A method for converting an analog signal to multiple different phase outputs with an analog-to-digital converter is provided. First, the analog signal is converted to a high-frequency datastream with a delta-sigma modulator. A plurality of low-frequency datastreams are then generated by periodically extracting the samples of the high-frequency datastream, wherein consecutively extracted samples of the high-frequency datastream are scattered to different low-frequency datastreams. The low-frequency datastreams have the same sampling rate, and the phases of the corresponding samples of the low-frequency datastreams are different from each other.