A Phase -Locking Synchronizer for Stabilizing Reflex Klystrons

MICROWAVE signal sources of high fre quency-stability and spectral purity are increasingly important to many fields. These include doppler systems, nuclear spectroscopy measurements, spectrum analyzers, as well as telemetry, radio astronomy, and other com munications-type work. All of these applica tions are characterized by the need for good shortand long-term stability as well as low residual f-m noise over a wide spectrum about the operating frequency. To meet these stability demands, -hp-'s Dymec division has developed a versatile frequency-stabilizing instrument that gives high stability to typical microwave frequency sources. The instrument is a synchronizer which phase locks a reflex klystron to a de sired frequency between 1 and 12.4 gigacycles. The frequency is a harmonic (± the i-f fre quency) of a crystal oscillator in the Synchron izer, and the klystron, when so controlled, pro vides a signal virtually as stable and spectrally pure as the rf crystal reference itself. When thus synchronized, the klystron will have a shortterm stability of 1 /10s (averaged over one sec ond) and a long term stability of 1/10° per week. At the same time residual fm in the klystron due to power supply ripple will be