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Operating at fixed frequencies in the 300MHz to 22GHz range the APL-02 series of fundamental frequency phase locked oscillators provide a low noise and stable local oscillator input for frequency converters in satellite communications, radar, radio astronomy and other high specification applications.The oscillators are either coaxial resonator based for frequencies up to 3.0 GHz and dielectric resonator based for frequencies above 3.0GHz, using low noise silicon bipolar active devices in the former and GaAs FETs or MMICs in the latter.

The use of fundamental frequency architecture has the double benefit of driving down phase noise and minimising physical size. For example, a 4GHz unit achieves considerably better than -110dBc/Hz phase noise at 10KHz offset from the carrier with a typical floor close to -140dBc/Hz. Using an internal reference the “close in” phase noise is better than -64dBc/Hz at 100Hz offset and can be improved further by the use of an external ultra low phase noise OCXO reference.

The spectral purity performance also features harmonics typically below -25dBc and non-reference related spurious rejection greater than 80dBc. Buffer amplifiers in the output line allow operation into load VSWRs of 2.5:1 whilst providing in excess of +13dBm and the input d.c. line is regulated for operation from +11 to +16 volts with a current draw of 300mA maximum.

The compact size of a standard unit with either internal or external reference is just 57 x 57 x 16mm. Connectors are SMA female as standard and, where an internal reference is used, this frequency is provided as an output for possible use elsewhere in the system.