SIGNAL MONITORING SYSTEM

• US 3,653,019 A
• Filed: 07/28/1970
• Issued: 03/28/1972
• Est. Priority Date: 07/28/1970
• Status: Expired due to Term

• Current Assignee: Fred H. Sawada, Sterling C. Barton
• Original Assignee: Fred H. Sawada, Sterling C. Barton
• Inventors: Barton, Sterling C., Sawada, Fred H.
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/058,902
• Time in Patent Office: 609 Days
• Field of Search: 340/248P,248R 325/478 328/167,165
• US Class Current: 340/659
• CPC Class Codes: H02H 1/04 Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks
• CPC Class Codes: H02H 7/065 against excitation faults

Abstract

A signal processing system for monitoring the brush arcing potential at the slip rings of a generator supplied through the brushes with a field potential having recurring high-energy noise spikes in the same frequency band as the signal to be monitored, and to give an alarm when the brush arcing potential exceeds a certain critical value. The system eliminates the noise spikes by gating the signal for a preset time at a predetermined time after the occurrence of a noise spike.

Claims

1. Apparatus for monitoring a composite signal including an information signal and recurring noise spikes, comprising:

an information signal path, a control signal path and gating means, said gating means including a first input, a second input and an output, means connecting said information signal path to said first input of said gating means, means connecting said control signal path to said second input of said gating means;

said control signal path including means for producing a triggering pulse in response to a noise spIke exceeding a preselected amplitude, delay means for delaying said triggering pulse, and a pulse forming means triggered by said delayed triggering pulse to produce an enabling signal; and

said information signal path including means for routing a signal through said gating means, said gating means being enabled by said enabling signal to pass said information signal only during a preset interval at a predetermined time after the occurrence of a noise spike, and means to produce an output signal at the output of said gating means.

2. Apparatus for monitoring a composite signal as set forth in claim 1, said apparatus including peak integrating means on the output side of said gating means, said peak integrating means being provided with an input and an output, the output of said gating means being fed into said input of said peak integrating means to produce a signal at said output of said peak integrating means which is proportional to the amplitude of said information signal between noise spikes.

3. Apparatus for monitoring a composite signal as set forth in claim 2, including threshold means on the output side of said peak integrating means, said threshold means being provided with an input and an output, the signal at said output of said peak integrating means being fed into said input of said threshold means to produce a signal at said output of said threshold means only when said signal at said input of said threshold means exceeds a predetermined level.

4. Apparatus for monitoring a composite signal as set forth in claim 3, including an alarm means activated by a signal at said output of said threshold means when a signal at said output of said peak integrating means exceeds a predetermined level.

5. Apparatus for monitoring a composite signal including an information signal and recurring noise spikes, comprising:

a filter means provided with an input and an output;

an information signal path, a control signal path and gating means, said gating means including a first input, a second input and an output, means connecting said information signal path to said first input of said gating means, means connecting said control signal path to said second input of said gating means;

said filter means including means for receiving said composite signal at said input of said filter means, means for removing undesired frequency components of said composite signal and means for delivering the output of said filter means to both said information signal path and said control signal path;

said control signal path including means for producing a triggering pulse in response to a noise spike exceeding a preselected amplitude, delay means for delaying said triggering pulse, and a pulse forming means triggered by said delayed triggering pulse to produce an enabling signal; and

said information signal path including means for routing a signal through said gating means, said gating means being enabled by said enabling signal to pass said information signal only during a preset interval at a predetermined time after the occurrence of a noise spike, and means to produce an output signal at the output of said gating means.

6. Apparatus for monitoring a composite signal as set forth in claim 5, said apparatus including peak integrating means on the output side of said gating means, said peak integrating means being provided with an input and an output, the output of said gating means being fed into said input of said peak integrating means to produce a signal at said output of said peak integrating means which is proportional to the amplitude of said information signal between noise spikes.

7. Apparatus for monitoring a composite signal as set forth in claim 6, including threshold means on the output side of said peak integrating means, said threshold means being provided with an input and an output, the signal at said output of said peak integrating means being fed into said input of said threshold means to produce a signal at said output of said threShold means only when said signal at said input of said threshold means exceeds a predetermined level.

8. Apparatus for monitoring a composite signal as set forth in claim 7, including an alarm means activated by a signal at said output of said threshold means when a signal at said output of said peak integrating means exceeds a predetermined level.

