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Complex heterodyne for undersampled chirped sinusoidal signals
Applied Optics, 2006We describe a method for analyzing frequency-chirped sinusoidal signals using a complex heterodyne, sometimes also known as complex demodulation on the digitized waveform. This method allows one to use prior knowledge of the signal to reduce the effective bandwidth of the signal. The method can be used to extract a frequency-chirped signal even when it
T M, Niebauer, A, Schiel, D, van Westrum
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Undersampling to acquire nuclear magnetic resonance images
Medical Engineering & Physics, 2004In this paper, we present a method that permits the application of a direct digital receiver based on undersampling techniques to NMR and MRI scanners working with incoherent excitation pulses, and we evaluate the performance of such receivers in the acquisition and reconstruction of images. The method has been tested on a BRUKER BIOSPEC BMT 47/40, and
Pablo, Pérez, Andrés, Santos
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Twinkle, twinkle, undersampled star
During the late subgiant/early giant stage, stars undergo fast evolutionary changes such as the readjustment of their internal rotation. It is of paramount importance to study this phase, in particular to understand the transport of angular momentum from the cores of stars to their envelopes.Liagre, Bastien +2 more
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Image degradation in undersampled holograms
Physics Letters A, 1969Abstract If we make a sampled hologram of an object with space-bandwidth product N but we use only M (⪡ N ) samples, the image will be degraded. The type of degradation (resolution or signal-to-noise ratio is determined by the type of sampling.
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