Profile: Precision Devices, Inc. is a manufacturer of crystal frequency control devices. Our crystal filters and oscillators are used for complex radio, RF/microwave, GPS, instrumentation and mil-aero applications. Our spread spectrum crystal clock oscillator is an oscillator that has the output frequency modulated in order to reduce EMI on the output signal. Frequency sources such as quartz crystal oscillators, phase lock loop (PLL) synthesisers and other types of clock signal generation are a major source of EMI in electronic circuits.