After reviewing the pros and cons of various approaches, the decision was made to go with a beat frequency oscillator (BFO) circuit. It’s not the greatest design, it might even be the worst ...

US firm OEwaves recently introduced an oscillator design based on the ... the spectral purity of the beat frequency is extremely high. Because optically transparent crystals such as calcium ...

In the quest for an accurate frequency standard there ... Back in the day such an oscillator would have been calibrated by generating an audible beat with a broadcast standard such as WWV, but ...