Browsing by Author "Salomon, Max-Elie"

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    A complete spurs distribution model for direct digital period synthesizers
    (IEEE, 2005) Salomon, Max-Elie; Khouas, Abdelhakim; Savaria, Yvon
    This paper presents a new, fully automated algorithm modeling the spurious frequencies in direct digital period synthesizers (DDPS). DDPS is a frequency synthesis technique that combines the speed and low jitter of a delay-locked-loop-based frequency multiplier, with the ability to digitally control the frequency. The algorithm is based on an analysis of the periodicity of the output signal produced by a DDPS circuit on which a time-domain Fourier analysis is performed. The resulting spectrum reflects two major known sources of spurious frequencies in DDPS: accumulator output truncation and delay line cell mismatch. Comparisons with results obtained from time-consuming simulations performed with SIMULINK and processed by FFT were performed to validate the model. An efficient implementation of the proposed algorithm allows comparing many different operating conditions that could not be analyzed with the SIMULINK model due to excessive processing time
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    Spur Model for a Fixed-Frequency Signal Subject to Periodic Jitter
    (IEEE, 2008) Salomon, Max-Elie; Izouggaghen, Badre; Khouas, Abdelhakim; Savaria, Yvon
    This paper presents an automated algorithm that is capable of predicting both the location and magnitude of spurs that are caused by different sources of jitter on a periodic signal. A practical circuit that produces this kind of jittered periodic signal is the direct digital period synthesis (DDPS) circuit that can be used as a flexible clock source for various applications such as adjusting a sampling rate in a measurement and signal processing. Points of interest with clocks that are subject to periodic perturbations are their spectral purity and jitter characteristics. Our algorithm is applied to the DDPS to greatly reduce the simulation time that is needed to accurately compute the spectrum of the signal and its spurious frequency content. The method is used to explore how the operating parameters of the DDPS influence the spectral purity of its output. The generic analysis method that has been used in this paper can be transposed to fractional- N synthesizers, delay-line-based direct digital synthesizers, or serializers