Analog TCXO using one chip LSI for mobile communication

The current type analog TCXO using resistor and thermistor does not have granular noise. So, phase noise is satisfactory. On the other hand, for an analog TCXO it is hard to realize an automatic adjustment process, because it requires replacement of the resistors. To achieve an automatic adjustment process in the analog method, we have developed an LSI for analog TCXOs which has an analog cubic function generator and a PROM to memorize coefficients of the cubic function generator and oscillation circuit. We have developed also a TCXO using LSI, an algorithm for the adjustment of temperature characteristics and a measurement system. We have established an assembly process, TC-adjustment process and an inspection process for multiple-cavity substrates. Therefore we have realized automatic adjustment of temperature characteristics using an analog TCXO for mass-production