INTERFERENCE REDUCTION TECHNIQUES EMPLOYING ACTIVE DEVICES.
Abstract
This report discusses the development and performance of several techniques employing active devices for the reduction of adjacent and co-channel interference in receivers. For operational situations where the interfering source is co-sited with the receiver, an automatic phase control system is described which detects the differential phase shift between the interference path and the direct path from the source and supplies a phase corrected signal for cancellation of the interfering signal. For the more general situation where the interference is not a cosite source, a feed forward system and a dual loop, phase locked system were developed. The dual loop cancellation system generates an auxiliary signal to cancel the interfering signal. The improved performance of passive preselectors that can be obtained through Q multiplication is demonstrated with a Q multiplier device for the UHF region. Active and passive circuit configurations which incorporate the extremely narrow passbands of quartz crystals are discussed. When used as band stop filters, interference rejection levels greater than 50 dB are possible with these filters. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1968
- Accession Number
- AD0667567
Entities
People
- Carl R. Driskell
- Charles S. Wilson
- Hugh W. Denny
- Robert A. Byers
Organizations
- Georgia Tech