At IMS 2011, Pascall Electronics Ltd. spotlighted its XMN and XMNP low-noise signal sources. Pascall's XMN and XMNP series are designed to provide a range of high performance building blocks for frequency synthesiser designers. They can also be used as stand-alone fixed-frequency signal sources.

The XMN combines a Pascall OCXOF with a frequency multiplier and bandpass filter, to give an output with ≤-80dBc sub-harmonics and exceptionally low noise floor. In addition to the multiplied frequency, an output is provided at the oscillator's frequency. The XMNP adds a phase-locked loop, to enable the module to be locked to an external reference.

Frequency multiplication of low noise signals presents significant design challenges. Care is needed at each stage, to avoid seriously degrading the noise floor or increasing flicker of phase noise. An integrated solution allows optimum interfacing between sections, and relieves system designers of the task of specifying separate oscillators, multipliers and filters. As an example, the 840 MHz output of the XM7P-E-840.0-10.0-15 has typical phase noise of -167 dBc/Hz at 100 kHz offset, which is equivalent to -184 dBc/Hz at the oscillator frequency of 120 MHz.

Because of their very low phase noise floor, the XMN / XMNP series can also offer an alternative to SAW oscillators in many applications, giving an improvement in close-in phase noise. A further advantage is the availability of crystals at custom frequencies, which eliminates the high development cost and lead time associated with non-standard SAW frequencies.

Typical applications:

•Low noise frequency synthesisers

•Phase noise test systems

•Radar and EW


•Scientific research.