for propagation delay matching in a transceiver front-end. The test signal is separately fed to the envelope path and the RF path. At the power amplifier stage, a phase modulator is used to obtain the envelope signal and the phase modulated RF signal for demodulation by an IQ demodulator. At the output end of the IQ demodulator, the I-signal is measured while the delay block is adjusted in order to vary the propagation delay. When the propagation delay matching is correct, the peak-to-peak value of the I-signal is a minimum. Preferably, during calibration using the test signal, the transmitter RF power amplifier is disabled so that no spurious signals will be sent. The transmitter can be an EDGE polar transmitter, a non-EDGE transmitter or a EER polar transmitter.

A power amplifier controller controls a power amplifier and is coupled to a polar modulator. The polar modulator generates an amplitude component and a phase-modulated component of the desired RF modulated signal, and outputs to the power amplifier controller. The power amplifier controller regenerates a combined phase and amplitude modulated RF signal to generate an input signal to a power amplifier by adjusting the gain of a VGA based on the amplitude component of the desired RF modulated signal. Concurrently, the power amplifier controller both controls an adjusted supply voltage to the PA and adjusts the gain of the VGA based upon an amplitude correction signal or amplitude error signal.

A power amplifier controller controls a power amplifier and is coupled to a polar modulator. The polar modulator generates an amplitude component and a phase-modulated component of the desired RF modulated signal, and outputs to the power amplifier controller. The power amplifier controller regenerates a combined phase and amplitude modulated RF signal to generate an input signal to a power amplifier by adjusting the gain of a VGA based on the amplitude component of the desired RF modulated signal. Concurrently, the power amplifier controller both controls an adjusted supply voltage to the PA and adjusts the gain of the VGA based upon an amplitude correction signal or amplitude error signal.

An output-power threshold is selected such that one or more signal requirements is not outside a pre-determined range when output power of a polar transmitter is less than the output-power threshold. A determination is made whether the output power is less than the threshold. In response to a determination that the output power is less than the threshold, amplitude modulation of a polar signal transmitted by the polar transmitter is disabled. When the output power meets or exceeds the output-power threshold, the polar signal transmitted by the polar transmitter is both amplitude and phase modulated.

An output-power threshold is selected such that one or more signal requirements is not outside a pre-determined range when output power of a polar transmitter is less than the output-power threshold. A determination is made whether the output power is less than the threshold. In response to a determination that the output power is less than the threshold, amplitude modulation of a polar signal transmitted by the polar transmitter is disabled. When the output power meets or exceeds the output-power threshold, the polar signal transmitted by the polar transmitter is both amplitude and phase modulated.

Methods and apparatus for dynamically compensating for signal variations in communications transmitters employing switch-mode PAs. An exemplary method includes first identifying a predetermined signal characteristic in an input signal applied to an input of a switch-mode PA. A modulated signal produced at the output of the switch-mode PA containing the identified signal characteristic is then sampled at approximately the same time the identified signal characteristic appears at the output of the switch-mode PA, to generate a digital sample representing an actual value of the identified signal characteristic. An error signal representing the extent to which the actual value deviates from an expected value is then generated. Finally, the DC level and / or gain of the input signal to the switch-mode PA is modified to reduce the error. By reducing the error in this manner, signal variations that adversely affect the accuracy of the switch-mode PA output signal are dynamically compensated for.

A novel apparatus for and method of delay alignment between amplitude and phase / frequency modulation paths in a digital polar transmitter. The invention provides a fully digital delay alignment mechanism where better than nanosecond alignment is achieved by accounting for processing delays in the digital circuit modules of the transmitter and by the use of programmable delay elements spread across several clock domains. Tapped delay lines compensate for propagation and settling delays in analog elements such as the DCO, dividers, quad switch, buffers, level shifters and digital pre-power amplifier (DPA). A signal correlative mechanism is provided whereby data from the amplitude and phase / frequency modulation paths to be matched is first interpolated and then cross-correlated to achieve accuracy better than the clock domain of comparison. Within the ADPLL portion of the transmitter, precise alignment of reference and direct point injection points in the ADPLL is provded using multiple clock domains, tapped delay lines and clock adjustment circuits.

