From few decades frequency control technology has been the heart of modern day electronics due to its huge area of applications in communication systems, computers, navigation and military defense. Frequency control devices provide high frequency stabilities and spectral purities in the short-term domain. Piezoelectric quartz crystal resonators are the backbone of most of the frequency control devices . However, improvement of the performance of these devices, in terms of frequency stability, remains a big challenge for the researchers. It is commonly admitted that the fundamental limitation of the short-term stability of quartz resonators is due to the flicker frequency noise. Reducing noise in order to increase the short term stability is thus very desirable. My research work provides theoretical and experimental investigations of the origin of 1/f noise in BAW quartz resonators. In addition to that, this book provides the idea of a model (with the help of the Fluctuation Dissipation Theorem and Dislocation Motion) of good piezoelectric resonators with better short-term frequency stability for high quality frequency control devices.