A direct-digital synthesizer with improved spectral performance

O’Leary, Paul; Maloberti, Franco

doi:10.1109/26.87209

Cited by 68 publications

(16 citation statements)

References 10 publications

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“…Therefore all of these are not candidate frequency-generators for the present application. In fact, there are two potential frequency modulators: one is by data scheduling [39][40][41][42][43] and the other is by online sinusoidal function [44,45]. One characteristic of the data scheduling for frequency generation is the low-resolution in the low-frequency span.…”

Section: Open Accessmentioning

confidence: 99%

System Identification and Resonant Control of Thermoacoustic Engines for Robust Solar Power

Hong

Lin

2015

Energies

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It was found that thermoacoustic solar-power generators with resonant control are more powerful than passive ones. To continue the work, this paper focuses on the synthesis of robustly resonant controllers that guarantee single-mode resonance not only in steady states, but also in transient states when modelling uncertainties happen and working temperature temporally varies. Here the control synthesis is based on the loop shifting and the frequency-domain identification in advance thereof. Frequency-domain identification is performed to modify the mathematical modelling and to identify the most powerful mode, so that the DSP-based feedback controller can online pitch the engine to the most powerful resonant-frequency robustly and accurately. Moreover, this paper develops two control tools, the higher-order van-der-Pol oscillator and the principle of Dynamical Equilibrium, to assist in system identification and feedback synthesis, respectively.

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Section: Open Accessmentioning

confidence: 99%

System Identification and Resonant Control of Thermoacoustic Engines for Robust Solar Power

Hong

Lin

2015

Energies

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“…This requires a large ROM size for long tables and produces wide frequency-span for radio modulation. Such ROM size is usually unavailable in DSP-controllers, and building special ICs for this purpose prevails [38][39][40][41]. One characteristic of data scheduling for frequency synthesizers is low frequency-resolution, since the number of entries being fetched is always an integer.…”

Section: Introductionmentioning

confidence: 99%

Realization of Thermal Inertia in Frequency Domain

Hong

Chou

2014

Entropy

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Abstract:To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conduction. The thermal hyperbolicity exhibits a special frequency response in Bode plot, wherein the amplitude ratios is kept flat after crossing some certain frequency, as opposed to Fourier heat-conduction. We apply this specialty to design an instrument that reliably identifies thermal inductances of some materials in frequency domain. The instrument is embedded with a DSP-based frequency synthesizer capable of modulating frequencies in utmost high-resolution. Thermal inertia implies a new possibility for energy storage in analogy to inductive energy storage in electricity or mechanics.

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“…The error associated with periodic control is approximated according to (11) and substituting for and representing by its Fourier series expansion gives:…”

Section: Appendix: Psd -Manchester Coded Fmmentioning

confidence: 99%

“…Further, spurious output components due to round-off in the ROM and DAC error can degrade the integrity of the generated signal [9]. In order to suppress spurious output components phase dithering and noise shaping techniques are invariably used [10,11]. In summary, good modulation performance can be achieved with such a structure but spurious output components can impair the signal integrity.…”

Section: Introductionmentioning

confidence: 95%