An on-chip calibration system comprises a transmitter, a receiver, a phase and amplitude determination element configured to determine amplitude and phase characteristics of an output signal generated in the transmitter, the signal representing transmitter characteristics, an amplitude comparison element configured to compare the signal representing transmitter characteristics with a desired amplitude signal and generate an amplitude compensation signal, an AM predistortion element configured to modify an ideal AM signal with the amplitude compensation signal, a phase comparison element configured to compare the signal representing transmitter characteristics with a desired phase signal and generate a phase compensation signal, and a PM predistortion element configured to modify an ideal phase signal with the phase compensation signal.

Systems and methods are disclosed for providing a linear polar transmitter. The systems and methods may include generating an input amplitude signal and an input phase signal, where the input amplitude signal and the input phase signal are orthogonal components of an input signal, and where the input amplitude signal and the input phase signal are generated on respective first and second signal paths. The systems and methods may also include processing the input amplitude signal along the first signal path using an amplitude error signal to generate a predistorted amplitude signal, and processing the input phase signal along the second signal path using an phase error signal to generate a predistorted phase signal. The systems and methods may also include providing the predistorted amplitude signal along the first signal path and the predistorted phase signal along the second signal path to a power amplifier to generate an output signal, where the amplitude error signal is generated from a comparison of at least an amplitude portion of the output signal with the predistorted amplitude signal and where the phase error signal is generated from a comparison of at least a phase portion of the output signal with the predistorted phase signal.

A novel and useful apparatus for and method of reducing phase and amplitude modulation bandwidth in polar transmitters. The bandwidth reduction mechanism of the present invention effectively reduces the phase modulation bandwidth of the polar modulation performed in the transmitter by modifying the zero-crossing trajectories in the IQ domain. This significantly reduces the phase modulation bandwidth while still meeting the output spectrum and error vector magnitude (EVM) requirements of the particular modern wideband wireless standard, such as 3G WCDMA, etc. The mechanism detects a zero crossing or a near zero crossing within a predetermined threshold of the origin and an offset vector is generated that when added to the input TX IQ data, shifts the trajectory to avoid the origin thus reducing the resultant polar modulation amplitude and phase bandwidth.

A polar transmitter, operable in linear mode or switched mode, uses a conversion module to convert baseband signals into amplitude data and phase data. The phase data is used to phase modulate a carrier frequency in a RF conversion module. The module comprises a plurality of parallel unit cells, each being a mixer cell type converter having a differential data switch section connected in series to a differential LO-switch pair. The differential LO-switch is connected in series to a current source. Each unit cell is adapted to receive a signal through an input end. In switched mode, the phase-modulated carrier frequency is amplitude modulated by the amplitude data through the supply voltage to a power amplifier. In linear mode, amplitude data is conveyed to the input end of the unit cells for modulating the phase-modulated carrier frequency in the conversion module.

A digitally controlled mechanism for the minimization of the self-interference caused by an amplitude modulated signal generated within a polar transmitter to the oscillator circuit, where the carrier of that transmitter is created. A digitally controlled delay between the circuit where the signal is generated and the circuit where it is amplitude-modulated allows adjustment of the delay or phase-shift between the aggressing and victim signals. The optimal delay that is to be introduced in the path is determined, and a corresponding control word is generated to arrive at the selected delay / phase-shift.

A digital polar transmitter includes a baseband processor configured to receive an input signal and to convert the input signal into a baseband amplitude component and a baseband phase component. The transmitter also includes a phase modulator in communication with the baseband processor. The phase modulator is configured to modulate an RF carrier signal based on the phase component and to generate a phase-modulated RF carrier signal. A power amplifier is provided in communication with the baseband processor and the phase modulator. The power amplifier is configured to amplify the phase-modulated RF carrier signal based on the baseband amplitude component and to generate an amplified RF signal. The transmitter also includes a digital feedback loop in communication with the power amplifier and the baseband processor. The digital feedback loop is configured to detect the amplified RF signal and to provide a digital amplitude feedback signal and a detected phase feedback signal to the baseband processor.

