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Fast Response YIG Tuned Oscillator

IP.com Disclosure Number: IPCOM000084595D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Owen, FD: AUTHOR

Abstract

The tuning speed of a conventional YIG (yttrium-indium garnet) oscillator 10 is significantly increased by compensation circuit 11.

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Fast Response YIG Tuned Oscillator

The tuning speed of a conventional YIG (yttrium-indium garnet) oscillator 10 is significantly increased by compensation circuit 11.

Oscillator 10 normally has an associated auxiliary tuning coil 12. This FM (frequency modulated) coil 12 is used for phase locking and modulation purposes. Also associated with oscillator 10 is a driver circuit 13 which drives the main tuning coil, not shown, of oscillator 10. In turn, circuit 13 is controlled by an adjustable step voltage applied to input terminal 14.

The output signal frequency present at the output terminal 15 of oscillator 10 is proportional to the input voltage amplitude at terminal 14. In the absence of circuit 11, the slow response of oscillator 10 to changes in the input signal level did not make it useful for certain applications such as, for example, a local oscillator (L0).

Compensation circuit 11 improves the response time of oscillator 10 by a factor of substantially 3 to 1. Its input operational amplifier state U1 is connected to terminal 14. The parameters of the R1,C1 network are selected to optimally match the basic settling time constant associated with the aforementioned main tuning coil of oscillator 10. Operational amplifier U2 and complementary transistors Q1, Q2 are configured as a drive circuit for FM coil 12.

It can be shown that current in coil 12 is determined by the value of resistor R2 and, hence, the frequency shift caused by coil 12 in the output of os...