Real-time rectangular-wave transmitting metal detector platform with user selectable transmission and reception properties
First Claim
1. A method for detecting a target using a real-time metal detector, comprising:
- generating a repeating transmit signal of a fundamental period, wherein the repeating transmit signal includes a rectangular-wave sequence, and a frequency spectrum of the repeating transmit signal includes a plurality of different spectral magnitude peaks, with one of the plurality of different spectral magnitude peaks, a first peak, at a first harmonic of a fundamental frequency corresponding to the fundamental period, and a highest peak, with a highest magnitude among the plurality of different spectral magnitude peaks, at a frequency different from the first harmonic of the fundamental frequency, wherein a magnitude of the first peak and a magnitude of the highest peak are within a factor of two; and
processing a receive signal using a broadband synchronous demodulation multiplication function for producing an output indicating a presence or absence of the target.
2 Assignments
0 Petitions
Accused Products
Abstract
A highly flexible real-time metal detector platform which has a detection capability for different targets and applications, where the operator is able to alter synchronous demodulation multiplication functions to select different types or mixtures of different types to be applied to different synchronous demodulators, and also different waveforms of the said synchronous demodulation multiplication functions; examples of the different types being time-domain, square-wave, sine-wave or receive signal weighted synchronous demodulation multiplication functions. The operator can alter the fundamental frequency of the repeating switched rectangular-wave voltage sequence, and an operator may alter the waveform of the repeating switched rectangular-wave voltage sequence and corresponding synchronous demodulation multiplication functions.
-
Citations
24 Claims
-
1. A method for detecting a target using a real-time metal detector, comprising:
-
generating a repeating transmit signal of a fundamental period, wherein the repeating transmit signal includes a rectangular-wave sequence, and a frequency spectrum of the repeating transmit signal includes a plurality of different spectral magnitude peaks, with one of the plurality of different spectral magnitude peaks, a first peak, at a first harmonic of a fundamental frequency corresponding to the fundamental period, and a highest peak, with a highest magnitude among the plurality of different spectral magnitude peaks, at a frequency different from the first harmonic of the fundamental frequency, wherein a magnitude of the first peak and a magnitude of the highest peak are within a factor of two; and processing a receive signal using a broadband synchronous demodulation multiplication function for producing an output indicating a presence or absence of the target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A real time metal detector, comprising:
-
a transmitter connected to a transmit coil for the transmission of alternating magnetic fields when operational, a magnetic field receiving means connected to signal processing and assessment electronics; the transmitter being adapted to apply a transmit signal to the said transmit coil when operational; the real-time metal detector configured to; generate a repeating transmit signal of a fundamental period, wherein the repeating transmit signal includes a rectangular-wave sequence, and a frequency spectrum of the repeating transmit signal includes a plurality of different spectral magnitude peaks, with one of the plurality of different spectral magnitude peaks, a first peak, at a first harmonic of a fundamental frequency corresponding to the fundamental period, and a highest peak, with a highest magnitude among the plurality of different spectral magnitude peaks, at a frequency different from the first harmonic of the fundamental frequency, wherein a magnitude of the first peak and a magnitude of the highest peak are within a factor of two; and process a receive signal using a broadband synchronous demodulation multiplication function for producing an output indicating a presence or absence of the target. - View Dependent Claims (19, 20, 21, 22, 23, 24)
-
Specification