A method of modulating and demodulating a signal includes modulating data information included in an input data signal provided from an external source and clock information included in an input clock signal provided from the external source into a transmission signal, using (n+1) delay clock signals generated based on the input clock signal, where n is a natural number. The transmission signal is demodulated into an output clock signal including restored clock information and an output data signal including restored data information, using (m+1) delay clock signals generated based on the clock information, where m is a natural number less than n.