NCO IP Core: User Guide

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

3.5. Frequency Modulation

You can add an optional frequency modulator to your custom NCO variation. You can use the frequency modulator to vary the oscillator output frequency about a center frequency set by the input phase increment. This option is useful for applications in which the output frequency is tuned relative to a free-running frequency, for example in all-digital phase-lock-loops.

You can also use the frequency modulation input to switch the output frequency directly.

You can set the frequency modulation resolution input in the IP core. The specified value must be less than or equal to the phase accumulator precision.

The NCO IP core also provides an option to increase the modulator pipeline level; however, the effect of the increase on the performance of the NCO IP core varies across NCO architectures and variations.