Improved Reference Sources for Low-Bit Error Rate Communication In Digital Wireless and Fiber Optic Systems

A fundamental component responsible for low bit error rate (BER) is the phase jitter of the frequency reference source, regardless if a network is wireless or fiber optic in nature. In the case of wireless the frequency reference source is typically a voltage controlled oscillator (VCO), and in the fiber optic case it is a clock. In order to maximize the full benefit of spread spectrum techniques, such as code division multiple access (CDMS), frequency hopping in secure communications, or allowing a high number of users to occupy the same frequency band , the BER must be kept to an acceptable level. Phase I work will primarily concentrate on devloping and measuring prototype reference sources that can satisfy the phase jitter and phase noise requirements required by high speed digital wireless and fiber optic systems. When defining a reference source, digital designers tend to specify phase jitter while RF engineers use phase noise. Although phase jitter and phase noise are related, they are not interchangeable in a casual sense. Therefore, part of Phse I will also be devoted to defining relationships between these parameters, allowing the reference sources developed to be characterized in a meaningful way. Anticipated Military Benefits/Potential Commercial Applications of the Research or Development: This effort will result in significantly better understanding of frequency reference sources capable of meeting phase noise and phase jitter performance requirements in dual use high digital data rate applications. Prototype sources investigated in Phase I will result in commercially available sources in Phase II.