The SRL-LLC NCO IP core generates numerically controlled oscillators (NCOs) customized for Altera and Xilinx devices. A numerically controlled oscillator (NCO) synthesizes a discrete-time, discrete-valued representation of a sinusoidal waveform.
Typically, you can use NCOs in communication systems as quadrature carrier generators in I-Q mixers, in which baseband data is modulated onto the orthogonal carriers in one of a variety of ways.
Here are some interesting links for you! Enjoy your stay :)