A 100-MHz, 16-b, direct digital frequency synthesizer with a 100-dBc spurious-free dynamic range

Abstract

This paper describes the architecture and the IC implementation of a direct digital frequency synthesizer (DDFS) that is based on an angle rotation algorithm (similar to CORDIC). It is shown that the architecture can be implemented as a multiplierless, feedforward, and easily pipelineable datapath. A prototype IC has been designed, fabricated in 1.0-m CMOS, and tested. The IC produces 16-b sine and cosine outputs with a spurious-free dynamic range of more than 100 dBc. A 36-b frequency control word gives a tuning resolution of 0.0015 Hz at a 100-MHz sampling rate.

Efficient FPGA-based QPSK Demodulation Loops: Application to the DVB Standard

“…On the other hand there are several CORDIC architectures [8,18,19,20]. Nevertheless these designs have been optimized for VLSI.…”

Direct Digital Frequency Synthesis Based on a Two-Level Table-Lookup Scheme

“…DDFS_s can be categorized as recursive [4,5], and non-recursive types [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The recursive DDFS_s are notorious for their error-propagation problem, due to their error feedback nature, although the algorithm [4] has the advantage of only needing two multiplication and two addition operations to generate one sine and one cosine values.…”

A Memory-Efficient and High-Speed Sine/Cosine Generator Based on Parallel CORDIC Rotations

“…IMPLEMENTATION AND COMPARISON Fig. 1(a) is a 24-bit sine/cosine generator based on unfolded CORDIC architecture where each numbered block (a stage) denotes a microrotation performing the recurrence of and in (1). Note that the microrotation of angle is repeated once and the microrotation of angle is repeated three times.…”

“…CORDIC is an arithmetic algorithm developed to compute various elementary functions through a series of iterations of a unified microrotations operation. In particular, in a circular rotation mode, microoperations as illustrated below will be executed for sign (1) After iterations, the accumulated rotation angle is Using the definition of , one has (note that ) Then, it can be easily deduced that where is a constant that can be precomputed in advance. Set , , , then , can be easily computed after iterations.…”

“…O NE OF THE key components in direct digital frequency synthesizer (DDFS) system [1] is the sine/cosine function generator that computes binary representation of and to a precision of fractional bits is. In this letter, we propose a novel realization of a sine/cosine generator based on the CORDIC algorithm [2].…”