SIGNAL ENHANCEMENT TECHNIQUES.
Quarterly progress rept. no. 2, 1 Aug-31 Oct 66,
RADIO CORP OF AMERICA NEW YORK ADVANCED COMMUNICATIONS LAB
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The report contains a theoretical study of the sources of noise in a varactor P-N junction. The purpose of this study was to determine whether the noise which is exhibited in the junction has a correlation property which can be utilized in the parametric amplifier circuit to reduce the total amount of output noise power. Experiments were conducted in which a parametric amplifier was demonstrated which exhibited the property of extremely low noise and also the ability to receive signals which appear to be imbedded in noise. Prior work in this area was primarily concentrated on analyzing the phenomenon of pulse width modulation by a parametric amplifier with large pump voltage swing. It appeared that pulse width modulation could result in amplification but not necessarily low noise. However, pulse width modulation when examined on a sampling basis could conceivably be able to reduce the total noise of the system with a sacrifice of sampling the information. Hence, for voice-type communication, it is possible that sampling could enhance the signal-to-noise ratio and still allow for a reasonable reception of an audible signal. This report also contains a technique which is being developed under this contract in which a signal can be received in the presence of a large interfering signal even though the sidebands of the interference overlap those of the desired signal.
- Electrical and Electronic Equipment
- Solid State Physics