Temperature controlled crystal oscillator arrangement
First Claim
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1. A temperature compensated crystal oscillator arrangement, comprisinga crystal oscillator circuit including an oscillator crystal and having a frequency selective positive feedback path incorporating a frequency pulling control element;
- anda temperature sensitive compensation circuit so connected to said feedback path as to drive said control element and includingtemperature sensing means operative for issuing an electrical output signal that is a monotonically varying function of temperature,power series function generator means connected to said temperature sensing means to receive said output signal therefrom and operative for generating a series of outputs that represent the terms of a Chebyshev-like polynomial function, the orders of the terms increasing from zero to the number of outputs less one,summing amplifier means having a plurality of inputs each receiving one of said outputs of said power series function generator means and operative for providing an output signal that is a weighted sum of said outputs of said power series function generator means, andmeans for applying said output of said summing amplifier means to said feedback path so as to drive said control element.
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Abstract
A temperature compensated crystal oscillator in which the base emitter voltage of transistors in an integrated circuit is used to provide substantially linearly temperature sensitive outputs which are employed to generate a series of polynomial functions of Chebyshev-like form which are summed and used to control a varicap diode in the oscillator feedback path.
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Citations
15 Claims
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1. A temperature compensated crystal oscillator arrangement, comprising
a crystal oscillator circuit including an oscillator crystal and having a frequency selective positive feedback path incorporating a frequency pulling control element; - and
a temperature sensitive compensation circuit so connected to said feedback path as to drive said control element and including temperature sensing means operative for issuing an electrical output signal that is a monotonically varying function of temperature, power series function generator means connected to said temperature sensing means to receive said output signal therefrom and operative for generating a series of outputs that represent the terms of a Chebyshev-like polynomial function, the orders of the terms increasing from zero to the number of outputs less one, summing amplifier means having a plurality of inputs each receiving one of said outputs of said power series function generator means and operative for providing an output signal that is a weighted sum of said outputs of said power series function generator means, and means for applying said output of said summing amplifier means to said feedback path so as to drive said control element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15)
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14. A temperature compensated crystal oscillator arrangement, comprising:
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a crystal oscillator circuit including an oscillator crystal and having a frequency selective positive feedback path incorporating a frequency pulling control element; a temperature sensitive compensation circuit so connected to said feedback path as to drive said control element and including; temperature sensing means operative for issuing an electrical output signal that is a monotonically varying function of temperature; power series function generator means connected to said temperature sensing means to receive said output signal therefrom and operative for generating a series of outputs that represent the terms of a polynomial function, the orders of the terms increasing from zero to the number of outputs less one; summing amplifier means having a plurality of inputs each receiving one of said outputs of said power series function generator means and operative for providing an output signal that is a weighted sum of said outputs of said power series function generator means; and means for applying said output of said summing amplifier means to said feedback path so as to drive said control elements; said temperature sensing means, said power series function generator means and said summing amplifier means including active components that are provided on at least one integrated circuit; and said temperature sensing means including circuitry adapted to provide first and second substantially linear temperature coefficient current output signals whose coefficients are respectively positive and negative with the modulus of the first coefficient being substantially equal to that of the second, both signals being derived from the temperature characteristic of the base emitter voltages of elements of the at least one integrated circuit.
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Specification