254 results about "Polar modulation" patented technology

A polar modulation transmitter circuit provides reduced ACPR in its output signal by controlling the relative delay between its envelope and phase modulation operations based on direct or indirect feedback measurement the output signal's ACPR. Such measurement and associated control may be based on a delay controller that includes an ACPR measurement circuit and a delay control circuit. Additionally, or alternatively, the polar modulation transmitter circuit provides a greatly extended transmit power control range by using a staged amplifier circuit that includes a driver amplifier circuit operating in combination with a power amplifier circuit to impart desired envelope modulation. In an exemplary embodiment, the driver amplifier circuit is implemented as differential transistor pairs responsive to tail current modulation. As such, the driver amplifier circuit is suited in particular for economical and space saving integration within a transmitter or transceiver integrated circuit (IC).

A method of data transmission according to one embodiment of the invention includes encoding a set of data values to produce a corresponding series of ordered n-tuples. The method also includes transmitting, according to the series of ordered n-tuples, a plurality of bursts over a plurality n of frequency bands. Specifically, for each of the plurality of bursts, a frequency band occupied by the burst is indicated by the order within its n-tuple of an element corresponding to the burst. A bandwidth of at least one of the plurality of bursts is at least two percent of the center frequency of the burst. Information is encoded into a polarity of at least one of the plurality of bursts.

A wireless transmission apparatus of multi-mode operation with superior power efficiency is provided. Switches (115 and 117) are switched over in such a manner that a modulation signal outputted from a wireless GSM/EDGE (UB) signal formation circuit (101-3) of a high-frequency signal processing circuit (101) is outputted to a high-frequency power amplifier (104) at the time of output of a GSM modulation signal, and is outputted to a high-frequency amplifier (105) at the time of output of an EDGE modulation signal. As a result, the EDGE modulation signal is power amplified using a high-frequency power amplifier (105) for an UMTS modulation signal use that is compatible with regards to the EDGE modulation signal and the maximum output power and presence or absence of envelope fluctuation. It is therefore possible to amplify the EDGE modulation scheme wireless signal with high efficiency.

The polar modulation apparatus of the present invention can control the output power of a transmission signal over a wide range and compensate characteristic degradation reliably upon temperature change. Polar modulation transmission apparatus 100 is provided with: temperature sensor 120; temperature compensation section 1601 that corrects an amplitude signal and performs temperature compensation for transmission power amplification section 190; temperature compensation section 160-2 that corrects a power amplification signal and performs temperature compensation for power adjustment section 180; and correction value setting section 130 that sets correction values for temperature compensation section 160-1 and temperature compensation section 160-2, and, while only the amplitude signal is corrected according to a measurement result in temperature sensor 120 in the first mode, the amplitude signal and the power adjustment signal are corrected according to a measurement result in the second mode.

An object of the invention is to provide a polar modulation transmitter that can perform adaptive distortion compensation processing without the need for a synchronization adjustment circuit for synchronizing an input baseband signal and an output signal of a power amplifier. An adaptive operation control section 1501 measures the unbalance amount of an output spectrum of a power amplifier 1 and a coefficient adjustment determination section of the adaptive operation control section 1501 performs iteration control so that if the unbalance amount is equal to or greater than a predetermined threshold value, coefficient information output to a distortion compensation processing circuit 1301 is adjusted and an adjustment is made to distortion compensation processing in the distortion compensation processing circuit 1301 and if the unbalance amount is less than the predetermined threshold value, the coefficient information is maintained, whereby the characteristic change of the power amplifier 1 at the environmental temperature change time can be adaptively compensated for without using a synchronization adjustment circuit for synchronizing an input baseband signal and an output signal from the power amplifier 1.

Methods of modulating a radio transmitter. An amplitude modulation signal is generated based on in-phase (I) and quadrature (Q) components of an information signal, and so that it has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal. A complex signal is formed that has substantially the same phase angle variation as the I and Q components of the information signal so that the product of the complex signal and the amplitude modulation signal is substantially equal to the information 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.

Methods and apparatus for predistorting signals in a polar modulation transmitter. An exemplary method includes predistorting an envelope component signal in an amplitude path of a polar modulation transmitter according to a set of AM/AM predistortion coefficients, and predistorting a phase component signal in a phase path of the polar modulation transmitter according to a set of AM/PM predistortion coefficients. The AM/AM and AM/PM predistortion coefficients are stored in a memory in the form of a look up table (LUT). The envelope component signal is scaled and/or offset, before predistortion is applied, by an amount dependent upon which average power level of a plurality of average power levels the power amplifier of the polar modulation transmitter is configured to operate. Scaling and/or offsetting the envelope component signal prior to applying predistortion affords the ability to share the AM/AM and AM/PM predistortion coefficients of the predistortion LUT over the plurality of average power levels.

Polar modulators include a phase splitter, a controller, variable current sources, transistor circuits, and a combiner. The phase splitter splits a RF carrier signal into quadrature component signals that are 90 degrees out of phase with each other. The controller generates modulation control signals based on information that is to be transmitted. The variable current sources each generate a variable amplitude current signal based on a different one of the modulation control signals. Each of the transistor circuits amplify a different one of the quadrature component signals with a variable amplification based on the variable amplitude current signal from a different one of the variable current sources to generate an amplitude adjusted quadrature component signal. The combiner combines the amplitude adjusted quadrature component signals from each of the transistor circuits to generate a phase-modulated RF carrier output signal.

