摘要 |
An apparatus and method for stabilizing the frequency of a piezoelectric crystal resonator, especially useful in common emergency positioning radio beacons. A temperature compensated crystal oscillator circuit (TCXO) (20) is mounted on one surface of a thin substrate. The TCXO includes a piezoelectric device compensation network to reduce the frequency fluctuations of the crystal through variations in temperature. A heating circuit (25) is mounted to the opposing surface of the substrate, thereby providing a thermal connection between the two circuits. The heating circuit includes a temperature sensor (70) for sensing changes in ambient temperatures and a heater control amplifier (60) for adjusting the power of a heating element. The substrate with the two circuits disposed thereon is suspended within a hermetically sealed enclosure by a plurality of support pins. The crystal oscillator is therefore maintained within a certain temperature range while temperatures at which activity dips often occur are avoided.
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