Amplitude stabilized oscillator circuit

Claim 2

An amplitude-stabilized sine-wave oscillator circuit comprising: a sine-wave oscillator for producing a sinusoidal output signal the amplitude of which is controllable by a control current supplied to the Sine-wave oscillator, which includes a transformer, and a pair of transistors with emitter-collector electrodes in push-pull connection to control current flow through a winding of the transformer, the transistors further having base electrodes which are connected to receive the supplied control current and operate at a substantially common potential; converter means connected to the oscillator to receive a sinusoidal signal representative of the amplitude of the output signal, and to generate a DC signal representative of such signal; a reference-signal source providing a constant-amplitude DC reference signal; and amplifying means connected to the converter means and referencesignal source for producing a control current representative of any difference in level between the two DC signals, the amplifying means being further connected to the bases of the pair of transistors to supply substantially all of the produced control current thereto.

Claim 3

The circuit defined in claim 1 wherein the transformer includes first and second windings each having three terminals including a center-tap terminal with the center-tap terminals serving as power input terminals and with the first winding being connected in series-circuit relationship between the emitter electrodes of the pair of transistors and with the second winding being connected in series-circuit relationship between the collector electrodes of the pair of transistors; and including a reactive element connected across the transformer for determining the frequency of the sinusoidal signal produced by the oscillator.

Claim 4

An amplitude-stabilized oscillator circuit for driving a transducer, comprising: first and second power-input terminals; an oscillator which includes a transformer with primary-winding input terminals, a primary center-tap terminal, secondary-winding output terminals, a secondary center-tap terminal coupled to the first power terminal, and means connecting the primary center-tap terminal to the second power terminal; a frequency-determining reactive element connected across the transformer; and a pair of alternately conducting transistors connected in push-pull relationship with the transformer primary winding, each transistor having emitter-collector electrodes connected between respective primary and secondary input and output terminals, the transistors having base electrodes which are connected together so as alternately to receive a control current for controlling amplitude of a sinusoidal oscillating output signal at the secondary output terminals; a reference-signal source connected across the power-input terminals and providing a constant-amplitude DC reference signal; and third and fourth transistors having interconnected emitter electrodes, the third transistor having a collector electrode connected to the second power terminal, and R-C network connected between the interconnected emitter electrodes and the secondary center-tap terminal, means connecting the transformer secondary to a base electrode of the third transistor, means connecting a base electrode of the fourth transistor to the reference-signal source to receive the reference signal, and means connecting a collector electrode of the fourth transistor to the interconnected base electrodes of the pair of transistors in the oscillator, the third and fourth transistors functioning as an amplifier to provide a control current substantially all of which flows through the fourth-transistor and collector electrode, and an alternate one of the pair of alternately conducting transistors, the control current being related in amplitude to any difference in amplitude between the reference signal and a DC signal representative of oscillator output-signal amplitude and derived through the interconnection of the R-C network, third transistor and transformer secondary.

Claim 5

An amplitude-stabilized oscillator circuit for driving a transducer, comprising: first and second power-input terminals; an oscillator which includes a transformer with primary-winding input terminals, a primary center-tap terminal, secondary-winding output terminals, a secondary center-tap terminal coupled to the first power terminal, and means connecting the primary center-tap terminal to the second power terminal; a frequency-determining reactive element connected across the transformer; and a pair of alternately conducting transistors connected in push-pull relationship with the transformer primary winding, each transistor having emitter-collector electrodes connected between respective primary and secondary input and output terminals, the transistors having base electrodes which are connected together so as alternately to receive a control current for controlling amplitude of a sinusoidal oscillating output signal at the secondary output terminals; a reference-signal source connected across the power-input terminals and providing a constant-amplitude DC reference signal; and third and fourth transistors having interconnected emitter electrodes, the third transistor having a collector electrode connected to the second power terminal, and R-C network connected between the interconnected emitter electrodes and the secondary center-tap terminal, means connecting the transformer secondary to a base electrode of the third transistor, means connecting a base electrode of the fourth transistor to the reference-signal source to receive the reference signal, and means connecting a collector electrode of the fourth transistor to the interconnected base electrodes of the pair of transistors in the oscillator, the third and fourth transistors functioning as an amplifier to provide a control current substantially all of which flows through the fourth-transistor and collector electrode, and an alternate one of the pair of alternately conducting transistors, the control current being related in amplitude to any difference in amplitude between the reference signal and a DC signal representative of oscillator output-signal amplitude and derived through the interconnection of the R-C network, third transistor and transformer secondary.

Claim 6

An amplitude-stabilized sine-wave oscillator circuit comprising: an amplitude-controllable sine-wave oscillator including a resOnant circuit having first and second terminals; two transistors each having a collector electrode, a base electrode, and a base-emitter junction; the collector electrodes being coupled to respective terminals; the base electrodes being coupled together to operate at a substantially common potential; positive feedback means for causing the two transistors alternately to conduct current through their collector electrodes and to develop a substantially sinusoidal output voltage between the first and second terminals the amplitude of which is controllable by control current carried by the base-emitter junctions; converter means connected to the oscillator to receive a sinusoidal signal representative of the amplitude of the output voltage, and to generate a DC signal representative of such signal; a reference-signal source providing a constant-amplitude DC reference signal; differential amplifier means having first and second inputs and an output, the first input being connected to the converter means, the second input being connected to the reference signal source, the differential amplifier means conducting through its output a variable-magnitude current that varies in accordance with any varying differences in voltage level between the two DC signals; and means for conducting substantially all of the variable-magnitude current to the base electrodes to serve as the control current carried by the base-emitter junctions.

Claim 7

An amplitude-stabilized sine-wave oscillator circuit comprising: an amplitude-controllable sine-wave oscillator including a resOnant circuit having first and second terminals; two transistors each having a collector electrode, a base electrode, and a base-emitter junction; the collector electrodes being coupled to respective terminals; the base electrodes being coupled together to operate at a substantially common potential; positive feedback means for causing the two transistors alternately to conduct current through their collector electrodes and to develop a substantially sinusoidal output voltage between the first and second terminals the amplitude of which is controllable by control current carried by the base-emitter junctions; converter means connected to the oscillator to receive a sinusoidal signal representative of the amplitude of the output voltage, and to generate a DC signal representative of such signal; a reference-signal source providing a constant-amplitude DC reference signal; differential amplifier means having first and second inputs and an output, the first input being connected to the converter means, the second input being connected to the reference signal source, the differential amplifier means conducting through its output a variable-magnitude current that varies in accordance with any varying differences in voltage level between the two DC signals; and means for conducting substantially all of the variable-magnitude current to the base electrodes to serve as the control current carried by the base-emitter junctions.

Claim 8

The circuit as defined in claim 4 including a transformer having first and second windings, and a reactive element; the first winding being connected in series circuit relationship between the two terminals and in parallel circuit relationship with the reactive element to form the resonant circuit; the second winding being connected in series-circuit relationship between emitter electrodes of the two transistors to form the positive feedback means.