Apparatus and methods for invertible sine-shaping for phase interpolation

A method of clock signal generation, the method comprising:

• filtering in-phase and quadrature-phase clock signals to generate sinusoidal in-phase and quadrature-phase clock signals;
• selectively inverting one or both of the in-phase and quadrature-phase clock signals based on an inversion control signal;
• and
• generating an interpolated clock signal based on a weighted sum of the selectively inverted sinusoidal in-phase clock signal and the quadrature-phase sinusoidal clock signal,
• wherein the in-phase clock signal and the quadrature-phase clock signal have a quadrature-phase relationship.

An apparatus for clock signal generation, comprising:

• means for filtering in-phase and quadrature-phase clock signals to generate sinusoidal in-phase and quadrature-phase clock signals;
• means for selectively inverting one or both of the in-phase and quadrature-phase clock signals based on an inversion control signal;
• and
• means for generating an interpolated clock signal based on a weighted sum of the selectively inverted sinusoidal in-phase clock signal and the quadrature-phase sinusoidal clock signal,
• wherein the in-phase clock signal and the quadrature-phase clock signal have a quadrature-phase relationship.