关键字:脉冲控制器 正弦查询表 频率和相位调制器 数模转换
Abstract
This DDS device is a numerically controlled oscillator employing a phase accumulator, a sine look-up table and a 10-bit D/A converter integrated on a single CMOS chip. Modulation capabilities are provided for phase modulation and frequency modulation.
The AD9831 contains functions which make it suitable for modulation applications. The part can be used to perform simple modulation such as FSK. More complex modulation schemes such as GMSK and QPSK can also be implemented using the AD9831. The AD9831 is also suitable for signal generator applications. With its low current consumption, the part is suitable for applications in which it can be used as a local oscillator. In addition, the part is fully specified for operation with a +3.3 V± 10%。 The AD9831 has four phase registers; this enables the part to perform PSK.
When it works ,Chip need for one reference clock, one short precision resistance and eight decouple capacitance,withal endue digitally bring sine wave forth with to. frequency approve reach 12.5mhz。Except to could bring these RF signal besides,Chip in addition realize compare complicated modulate function forth. At Digit region,DSP is used for realizing these modulation scheme simply and accurately.
Key word: Push controller Sine look-up table D/A converter
Modulator for frequency and phase