A Novel Broadband All-Digital Transmitters Architecture Based on State Switching

In order to improve the performance of all-digital transmitters (ADTx) in different frequency bands, this paper proposes an ADTx architecture based on state switching. The architecture combines the radio-frequency pulse width modulation (RF-PWM) and the mapping pulse width modulation (MPWM) algorithm. The 5-level RF-PWM signal with third harmonic elimination is generated in parallel at lower frequency, which ensures the output performance and spectrum quality by improving the amplitude resolution and suppressing the component at third carrier frequency. Using MPWM algorithm based on intermediate frequency (IF) at higher frequency can realize more flexible and efficient signal modulation only at sampling frequency several times of carrier frequency. At the same time, the output signal of parallel RF-PWM up-conversion is used as the input signal of MPWM algorithm through specific parameter, and a certain protect band is set during the state switching. For the 16QAM signal at the frequency range of 2-2000MHz with a sample rate of 12.8GHz, the proposed structure can reach about −45dBc in the ACPR, and 1.79% in the EVM.