9. Apparatus for monitoring a composite signal including an information signal and recurring noise spikes, comprising:

a filter means provided with an input and an output;

an information signal path, a control signal path and gating means, said gating means including a first input, a second input and an output, means connecting said information signal path through said first input of said gating means, means connecting said control signal path to said second input of said gating means;

said filter means including means for receiving said composite signal at said input of said filter means, means for removing undesired frequency components of said composite signal and means for delivering the output of said filter means to both said information signal path and said control signal path;

said control signal path including clipping and biasing means for passing only a portion of a noise spike exceeding a preselected amplitude, means for producing a triggering pulse in response to said portion of a noise spike, a first pulse forming means controllable by said triggering pulse to produce an output pulse, a second pulse forming means, and means for causing said second pulse forming means to be triggered on the trailing edge of the output pulse formed by said first pulse forming means to produce an enabling signal; and

said information signal path including means for routing a signal through said gating means, said gating means being enabled by said enabling signal to pass said information signal only during a preset interval at a predetermined time after the occurrence of a noise spike, and means to produce an output signal at the output of said gating means.

10. Apparatus for monitoring a composite signal as set forth in claim 9, said apparatus including peak integrating means on the output side of said gating means, said peak integrating means being provided with an input and an output, the output of said gating means being fed into said input of said peak integrating means to produce a signal at said output of said peak integrating means which is proportional to the amplitude of said information signal between noise spikes.

11. Apparatus for monitoring a composite signal as set forth in claim 10, including comparator means provided with a first input, a second input and an output, said first input of said comparator means being supplied with a preset voltage, said second input of said comparator means being supplied with the signal at said output of said peak integrating means to produce a signal at said output of said comparator means only when said signal at said second input of said comparator means exceeds said preset voltage at said first input of said comparator means.

12. Apparatus for monitoring a composite signal as set forth in claim 11 where said comparator means is a differential amplifier.

13. Apparatus for monitoring a composite signal as set forth in claim 12, including an alarm means activated by a signal at said output of said comparator means when a signal at said second input of said comparator means exceeds said preset voltage at said first input of said comparator means.

14. Apparatus for monitoring a composite signal including an information signal and recurring noise spikes, comprising:

a filter means provided with an input and an output;

an information signal path, a control signal path and gating means, said gating means including a first input, a second input and an output, means connecting said information signal path through said first input of said gating means, means connecting said control signal path to said second input of said gating means;

SAID filter means including means for receiving said composite signal at said input of said filter means, means for removing undesired frequency components of said composite signal delivered at said input of said filter means, and means for delivering the output of said filter means to both said information signal path and said control signal path;

said control signal path including clipping and biasing means for passing only a portion of a noise spike exceeding a preselected amplitude, means for producing a triggering pulse in response to said portion of a noise spike, a first pulse forming means controllable by said triggering pulse to produce an output pulse, a second pulse forming means, and means for causing said second pulse forming means to be triggered on the trailing edge of the output pulse formed by said first pulse forming means to produce an enabling signal; and

said information signal path including a second clipping means to limit noise spikes above and below predetermined levels, and means for routing a signal through said gating means, said gating means being enabled by said enabling signal to pass said information signal only during a preset interval at a predetermined time after the occurrence of a noise spike, and means to produce an output signal at the output of said gating means.

15. Apparatus for monitoring a composite signal as set forth in claim 14 where said first and second pulse forming means are monostable multivibrators.

16. Apparatus for monitoring a composite signal as set forth in claim 14, said apparatus including peak integrating means on the output side of said gating means, said peak integrating means being provided with an input and an output, the output of said gating means being fed into said input of said peak integrating means to produce a signal at said output of said peak integrating means which is proportional to the amplitude of said information signal between noise spikes.

17. Apparatus for monitoring a composite signal as set forth in claim 16, including comparator means provided with a first input, a second input and an output, said first input of said comparator means being supplied with a preset voltage, said second input of said comparator means being supplied with the signal at said output of said peak integrating means to produce a signal at said output of said comparator means only when said signal at said second input of said comparator means exceeds said preset voltage at said first input of said comparator means.

18. Apparatus for monitoring a composite signal as set forth in claim 17, including an alarm means activated by a signal at said output of said comparator means when a signal at said second input of said comparator means exceeds said preset voltage at said first input of said comparator means.