This paper describes the system developed jointly at SRI and OGI for participation in the 2006 NIST Spoken Term Detection (STD) evaluation. We participated in the three genres of the English track: Broadcast News (BN), Conversational Telephone Speech (CTS), and Conference Meetings (MTG). The system consists of two phases. First, audio indexing, an offline phase, converts the input speech wavefo...

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined ort...

Recognizing different features of a waveform to later recompose the music that was originally present in the signal is a difficult task. There are numerous fields of application where these techniques are known to be useful including music authoring, digitizer design, automatic music transcription. There are many different methods that can be used for this purpose giving somehow inadequate qual...

Animated mimic displays can be used to present system information regarding physical form, function, and causality. However, a potential limitation in current designs has been identified: the presence of ambiguous apparent motion. Two theoretical explanations of ambiguous apparent motion are discussed (Fourier and correspondence hypotheses). Two alternative designs (stair-step and approximate s...

In this paper, the multiple-input multiple-output (MIMO) transmit beampattern matching problem is considered. The problem is formulated to approximate a desired transmit beampattern (i.e., an energy distribution in space and frequency) and to minimize the cross-correlation of signals reflected back to the array by considering different practical waveform constraints at the same time. Due to the...

Antenna design in ultra-wideband (UWB) systems is a major challenge. For, in contrast to conventional systems, wherein waveform distortion by the antenna is negligible, there is potentially significant waveform distortion by UWB antennas. A further challenge to UWB system design is posed by mandated limits on power spectrum density, such as the FCC emission mask. In this paper, we join these tw...

This paper derives a family of digital non-linear waveform generators fundamental to the developement of an adaptive mixed-signal IC controller for power-factor-correction (PFC) of high-frequency switching AC-to-DC converters with the objective of significanlty lowering the cost of rectifier design. The controller application is described along with combined controller and power stage simulatio...

A new mathematical treatment and algorithm for the design of |B1(+)|-selective RF excitation pulses is presented and validated. The algorithm is based on a rotated Shinnar-Le Roux pulse design algorithm, wherein the pulse's frequency modulation waveform is directly designed by the algorithm, and its amplitude and sign modulation waveform takes the place of the gradient field. A new pulse config...

One question commonly asked about software defined radios is “How much memory do I need?”. While the answer depends greatly on the software framework and underlying operating system, this paper describes tools used to measure memory usage on a Linux based system running the OSSIE SCA framework. In addition to the conventional tools commonly used to study memory usage, this paper introduces the ...

We introduce a novel photonic-assisted ultrabroadband radio-frequency arbitrary waveform generation setup capable of high-speed phase and amplitude modulation of the individual arbitrary waveforms. The waveform generator is based on an optical interferometer, within which a high-resolution optical pulse shaper and integrated optic phase and intensity modulators are placed, followed by frequency...