Modulator circuit of digital transmitter, digital transmitter and signal modulation method

Abstract

The invention relates to a modulator circuit of a digital transmitter, the digital transmitter and a signal modulation method. The modulator circuit comprises a first synchronous circuit and a digital modulator, wherein the first synchronous circuit comprises a first synchronous unit and a second synchronous unit, the first synchronous unit and the second synchronous unit are used for obtaining corresponding delayed signals after carrying out phase delay on a first local oscillator signal and a second local oscillator signal respectively, and carrying out phase adjustment on digital baseband signals through the delayed signals to generate a first adjusting signal and a second adjusting signal respectively, and the rising edge and the falling edge of the first adjusting signal can fall in a low-level interval of the first local oscillator signal; the rising edge and the falling edge of the second adjusting signal fall in the low-level interval of the second local oscillator signal; the digital modulator modulates the first adjusting signal through the first local oscillator signal to generate a first radio frequency signal, and modulates the second adjusting signal through the second local oscillator signal to generate a second radio frequency signal.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a modulation circuit of a digital transmitter, a digital transmitter and a signal modulation method. Background technique [0002] At present, the more mainstream digital transmitters are divided into Digital Cartesian Transmitter (DCT) and Digital Polar Transmitter (DPT), both of which include digital baseband signal modulation Digital modulator for radio frequency signals. [0003] Existing digital modulators usually modulate a digital baseband signal (Baseband, BB) with a local oscillator signal LO through a logic gate (AND gate). Such as figure 1 As shown, to ensure that the modulated radio frequency signal RF_data achieves an ideal waveform, it is necessary to control the digital baseband signal BB and the local oscillator signal (local frequency, LO) well before the digital baseband signal BB and the local oscillator signal LO enter the logic gate. phase. ...

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Problems solved by technology

[0004] In fact, when the frequency of the local oscillator signal LO and the data rate of the digital baseband signal BB are as high as GHz (G samples / s), coupled with the presence of voltage, temperature and process deviations, it is difficult to make the digital baseband signal BB and local oscillator signal LO edge aligned

like figure 2 As shown, the logical AND operation is performed when the edges of the digital baseband signal BB and the local oscillator signal LO are not aligned, which will cause redundant high-frequency harmonic components in the modulated radio frequency signal RF_data, and introduce harmonic components from the digital baseband signal BB phase noise

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