| 摘要 |
The present invention relates to a modulation circuit of a digital transmitter, a digital transmitter, and a signal modulation method. The modulation circuit includes: a first synchronizing circuit and a digital modulator, where the first synchronizing circuit separately perform phase delay on a first local-frequency signal or a second local-frequency signal to obtain corresponding delay signals, and perform phase adjustment on a digital baseband signal by using the delay signals, to generate a first adjusted signal and a second adjusted signal; and the digital modulator modulates the first adjusted signal by using the first local-frequency signal, to generate a first radio-frequency signal, and modulates the second adjusted signal by using the second local-frequency signal, to generate a second radio-frequency signal. |
| 主权项 |
1. A modulation circuit of a digital transmitter, wherein the modulation circuit comprises: a first synchronizing circuit and a digital modulator, and the first synchronizing circuit comprises: a first synchronizing unit and a second synchronizing unit, wherein
the first synchronizing unit is configured to separately receive a first digital baseband signal and a first local-frequency signal, perform phase delay on the first local-frequency signal to obtain a first delay signal, and perform phase adjustment on the first digital baseband signal by using the first delay signal, to generate a first adjusted signal, so that both a rising edge and a falling edge of the first adjusted signal fall in a low level range of the first local-frequency signal, wherein the first synchronizing unit comprises: a first delayer and a first D flip flop; the second synchronizing unit is configured to separately receive the first digital baseband signal and a second local-frequency signal, perform phase delay on the second local-frequency signal to obtain a second delay signal, and perform phase adjustment on the first digital baseband signal by using the second delay signal, to generate a second adjusted signal, so that a rising edge and a falling edge of the second adjusted signal fall in a low level range of the second local-frequency signal, wherein the first local-frequency signal and the second local-frequency signal are differential signals, and phase delays of the first delay signal and the second delay signal are the same, wherein the second synchronizing unit comprises: a second delayer and a second D flip flop; and the digital modulator is configured to separately modulate the first adjusted signal by using the first local-frequency signal, to generate a first radio-frequency signal, and modulate the second adjusted signal by using the second local-frequency signal, to generate a second radio-frequency signal; and wherein the modulation circuit further comprises: a second synchronizing circuit, and the second synchronizing circuit comprises: a third synchronizing unit and a fourth synchronizing unit, wherein the third synchronizing unit is configured to separately receive a second digital baseband signal and the first local-frequency signal, perform phase delay on the first local-frequency signal to obtain a third delay signal, and perform phase adjustment on the second digital baseband signal by using the third delay signal, to generate a third adjusted signal, so that both a rising edge and a falling edge of the third adjusted signal fall in the low level range of the first local-frequency signal, wherein the third synchronizing unit comprises: a third delayer and a third D flip flop; the fourth synchronizing unit is configured to separately receive the second digital baseband signal and the second local-frequency signal, perform phase delay on the second local-frequency signal to obtain a fourth delay signal, and perform phase adjustment on the second digital baseband signal by using the fourth delay signal, to generate a fourth adjusted signal, so that both a rising edge and a falling edge of the fourth adjusted signal fall in the low level range of the second local-frequency signal, wherein the first digital baseband signal and the second digital baseband signal are differential signals, and phase delays of the third delay signal and the fourth delay signal are the same, wherein the fourth synchronizing unit comprises: a fourth delayer and a fourth D flip flop; and the digital modulator is further configured to separately modulate the third adjusted signal by using the first local-frequency signal, to generate a third radio-frequency signal, and modulate the fourth adjusted signal by using the second local-frequency signal, to generate a fourth radio-frequency signal; and overlap the first radio-frequency signal and the fourth radio-frequency signal, to obtain a first radio-frequency output signal, and overlap the second radio-frequency signal and the third radio-frequency signal, to obtain a second radio-frequency output signal. |
