The characteristics of a class of pulsed quartz oscillators

Chemically etched and plasma etched `VHF´ quartz crystals potentially offer the RF designer a significant advantage over conventional quartz crystals when employed in oscillator configurations. Instead of obtaining a stable VHF or UHF frequency source by multiplication and filtering, oscillation is possible directly at the wanted frequency. For the systems designer this can mean fewer or possibly no frequency multiplication stages to obtain a stable VHF/UHF frequency. Because of low spurious outputs the advantages may well prove significant in the overall RF systems performance. Two potential advantages are the elimination of multiplicative frequency drift and phase noise of the oscillator which increases by {20log×(multiplication factor)}. A real bonus is that harmonic filtering requirements become less critical or indeed filters may be eliminated altogether. In the application considered here, this is an important point because the unavoidable additional loss resulting from filters and the increased component count can be very significant and to be avoided if at all possible, hence the potential attractiveness of `VHF´ crystals