  Over the past decade, fiber based frequency dissemination has achieved
significant progresses in following aspects. To study the dissemination
stability and phase noise specifications of the fiber-cascaded RF frequency
dissemination system, we perform a lab-top experiment using three sets of RF
modulated frequency dissemination systems. They are linked by 50 km + 50 km +45
km fiber spools. The dissemination stabilities of each segments and whole
system are measured simultaneously. After that, the phase noise of each segment
is also measured and the result shows that the phase noise spectrums of
recovered frequency signal can be optimized via narrow band phase lock loop.
