Abstract:
When switching the mode of a power amplifier between compressed mode and uncompressed mode, accurate transmission power control is realized. A transmission power control method includes setting a power setting value of mode to switch to, such that an inter-mode output power error is canceled (equal to step ST21), calculating an intra-mode output power error from the power setting value of the mode to switch to (equal to step ST23), calculating a gain linearity value based on the power setting value of the mode to switch to and an output power error of the intra-mode (equal to step ST24), and resetting the power setting value of the mode to switch to based on the gain linearity value (equal to steps ST25 and 26).
Abstract:
A polar modulator of the present invention includes: a first function block which generates an amplitude signal and a phase signal; a second function block which adjusts the signal delay between the amplitude signal and the phase signal; a third function block which allows the low frequency component of the amplitude signal to pass therethrough; a fourth function block which modulates the phase of the phase signal; a fifth function block which outputs a modulation voltage, based on the amplitude signal; a sixth function block which modulates the amplitude of the phase signal, based on the modulation voltage; a seventh function block which measures the temperature of at least one function block; and an eighth function block which calculates a compensation amount for the signal delay, based on the measured temperature. The second function block adjusts the signal delay, based on the compensation amount.
Abstract:
A radio transmission apparatus according to the present invention detects an output current of a power supply section that varies in response to a variation of the output impedance of an amplification section, and corrects a distortion of the input/output characteristic of the amplification section by using an LUT corresponding to the detected output current. In addition, a threshold used for switching an LUT is caused to be different depending on a switching direction between LUTs, thereby suppressing frequent occurrence of switching of the LUT.
Abstract:
A transmission circuit switches a bias circuit without allowing a power amplifier to enter a non-bias state. A first bias circuit supplies a first bias signal to a power amplifier, and a second bias circuit supplies a second bias signal to the power amplifier. A first delay circuit delays the switching of an operation of the first bias circuit using a first delay time, and a second delay circuit delays the switching of an operation of the second bias circuit using a second delay time. The first bias circuit and the second bias circuit are both simultaneously operated for a predefined time period, in order to prevent a transistor for amplification from entering a non-bias state when switching an operation mode of the power amplifier.
Abstract:
A polar modulator of the present invention includes: a first function block which generates an amplitude signal and a phase signal; a second function block which adjusts the signal delay between the amplitude signal and the phase signal; a third function block which allows the low frequency component of the amplitude signal to pass therethrough; a fourth function block which modulates the phase of the phase signal; a fifth function block which outputs a modulation voltage, based on the amplitude signal; a sixth function block which modulates the amplitude of the phase signal, based on the modulation voltage; a seventh function block which measures the temperature of at least one function block; and an eighth function block which calculates a compensation amount for the signal delay, based on the measured temperature. The second function block adjusts the signal delay, based on the compensation amount.
Abstract:
A compact transmission circuit for outputting a highly linear transmission signal regardless of the output power level and operating at a high efficiency is provided. A signal generation section 11 generates an amplitude signal and quadrature data based on input data. A calculation section 21 calculates using the amplitude signal and the quadrature data to output a discrete value having a level discrete at every predetermine time period, and first and second phase signals. An amplitude amplification section 17 outputs a voltage controlled in accordance with the discrete value. Angular modulation sections 13 and 14 angular-modulate the phase signals and output first and second angle-modulated signals. Amplitude modulation sections 15 and 16 amplitude-modulate the angle-modulated signals with the voltage from the amplitude amplification section 17 and output first and second modulated signals. A combining section 18 combines the first and second modulated signals and outputs a transmission signal.
Abstract:
A nonlinearity-compensated section 23 has a pre-set compensation table containing a measured value of a voltage vtc, outputted from a loop filter 16, which is changed accordingly with respect to a change in a voltage vtfc outputted from a frequency controlling section 11. The nonlinearity-compensated section 23 sets, in the compensation table, the voltage vtfc of an oscillatory frequency oscillated by a VCO 21 and the voltage vtc associated therewith as reference voltages, and creates a look-up table containing voltage differences obtained by subtracting the above-described reference voltages from the voltages vtfc and vtc, respectively. Thereafter, the nonlinearity-compensated section 23 extracts a compensation value corresponding to the voltage vtc actually outputted from the loop filter 16 by means of the look-up table, and adds the compensation value to an input modulated signal adjusted by a multiplier 22 so as to be outputted.
Abstract:
A transmission circuit operating at a high efficiency and a low distortion is provided. A signal generation section 11 generates a vector signal and an amplitude signal. A vector modulation section 13 performs vector modulation on the vector signal. An amplification section 15 amplifies the signal processed with the vector modulation. A signal processing section 12 performs predetermined signal processing on the amplitude signal and outputs the resultant signal. A regulator 14 controls a voltage to be supplied to the amplification section 15 based on the magnitude of the signal which is output from the signal processing section 12. The signal processing section 12 determines whether or not the amplitude signal exceeds a threshold value at an interval of a predetermined time period, selects a discrete value to be output based on the determination result, and outputs a signal having the selected discrete value.
Abstract:
A multi-mode transmitter circuit is provided for selectively switching over between a TDMA mode and a CDMA mode, where a transmission frequency of the CDMA mode is substantially identical to a transmission frequency of the TDMA mode. In the TDMA and CDMA modes, a filter device attenuates frequency band components other than a transmission frequency band of a phase-modulated signal, and filters an attenuated phase-modulated signal to pass therethrough a filtered phase-modulated signal. In the TDMA mode, an amplitude modulator generates a transmitting radio signal by modulating an amplitude of the phase-modulated signal according to an amplitude component of the inputted signal to be modulated, and in the CDMA mode, the amplitude modulator outputs the phase-modulated signal as a transmitting radio signal.
Abstract:
A predistortion linearizer has signal dividing circuit dividing an input signal into two signals; signal adjusting circuit using one of the divided signals to execute predetermined adjustment and outputting a signal based on the adjustment; distortion signal generating circuit generating a distortion signal using the signal output from the signal adjusting circuit; signal synthesizing circuit synthesizing the other of the divided signals with the generated distortion signal; and signal amplifying circuit amplifying the synthesized signal and outputting an output signal, and wherein the signal adjusting circuit executes the predetermined adjustment such that there is a predetermined relationship between the level of a difference between the signal amplitudes of predetermined frequency components contained in a distortion signal and the level of a difference between the signal amplitudes of the predetermined frequency components contained in a distortion signal.