257 results about "Polar modulation" patented technology

The present invention provides temperature compensation for a power amplifier by varying a supply voltage applied to the power amplifier. The supply voltage is varied based on operating temperature in light of the temperature characteristics of the power amplifier. Thus, the variation in the supply voltage offsets variations in the characteristics of the power amplifier due to changes in temperature. Whether the power amplifier is used to control the output power of a transmitter or as part of a polar modulation system, temperature compensation of the power amplifier allows the power amplifier to provide an accurate and repeatable output signal having essentially no fluctuations due to changes in temperature.

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 transmitting apparatus includes a polar signal producing circuit which produces signals corresponding to the amplitude and the phase of a transmitting modulated wave from an input signal and multiplies the amplitude signal by the phase signal by a multiplying circuit to amplitude modulate a phase-modulated wave to produce a transmitting modulated wave and radiates this transmitting modulated wave as radio wave from an antenna. An amplitude / phase detecting circuit detects an amplitude signal and a phase signal from the input of the multiplying circuit and the input of a phase-modulated signal producing circuit. A delay difference computing circuit computes a correlation function between the amplitude signal produced by the polar signal producing circuit and the amplitude signal detected by the amplitude / phase detecting circuit and a correlation function between the phase signal produced by the polar signal producing means and the phase signal detected by the amplitude / phase detecting means, and computes a delay difference between the amplitude signal and the phase signal from maximum values of the respective correlation functions. Then, a timing adjusting circuit adjusts the delay time between the amplitude signal and the phase signal on the base of the computed delay difference.

The object of the present invention is to automatically adjust the synchronization of an amplitude signal and a phase signal in a transmitting apparatus such as polar modulation transmitting apparatus. A polar signal producing circuit (101) produces signals corresponding to the amplitude and the phase of a transmitting modulated wave from an input signal and multiplies the amplitude signal by the phase signal by a multiplying circuit (107) to amplitude modulate a phase-modulated wave to produce a transmitting modulated wave and radiates this transmitting modulated wave as radio wave from an antenna (108). An amplitude / phase detecting circuit (109) detects an amplitude signal and a phase signal from the input of the multiplying circuit (107) and the input of a phase-modulated signal producing circuit (106). A delay difference computing circuit (110) computes a correlation function between the amplitude signal produced by the polar signal producing circuit and the amplitude signal detected by the amplitude / phase detecting circuit and a correlation function between the phase signal produced by the polar signal producing means and the phase signal detected by the amplitude / phase detecting means, and computes a delay difference between the amplitude signal and the phase signal from maximum values of the respective correlation functions. Then, a timing adjusting circuit (102) adjusts the delay time between the amplitude signal and the phase signal on the base of the computed delay difference.

The present invention provides temperature compensation for a power amplifier by varying a supply voltage applied to the power amplifier. The supply voltage is varied based on operating temperature in light of the temperature characteristics of the power amplifier. Thus, the variation in the supply voltage offsets variations in the characteristics of the power amplifier due to changes in temperature. Whether the power amplifier is used to control the output power of a transmitter or as part of a polar modulation system, temperature compensation of the power amplifier allows the power amplifier to provide an accurate and repeatable output signal having essentially no fluctuations due to changes in temperature.

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 polar modulation power amplifier circuit includes a control circuit (101) to determine and provide a load selection signal (127), wherein the load selection signal (127) is determined responsive to a requested power signal (119). A power amplifier (113) is responsive to a power control signal (141), for amplifying an RF signal (139) to produce an amplified signal (145), having an output power level. A variable impedance matching circuit (117) is responsive to the load selection signal (127), to adjust a relationship between the control level and the output power level, to produce a range-adjusted amplified signal (147).

A polar modulation transmission apparatus is provided which can adjust synchronization between an amplitude signal and phase signal in a simple configuration accurately and automatically. A polar signal generation circuit 101 sends an amplitude signal and phase signal for synchronization adjustment to transmission lines of these signals, incorporates the amplitude signal and phase signal for synchronization adjustment output from low pass filters 104, 132 which are final stage circuits that process the respective signals in their baseband signal states into a delay difference detection circuit 109, a synchronization adjustment control circuit 110 obtains a synchronization adjustment value at which the delay difference between the signals is eliminated based on the delay difference detection result and a synchronization adjustment circuit 102 gives delays corresponding to the synchronization adjustment value to the respective signals.

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.

An object of the invention is to provide a polar modulation circuit capable of reducing the capacity of data stored in memory and suppressing an increase in the circuit scale related to distortion compensation while assuring the compensation accuracy. The polar modulation circuit according to the invention stores output signal characteristic relative to the control voltage at the steady state after input of the control voltage for a predetermined input amplitude of an input high frequency signal as the basis of distortion compensation of an amplifier separately into an offset storage section 101a which stores data used to add a predetermined DC offset voltage and a coefficient storage section 102 which stores data used for multiplication by a predetermined constant, thus reducing the circuit scale related to distortion compensation while assuring the compensation accuracy.

The present invention, generally speaking, provides a method of obtaining very accurate estimates of the phase and amplitude distortions introduced by radio frequency or microwave power amplifiers even where polar modulation is used.

First and second calibration signals (308, 309) are sent to a frequency divider (102) and an adder (116) of a PLL section (100A), demodulated in a demodulator (111), filtered through a low pass filter (113) and a high pass filter (114) and thereafter sent to a modulation signal control circuit (115). The modulation signal control circuit (115) generates control information (318) in comparison with the phase and amplitude of the first and second calibration signals (308 and 309) and sends the control information (318) to a modulation control signal generator (106). Modulation control signal generator (106) holds the control information (318) and controls the values of the first modulation signal and second modulation signal sent to the frequency divider (102) and adder (116) on the based on the control information (318) held in modulation operation.