A polar transmitter, operable in linear mode or switched mode, uses a conversion module to convert baseband signals into amplitude data and phase data. The phase data is used to phase modulate a carrier frequency in a radio frequency conversion module. The module comprises a plurality of parallel unit cells, each being a mixer cell type converter having a differential data switch section connected in series to a differential local oscillator-switch pair. The differential local oscillator-switch is connected in series to a current source. Each unit cell is adapted to receive a signal through an input end. In switched mode, the phase-modulated carrier frequency is amplitude modulated by the amplitude data through the supply voltage to a power amplifier. In linear mode, amplitude data is conveyed to the input end of the unit cells for modulating the phase-modulated carrier frequency in the conversion module.

Certain aspects of a method and system for a wideband polar transmitter may be disclosed. Aspects of the method may include polar modulating a plurality of signals by generating a plurality of modulated intermediate frequency (IF) signals corresponding to each of a plurality of wireless communication protocols within a transmitter that handles the plurality of wireless communication protocols. The generated plurality of modulated IF signals may be upconverted to a plurality of radio frequency (RF) signals. The plurality of RF signals may be combined and the combined plurality of RF signals may be amplitude modulated.

Systems and methods are disclosed for providing a linear polar transmitter. The systems and methods may include generating an input amplitude signal and an input phase signal, where the input amplitude signal and the input phase signal are orthogonal components of an input signal, and where the input amplitude signal and the input phase signal are generated on respective first and second signal paths. The systems and methods may also include processing the input amplitude signal along the first signal path using an amplitude error signal to generate a predistorted amplitude signal, and processing the input phase signal along the second signal path using an phase error signal to generate a predistorted phase signal. The systems and methods may also include providing the predistorted amplitude signal along the first signal path and the predistorted phase signal along the second signal path to a power amplifier to generate an output signal, where the amplitude error signal is generated from a comparison of at least an amplitude portion of the output signal with the predistorted amplitude signal and where the phase error signal is generated from a comparison of at least a phase portion of the output signal with the predistorted phase signal.

A novel apparatus for and method of delay alignment between amplitude and phase / frequency modulation paths in a digital polar transmitter. The invention provides a fully digital delay alignment mechanism where better than nanosecond alignment is achieved by accounting for processing delays in the digital circuit modules of the transmitter and by the use of programmable delay elements spread across several clock domains. Tapped delay lines compensate for propagation and settling delays in analog elements such as the DCO, dividers, quad switch, buffers, level shifters and digital pre-power amplifier (DPA). A signal correlative mechanism is provided whereby data from the amplitude and phase / frequency modulation paths to be matched is first interpolated and then cross-correlated to achieve accuracy better than the clock domain of comparison. Within the ADPLL portion of the transmitter, precise alignment of reference and direct point injection points in the ADPLL is provded using multiple clock domains, tapped delay lines and clock adjustment circuits.

A test signal comprising a periodic waveform, such as a triangular waveform and sawtooth waveform, is used for propagation delay matching in a transceiver front-end. The test signal is separately fed to the envelope path and the RF path. At the power amplifier stage, a phase modulator is used to obtain the envelope signal and the phase modulated RF signal for demodulation by an IQ demodulator. At the output end of the IQ demodulator, the I-signal is measured while the delay block is adjusted in order to vary the propagation delay. When the propagation delay matching is correct, the peak-to-peak value of the I-signal is a minimum. Preferably, during calibration using the test signal, the transmitter RF power amplifier is disabled so that no spurious signals will be sent. The transmitter can be an EDGE polar transmitter, a non-EDGE transmitter or a EER polar transmitter.

A novel sigma delta amplitude modulator having a noise transfer function adapted to shift quantization noise outside at least one frequency band of interest. In one embodiment, the sigma delta amplitude modulator includes a programmable order low pass stage. In a second embodiment, the sigma delta amplitude modulator incorporates comb filtering wherein each comb filter comprises a plurality of fingers to permit greater programmability in the frequency location of notches. A polar transmitter incorporating the sigma delta amplitude modulator is presented that shapes the spectral emissions of the digitally-controlled power amplifier such that they are significantly and sufficiently attenuated in one or more desired frequency bands.

