Abstract: A digital pre-distortion circuit includes a memoryless non-linear operating circuit, an intermodulation shaping filter circuit, and a signal combination circuit. The memoryless non-linear operating circuit performs a memoryless non-linear operation upon a transmission signal to generate a first signal, wherein the first signal is an output simulation signal of a radio frequency (RF) power amplifier under the memoryless effect, and the first signal includes a signal component corresponding to the transmission signal and a signal component corresponding to an intermodulation signal of the transmission signal. The intermodulation shaping filter circuit filters the first signal to generate a second signal, wherein the second signal simulates an intermodulation signal generated by the RF power amplifier in response to the transmission signal under a memory effect. The signal combination circuit combines the transmission signal and the second signal to generate a pre-distortion signal.

Abstract: A transceiving device includes a calibration signal generation unit, a phase adjusting unit, a transmission unit, a receiving unit, and a calibration unit. In a calibration mode, the calibration signal generation unit generates an in-phase (I) test signal and a quadrature (Q) test signal. The phase adjusting unit adjusts the I test signal and the Q test signal to generate an adjusted I test signal and an adjusted Q test signal according to a phase controlling signal. The transmission unit generates a radio frequency (RF) signal according to the adjusted I test signal and the adjusted Q test signal. The receiving unit receives the RF signal so as to generate an I receiving signal and a Q receiving signal. The calibration unit generates the phase controlling signal according to the I test signal, the Q test signal, the I receiving signal, and the Q receiving signal.

Abstract: A transceiving device includes a calibration signal generation unit, a phase adjusting unit, a transmission unit, a receiving unit, and a calibration unit. In a calibration mode, the calibration signal generation unit generates an in-phase (I) test signal and a quadrature (Q) test signal. The phase adjusting unit adjusts the I test signal and the Q test signal to generate an adjusted I test signal and an adjusted Q test signal according to a phase controlling signal. The transmission unit generates a radio frequency (RF) signal according to the adjusted I test signal and the adjusted Q test signal. The receiving unit receives the RF signal so as to generate an I receiving signal and a Q receiving signal. The calibration unit generates the phase controlling signal according to the I test signal, the Q test signal, the I receiving signal, and the Q receiving signal.

Abstract: A communication system is provided, which includes a power amplifier, a receive-end filter, an ADC, an output simulation circuit, and a predistortion circuit. The power amplifier amplifies a RF input signal to generate a RF output signal. The RF input signal is generated according to a baseband signal. The receive-end filter filters a feedback signal generated according to the RF output signal to output a filtered feedback signal. A bandwidth of the filtered feedback signal is at least 3 to 5 times a bandwidth of the RF input signal. The ADC converts the filtered feedback signal to a digital input signal. The output simulation circuit generates, according to the digital input signal and the baseband signal, a reference signal simulating the RF output signal. The predistortion circuit builds a predistortion model according to the reference signal.

Abstract: A communication system is provided, which includes a power amplifier, a receive-end filter, an ADC, an output simulation circuit, and a predistortion circuit. The power amplifier amplifies a RF input signal to generate a RF output signal. The RF input signal is generated according to a baseband signal. The receive-end filter filters a feedback signal generated according to the RF output signal to output a filtered feedback signal. A bandwidth of the filtered feedback signal is at least 3 to 5 times a bandwidth of the RF input signal. The ADC converts the filtered feedback signal to a digital input signal. The output simulation circuit generates, according to the digital input signal and the baseband signal, a reference signal simulating the RF output signal. The predistortion circuit builds a predistortion model according to the reference signal.

Abstract: A method for characterizing nonlinear distortion of a transmitter, an associated transmitter and a characterization circuit thereof are provided. The method includes: utilizing a transmitting chain circuit within the transmitter to generate an output signal according to a test signal; utilizing a loop back circuit within the transmitter to generate a loop back signal according to the output signal; calculating a plurality of distorted indices respectively corresponding to a plurality of test samples of the test signal according to a plurality of loop back samples of the loop back signal, wherein the plurality of test samples correspond to the plurality of loop back samples, respectively; dividing the plurality of distortion indices into multiple groups according to power of the plurality of test samples; calculating an average value of distortion indices within each group of the multiple groups; and characterizing the nonlinear distortion of the transmitter according to the average value.

Abstract: A method for characterizing nonlinear distortion of a transmitter, an associated transmitter and a characterization circuit thereof are provided. The method includes: utilizing a transmitting chain circuit within the transmitter to generate an output signal according to a test signal; utilizing a loop back circuit within the transmitter to generate a loop back signal according to the output signal; calculating a plurality of distorted indices respectively corresponding to a plurality of test samples of the test signal according to a plurality of loop back samples of the loop back signal, wherein the plurality of test samples correspond to the plurality of loop back samples, respectively; dividing the plurality of distortion indices into multiple groups according to power of the plurality of test samples; calculating an average value of distortion indices within each group of the multiple groups; and characterizing the nonlinear distortion of the transmitter according to the average value.