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RC Sine Wave Oscillator

IP.com Disclosure Number: IPCOM000078440D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Buckley, F: AUTHOR [+2]

Abstract

Adjustable oscillator 10 provides a sine-wave output signal Vo. It Provides simultaneously excellent waveform quality, frequency stability and frequency tuning characteristics over a wide frequency range.

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RC Sine Wave Oscillator

Adjustable oscillator 10 provides a sine-wave output signal Vo. It Provides simultaneously excellent waveform quality, frequency stability and frequency tuning characteristics over a wide frequency range.

Negative feedback loop 11 is formed by resistors R1, R2, capacitors C1, C2 and differential amplifiers 1, 2. Loop 11 is a highly frequency selective system with the following parameters: (1) Q = [(R1C1)/(R2C2)]/1/2/ ; and

(2) Wc = [R1C1R2C2]/-1/2/ where Q = figure of merit (to 30 or higher) Wc = center frequency.

The transfer function Vo/I, where Vo is the output voltage at terminal 12 and I is the current passing through resistor R6, together with resistors R3, R4. R5, R6 and differential amplifier 3 provide the positive feedback for oscillator 10.

Block 4, which has the idealized waveform characteristic shown in Fig. 2, represents a nonlinearity introduced to limit the amplitude of current I. By way of example, block 4 may be a diode limiter circuit.

Frequency adjustment is made by varying R2. The amplitude of the output signal Vo remaining substantially constant over a wide frequency range when R2 is varied. Thus, frequency tuning is simplified by adjustment of a single parameter, viz the resistance of R2.

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