Low noise VHF oscillator with circuit matching transistors

Claim 2

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensation transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of said first and second transistors; c. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained, free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and d. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor.

Claim 3

The oscillator circuit as claimEd in claim 1, wherein said first resonant circuit comprises an inductive element and a capacitive element, and said coupling means comprises a transformer whose input coil comprises said inductive element of said first resonant circuit and an output coil coupled to said base terminals of said first and second transistors.

Claim 4

The oscillator circuit as claimed in claim 1, wherein there is included a resistive network for establishing the proper biasing potential signals to be applied to the base terminals to said first and second transistors.

Claim 5

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator compising: a. amplifier transistor means having a first input terminal for determining its output derived from second and third terminals thereof, said amplifier means presenting a variable capacitance characteristic between its first and second terminals; b. compensation transistor means having a variable capacitance characteristic between its first and second terminals substantially identical to that of said amplifier means, and a third terminal; c. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said second terminals of said amplifier means and said compensation means; d. isolation means coupled to said third terminal of said compensation transistor means for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents; and e. means for coupling energy from said first resonant circuit to said amplifier means so that sustained, free oscillation is established in said first resonant circuit, said coupling means applying signals of sustantially equal amplitude but opposite phase to said first terminals of said amplifier means and said compensation means, whereby the dynamic variable capacitance of said compensation means is coupled effectively in a feedback circuit established through said coupling means to said amplifier means.

Claim 6

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator compising: a. amplifier transistor means having a first input terminal for determining its output derived from second and third terminals thereof, said amplifier means presenting a variable capacitance characteristic between its first and second terminals; b. compensation transistor means having a variable capacitance characteristic between its first and second terminals substantially identical to that of said amplifier means, and a third terminal; c. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said second terminals of said amplifier means and said compensation means; d. isolation means coupled to said third terminal of said compensation transistor means for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents; and e. means for coupling energy from said first resonant circuit to said amplifier means so that sustained, free oscillation is established in said first resonant circuit, said coupling means applying signals of sustantially equal amplitude but opposite phase to said first terminals of said amplifier means and said compensation means, whereby the dynamic variable capacitance of said compensation means is coupled effectively in a feedback circuit established through said coupling means to said amplifier means.

Claim 7

An oscillating circuit as claimed in claim 4, wherein said isolation means comprises a capacitor which is further coupled to circuit ground.

Claim 8

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of said first and second transistors; c. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and d. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit ot D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor, said isolation means comprising a capacitor which is further coupled to circuit ground.

Claim 9

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of said first and second transistors; c. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and d. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit ot D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor, said isolation means comprising a capacitor which is further coupled to circuit ground.

Claim 10

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of sAid first and second transistors; c. second resonant circuit coupled to said emitter terminal of said first transistor, including a reference frequency element, whereby the frequency of the resonating signal established through said first transistor is slaved to that of said reference frequency element; d. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and e. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor.

Claim 11

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of sAid first and second transistors; c. second resonant circuit coupled to said emitter terminal of said first transistor, including a reference frequency element, whereby the frequency of the resonating signal established through said first transistor is slaved to that of said reference frequency element; d. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and e. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor.

Claim 12

The oscillator circuit as claimed in claim 7, wherein said reference frequency element comprises a crystal unit.

Claim 13

The oscillator circuit as claimed in claim 7, wherein the reference frequency element comprises an AT-cut overtone crystal unit.

Claim 14

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. a limiting circuit coupled to each of said collector terminals of said first and second transistors, for establishing a range of voltages in which said first and second transistors may be driven without reaching the saturation limits of said first and second transistors; c. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of said first and second transistors; d. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and e. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor.

Claim 15

An oscillator circuit for generating a low noise, high frequency output signal, said oscillator circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. a limiting circuit coupled to each of said collector terminals of said first and second transistors, for establishing a range of voltages in which said first and second transistors may be driven without reaching the saturation limits of said first and second transistors; c. first resonant circuit resonating at a frequency within a prescribed frequency range, said first resonant circuit coupled to said collector electrodes of each of said first and second transistors; d. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transistors; and e. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected in a feedback circuit established through said coupling means to said first transistor.

Claim 16

The oscillator circuit as claimed in claim 10, wherein said limiting circuit includes first and second unidirectional conducting means coupled respectively to low noise power sources of first and second levels, corresponding to the limits of said range.

Claim 17

An oscillator circuit for generating a low noise, high frequency output signal, said oscillation circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said resonant circuit coupled to said collector electrodes of each of said first and second transistors, said first resonant circuit comprising an inductive element and a capacitive element; c. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained, free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transiStors, said coupling means comprising a transformer whose input coil comprises said inductive element of said first resonant circuit and an output coil coupled to said base terminals of said first and second transistors; d. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected to a feedback circuit established through said coupling means to said first transistor; and e. a network coupled to a tap of said transformer and comprising a capacitor disposed between said tap and circuit ground, and a resistor bridge coupled to said tap for applying a biasing signal thereto.

Claim 18

An oscillator circuit for generating a low noise, high frequency output signal, said oscillation circuit comprising: a. a first amplifier transistor and a second compensating transistor, each having base, collector and emitter terminals, said first and second transistors having matched collector-to-base properties; b. first resonant circuit resonating at a frequency within a prescribed frequency range, said resonant circuit coupled to said collector electrodes of each of said first and second transistors, said first resonant circuit comprising an inductive element and a capacitive element; c. means for coupling energy from said first resonant circuit to said first and second transistors so that sustained, free oscillation is established in said first resonant circuit, said coupling means applying signals of substantially equal amplitude but opposite phase to said base electrodes of said first and second transiStors, said coupling means comprising a transformer whose input coil comprises said inductive element of said first resonant circuit and an output coil coupled to said base terminals of said first and second transistors; d. isolation means coupled to said emitter terminal of said second transistor for providing a low A.C. impedance path to circuit ground and for providing an open circuit to D.C. currents, whereby only the dynamic collector-to-base capacitance of said second transistor is effectively connected to a feedback circuit established through said coupling means to said first transistor; and e. a network coupled to a tap of said transformer and comprising a capacitor disposed between said tap and circuit ground, and a resistor bridge coupled to said tap for applying a biasing signal thereto.