A direct digital synthesizer with 100-MHz output capability

Saul, P.H.; Mudd, M.S.J.

doi:10.1109/4.323

Cited by 30 publications

(9 citation statements)

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“…DDFS is based on the principle that phase change accumulation can generate a digitized waveform at higher frequencies. (15) DDFS can be implemented with three distinct parts, as shown in Fig. 4.…”

Section: Ddfsmentioning

confidence: 99%

“…The advantages of DDFS include fine frequency steps, smooth frequency transitions, and fast switching times. (15)(16)(17) In particular, the property of fine frequency steps can make the frequency of the two transmitting signals of our system be very close (even smaller than 1 Hz). Therefore, the measurement range of temperature can easily be expanded just by using two signals, instead of increasing the number of transmitting signals.…”

Section: Introductionmentioning

confidence: 99%

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Two-Frequency Ultrasonic System with Direct Digital Frequency Synthesizers and Vernier Caliper Phase Meter for Measuring Air Temperature

Lee

Huang²,

Huang³

et al. 2012

Sensors and Materials

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Key words: two-frequency continuous wave, direct digital frequency synthesizer, vernier caliper phase meter, ultrasonic temperature measurementIn this article, we present an improved algorithm for two-frequency continuous wave (TFCW) ultrasonic temperature measurement. This method is based on the transmission of a TFCW signal that is generated by two direct digital frequency synthesizers (DDFSs). The phase shift between the transmitted and received signals is measured using a vernier caliper phase meter (VCPM). The phase shift data is recorded to determine the ultrasound speed. The changes in the ultrasound speed are then calculated and used to determine the average temperature of bulk air. In a temperature-controlled chamber, two 40±2 kHz ultrasonic transducers are placed face to face with a fixed distance between them. The DDFS algorithm is programmed into a single-chip microprocessor to generate highly accurate TFCW signals for temperature measurement. Experimental results show that the proposed measurement system reaches a high accuracy of ±0.2°C within a temperature range from 0 to 80°C, with a resolution of 0.01%. The main advantages of this ultrasonic temperature measurement system (UTMS) include high accuracy, high resolution, low cost, and ease of implementation.

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Section: Ddfsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Two-Frequency Ultrasonic System with Direct Digital Frequency Synthesizers and Vernier Caliper Phase Meter for Measuring Air Temperature

Lee

Huang²,

Huang³

et al. 2012

Sensors and Materials

View full text Add to dashboard Cite

show abstract

“…In this method, a parabola whose maximum and -axis intersections are the same as that of the sine half-period is generated by digital hardware and is considered as the initial guess for the sine function. Such a parabola is expressed as (2) for . A quarter-period and complete period of a sinusoid and the fitted parabola described by (2) are depicted in Fig.…”

Section: Idea Descriptionmentioning

confidence: 99%

“…Manuscript 1) Based on ROM lookup tables, containing amplitude samples of a complete-, half-, or quarter-period of a sinusoid, and addressed by the digital phase, which is generated by the phase accumulator. In the case of half-or quarter-period ROM lookup tables, the other half-or quarter periods are reconstructed from the stored data [2]- [9]. 2) Computational methods, trying to compute the sine amplitude samples from the digital phase, which is generated by the phase accumulator.…”

Section: Introductionmentioning

confidence: 99%

Mapping from phase to sine-amplitude in direct digital frequency synthesizers using parabolic approximation

Sodagar

Lahiji

2000

IEEE Trans. Circuits Syst. II

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This paper describes a new approach in sine-amplitude approximation for sine-output direct digital frequency synthesizers, which provides an initial guess much closer to the target sine amplitude than previous approximations. Another important advantage of the proposed idea is that it can be simply implemented using full-digital circuitry. Gate-and transistor-level simulations demonstrate the feasibility of the idea, and the simulation results are in complete agreement with the experimental results for the implemented test architecture.

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“…Traditionally, PLLs are analog circuits that employ a voltage-controlled oscillator (VCO) for converting voltage levels to frequencies. Although analog PLLs can feature high output frequencies and excellent spectral purity [3], they exhibit shortcomings such as narrow operating frequency ranges [4], highly nonlinear frequency versus voltage characteristics [5], etc.. These shortcomings come to the fore when PLL designs migrate to deep-submicron (DSM) CMOS processes, which offer very limited voltage headroom [6].…”

Section: Introductionmentioning

confidence: 99%

A multilevel technique for robust and efficient extraction of phase macromodels of digitally controlled oscillators

Lai

Roychowdhury

2006

2006 43rd ACM/IEEE Design Automation Conference

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PPV phase macromodels are important for speeding up simulation of oscillator related circuits, such as PLLs, without sacrificing accuracy. Prior numerical methods for extracting PPVs face very significant robustness and accuracy problems when confronted with digitally controlled oscillators (DCOs, core building blocks in digital phase-locked loops), due to large RC time-constants from gated capacitors. In this paper, we present a hierarchical harmonic balance based technique for numerically extracting the PPV of DCOs from their SPICE-level circuit descriptions. The proposed method applies hierarchical circuit partitioning and multi-level Newton methods to achieve dramatically superior convergence and PPV accuracy in the presence of large RC time-constants. We validate the method on a large DCO with many gated capacitors and demonstrate that it can extract the PPV efficiently and robustly, succeeding when prior methods fail. The method also provides speedups of an order of magnitude for large circuits, in addition to having significantly smaller memory requirements.

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A direct digital synthesizer with 100-MHz output capability

Cited by 30 publications

References 1 publication

Two-Frequency Ultrasonic System with Direct Digital Frequency Synthesizers and Vernier Caliper Phase Meter for Measuring Air Temperature

Two-Frequency Ultrasonic System with Direct Digital Frequency Synthesizers and Vernier Caliper Phase Meter for Measuring Air Temperature

Mapping from phase to sine-amplitude in direct digital frequency synthesizers using parabolic approximation

A multilevel technique for robust and efficient extraction of phase macromodels of digitally controlled oscillators

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