Signal decision system

• US 4,165,458 A
• Filed: 04/14/1977
• Issued: 08/21/1979
• Est. Priority Date: 04/23/1976
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Koizumi, Takayuki, Usami, Teruo
• Primary Examiner(s): Thesz, Joseph M.
• Application Number:
  US05/787,454
• Time in Patent Office: 859 Days
• Field of Search: 235/92 PE, 235/92 PK, 235/92 PB, 235/92 CA, 235/92 TF, 235/92 QC, 340/558, 340/559, 340/560
• US Class Current: 377/19
• CPC Class Codes: G01V 1/001 Acoustic presence detection

Abstract

An electrical signal originating from an abnormal sound is passed through a bandpass filter and compared with a reference signal by a comparator. When the electrical signal is not less than the reference signal, the comparator produces a pulse. A counter counts the pulses from the comparator and causes a display device to display the presence of the abnormal sound when its count exceeds a predetermined value within a predetermined time interval.

Claims

1. A signal decision system comprising, in combination, a detector means for detecting a signal from an object to be measured, a filter means connected to said detector means for filtering the output signal from said detector means, a comparison means connected to said filter means for comparing the output signal from said filter means with a reference signal for producing a pulsed signal when said output signal from said filter means has a level not less than a predetermined level, and a decision generation means connected to said comparison means for counting said pulsed signals successively produced from said comparison means for producing a decision signal when the counted number of said pulsed signals equals at least a predetermined value within a predetermined time interval.

2. A decision system as claimed in claim 1 wherein said decision signal is a signal indicating an abnormality.

3. A signal decision system as claimed in claim 1 wherein said signal from said object to be measured is an abnormal sound.

4. A signal decision system as claimed in claim 3 wherein said detector means includes means for converting said abnormal sound to an electrical signal.

5. A signal decision system as claimed in claim 4 wherein said means for converting said abnormal sound to said electrical signal comprises a sound collector.

6. A signal decision system as claimed in claim 3 wherein said means for converting said abnormal sound to said electrical signal comprises a sound collector.

7. A signal decision system as claimed in claim 1 wherein said signal from said object to be measured is an abnormal electrical signal.

8. A signal decision system as claimed in claim 1 wherein said filter means is a bandpass filter.

9. A signal decision system as claimed in claim 1 wherein said decision generation means comprises a counter, a time setter for setting said predetermined time interval, and a number setter for setting said predetermined value.

10. A signal decision system as claimed in claim 1 wherein said predetermined time interval is infinitely large.

11. A signal decision system as claimed in claim 1 wherein said decision generation means comprises a time setter for setting said predetermined time interval.

12. A signal decision system as claimed in claim 1 wherein said decision generation means comprises a number setter for setting said predetermined value.

13. A signal decision system comprising, in combination, a detector means for detecting a signal from an object to be measured, a plurality of filter means connected to said detector means, each of said plurality of filter means for filtering the output signal from said detector means, a plurality of comparison means each connected to a corresponding one of said plurality of filter means for comparing the output signal from said corresponding filter means with a reference signal to produce a pulsed signal when said output signal from said corresponding filter means has a level not less than a predetermined level, a plurality of decision generation means each connected to a corresponding one of said comparison means for counting said pulsed signals successively produced by said corresponding comparison means and for producing a decision signal when the counted number of said pulsed signals equals at least a predetermined value, and a single display means connected to all of said plurality of decision generation means to display the presence of said decision signal.

14. A signal decision system as claimed in claim 13 wherein said system further comprises a logic circuit connected between all of said plurality of decision generation means and said display means for performing a logic conjunction of said decision signals from said decision generation means.