A signal process device and method is provided to obtain a wobble signal from a set of retrieved signals. The signal process device comprises: an RF amplifier, band-pass filter, and a feedback control module. The RF amplifier generates a mix signal by synthesizing the set of retrieved signals reflected from an optical information recordable medium. The band-pass filter generates a transient-state wobble signal by performing band-pass filtering on the mix signal based on a target frequency. The feedback control module provides that target frequency by receiving the transient-state wobble signal and performing phase-locked loop and frequency dividing operations thereon. The feature and characteristic of the invention resides especially on repeatedly amending the target frequency via the feedback control module. In this setting, the band-pass filter is able to perform band-pass filtering on the mix signal based on the amended target frequency and obtain the desired wobbly signal.