NCO IP Core: User Guide

ID 683406
Date 11/06/2017
Document Table of Contents

3.3. Frequency Hopping

The NCO IP core supports frequency hopping (except the serial CORDIC architecture). Frequency hopping allows control and configuration of the NCO IP core at run time so that carriers with different frequencies can be generated and held for a specified period of time at specified slot intervals.

The IP core supports multiple phase increment registers that you can load using an Avalon-MM bus. You select the phase increment register using an external hardware signal; changes on this signal take effect on the next clock cycle. The maximum number of phase increment registers is 16.

Note: During frequency hopping, the phase of the carrier should not experience discontinuous change. Discontinuous carrier phase changes may cause spectral emission problems.
Figure 11. Frequency Hopping Block Diagram

The RAM stores all hopping frequencies. The RAM size is <width>×<depth>, where <width> is the number of bits required to specify the phase accumulator value to the precision you select in the parameter editor, and <depth> is the number of bands you select in the parameter editor.