Apparatus and method for detecting sharp signal variations against ambient signals
First Claim
1. An apparatus for detecting an event against background in an input time varying signal having an input time coordinate, which comprises:
- a) envelope detector means for receiving the input signal and providing equivalent first and second envelope detector outputs in response thereto;
b) background filter means for inputting the first envelope detector output and providing a background filter output responsive thereto;
c) event filter means for inputting the second envelope detector output and providing an event filter output responsive thereto, the background filter means and the event filter means independently providing a background filter output and an event filter output, and the background filter output and event filter output differing in response to at least one particular input signal;
d) decision means for making a comparison between a background filter base reference responsive to the background filter output and an event filter base reference responsive to the event filter output, and providing an output signal having an output signal time coordinate related to the input signal being in either a detection state or a non-detection state, but not both, in response to the background filter base reference and the event filter base reference.
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Accused Products
Abstract
For detecting a quickly or sharply varying signal (the event) against a background of a more slowly changing ambient signal (the background), the envelope detector inputs the signal and full wave rectifies it. It sends the signal to the background filter and event filter, each of which includes an RC circuit. The background filter and event filter each independently process the signal to be evaluated in different manners based on the intrinsic frequency characteristics of the event signal, and of the background signal. The outputs of the two filter sections are sent to the decision section. Based on its processing, the decision section outputs a signal in one of two states, one corresponding to detection, and the other corresponding to non-detection.
16 Citations
52 Claims
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1. An apparatus for detecting an event against background in an input time varying signal having an input time coordinate, which comprises:
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a) envelope detector means for receiving the input signal and providing equivalent first and second envelope detector outputs in response thereto; b) background filter means for inputting the first envelope detector output and providing a background filter output responsive thereto; c) event filter means for inputting the second envelope detector output and providing an event filter output responsive thereto, the background filter means and the event filter means independently providing a background filter output and an event filter output, and the background filter output and event filter output differing in response to at least one particular input signal; d) decision means for making a comparison between a background filter base reference responsive to the background filter output and an event filter base reference responsive to the event filter output, and providing an output signal having an output signal time coordinate related to the input signal being in either a detection state or a non-detection state, but not both, in response to the background filter base reference and the event filter base reference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for detecting an event against background in a time varying input signal having an input signal time coordinate, which comprises:
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a) receiving the input signal and providing equivalent first and second envelope detector outputs in response thereto; b) filtering the first envelope detector output with a background filter and providing a background filter output responsive thereto; c) filtering the second envelope detector output with an event filter and providing an event filter output responsive thereto, the background filtering step and the event filtering step independently providing a background filter output and an event filter output, and the background filter output and event filter output differing in response to at least one particular input signal; d) comparing a background filter base reference responsive to the background filter output and an event filter base reference responsive to the event filter output, and providing an output signal having an output signal time coordinate related to the input signal time coordinate, the output signal being in either a detection state or a non-detection state, but not both, in response to the background filter base reference and the event filter base reference. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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Specification