A signal generator may include a reference horizontal synchronization signal generation block which generates reference horizontal synchronization signals based on a number of clock signals per a horizontal time, a frame clock calculation block which calculates a first frame clock number based on a number of the clock signals per the horizontal time, a frame clock comparation block which calculates a clock offset by comparing the first frame clock number and a second frame clock number generated based on a number of the clock signals per a frame time, a clock distribution block which generates horizontal synchronization signals by distributing a number of the clock signals corresponding to the clock offset to the reference horizontal synchronization signals, and a vertical synchronization signal generation block which generates a vertical synchronization signal based on the horizontal synchronization signals.