Phase noise comparison for 60 MHz and 120 MHz OCXOs with different multiplication configurations

Modern Communication Systems for Defense, Aerospace, Industrial and Commercial Applications require reference sources with very good phase noise like OCXOs. 60MHZ and 120MHz OCXOs are widely used for Defense and Radar applications. OCXOs are developed using different types of crystal frequencies and are multiplied to achieve the desired output frequency. To make 60MHz OCXO, crystals with frequencies of 20MHz, 30MHz and 60MHz are used and multiplied by x3, x2 and x1 respectively. For 120 MHz OCXO, 60 MHz crystal is used and multiplied by x2. Phase Noise comparison data for the above OCXOs at Close-in and at Floor Phase Noise for these oscillators were studied. Choice of OCXO configurations depends on the performance and the cost. This paper focuses mainly on the close-in phase noise with respect to the crystal parameters than on the floor noise.