US3873943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-distortion constant-amplitude oscillator
Assignee: US Philips Corp
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Filing: 1973-08-17
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Granted: 1975-03-25
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Expires: 1993-08-17
Abstract
Abstract An oscillator circuit is proposed, which has a low distortion, a good amplitude stability, a very low self-modulation and which is of simple design. For instantaneous variations use is made of an amplifier circuit which operates in the linear region and which has a gain factor which is smaller than is required for undamping, and a source of auxiliary oscillations, which provides the excitation of the oscillator circuit. The constant excitation is preferably derived from the oscillator output voltage.
Inventors
- 👤 Joseph Lodewijk Mari Reijnders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:12
CPC Classifications
H; H03; H03L; H03L5/00; H03B; H03B5/00; H03B5/20; H03B5/26
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
138 words
A low-distortion sinusoidal oscillator, comprising frequency selective means, an amplifier circuit connected thereto having means for compensating for rapid amplitude variations that includes means for operating the amplifier in the linear region of its characteristic and with a gain factor which is smaller than the gain factor required for undamping the frequency selective means to produce sinusoidal oscillations, said oscillator further comprising means coupled to the amplifier circuit for providing a slow-acting amplitude control relative to said rapid amplitude variations, a source of auxiliary oscillations of the same frequency as the sinusoidal oscillations and of constant amplitude, and means connecting said auxiliary oscillation source to the amplifier circuit to provide positive feedback so that the auxiliary oscillation source, in conjunction with the slow-acting amplitude control means, determines the value and stability of the amplitude of the sinusoidal oscillations.
Claim 2
Dependent Claim
138 words
A low-distortion sinusoidal oscillator, comprising frequency selective means, an amplifier circuit connected thereto having means for compensating for rapid amplitude variations that includes means for operating the amplifier in the linear region of its characteristic and with a gain factor which is smaller than the gain factor required for undamping the frequency selective means to produce sinusoidal oscillations, said oscillator further comprising means coupled to the amplifier circuit for providing a slow-acting amplitude control relative to said rapid amplitude variations, a source of auxiliary oscillations of the same frequency as the sinusoidal oscillations and of constant amplitude, and means connecting said auxiliary oscillation source to the amplifier circuit to provide positive feedback so that the auxiliary oscillation source, in conjunction with the slow-acting amplitude control means, determines the value and stability of the amplitude of the sinusoidal oscillations.
Claim 3
Dependent Claim
42 words
An oscillator as claimed in claim 1, wherein one input of the source of auxiliary oscillations is connected to an output of the amplifier circuit and one output of the auxiliary oscillation source is connected to an input of the amplifier circuit.
Claim 4
Dependent Claim
67 words
An oscillator as claimed in claim 2, wherein the source of auxiliary oscillations comprises a resistor connected to the input of the auxiliary oscillation source and to two diodes connected in anti-parallel to a point of reference potential, said diodes operating symmetrically to provide instantaneous limiting action, and means connecting the junction of the resistor and the diodes to the output of the source of auxiliary oscillations.
Claim 5
Dependent Claim
60 words
An oscillator as claimed in claim 1 wherein said frequency selective means is connected between the output and the input of the amplifier circuit to form a feedback loop and said auxiliary oscillation source includes an amplitude limiter and means coupling the input and output of the auxiliary oscillation source to the output and input, respectively, of the amplifier circuit.
Claim 6
Dependent Claim
74 words
An oscillator as claimed in claim 1 wherein said frequency selective means comprises a Wien bridge circuit connected between the output and the input of the amplifier circuit to form a feedback loop and said auxiliary oscillation source comprises a resistor connected in series with a pair of anti-parallel connected diodes across the output of the amplifier circuit with the junction of said resistor and diodes connected to an input of the amplifier circuit.
Claim 7
Dependent Claim
138 words
An oscillator for producing sinusoidal oscillations of low distortion and with a constant, stable and fast setting amplitude comprising, frequency selective means, an amplifier circuit connected thereto to form a feedback loop therewith and having a linear amplifying characteristic for instantaneous oscillation amplitude variations, means coupled to the amplifier circuit for providing a slow-acting amplitude control for the oscillations, a source of auxiliary oscillations connected to the amplifier circuit with oscillations of the same frequency and phase as the sinusoidal oscillations and of constant amplitude, means including the slow-acting amplitude control in conjunction with the auxiliary oscillation source for adjusting the amplifier circuit to an operating point such that the gain factor of the amplifier circuit at the operating point is smaller than the gain factor required for undamping the frequency selective means to produce said sinusoidal oscillations.
Claim 8
Dependent Claim
138 words
An oscillator for producing sinusoidal oscillations of low distortion and with a constant, stable and fast setting amplitude comprising, frequency selective means, an amplifier circuit connected thereto to form a feedback loop therewith and having a linear amplifying characteristic for instantaneous oscillation amplitude variations, means coupled to the amplifier circuit for providing a slow-acting amplitude control for the oscillations, a source of auxiliary oscillations connected to the amplifier circuit with oscillations of the same frequency and phase as the sinusoidal oscillations and of constant amplitude, means including the slow-acting amplitude control in conjunction with the auxiliary oscillation source for adjusting the amplifier circuit to an operating point such that the gain factor of the amplifier circuit at the operating point is smaller than the gain factor required for undamping the frequency selective means to produce said sinusoidal oscillations.
Claim 9
Dependent Claim
41 words
An oscillator as claimed in claim 6 wherein the output of the auxiliary oscillation source is connected to the input of the amplifier circuit and said frequency selective means is connected between the output and the input of the amplIfier circuit.
Claim 10
Dependent Claim
32 words
An oscillator as claimed in claim 7 wherein said slow-acting amplitude control means includes a resistor having a selected non-linear temperature coefficient of resistance connected to the input of the amplifier circuit.
Claim 11
Dependent Claim
43 words
An oscillator as claimed in claim 7 wherein the input of the auxiliary oscillation source is connected to the output of the amplifier circuit, and said auxiliary oscillation source includes an amplitude limiter for oscillations received from the output of the amplifier circuit.
Claim 12
Dependent Claim
77 words
An oscillator as claimed in claim 7 wherein said frequency selective means comprises a Wien bridge circuit with first and second output terminals connected to first and second input terminals respectively of the amplifier circuit to supply thereto a positive feedback voltage that is frequency dependent and a negative feedback voltage that is frequency independent, respectively, and said auxiliary oscillation source provides positive feedback oscillations that support the oscillations produced at the output of the amplifier circuit.
References Cited (Backward Citations)
US3339156A
Cited
US3137826A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |