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# Amplification of Side Bands by a Power Sensitive Impedance

IP.com Disclosure Number: IPCOM000096080D
Original Publication Date: 1964-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 34K

IBM

## Related People

Nethercot, AH: AUTHOR

## Abstract

When power at a pump frequency omega(p), having two side bands whose frequencies are omega(p) + delta and omega(p) - delta, is incident on an impedance in a transmission line, the power absorbed by such impedance varies at the difference frequency. If the magnitude of the impedance is sensitive to the power absorbed by the impedance, the resulting changes in impedance alter the amount of power reflected from or transmitted through such impedance. Such impedance changes at the difference frequency act on the pump frequency so that power is transferred from the pump frequency to the side band frequencies. Thus, more output signal is produced at the side band frequencies than is originally present, resulting in side band amplification.

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Amplification of Side Bands by a Power Sensitive Impedance

When power at a pump frequency omega(p), having two side bands whose frequencies are omega(p) + delta and omega(p) - delta, is incident on an impedance in a transmission line, the power absorbed by such impedance varies at the difference frequency. If the magnitude of the impedance is sensitive to the power absorbed by the impedance, the resulting changes in impedance alter the amount of power reflected from or transmitted through such impedance. Such impedance changes at the difference frequency act on the pump frequency so that power is transferred from the pump frequency to the side band frequencies. Thus, more output signal is produced at the side band frequencies than is originally present, resulting in side band amplification.

As shown in A, wave guide 2 is terminated with power sensitive impedance element 4. Wave guide 2 has a tuning plunger 6 for altering its impedance properties. Pump power P(p) at frequency omega(p) is applied to wave guide 2 at point 8. Signal power P(s) also enters wave guide 2. The combined power is reflected as P by impedance element 4. Such element 4 can be a superconductive film of pure tin, indium or the like having a thickness of 100A - 1000A and having a resistance of the order of several hundred ohms when it is driven to its resistive state. The film is maintained at a temperature of l degree K - 20 degrees K and near its critical temperature. The combined power is amp...