Stress test system with bidirectional filter
First Claim
1. A stress test system for eliminating noise contained in an accelerated ECG signal comprising:
- electrode means for detecting bioelectric signals generated by accelerated hearts of human subjects and generating, therefrom, an analog electrical signal;
digitizing means for converting said analog signal into a series of digital signals;
processing means for performing digital processing on said series of digital signals;
storage means operatively coupled to said processing means for storing data relating to said processing means operation, including storage of a predetermined length;
segmentation means contained within said processing means for dividing said series of digital signals into a series of windows, each of said windows being of said predetermined length;
filtering means contained within said processing means, said filtering means performing a bidirectional infinite impulse response (IIR) filter upon each of said windows; and
comparison means contained within said processing means for determining when said filtering means has completed each pass of said bidirectional IIR filter by comparing the length filtered in each direction against said predetermined length.
2 Assignments
0 Petitions
Accused Products
Abstract
A system for filtering stochastic signals as embodied in stress test systems for measuring electrocardiographic (ECG) activity in response to exercise employs a bidirectional Infinite Impulse Response (IIR) filtering process over a predetermined window on a digitized version of an ECG signal to eliminate noise up to the 0.67 Hz frequency range. To eliminate phase shifting distortion in the ECG signal, the IIR filter is applied in a first direction over a predetermined window of the ECG and then applied in a second direction opposite the first direction segment over the identical window. In this manner the phase shift distortion normally associated with IIR filters is completely eliminated and superior bandwidth (as compared to FIR filters) is obtained. The response is achieved fast enough to be used in real time purpose.
-
Citations
14 Claims
-
1. A stress test system for eliminating noise contained in an accelerated ECG signal comprising:
-
electrode means for detecting bioelectric signals generated by accelerated hearts of human subjects and generating, therefrom, an analog electrical signal; digitizing means for converting said analog signal into a series of digital signals; processing means for performing digital processing on said series of digital signals; storage means operatively coupled to said processing means for storing data relating to said processing means operation, including storage of a predetermined length; segmentation means contained within said processing means for dividing said series of digital signals into a series of windows, each of said windows being of said predetermined length; filtering means contained within said processing means, said filtering means performing a bidirectional infinite impulse response (IIR) filter upon each of said windows; and comparison means contained within said processing means for determining when said filtering means has completed each pass of said bidirectional IIR filter by comparing the length filtered in each direction against said predetermined length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A system for filtering electrocardiographic signals generated as a result of accelerated cardiac activity comprising:
-
at least one electrocardiographic sensor capable of detecting bioelectric signals generated by accelerated hearts of human subjects, said sensor being attached to human subjects to detect heartbeats, and generate an analog electrical signal, therefrom; digitizing means for converting said analog electrical signal into a series of digital electrical signals; computational means for dividing said series of digital electrical signals into a series of segments each of said segments having a predetermined length; filtering means contained within said computational means, for performing a zero phase bidirectional infinite impulse response (IIR) filter on said series of segments; and means responsive to said filtering means for reconstructing said series of segments to create an estimated baseline level of said analog signal. - View Dependent Claims (11, 12, 13, 14)
-
Specification