precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra precision low constant OCK-2S OCXO cut high temperature clock SC noise phase 10Mhz ultra