首页>
外国专利>
Method and apparatus for digital vector QAM modulator
Method and apparatus for digital vector QAM modulator
展开▼
机译:数字矢量qam调制器的方法和装置
展开▼
页面导航
摘要
著录项
相似文献
摘要
Direct digital QAM modulation at an RF frequency is obtained from digitally synthesized RF signals which are generated for use as the two vectors. The two vectors are individually controlled in phase and summed to provide a combined phase and amplitude modulation that forms the modulated signal. The synthesized RF signal is generated from a higher reference frequency using a variable pulse stretching technique implemented with programmable delay lines. The amount of the pulse stretch in each cycle is controlled by a phase increment value. Pulse stretching can be extended beyond one cycle by pulse swallowing, allowing the generation of an RF signal from DC up to and including the input reference frequency. Phase modulation is added by digital control of the pulse stretching according to the phase modulation data bits.
展开▼