摘要 |
Apparatus and methods for quadrature clock signal generation are provided. In certain implementations, a quadrature clock signal generator includes a sine-shaping filter and a polyphase filter. The sine-shaping filter can receive an input clock signal such as a square or rectangular wave and can filter the input clock signal to generate a sinusoidal clock signal. Additionally, the polyphase filter can use the sinusoidal clock signal to generate in-phase (I) and quadrature-phase (Q) clock signals, which can have a phase difference of about ninety degrees. In certain configurations, the in-phase and quadrature-phase clock signals generated by the polyphase filter can be buffered by a buffer circuit to generate in-phase and quadrature-phase sinusoidal reference clock signals suitable for use in a clock and data recover (CDR) system. |