Electric arc and radio frequency spectrum detection

Apparatus for detecting a signal having a spectrum of a broad band of distinct instantaneous radio frequencies in radio frequency noise, comprising in combination:

• means for converting a multitude of said distinct instantaneous radio frequencies into a combination frequency of said distinct instantaneous radio frequencies, while rejecting extraneous narrow-band signals having frequencies within said broad band;
• said converting means including two noise signal paths, means for duplicating said radio frequency noise into said two paths, and means for mixing the radio frequency noise from one of said two paths with the radio frequency noise from the other of said two paths;
• and
• means connected to said converting means for detecting said spectrum from said combination frequency, including means for detecting from the mixed radio frequency noise said combination frequency of a multitude of said distinct instantaneous radio frequencies indicative of said signal having said spectrum, in contradistinction to said extraneous narrow-band signals.

A method of detecting a signal having a spectrum of a broad band of distinct instantaneous radio frequencies in radio frequency noise including extraneous narrow-band signals having frequencies within said broad band, comprising in combination:

• deriving from said signal having said spectrum of a broad band of distinct instantaneous radio frequencies in radio frequency noise a wide band noise signal also including distinct radio frequencies;
• mixing said radio frequency noise with said wide band noise signal to produce a signal having a combination frequency of a multitude of distinct instantaneous radio frequencies;
• and
• detecting said signal having said spectrum from said combination frequency in contradistinction to said extraneous narrow-band signals.

Apparatus for detecting a signal having a spectrum of a broad band of distinct instantaneous radio frequencies in radio frequency noise including extraneous narrow-band signals having frequencies within said broad band, comprising in combination:

• a wide band noise signal path having an input for a version of said radio frequency noise;
• a radio frequency mixer having a first input for said radio frequency noise, and a second input connected to said wide band noise signal path for said version of said radio frequency noise, and an output for a signal having a combination frequency of a multitude of distinct instantaneous radio frequencies from said radio frequency noise and from said version of said radio frequency noise;
• and
• a frequency combination detector having an input coupled to said radio frequency mixer output, and having an output for a signal indicative of a detected combination of said distinct instantaneous radio frequencies in contradistinction to said extraneous narrow-band signals.