7 Numerically Controlled Oscillator (NCO)

The NCO is designed to generate a periodic waveform by adding a programmable increment to an accumulated total. When the total overflows, the overflow is kept, and a pulse is generated. The pulse can be a fixed number of input clock cycles in width or it can be 50% output at the cost of halving the output frequency. While the NCO is not designed for measurement, it can be used if the NCO is stopped, read and then restarted.