We present our latest results on the ultrasensitive molecular overtone spectroscopy using the cavity-enhanced frequency modulation (FM) technique. The principle of this technique makes use of a high-finesse external cavity to enhance the intrinsic resonance contrast, while an FM modulation approach provides shot-noise limited signal recovery. Working with a 1.064 m Nd:YAG laser, we have obtain...

Frequency modulation (FM) and random switching methods have been used for reducing conducted electromagnetic interference (EMI) in power converters. Limited theoretical studies and comparisons of these schemes, however, are available. In this paper, a detailed analysis and the spectral characteristics of a random carrier-frequency (RCF) technique for suppressing conducted EMI in an offline swit...

The accuracy of target position detection in IR seeker depends on the accuracy of tracking error signal (TES) extraction from seeker Field of View (FOV). The type of reticle inside the seeker determines the output modulation signal that carries the TES. In this paper, the stationary wagon wheel reticle is used, which makes the type of the output signal as FM modulation in the linear region of F...

Although relatively neglected in auditory analysis, phase information plays an important role in human auditory intelligibility. This paper investigates a Frequency Modulation (FM) based feature and its contribution to a Language Identification (LID) system, using a Hierarchical LID framework. FM components represent the phase information of a given signal in an AM-FM model. In this paper, we e...

The propagation of a weakly modulated light beam through a nonlinear material is treated. The optical field representing such a beam consists of a strong carrier-frequency component and two weak, symmetrically displaced sidebands that combine to form a field, which may be purely amplitude modulated (AM), frequency modulated (FM), or some combination of these two modulation forms. It is shown th...

Frontal-midline (fm) theta oscillations as measured via the electroencephalogram (EEG) have been suggested as neural "working language" of executive functioning. Their power has been shown to increase when cognitive processing or task performance is enhanced. Thus, the question arises whether learning to increase fm-theta amplitudes would functionally impact the behavioral performance in tasks ...

Interaural-delay sensitivity to high-frequency (> or = 3 kHz) sinusoidal-frequency-modulated (SFM) tones is examined for rates from 25 to 800 Hz and depths of -12 to 18 dB. Comparison is made to thresholds obtained for sinusoidal-amplitude-modulated (SAM) tones for the same observers and modulation rates. Both SAM and SFM threshold-by-rate functions are U-shaped with optimum sensitivity to SFM ...

In this paper, a method using dynamic programming to predict frequency boundaries is proposed for the joint demodulation of amplitude modulation (AM) and frequency modulation (FM) for speech signals. Because of the existence of modulations in speech signal, an algorithm called energy separation algorithm (ESA) has been developed to track the energy needed by a source to produce the speech signa...

Previous research with young adults has shown that temporal (amplitude modulated, AM) cues are sufficient for recognizing speech in quiet but not for speech in noise. Speech perception in noise is more robust when spectral (frequency modulated, FM) cues are provided in addition to AM ones; visual cues (AV) provide an additional benefit. The elderly typically have problems recognizing speech in ...