Low-Noise Oscillators for Airborne Radar Applications. Revision 1
Abstract
Vibration-induced phase noise can change the probability of detection of moving-target indicator (MTI) radar from near-100 percent to zero. Oscillators that are capable of meeting the requirements of MTI radar systems in a quiet environment are readily available. In the vibrating environments of airborne platforms, however, the phase noise of oscillators degrades very significantly. For example, a 10-MHz crystal oscillator may have a phase noise of -140 dBc/Hz, 100 Hz from the carrier. Assuming a typical one part per billion per g acceleration sensitivity, this phase noise degrades to -93 dBc/Hz under a 0.1 sq g/Hz random vibration at 100 Hz away from the carrier. If there is a 1g sinusoidal vibration at 100 Hz, there will be a pair of -86 dBc spectral lines superimposed on the signal. Of course, upon multiplication to 10 GHz, the phase noise increases by at least another 60 dB. This report reviews the causes and effects of acceleration sensitivity of bulkwave quartz crystal resonators, and the methods that reduce or compensate for that sensitivity. Most of what is discussed is equally relevant to surface acoustic wave (SAW), shallow bulk acoustic wave (SBAW), dielectric resonator-oscillators (DRO), and other types of oscillators.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1993
- Accession Number
- ADA269372
Entities
People
- John R. Vig
- Raymond L. Filler