Temperature compensator for a crystal oscillator

Claim 1

An improved temperature compensator for use with a crystal oscillator operating in a cold range, a middle range, and a hot range of temperature, said oscillator having at least one middle range negative temperature characteristic capacitor, and having at least one voltage sensitive capacitor, said improved temperature compensator comprising: a. first and second source terminals adapted to be connected to a source of direct current; b. first and second output terminals adapted to be connected to the voltage sensitive capacitor in an oscillator; c. means connecting said second source terminal to said second output terminal; d. a middle range temperature compensating circuit comprising: 1. first and second substantially equal resistors connected in series between said first and second source terminals; 2. means connecting the junction of said first and second resistors to said first output terminal; e. a cold range termperature compensating circuit comprising: 1. a first transistor having an emitter, a base, and a collector; 2. a first resistor having an inverse resistor-temperature characteristic; 3. means connecting the emitter-collector path of said first transistor and said first resistor in series between said first and second source terminals; 4. means connected from said first and second source terminals to said base of said first transistor for applying a selected bias voltage thereto; 5. a second transistor having an emitter, a base, and a collector; 6. a second resistor; 7. means connecting said second resistor and the emittercollector path of said second transistor in series between said first source terminal and said first output terminal; 8. means connecting said base of said second transistor to the junction of said emitter-collector path of said first transistor and said first resistor; 9. means connected to the junction of said second resistor and said emitter-collector path of said second transistor for deriving a first blocking signal from said cold range termperature compensating circuit; f. a hot range temperature compensating circuit comprising: 1 a third resistor having inverse resistor-temperature characteristics; 2. means connecting said third resistor in series between said fiRst and second source terminals; 3. a fourth transistor having an emitter, a base, and a collector; 4. a fourth resistor; 5. means connecting the emitter-collector path of said fourth transistor and said fourth resistor in series between said first output terminal and said second source terminal; 6. means connecting said base of said fourth transistor to said third resistor; 7. means connected to the junction of said fourth transistor and said fourth resistor for deriving a second blocking signal from said hot range temperature compensating circuit; g. means for connecting said cold range temperature deriving means to said base of said fourth transistor for applying said first blocking signal thereto; h. and means for connecting said hot range temperature deriving means to said base of said second transistor for applying said second blocking signal thereto.