HIGH-G TIME BASES

For many military applications, low frequency oscillators (approx 100 Hz) are required which maintain their frequency within 5 parts in 10,000 after they have been exposed to an acceleration of 30,000 g for 100 ms, and also after a storage period of 5 yr. In addition, the same stability must exist over the total military temperature range while a constant acceleration of, say, 5000 g in any direction is applied for about 200 sec. The characteristics of mechanical systems and various electrical circuits proposed for the time bases will be summarized. It will be shown that oscillators, based on the use of RC networks and solidstate negative feedback amplifiers, can fulfill the requirements. It will also be shown that, for cost reduction, the conventional amplitude control over many cycles can be replaced by an instantaneous limiter without detrimental effects on stability. (Author)