Browsing by Author "NAVEEN, KUMAR S"

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    Analysis of Frequency Stability for Temperature Compensated Crystal Oscillator (TCXO)
    (2019-07-22T06:35:07Z) BHAVAN, N; NAVEEN, KUMAR S; PRABHU, K; PRAMOD, KUMAR
    Quartz crystal based oscillators are used as clock sources in the synchronization and synchronization of distributed systems to a common time or frequency scale. One such system is that of a cellular network in which base station transceivers are operated within a specified time or frequency accuracy with reference to a system reference. The accuracy of the entrainment of the distributed clocks to the reference clock is subject to the design of the servo control system. In the event the servo fails the slave clock accuracy is a function of the local environmental and electrical stimuli applied to the clock. As loss of the servo signal is a practical issue in a real system, this ultimate system entrainment accuracy is dependent on the accuracy with which the free running clocks can be corrected. It is the subject of the current paper to review the fundamental physical properties of crystal oscillators and in so doing determine all significant frequency perturbing stimuli. Identification and quantification of these stimuli in terms of analytical expressions is the first stage in the creation of an accurate clock model suitable for compensation of the clock in the absence of the servo signal from the reference. Thus a fundamental understanding of the parameters affecting the clock drift becomes paramount to determining the overall synchronization accuracy achievable by the system. For decades, the quartz crystal has been used for precise frequency control. In the increasingly popular field of wireless communications, available frequency spectrum is becoming very limited, and therefore regulatory agencies have imposed tight frequency stability requirements. There are generally two techniques for controlling the stability of a crystal oscillator with temperature variations of the environment. They are temperature control and temperature compensation.