Image rejection quadratic filter
AssigneeRfStream Corporation
InventorsTakatsugu Kamata, Kimitake Utsunomiya
Life of this patent
Estimating the term…
Abstract
An image rejection quadratic filter is tunable to filter image frequencies over a wide band. In one embodiment, the image rejection filter includes in-phase and quadrature phase mixers. The image rejection has a fractional transfer function. The image rejection filter has two sub-circuits, wherein the first sub-circuit produces the imaginary component of the transfer function, and the second sub-circuit produces the real component of the transfer function. The first sub-circuit receives the Q signal, and the second sub-circuit receives the I signal. In one embodiment, to create the fractional transfer function, a multi-feedback looped integrator is used.
Claims16
An image rejection filter comprising a transfer function, said filter comprising:
- first sub-circuit for receiving a quadrature-phase signal for filtering and for generating an imaginary component from said quadrature-phase signal;
- second sub-circuit for receiving an in-phase signal for filtering and for generating a real component from said in-phase signal;
- and
- wherein a numerator of said transfer function is factorizable into factor terms that are real only and a denominator of said transfer function is factorizable into factor terms that are complex only.
Dependencies are inferred from the claim text.