1. A wireless access system comprising:a center unit; and
a remote unit that is placed in a location away from the center unit, converts a baseband signal generated at the center unit to a high-frequency signal, and emits the high-frequency signal through an antenna, wherein
the center unit comprises a digital baseband that generates the baseband signal, an oscillator that generates a clock signal, and a 1-bit modulator that converts the baseband signal to a 1-bit signal, based on the clock signal, and outputs the 1-bit signal, and
the remote unit comprises a local generation unit that extracts a clock signal from the 1-bit signal output from the center unit and generates a local signal by using the extracted clock signal as a reference signal, a filter that extracts a desired band component from the 1-bit signal, and an up-converter that converts an output signal of the filter to the high-frequency signal by using the local signal.