NCO IP Core: User Guide

ID 683406
Date 11/06/2017
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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.