a baseband receiver using a transition trigger and a method thereof are disclosed . the baseband receiver is provided in a radio frequency identification reader in order to receive a pulse amplitude modulation signal , and can improve a bit error rate performance by mapping transition waveforms generated whenever the received signal is triggered on new symbols , and filtering the new symbols to recover to the original symbols . since no complex and high performance dc drift estimator is required and dc drifts can stably be removed along with white noise among noise components , it is possible to improve ber .