NDK Develops VCXO with Low Phase Jitter Improving Signal Quality of Optical Communication Networks
Miniaturization of devices is required at high-speed wireless broadband networks and base stations for mobile communications from the perspective of establishing low-cost installations and operation. High frequency clock signals between 600 MHz to 700 MHz are required for the optical transmission devices and optical multiple-wavelength transmission devices used in these base stations and core networks.
In order to meet the market requirements, NDK has developed the “NV7050SA” VCXO. It handles high frequency and has a small package, 7.0 × 5.0mm (one-tenth volume compared to the conventional products) while maintaining the same frequency stability and pull-ability range as the conventional products. Furthermore, ultralow phase jitter is achieved at a few tens of femtoseconds, which is an order of magnitude lower than previously developed products.
PLL frequency multiplication is generally used to obtain high frequencies in the range of hundreds of MHz, however the drawback is phase jitter is magnified during this process which can significantly degrade the quality of transmission signals. Through NDK's proprietary technical knowledge, high frequency fundamental crystal units were designed and applied to obtain high frequencies without the need for PLL frequency multiplication processing. This has enabled the phase jitter to reduce to values of one quarter to one fifth the level of phase jitter produced by conventional PLL multiplication type VCXO.
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