Signal detector and method for detecting signals having selected frequency characteristics
First Claim
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1. A signal detector for monitoring sound signals having frequencies within selected ranges and for producing at least a first output signal in response thereto, comprising:
- (a) a first sensor element of a first type operative in response to presence of the sound signals to produce a first electrical signal;
(b) first amplification and filter circuitry operative to receive the first electrical signal to remove all frequency components thereof not within a first selected range and to produce a first input signal at a selected first input signal frequency and first input signal amplitude;
(c) a second sensor element of a second type different from the first type, said second sensor element operative in response to presence of the sound signals to produce a second electrical signal;
(d) second amplification and filter circuitry operative to receive the second electrical signal to remove all frequency components thereof not within a second selected range and to produce a second input signal at a selected second input signal frequency and second input signal amplitude;
(e) an oscillator circuit operative to produce a reference signal at a selected reference signal frequency;
(f) a mixer operative to receive the reference signal and a selected one of said first and second input signals to produce a mixed composite signal at a mixed composite signal frequency and at a mixed composite signal amplitude;
(g) a first switch operative in a first switch condition to selectively interconnect said mixer to said first input signal and operative in a second switch condition to selectively interconnect said mixer to said second input signal;
(h) a first amplifier operative to amplify the mixed composite signal to produce a first output signal; and
(i) a first output device for producing a display in response to said first output signal.
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Abstract
The present invention generally relates to procedures and apparatus for monitoring incoming signals to detect the presence of selected target signals contained within the universe of signals received. More particularly, the present invention is directed to monitoring audio signals to detect selected ultrasonic and sonic signals in an ambient environment. Thus, the present invention is even more specifically directed to leak detectors and bearing wear indicators and methods for detecting sound signals which either travel in the air or are present in solids.
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Citations
27 Claims
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1. A signal detector for monitoring sound signals having frequencies within selected ranges and for producing at least a first output signal in response thereto, comprising:
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(a) a first sensor element of a first type operative in response to presence of the sound signals to produce a first electrical signal; (b) first amplification and filter circuitry operative to receive the first electrical signal to remove all frequency components thereof not within a first selected range and to produce a first input signal at a selected first input signal frequency and first input signal amplitude; (c) a second sensor element of a second type different from the first type, said second sensor element operative in response to presence of the sound signals to produce a second electrical signal; (d) second amplification and filter circuitry operative to receive the second electrical signal to remove all frequency components thereof not within a second selected range and to produce a second input signal at a selected second input signal frequency and second input signal amplitude; (e) an oscillator circuit operative to produce a reference signal at a selected reference signal frequency; (f) a mixer operative to receive the reference signal and a selected one of said first and second input signals to produce a mixed composite signal at a mixed composite signal frequency and at a mixed composite signal amplitude; (g) a first switch operative in a first switch condition to selectively interconnect said mixer to said first input signal and operative in a second switch condition to selectively interconnect said mixer to said second input signal; (h) a first amplifier operative to amplify the mixed composite signal to produce a first output signal; and (i) a first output device for producing a display in response to said first output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A signal detector for monitoring sound signals having frequencies over a selected frequency range and for producing an audible signal in response thereto, comprising:
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(a) a sensor element operative in response to presence of sound signals to produce an electrical signal; (b) a sensitivity control circuit operative in response to the electrical signal to remove all components thereof above a selected amplitude range; (c) amplification and filter circuitry operative in response to the electrical signal to remove all frequency components thereof not within the selected frequency range and to produce an input signal at a selected input signal frequency and input signal amplitude; (d) an oscillator operative to produce a reference signal at a selected reference signal frequency; (e) a mixer operative to receive the input signal and the reference signal to produce a mixed composite signal at a selected composite signal frequency and at a composite signal amplitude corresponding to the input signal amplitude; (f) a volume control circuit operative to selectively vary said composite signal amplitude, said sensitivity control circuit and said volume control circuit being independently adjustable; (g) an amplifier operative to amplify the mixed composite signal to produce an audio signal; and (h) an audio output device for producing an audio sound in response to said audio signal.
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16. A signal detector for monitoring sound signals having frequencies over a selected frequency range and for producing an audible signal in response thereto, comprising:
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(a) a sensor element operative in response to presence of sound signals to produce an electrical signal; (b) a first amplifier operative to amplify the electrical signal to produce an amplified electrical signal, said amplified electrical signal thereafter being split into first and second components thereof; (c) a filter operative to receive the first component of said electrical signal to remove all frequency components thereof not within the selected frequency range and to produce an input signal at a selected input signal frequency and input signal amplitude; (d) an oscillator operative to produce a reference signal at a selected reference signal frequency; (e) a mixer operative to receive the input signal and the reference signal to produce a mixed composite signal at a selected composite signal frequency and at a composite signal amplitude corresponding to the input signal amplitude; (f) a switch operative in a first switch condition to receive said composite signal and operative in a second switch condition to receive said amplified electrical signal; (g) a second amplifier operative to amplify a selected one of said composite signal and said amplified electrical signal to produce an output signal; and (h) an output device for producing a display in response to said output signal.
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17. A method for monitoring sound signals in order to indicate a presence of those signals having frequencies within a selected range, comprising the steps of:
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(a) providing a first sensor element of a first type operative to receive sound signals emanating from a first medium and to generate a first electrical signal in response thereto; (b) providing a second sensor element of a second type different from the first type, said second sensor element operative to receive sound signals emanating from a second medium and to generate a second electrical signal in response thereto; (c) selecting one of said first and second electrical signals for processing; (d) processing the selected one of said first and second electrical signals to generate at least a first output signal at a selected first output signal frequency and first output signal amplitude; and (e) displaying said first output signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification