Noise reduction device

摘要

A passive noise reduction device may be used with an instrument having at least one electromagnetic pickup. The device may include a device coil wound so as to form at least one free-shaped ring, a first terminal for connection to the pickup coil, and a second terminal for connection to ground. The device coil is responsive to the one or more stimuli so as to produce a noise electrical signal component in the device coil. The pickup coil and the device coil are in substantially the same plane. The noise reduction device coil is wound such that the pickup noise electrical signal component is substantially 180° out of phase with respect to the device noise electrical signal component, and such that the device noise electrical signal component destructively interferes with the pickup noise electrical signal component so as to reduce noise in a resultant electrical signal into the output circuit.

主权项

1. A passive noise reduction device for use with an instrument having one or more strings, the instrument including at least one electromagnetic pickup including at least one coil, the pickup responsive to vibration of at least one string so as to produce a music electrical signal component in the pickup coil and responsive to one or more stimuli in addition to the string vibration so as to produce a noise electrical signal component in the pickup coil, a first terminal of the pickup coil for connection to an output circuit, a second terminal of the pickup coil for connection to the device, the noise reduction device including:
a device coil including a conductor, wherein the conductor is wound so as to form at least one free-shaped ring, a first terminal of the device coil for connection to the second terminal of the pickup coil, a second terminal of the device coil for connection to ground, the device coil responsive to the one or more stimuli so as to produce a noise electrical signal component in the device coil, wherein the conductor substantially accords with formula:8⁢⁢ρ⁢⁢LA=R, where: ρ is resistivity of the conductor, L is length of the conductor, A is cross-sectional area of the conductor, and R is resistance of the pickup coil, wherein the pickup coil and the device coil are in substantially the same plane, and wherein the noise reduction device coil is wound such that the pickup noise electrical signal component is substantially 180° out of phase with respect to the device noise electrical signal component, and such that the device noise electrical signal component destructively interferes with the pickup noise electrical signal component so as to reduce noise in a resultant electrical signal into the output circuit.