Oscillator with two quartz crystals and transistor - has oscillator and frequency mixer producing sum and difference signals

摘要

The quartz crystal oscillator has the working point of its transistor (31) chosen so that with the aid of an excitation circuit two crystal frequencies are generated simultaneously. The transistor also forms part of a mixer for these two frequencies and is coupled to an amplitude stabilising circuit (2). The two frequencies are produced by two quartz crystals (51,53) connected into the transistor base circuit. The sum and difference signals obtained by mixing are set by damping one of the crystals before sealing the shared housing containing both of them.