Direct digital frequency synthesiser with highmemory compression ratio

Curticapean, F.; Palomaki, K.I.; Niittylahti, J.

doi:10.1049/el:20010875

Cited by 17 publications

(5 citation statements)

References 4 publications

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“…Large ROMs slow down DDFS operation and increase power consumption. Hence, many ROM compression techniques aimed to reduce the lookup table size have been proposed [8][9][10]. Different techniques are available for ROM compression , like Exploitation of sine function symmetry, Taylor series approximation, Sunderland and modified Sunderland architectures, and Nicholas architecture [11] .…”

Section: Compression Technique Based On the Piecewise Parabolic Intermentioning

confidence: 99%

An Eifficient Method for Generating Coherent Digital Sweep Signals

Samarah

Al-Ibrahim

Loffeld

2009

2009 First International Conference on Computational Intelligence, Communication Systems and Networks

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This paper presents an efficient method for generating coherent digital sweep signals. This proposed system is a hybrid of the digital sweep generator with the system using interpolation based direct digital frequency synthesis, where the start and end frequencies can be controlled by the initial content of the counter and the accumulator. The main idea of the new architecture is the use of the interpolator to generate the sine wave and it is summarized by using the predetermined interpolation coefficients to fit the sine wave from the calculated phase, instead of using a stored predetermined waveform in a big sized memory. This implies that a smaller look-up table for sine and cosine with minimum hardware overhead will be achieved. The computation of the sinusoidal values are performed by a piecewise parabolic interpolation structure and consequently the interpolation coefficients are stored only in the memory, because of that the size of the ROM is reduced by factor more than 128 with using 12 address lines and 15 bits word size.

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Section: Compression Technique Based On the Piecewise Parabolic Intermentioning

confidence: 99%

An Eifficient Method for Generating Coherent Digital Sweep Signals

Samarah

Al-Ibrahim

Loffeld

2009

2009 First International Conference on Computational Intelligence, Communication Systems and Networks

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“…5 (8) Where fl] denotes I bits quantization, sc the total error from cosine approximation and cm the total error from the finite word length effects.…”

Section: Trigonometry Approximationmentioning

confidence: 99%

“…0.125a comes from a >> 3 ; and 0.25a comes from a >> 2 . Fig.4 shows a selector ,to realizes h(a) and the same selector for r(a) is added to the architecture and the Control Line is changed to MSB3 & MSB 5 Table 1 shows the comparison between two methods to reduce bits. The size of the ROM LUT is …”

Section: Non-linear Approachmentioning

confidence: 99%

“…Generally, quantization error is about 0.5LSB If the signal amplitude is 1, SNRP P will be: SNRp-P = 201g ( From table4, we can see that x can be equal or larger 20bits. F.Curticapean [5] provided the expression of ROM size:…”

Section: Non-linear Approachmentioning

confidence: 99%

“…In 2001, Curticapean [5] improved the Trigonometry Approximation Method, and the compression ratio reached to 455:1.…”

Section: Introductionmentioning

confidence: 99%

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New Methods for QDDFS with Millions' Compression Ratio

Zhao

Zhou

et al. 2006

APCCAS 2006 - 2006 IEEE Asia Pacific Conference on Circuits and Systems

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Two improved methods are introduced to compress the LUT ROM of QDDFS in this paper. Based on the principles of Non-linear Approach and Trigonometry Approximation, a new QDDFS Architecture with high compression ratio is presented in the first method. Compression ratio with 762.05 is achieved in a 16bit system, using the first method. Another improved QDDFS method, with the Taylor Expression, is proposed in the second method, which ten millions' compression ratio can be achieved.The new methods have been analyzed theoretically and all the parameters have been optimized in the experiments. In the end, a simple system configuration is given in the paper.

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9. Blocks of Direct Digital Synthesizers

Digital Synthesizers and Transmitters for Software Radio

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Direct digital frequency synthesiser with highmemory compression ratio

Cited by 17 publications

References 4 publications

An Eifficient Method for Generating Coherent Digital Sweep Signals

An Eifficient Method for Generating Coherent Digital Sweep Signals

New Methods for QDDFS with Millions' Compression Ratio

9. Blocks of Direct Digital Synthesizers

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