Wide range electronic oscillator
First Claim
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1. A wideband electronic oscillator having an improved performance at higher frequencies comprising:
- a resonant tank circuit including an inductance means, a main capacitance, and two feedback signal dividing capacitors connected in series with one another for producing oscillations;
a signal amplifier for overcoming losses to sustain oscillations in the tank circuit, said amplifier having an input and a feedback output, said amplifier being connected in a feedback loop for said tank circuit which includes one of said feedback signal dividing capacitors;
a first impedance connected between said feedback output and ground; and
a second impedance including a reactance connected between said feedback signal dividing capacitors and said feedback output for maintaining the phase shift of a feedback signal produced in said feedback loop at the input and output of said amplifier at substantially zero degrees and for reducing noise components near the oscillating frequency, said second impedance having a high value at low frequencies in relation to the first impedance so that the low frequency noise components are dissipated in said first impedance,said second impedance reducing the loading of said first impedance on said tank circuit to raise the Q and thereby improve the stability of the oscillations in said tank circuit.
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Abstract
An oscillator disclosed has a resonant tank circuit inclusive of an inductor (L1), a capacitor (C1), a capacitor (C3) and a capacitor (C4) connected in series with one another. A signal amplifier (A) is connected in a feedback loop which includes capacitor (C3). An additional impedance (C5) is connected between the feedback output of the amplifier and the feedback signal dividing capacitors (C3) and (C4). This additional impedance (C5) improves tuning range, tuning linearity, phase noise performance, and provides a very flat power output at ultra high frequencies.
46 Citations
29 Claims
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1. A wideband electronic oscillator having an improved performance at higher frequencies comprising:
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a resonant tank circuit including an inductance means, a main capacitance, and two feedback signal dividing capacitors connected in series with one another for producing oscillations; a signal amplifier for overcoming losses to sustain oscillations in the tank circuit, said amplifier having an input and a feedback output, said amplifier being connected in a feedback loop for said tank circuit which includes one of said feedback signal dividing capacitors; a first impedance connected between said feedback output and ground; and a second impedance including a reactance connected between said feedback signal dividing capacitors and said feedback output for maintaining the phase shift of a feedback signal produced in said feedback loop at the input and output of said amplifier at substantially zero degrees and for reducing noise components near the oscillating frequency, said second impedance having a high value at low frequencies in relation to the first impedance so that the low frequency noise components are dissipated in said first impedance, said second impedance reducing the loading of said first impedance on said tank circuit to raise the Q and thereby improve the stability of the oscillations in said tank circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29)
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28. A wideband electronic oscillator having an improved tuning range, improved tuning linearity, improved phase noise performance and an improved power output flatness comprising:
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a resonant tank circuit including an inductor, a tuning varactor diode, a blocking capacitor and two feedback signal dividing capacitors connected in series with one another for producing oscillations; a signal amplifier including an active device with three electrodes and an input and a feedback output at two of said three electrodes, said amplifier overcoming losses to sustain oscillations in the tank circuit, said amplifier being connected in a feedback loop for said tank circuit which includes one of said feedback signal dividing capacitors; a first impedance connected between said feedback output and ground; and a capacitor connected between said feedback signal dividing capacitors and said feedback output for maintaining the phase shift of a feedback signal produced in said feedback loop at the input and output of said amplifier at substantially zero degrees and for reducing noise components near the oscillating frequency, said capacitor having a high impedance value at low frequencies in relation to the first impedance so that the low frequency noise components are dissipated in said first impedance, said second impedance reducing the loading of said first impedance on said tank circuit to raise the Q and thereby improve the stability of the oscillations in said tank circuit.
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Specification