Process and apparatus for detecting pulses due to electrostatic discharges from furniture or human beings

• US 4,975,686 A
• Filed: 11/14/1989
• Issued: 12/04/1990
• Est. Priority Date: 11/14/1988
• Status: Expired due to Term

• Current Assignee: Gilles Delcourt
• Original Assignee: Gilles Delcourt
• Inventors: Delcourt, Gilles
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US07/435,675
• Time in Patent Office: 385 Days
• Field of Search: 340/659, 340/522, 340/601, 324/457, 324/458, 324/102, 324/72.5, 324/72, 361/111, 73/170 R
• US Class Current: 340/659
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
• CPC Class Codes: G01R 29/12 Measuring electrostatic fields or voltage-potential
• CPC Class Codes: G01W 1/16 Measuring atmospheric potential differences, e.g. due to electrical charges in clouds measuring potentiels in general G01R

Abstract

The detection of brief pulses generating high frequencies is carried out by a system including: sensor for detecting an electrostatic field and for detecting an electromagnetic field, such that the variation of the electrostatic field ocurring in a period of time of less than 1 millisecond may be identified. A signal activator for warning about the presence, in an interval of time of less than 1 millisecond, of the variation of the electrostatic field detected and of the electromagnetic field, allowing identification of a pulse due to an electrostatic discharge from furniture or human beings. The invention is applicable to the detection of pulses due to electrostatic discharges.

Claims

1. A process for detecting pulses, of the type of which an electromagnetic field and an electrostatic field are detected, comprising the steps of:

detecting the electromagnetic field and the electrostatic field within a predefined location;

detecting the electromagnetic field using a high pass filter of which the cut-off frequency lies between approximately 15 MHz and 200 MHz inclusive;

detecting a variation of the electrostatic field, said variation having a duration less than one millisecond; and

producing a warning signal when the variation of the electrostatic field and the presence of the electromagnetic field are both detected within an interval of time less than one millisecond of each other.

2. The process as claimed in claim 1, wherein the warning signal is only produced if said electromagnetic field at least equals about one ampere per meter.

3. The process as claimed in claim 1, wherein the presence of the electromagnetic field is detected by detecting its electric field component.

4. The process as claimed in claim 1, wherein the presence of the electromagnetic field is detected by detecting its magnetic field component.

5. An apparatus for detecting pulses of the type of which an electromagnetic field and the electrostatic field are detected, comprising:

a sensor for detecting an electrostatic field;

a detector for detecting an electromagnetic field;

a means for detecting a variation of the electrostatic field having a duration less than one millisecond; and

a means responsive to both said electrostatic field sensor and said electromagnetic field sensor for producing a warning signal when the variation of the electrostatic field and the presence of the electromagnetic field are both detected within an interval of time less than one millisecond.

6. The apparatus as claimed in claim 5, further comprising means for detecting when the electromagnetic field at least equals about one ampere per meter and for providing an enabling signal to said warning signal producing means only when said electromagnetic field at least equals one ampere per meter.

7. The apparatus as claimed in claim 6, further comprising a circuit for receiving a signal issuing from said means for detecting when said electromagnetic field at least equals one ampere per meter, and for providing an enabling signal for said warning signal producing means for no longer than one millisecond after said electrostatic sensor detects said electrostatic field variation.

8. The apparatus as claimed in claim 5, wherein said warning signal producing means means further comprises means for recording the fact of issuance of said warning signal.