求一篇关于信号发生器的英文文章

DDS and converter form signal generator

Many applications require low-frequency signal generators that can deliver high-performance, high-resolution signals. This Design Idea presents a circuit that generates frequencies of 0 to 1 MHz. Sinusoidal, triangular, and square-wave outputs are available. You can achieve frequency resolution of better than 0.1 Hz and phase resolution of better than 0.1°; thus, you can program exact coherent frequencies. This feature is useful in digital modulation and frequency-tuning applications. The circuit uses the ADµC831 and AD9834 to generate the required frequencies (Figure 1). You can program the microcontroller from either a PC or a Unix-based workstation. You then program the AD9834 using a three-wire serial interface via the microcontroller. The interface word is 16 bits long.

You can program the AD9834 to provide sinusoidal, triangular, and square-wave outputs using the DDS (direct-digital-synthesis) architecture. Th