‘Electrical leak detection system’ to detect abnormal conduction within a catheter in the presence of electrical interferers
A system, method and leak signal discriminator for detection of a leak or mechanical breach in a catheter shaft in the presence of an electrical interferer are disclosed. According to one aspect, a leak signal discriminator having a leak detection circuit is configured to distinguish between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer. The leak signal discriminator includes circuitry configured to receive from the leak detection circuit a response signal responsive to a test signal the test signal having component signals, each component signal being at a different frequency, and distinguish between a leak and an electrical interferer based at least in part on an evaluation of the response signal.
1 . A method of distinguishing between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer, the method comprising:
transmitting a test signal to a leak detection circuit of the catheter within the catheter, the test signal having multiple component signals injected simultaneously, each component signal being at a different frequency with a known amplitude;
receiving from the leak detection circuit a response signal arising from modulation of the test signal by an environment within the catheter; and
distinguishing between a leak and an electrical interferer based on an evaluation of the response signal by filtering the response signal at a first frequency of the different component signal frequencies to generate a first filtered response signal.
2 . The method of claim 1 , wherein distinguishing between the leak and the electrical interferer includes:
comparing the first filtered response signal to a first threshold; and
when the first filtered response signal exceeds the first threshold:
filtering the response signal at a second frequency of the different component signal frequencies to generate a second filtered response signal;
comparing the second filtered response signal to a second threshold; and
when the second filtered response signal exceeds the second threshold, indicating a leak.
3 . The method of claim 2 , wherein the first threshold and the second threshold are set according to a measured noise power in the response signal.
4 . The method of claim 3 , wherein the measured noise power for setting the first threshold is measured at a frequency that is different than the first frequency.
5 . The method of claim 1 , wherein distinguishing between the leak and the electrical interferer includes turning off the test signal to determine whether the evaluation of the response signal indicates a presence of an electrical interferer when the test signal is turned off.
6 . The method of claim 1 , wherein no one component signal frequency is an integer multiple of any other of the different component signal frequencies.
7 . The method of claim 1 , wherein the method includes measuring, via a peak detector, an amplitude peak of the response signal.
8 . The method of claim 1 , wherein distinguishing between the leak and the electrical interferer includes selecting an order of a filter to filter the response signal at the first frequency.
9 . A method of distinguishing between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer, the method comprising:
transmitting a test signal to a leak detection circuit of the catheter within the catheter, the test signal having multiple component signals injected simultaneously, each component signal being at a different frequency with a known amplitude;
receiving from the leak detection circuit a response signal arising from modulation of the test signal by an environment within the catheter; and
distinguishing between a leak and an electrical interferer based on an evaluation of the response signal by passing the response signal through a filter configured to pass the response signal at one of the different component signal frequencies and filter out other frequencies of the different component signal frequencies.
10 . The method of claim 9 , wherein distinguishing between the leak and the electrical interferer includes selecting a center frequency of the filter.
11 . The method of claim 9 , wherein distinguishing between the leak and the electrical interferer includes selecting an order of the filter.
12 . The method of claim 9 , wherein distinguishing between a leak and an electrical interferer includes turning off the test signal to determine whether the evaluation of the response signal indicates a presence of an electrical interferer when the test signal is turned off.
13 . The method of claim 9 , wherein no one component signal frequency is an integer multiple of any other of the different component signal frequencies.
14 . The method of claim 9 , wherein the method includes measuring, via a peak detector, an amplitude peak of the response signal.
15 . The method of claim 9 , wherein the method includes:
simultaneously sampling the test signal and the response signal; and
comparing the sampled test signal to the sampled response signal.
16 . The method of claim 15 , wherein the response signal is sampled at a rate that is an integer multiple of one of the different component signal frequencies but not an integer multiple of other frequencies of the different component signal frequencies.