Abstract: The method and system are disclosed for operating a metal detector having a balanced coil system with a drive coil that is connected to a transmitter unit which provides a transmitter signal with at least one operating frequency (fTX), and with first and second detection coils that provide an output signal to a receiver unit that processes a related receiver signal which includes an imbalance signal, and that provides digital in-phase and quadrature components (dI, dQ) of the demodulated imbalance signal.

Abstract: The method and system are disclosed for operating a metal detector having a balanced coil system with a drive coil that is connected to a transmitter unit which provides a transmitter signal with at least one operating frequency (fTX), and with first and second detection coils that provide an output signal to a receiver unit that processes a related receiver signal which includes an imbalance signal, and that provides digital in-phase and quadrature components (dI, dQ) of the demodulated imbalance signal.

Abstract: A metal detection apparatus has a passage channel (100) through which products (P) that may contain metal contaminants (C) pass. The apparatus has at least one transmitter unit (1) that provides transmitter signals to a transmitter coil (2) that is inductively coupled to a first and a second receiver coil (31; 32). The receiver coils are balanced and connected separately or combined to an input of a receiver unit (4). The transmitter coil has at least two coil sections (211, 212; 221, 222) that are arranged inclined to one another, with each coil section generating at least a first and a second magnetic field (My; MZ). Each of the first and the second receiver coils has at least a first coil section (311; 321) that is engaged in the first magnetic field and at least a second coil section (312; 322) that is engaged in the second magnetic field.

Abstract: A metal detection apparatus has a passage channel (100) through which products (P) that may contain metal contaminants (C) pass. The apparatus has at least one transmitter unit (1) that provides transmitter signals to a transmitter coil (2) that is inductively coupled to a first and a second receiver coil (31; 32). The receiver coils are balanced and connected separately or combined to an input of a receiver unit (4). The transmitter coil has at least two coil sections (211, 212; 221, 222) that are arranged inclined to one another, with each coil section generating at least a first and a second magnetic field (My; MZ). Each of the first and the second receiver coils has at least a first coil section (311; 321) that is engaged in the first magnetic field and at least a second coil section (312; 322) that is engaged in the second magnetic field.

Abstract: Bi-directional direct current (DC) power circuit having: a signal processing module for processing feedbacks of output voltage and voltage drop, and outputting pulse control and directional control signals; a pulse width modulation (PWM) module for outputting pulse signals in response to the control signals from the signal processing module; and a switch rectifying module for switching on and off in response to the pulse signals from the PWM module. The pulse control signal from the signal processing module can be in response to an input current signal from a sense resistor. The circuit is capable of achieving both step-up and step-down voltage conversions.

Abstract: Bi-directional direct current (DC) power circuit having: a signal processing module for processing feedbacks of output voltage and voltage drop, and outputting pulse control and directional control signals; a pulse width modulation (PWM) module for outputting pulse signals in response to the control signals from the signal processing module; and a switch rectifying module for switching on and off in response to the pulse signals from the PWM module. The pulse control signal from the signal processing module can be in response to an input current signal from a sense resistor. The circuit is capable of achieving both step-up and step-down voltage conversions.