Ruislip, UK The Herley-CTI Series PDROs, phase-locked dielectric resonator oscillators, available in the UK from Aspen Electronics , are designed for high reliability, cost critical applications, suiting both commercial and military, satellite and microwave, communications systems. Key features of the PDROs are their small size, extremely low phase noise, no subharmonics and high efficiency, achieved by taking advantage of advanced GaAs MESFET and BJT DRO technology, combined with the standard unit’s ability to phase-lock to an external reference, in the 50 to 300MHz range. In addition to the standard model, two other designs are available. The first features an integrated, high stability, internal crystal oscillator. The second is a dual loop design that is phase locked to an external frequency standard between 5 and 15 MHz. All models use digital synthesis techniques that allow the output frequency to be phase locked to an integer or fractional multiple of the reference used. The dual loop version appeals particularly to the satellite communications sector, where users will typically require to lock on to the supplied 10 MHz reference signal. Operating from 12 or 15V dc power supplies (8V optionally available), the oscillators feature very low power consumption. Output power is +15dBm, with the units also offering low current levels. The low profile devices in the series are particularly compact, with overall dimensions of just 51 x 48 x 16 mm or 51 x 51 x 18.5 mm, depending upon frequency and standard or flush tuner selection. The XPDRO Series of dual loop versions are only slightly larger, at 57 x 57 x 15.75 mm. Both the PDRO and XPDRO are available in the frequency range 3 to 45GHz. Aspen Electronics Ltd , Ruislip, UK. www.aspen-electronics.com.