High thermal gain oven

摘要

An oven assembly for a crystal resonator and oscillator utilizes a thermally symmetrical design to provide a high thermal gain. The oven assembly includes an encasement (20, 22) that forms a hermetically sealed oven chamber (24) that is substantially cylindrical. Concentric with the oven chamber is an annular oven mass (34) that functions as a heat reservoir for the crystal resonator (36) that is contained within the oven mass. The cylindrical oven chamber (24) and the concentric annular oven mass (34) provide two levels of circular symmetry that help achieve a thermally isotropic oscillator environment. Wide-area uniform heat transfer promotes high thermal gain and minimizes thermal gradients. Another factor is the geometry and circuitry for temperature monitoring. Temperature sensors (42, 44, 50) are equidistantly spaced from each other and are equidistant from the center of the oven chamber (24). Signals from the various temperature sensors, e.g. thermistors are averaged to provide a more accurate temperature determination for regulating the heaters