A Direct Digital Frequency Synthesizer Based on the Quasi-Linear Interpolation Method

Ashrafi, Ashkan; Adhami, Reza R.; Milenkovic, Aleksandar

doi:10.1109/tcsi.2009.2027645

Cited by 34 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To provide a redundant CORDIC applicable to all modes and coordinate system, this paper propose the following enhancement: (1) we extend the double rotation technique to work in hyperbolic coordinate (2) in order to decide the rotation direction for vector mode, we develop a scheme to estimate the angle of vector from its redundant representation (3) we show that the calculation of rotation direction and next vector components can be parallelized to achieve shorter cycle time.…”

Section: Proposed Algorithm and Implementationmentioning

confidence: 99%

“…Direct digital frequency synthesizer [1] [2], Phong shaders [3] [4], geometrical transformation [5] [6], and N-body simulation [7] are some examples. Although software implementations based on polynomial approximation are available and easy to implement, they usually become the bottle neck for computation intense and real-time applications like 3D graphics processing and robotics.…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Low Latency High-Throughput Elementary Function Generator Based on Enhanced Double Rotation CORDIC

Deng

2014

2014 IEEE Symposium on Computer Applications and Communications

View full text Add to dashboard Cite

Coordinate Rotation Digital Computer (CORDIC) algorithm is well known and widely used in many computer systems due to its simplicity and the variety of functions it provides. Although CORDIC is known to be able to work in several modes and coordinate to provide elementary functions including trigonometric and transcendental functions, most proposed CORDIC enhancement and application were only limited to a single or only a few modes, and that does not help to build a CORDIC coprocessor that works in all modes. This paper presents an enhanced version of double rotation method which is a scaling-free and redundant arithmetic based CORDIC variation. The proposed algorithm has been implemented and it is shown that the new architectures have great advantage on both FPGA and ASIC platforms and are extremely attractive for high precision and high performance computing.

show abstract

Section: Proposed Algorithm and Implementationmentioning

confidence: 99%

mentioning

confidence: 99%

A Low Latency High-Throughput Elementary Function Generator Based on Enhanced Double Rotation CORDIC

Deng

2014

2014 IEEE Symposium on Computer Applications and Communications

View full text Add to dashboard Cite

show abstract

“…The II-bit frequency control word (FCW) fed to the accumulator determines the phase step and the frequency resolution. In the proposed architecture, the phase accumulator output is quantized according to (7). After the phase accumulator output reaches (rr/4)*2 N , the comparator resets the accumulator content to O.…”

Section: Digital Realiza Nonmentioning

confidence: 99%

“…This method has several drawbacks including a large chip area and high power consumption [3]. There are various algorithms for DDFS design, including methods of table lookup, CORDIC algorithm [4], polynomial approximation [5] - [7]. The CORDIC DDFS algorithms have the trouble of slow sequential convergence operation.…”

Section: Introductionmentioning

confidence: 99%

Direct digital frequency synthesizer using cubic spline approximations

Shamalla¹,

Gayathri²,

Sugumar³

et al. 2012

2012 International Conference on Computing, Electronics and Electrical Technologies (ICCEET)

View full text Add to dashboard Cite

The conventional direct digital frequency synthesizer (DDFS) based on polynomial approximations has a very high complexity. This paper describes a low complexity DDFS with a high spectral purity. It is based on the cubic spline approximation for sine and cosine functions, exploiting the symmetry of the sine function. The proposed DDFS offers maximum smoothness of the output signal and has a high SFDR (spurious free dynamic range) of about 121.7 dBc.Keywords -DDFS, cubic spline, spurious free dynamic range, frequency control word (FeW), quarter wave symmetry.

show abstract

“…The PSM could be as simple as a lookup table or as complex as a Coordinate Rotation Digital Computer (CORDIC) system [2]. Piecewise polynomial interpolation methods are also used to approximate the sine signal by polynomials [3]- [6]. In this method, the first quadrant of the sinusoid is divided into s = 2 u segments, and each segment is approximated by Manuscript a polynomial.…”

Section: Introductionmentioning

confidence: 99%

On the SFDR Upperbound in DDFS Utilizing Polynomial Interpolation Methods

Ashrafi

2012

IEEE Trans. Circuits Syst. II

Self Cite

View full text Add to dashboard Cite

In this brief, the theoretical analysis that obtains the upperbound of the spurious free dynamic range (SFDR) of the direct digital frequency synthesizers (DDFSs) with phaseto-sine mapper (PSM) structured by polynomial interpolation is revisited. A complete analysis of the SFDR upperbound of these DDFS architectures was provided by Ashrafi and Adhami in 2007, where the authors formulated the SFDR upperbound as the Chebyshev minimax solution to an overdetermined system of linear equations. However, some issues in finding the Chebyshev minimax solution were not made clear in that paper regarding the minimax error at the fundamental harmonic of the output sinusoid. These issues, along with the erroneous behavior of numerical computation packages used for solving the Chebyshev minimax problem, misled Chau and Chen to claim that the results of the aforementioned paper were wrong. This brief clarifies the issues with the original paper, exhibits the problems with some of the available numerical computation packages, and refutes the claims that Chau and Chen made.Index Terms-Chebyshev minimax approximation, direct digital frequency synthesizers (DDFSs), spurious free dynamic range (SFDR).

show abstract

A Direct Digital Frequency Synthesizer Based on the Quasi-Linear Interpolation Method

Cited by 34 publications

References 33 publications

A Low Latency High-Throughput Elementary Function Generator Based on Enhanced Double Rotation CORDIC

A Low Latency High-Throughput Elementary Function Generator Based on Enhanced Double Rotation CORDIC

Direct digital frequency synthesizer using cubic spline approximations

On the SFDR Upperbound in DDFS Utilizing Polynomial Interpolation Methods

Contact Info

Product

Resources

About