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Signal Generator and Attenuation circuit board The board uses an Atmel AT32UC3A0512 µprocessor with an Ethernet port, USB, and SPI interfaces. The SPI interface is primarily used to communicate with the Little Nik Controller-Attenuator. The frequency generator, AD9832, the DAC’s, AD5680, and the relay drivers, MAX4820, are parts on the board and all use the SPI port addresses as outlined in the specifications document. There is a computer running the user interface software (GUI) that is connected to the microprocessor via an Ethernet interface. The signal generator produces the precise amplitude for the desired magnetic field. The generator is capable of 1 millivolt to 4 volts amplitude generation into a 1000-ohm load termination. The attenuator uses the signal produced by the generator to drive the coils of the resonator. The attenuation circuit uses the signal produced by the generator to drive the Helmholtz coils. The circuitry is custom designed to provide impedance matching to the generator and selectable attenuation of the signal. The attenuation range is from 10 milli gauss to 1 nano gauss by combining the generator range and the attenuator selection ranges. Circuitry within the unit provides for continuity verification after assembly of the system to confirm a complete circuit for the signal generator. The magnetic fields are produced by simplified Helmholtz coils. The coils are 7 feet in diameter with a separation of 3 ½ feet. The coils’ uniformity, density, wire gauge, current and voltage were determined by the requirements to produce the required magnetic fields as defined by the foregoing signal parameter’s intended use. The system to be used in this study includes a fiberglass platform with steps for the subject to walk up and mount the platform. Handrails serve to provide stability as the subject walks up the steps to the platform. The coils are fiberglass rings with copper wire wound around an end groove. Because of the size of the coils, a support connects one coil to the other coil, to provide stability, and the coils are mounted onto the platform through coil supports. No ferrous metals are used in the construction of the Resonator™ device. |
4700 140th Ave. N., Suite 101 • Clearwater, FL 33762 • 727-474-3722 |
