Broadcast Data Systems Limited Partnership

Ensco, Inc.

Digital Signal Corporation

Stephen C Kenyon

Laura J Simkins

Anthony R Slotwinski

Richard Sebastian

Richard L Sebastian

Leroy L Brown

Recognizing a signal begins by receiving the signal and sampling it at a plurality of sampling points to produce a plurality of signal values. A statistical moment of the signal is calculated using the signal values according to the formula: ##EQU1## where: N=the number of sampling points;

Signal recognition system and method

Method and apparatus for classifying broadcast information first receives the broadcast information and processes it to provide a plurality of a low bandwidth analyzed waveforms. The analyzed waveforms are used to generate a spectragram which is then compared with a plurality of reference spectragrams stored in a first stage reference library. The first stage reference spectragrams are then queued in order of their similarity to the generated spectragram. Next, a plurality of second stage reference patterns, which correspond to the first stage reference spectragrams, are correlated with one of the analyzed waveforms in the queueing order established previously. A correlation value is provided for each second stage reference pattern stored in the second stage reference library. When it is determined that a correlation value exceeds the threshold value, a recognition is declared and the broadcast information is classified as similar to the second stage reference pattern whose correlation value exceeds the threshold. The analyzed waveform used in the second stage classification may be time warped to account for speed fluctuations in the broadcast information.

Broadcast information classification system and method

A precision optical distance measuring device utilizes coherent optical detection for extreme precision, and polarization preserving fiber to enable its use in limited access environments. A laser diode provides a linearly polarized source light beam which is directed to a polarizing beam splitter. The source beam passes through the beam splitter and is focused by a lens into a polarization preserving fiber where it travels along one optical axis toward a probe head disposed at the target location. In the probe head, the source beam is focused by a lens onto the target. After focusing, the source beam is passed through a quarter-wave plate. The interface between ambient air and the target-side of the quarter-wave plate reflects a local oscillator beam back through the quarter-wave plate. Meanwhile, the source beam is reflected from the target as a return beam. Mixing of the two beams occurs at the interface and the mixed beam is focused back into the polarization preserving fiber where it is transmitted along a second transmission axis of the fiber. The mixed beam emerges from the fiber and is reflected by the polarizing beam splitter along a second optical axis. The mixed beam is then focused by a detection lens onto a photo detector which coherently detects the mixed beam. The source laser beam is frequency swept so that the photo detector provides an output signal regarding the precise distance between the probe head and the target.

Optical position sensor using coherent detection and polarization

The method for the automatic electronic recognition of a program unit broadcast by radio waves includes the formation of a plurality of reference signal segments from the program unit and the processing of such segments to obtain digitized reference signal segments which are then normalized and stored. When the program unit is broadcast, the broadcast signal is processed to generate successive digitized broadcast signal segments which are correlated with the digitized, normalized reference signal segments to obtain correlation function peaks for each resultant correlation segment. The spacing between the correlation function peaks for each correlation segment is then compared to determine whether such spacing is substantially equal to the reference signal segment length. Also, the RMS value coincident with each correlation function peak is determined and the pattern of such RMS values coincident with the correlation function peaks is compared with the pattern of the RMS values of the normalized reference signal segments.

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Stafford, VA, United States of America

Stephen C Kenyon