NCO IP Core: User Guide

ID 683406
Date 11/06/2017
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

3.2. Multichannel NCOs

The NCO IP core allows you to implement multichannel NCOs. You can generate multiple sinusoids of independent frequency and phase t at a very low cost in additional resources. The waveforms have an output sample-rate of fclk/M where M is the number of channels. You can select 1 to 8 channels.

Multichannel implementations are available for all single-cycle generation algorithms. The input phase increment, frequency modulation value and phase modulation input are input sequentially to the NCO with the input values corresponding to channel 0 first and channel (M–1) last. The inputs to channel 0 should be input on the rising clock edge immediately following the de-assertion of the NCO reset.

On the output side, the first output sample for channel 0 is output concurrent with the assertion of out_valid and the remaining outputs for channels 1 to (M–1) are output sequentially.

If you select a multichannel implementation, the NCO MegaCore function generates VHDL and Verilog HDL testbenches that time-division-multiplex the inputs into a single stream and demultiplex the output streams into their respective downsampled channelized outputs.