直接数字射频调制器的实现

Design of Direct Digital-RF Modulator

介绍了将I/Q两路8Bit信号转换成射频信号的一种直接数字射频调制实现方式,它通过采用温度计码编码减小数字信号跳变导致的噪声毛刺,而采用8-fold线性内插信号作为一阶保持信号的近似处理,大大抑制了数字信号镜像成分。对电路进行模拟后,双边带调制后信号镜像成分抑制53.52dB以上,噪声毛刺抑制53.01dB以上,单边带调制后信号镜像成分抑制59.15dB以上,噪声毛刺抑制53.92dB以上。

The thesis introduces a new structure of Direct Digital-RF Modulator which converts I/Q 8Bit digital signals to RF signals directly. Thermometer decoder converter and 8-Fold Linear Interpolation are used in the new structure. The simulated DSB digital image rejection of above 53.52dB and spur rejection of above 53.01dB is realized.The simulated SSB digital image rejection of above 59.15dB and spur rejection of above 53.92dB is realized.