NCO IP Core: User Guide

Download PDF
ID 683406
Date 11/06/2017
Public
Document Table of Contents
Document Table of Contents x
1. About the NCO IP Core 2. NCO IP Core Getting Started 3. NCO IP Core Functional Description A. NCO IP Core User Guide Document Archives 4. Document Revision History
1. About the NCO IP Core x
1.1. Intel® DSP IP Core Features 1.2. NCO IP Core Features 1.3. DSP IP Core Device Family Support 1.4. NCO IP Core MegaCore Verification 1.5. NCO IP Core Release Information 1.6. NCO IP Core Performance and Resource Utilization
2. NCO IP Core Getting Started x
2.1. Installing and Licensing Intel® FPGA IP Cores 2.2. IP Catalog and Parameter Editor 2.3. Generating IP Cores ( Intel® Quartus® Prime Pro Edition) 2.4. Simulating Intel® FPGA IP Cores
2.1. Installing and Licensing Intel® FPGA IP Cores x
2.1.1. Intel® FPGA IP Evaluation Mode 2.1.2. NCO IP Core Intel® FPGA IP Evaluation Mode Timeout Behavior
2.3. Generating IP Cores ( Intel® Quartus® Prime Pro Edition) x
2.3.1. IP Core Generation Output ( Intel® Quartus® Prime Pro Edition)
3. NCO IP Core Functional Description x
3.1. NCO IP Core Architectures 3.2. Multichannel NCOs 3.3. Frequency Hopping 3.4. Phase Dithering 3.5. Frequency Modulation 3.6. Phase Modulation 3.7. NCO IP Core Parameters 3.8. NCO IP Core Interfaces and Signals
3.1. NCO IP Core Architectures x
3.1.1. Large ROM Architecture 3.1.2. Small ROM Architecture 3.1.3. CORDIC Architecture 3.1.4. Multiplier-Based Architecture
3.7. NCO IP Core Parameters x
3.7.1. Architecture Parameters 3.7.2. Frequency Parameters 3.7.3. Optional Ports Parameters
3.8. NCO IP Core Interfaces and Signals x
3.8.1. Avalon-ST Interfaces in DSP IP Cores 3.8.2. NCO IP Core Signals 3.8.3. NCO IP Core Timing Diagrams
1. About the NCO IP Core
2. NCO IP Core Getting Started
3. NCO IP Core Functional Description
A. NCO IP Core User Guide Document Archives
4. Document Revision History

3.1.3. CORDIC Architecture

The CORDIC algorithm, which can calculate trigonometric functions such as sine and cosine, provides a high-performance solution for very-high precision oscillators in systems where internal memory is at a premium.

The CORDIC algorithm is based on the concept of complex phasor rotation by multiplication of the phase angle by successively smaller constants. In digital hardware, the multiplication is by powers of two only. Therefore, the algorithm can be implemented efficiently by a series of simple binary shift and additions/subtractions.

In an NCO, the CORDIC algorithm computes the sine and cosine of an input phase value by iteratively shifting the phase angle to approximate the cartesian coordinate values for the input angle. At the end of the CORDIC iteration, the x and y coordinates for a given angle represent the cosine and sine of that angle, respectively.

Figure 10. CORDIC Rotation for Sine & Cosine Calculation

With the NCO MegaCore function, you can select parallel (unrolled) or serial (iterative) CORDIC architectures:

  • You an use the parallel CORDIC architecture to create a very high-performance, high-precision oscillator—implemented entirely in logic elements—with a throughput of one output sample per clock cycle. With this architecture, there is a new output value every clock cycle.
  • The serial CORDIC architecture uses fewer resources than the parallel CORDIC architecture. However, its throughput is reduced by a factor equal to the magnitude precision. For example, if you select a magnitude precision of N bits in the NCO MegaCore function, the output sample rate and the Nyquist frequency is reduced by a factor of N. This architecture is implemented entirely in logic elements and is useful if your design requires low frequency, high precision waveforms. With this architecture, the adder stages are stored internally and a new output value is produced every N clock cycles.
Level Two Title