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All the PI detector information I see, involves generating a pulse (which is a ringing damped sinusoid) and damping it so it doesn't ring. Then extracting information from the decay slope.
This is leaving valuable information behind. This post should be considered prior art for anyone thinking about patenting this idea.
I work on a medical device that is essentially a PI pain killer. Basically, we generate a pulse train. This train fires a small flyback transformer, that causes a low amperage (micro amps), high voltage +/- (700-1000 volt min.max) signal to be emitted on the first swing of the flyback transformer (after we take the charge pulse away) and applied to the body subsequent swings have less amplitude based on the load on the transformer. For a PI detector, it is the same, except that a loop is used, and the amps out are much higher, and the signal is not applied to the body. Impedance causes the pulses to decay basically exponentially. If you hang a damping resistor (which we can also do) across the coil, it sucks the power out. In the case of a PI detector, this
curve is sampled periodically to look for metal and or type of metal. HOWEVER:
The WIDTH of the zero crossings of the swings changes from pulse to pulse, as do the number of swings absent the damping circuit. In our case, this is used to monitor the body's reactions to the simulation signal, and also makes the signal such that the body does not accommodate to it.
the same principle can be used to extract further information from a PI metal detector pulse. Go ahead, generate the pulse, dampen it and extract the standard information. At some point, periodically generate an UNDAMPED ringing pulse and measure the width of the swings. Impedance changes in the soil will affect this. I would suspect that these would be diagnostic of soil condition and potentially target acquisition. So the concept of analyzing a non damped signal in a pulse induction metal detector for information concerning the ground, ground balance, and target composition is here by in the public domain if it has not already been patented.
The use of this in the medical world is patented.
This is leaving valuable information behind. This post should be considered prior art for anyone thinking about patenting this idea.
I work on a medical device that is essentially a PI pain killer. Basically, we generate a pulse train. This train fires a small flyback transformer, that causes a low amperage (micro amps), high voltage +/- (700-1000 volt min.max) signal to be emitted on the first swing of the flyback transformer (after we take the charge pulse away) and applied to the body subsequent swings have less amplitude based on the load on the transformer. For a PI detector, it is the same, except that a loop is used, and the amps out are much higher, and the signal is not applied to the body. Impedance causes the pulses to decay basically exponentially. If you hang a damping resistor (which we can also do) across the coil, it sucks the power out. In the case of a PI detector, this
curve is sampled periodically to look for metal and or type of metal. HOWEVER:
The WIDTH of the zero crossings of the swings changes from pulse to pulse, as do the number of swings absent the damping circuit. In our case, this is used to monitor the body's reactions to the simulation signal, and also makes the signal such that the body does not accommodate to it.
the same principle can be used to extract further information from a PI metal detector pulse. Go ahead, generate the pulse, dampen it and extract the standard information. At some point, periodically generate an UNDAMPED ringing pulse and measure the width of the swings. Impedance changes in the soil will affect this. I would suspect that these would be diagnostic of soil condition and potentially target acquisition. So the concept of analyzing a non damped signal in a pulse induction metal detector for information concerning the ground, ground balance, and target composition is here by in the public domain if it has not already been patented.
The use of this in the medical world is patented.