Systems and methods for optical communication that use a transmitter/receiver. The systems and methods include receiving a modulated, encoded input stream. Channel memory is reduced using coarse digital backpropagation and other channel impairments are removed using turbo equalization. Symbols are detected in the input stream that conform to a non-uniform, polar constellation having a Gaussian source distribution to produce a stream of encoded data. The stream of encoded data is decoded with one or more low density parity check (LDPC) decoders.

Polar modulation input signals to a polar modulated power amplifier include a phase modulated (PM) input signal, which feeds a power amplifier input, and an amplitude modulated (AM) input signal, which provides an envelope supply voltage for the power amplifier. The present invention is a large signal polar modulated power amplifier that extends the effective amplitude range of AM input signals that can be handled by the power amplifier by amplitude modulating the PM input signal using the AM input signal. Amplitude modulating the PM input signal effectively lowers the amplitude of the PM input signal when the amplitude of the AM input signal is lowered, which maintains adequate headroom between the power amplifier's signal input and envelope supply voltage input in the presence of large amplitude AM input signals. As a result, the power amplifier can amplify larger amplitude AM input signals than traditional power amplifier designs.

A method and apparatus for dynamically compensating for delay mismatch between a supply signal and an input signal of a power amplifier in polar modulation transmitters. One exemplary polar modulation transmitter according to the present invention comprises a power amplifier, a phase modulator, a regulator, a delay tracking circuit, and a delay circuit. The phase modulator derives the amplifier input signal responsive to one or more phase signals, while the regulator derives the amplifier supply signal responsive to an amplitude signal. Based on the amplitude signal and the amplifier supply signal, the delay tracking circuit tracks an observed amplitude path delay. The delay circuit adjusts a path delay associated with the phase signal, responsive to the observed amplitude path delay, to compensate for the delay mismatch.

A modulated carrier signal is produced from a phase modulation signal in a phase locked loop in a polar modulator. This carrier signal is converted via a limiting amplifier to a square-wave signal, which is supplied to an amplifier. At the same time, an amplitude modulation signal at one input is connected to a control input of a controllable current source. The controllable current source is designed to emit a supply current at a current output as a function of the amplitude modulation signal at the control input. The current output of the controllable current source is connected to a supply input of the amplifier. The supply current for the amplifier is thus modulated on the basis of the amplitude information to be transmitted. The processing of the amplitude information within the current domain makes it possible to produce the polar modulator according to the invention as an integrated circuit, using CMOS technology.

Aspects of a method and system for digital tracking in direct and polar modulation are presented. Aspects of the system may include at least one circuit within a phase locked loop (PLL) circuit that enables adaptive and digital control of an analog fractional N (Frac N) PLL during direct modulation of a signal or polar modulation of the signal.

There provides a two-point modulation phase modulation apparatus capable of obtaining an RF phase modulation signal of superior modulation precision with low power consumption and a simple configuration even in the event of inputting a wide band baseband modulation signal. A differentiator (21) of the opposite characteristics to the attenuation characteristics of anti-alias filter (22) is provided at the front stage of a D/A converter (6). As a result, it is possible to sufficiently suppress an alias signal without raising the sampling frequency of the D/A converter (6) (i.e. low power consumption) using an anti-alias filter (22) of a simple configuration (i.e. low cost) with a low order for a narrower bandwidth than a PLL modulation frequency bandwidth, and it is possible to obtain an RF phase modulation signal where the entire frequency band of input digital baseband modulation signal (S1) is reflected in a superior manner.

A phase modulation apparatus is provided whereby excellent RF phase modulation signals can be obtained even when the modulation sensitivity of a voltage controlled oscillator varies. Phase modulation apparatus 100 has: phase detector 105 that performs phase detection with respect to an RF phase modulation signal outputted from VCO 101; comparator 106 that compares the phase of the detected signal with the phase of a baseband phase modulation signal and outputs the difference between the signals; variable gain amplifier 107 that controls the gain of the baseband phase modulation signal based on the output of comparator 106 and supplies the gain-controlled baseband phase modulation signal to VCO 101. By this means, the signal level of the baseband phase modulation signal that is supplied to VCO 101 can be controlled in accordance with the modulation sensitivity of VCO 101, so that phase modulation apparatus 100 can be realized whereby excellent RF phase modulation signals even when the modulation sensitivity of VCO 101 varies.

The invention provides systems, methods and apparatuses for linear envelope elimination and restoration transmitters, based on the polar modulation operation combined with the orthogon recursive predistortion. The polar modulation technique dynamicly regulates bias level to increase battery life. Moreover, the analogy orthogon recursive predistortion corrects amplitude and phase errors in a radiofrequency (RF) power amplifier (PA) effectively, enhances PA output capability. Even-order distortion components are used for predistortion of input signals by means of multiplication, improve effective correcting bandwidth. Moreover, the predistortion proposal of a temporary feedback envelope distortion signal allows to correct any distortion of correcting loop bandwidth including envelope memory effect.

A two-point polar modulator for generating a polar-modulated signal based on an amplitude information and a phase information includes a two-point modulation phase-locked loop which is implemented to enable a frequency setting depending on a first control value via a feedback path of the two-point modulation phase-locked loop and to enable a frequency setting depending on a second control value, directly, bypassing the feedback path, wherein the two-point modulation phase-locked loop is implemented to provide a phase-locked loop output signal depending on the two control values. The two-point polar modulator further includes a modulator which is implemented to combine an amplitude signal derived from the amplitude information with the phase-locked loop output signal, to generate the polar-modulated signal and a control value generator which is implemented to generate the first control value depending on the phase information and independent of the amplitude information and which is implemented to generate the second control value depending on the amplitude information.