A digital polar transmitter includes a baseband processor configured to receive an input signal and to convert the input signal into a baseband amplitude component and a baseband phase component. The transmitter also includes a phase modulator in communication with the baseband processor. The phase modulator is configured to modulate an RF carrier signal based on the phase component and to generate a phase-modulated RF carrier signal. A power amplifier is provided in communication with the baseband processor and the phase modulator. The power amplifier is configured to amplify the phase-modulated RF carrier signal based on the baseband amplitude component and to generate an amplified RF signal. The transmitter also includes a digital feedback loop in communication with the power amplifier and the baseband processor. The digital feedback loop is configured to detect the amplified RF signal and to provide a digital amplitude feedback signal and a detected phase feedback signal to the baseband processor.

A polar transmitter and a method of linearizing a polar transmitter. In one embodiment, the transmitter includes: (1) a transmit chain having a predistorter configured to employ first amplitude and phase compensation lookup tables to carry out predistortion in the transmit chain, (2) a receiver coupled to the transmit chain and (3) predistortion compensation circuitry associated with the receiver and configured to update second amplitude and phase compensation lookup tables associated therewith based on at least one signal from the transmit chain, the values in the updated second amplitude and phase compensation lookup tables thereby available for subsequent predistortion.

An RF power amplifier for a polar transmitter converts an amplitude component signal into a 1-bit digital amplitude signal, which is fed to a digital finite impulse response filter. Successive taps of the filter each have an RF amplification stage arranged to amplify successively delayed versions of the 1-bit digital amplitude signal, the amplifying being according to a respective tap coefficient, and according to the RF carrier modulated by the phase component. The filter is arranged to combine the outputs of the taps to provide the amplified RF signal. The power amplifier uses a one bit stream which therefore has only two states (2 values), thus achieving linearity in principle. Device mismatch between taps does not lead to non-linearity or distortion.

The invention provides a polar coordinate transmitter, which can meet the requirement of high speed rate at a low-speed clock frequency, i.e., compensate for integer time delay and fraction time delay under the condition of not increasing the sampling rate. The polar coordinate transmitter comprises a polar coordinate generating unit, an amplitude modulating unit, a phase modulating unit, a switch power amplifying unit, a time delay estimating unit and a variable fraction time delay filter, wherein the time delay estimating unit is used for estimating integer time delays of a phase channel and an amplitude channel on a time domain respectively, compensating for the integer time delays, estimating fraction time delays of the phase channel and the amplitude channel on a frequency domain respectively, adding an integer time delay error and a fraction time delay error between the phase channel and the amplitude channel to obtain a time delay error, and setting the variable fraction time delay filter according to the obtained time delay error; and the variable fraction time delay filter is used for performing time delay on a signal input into the phase channel and compensating for the time delay error between the phase channel and the amplitude channel.

A frequency synthesizer includes a distributed phase detector circuit, a multiple charge pump, a loop filter, a voltage-controlled oscillator and a dividing circuit. The distributed phase detector circuit delays an up signal and a down signal to generate a delayed up signal and a delayed down signal. The multiple charge pump generates a distributed current signal including a plurality of current pulse signals. Each of the current pulse signal is based on each bit of the delayed up signal and the delayed down signal. The loop filter filters the distributed current signal to generate a control voltage. The voltage-controlled oscillator generates an oscillation frequency signal based on the control voltage. The dividing circuit divides the oscillation frequency signal to generate a plurality of division frequency signals in response to a plurality of control signals, where the frequency signals are fedback to the distributed phase detector circuit.

The invention includes methods for transmission power control in a wireless communication system. The method includes receiving at least one input parameter indicative of a transmission power level, generating a control parameter based on the at least one parameter and regulating an output transmission power level of a wireless terminal based on the control parameter. The invention further includes transmission power control methods for a digital polar transmitter.

A polar transmitter using a binary phase shift key (BPSK) method includes a data dividing unit which divides input data into an amplitude component and a phase component, a frequency synthesizer which produces an I value of a passband having a phase component of an I signal and a Q value of a passband having a phase component of a Q signal, a polar modulation circuit for the I signal which produces an I carrier wave to the I signal using the amplitude component from the data dividing unit and the I value from the frequency synthesizer, a polar modulation circuit for the Q signal which produces a Q carrier wave to the Q signal using the amplitude component and the Q value, and a carrier wave producing unit which combines the I carrier wave and the Q carrier wave thus to produce a carrier wave.