Three-Frequency Nonlinear Heterodyne Detection. 1: cw Radar and Analog Communications

Applied Optics
M C Teich, R Y Yen

Abstract

Though heterodyne detection provides a valuable technique for detecting small signals, the conventional system has several inherent disadvantages. In applications such as communications and radar, obtaining a reasonably high signal-to-noise ratio (SNR) requires (1) a good knowledge of the velocity of the transmitter or target, (2) a stable yet tunable local oscillator, and (3) a target or source that presents a minimum of frequency broadening. These conditions are frequently not adhered to by real systems, particularly in the ir and optical, giving rise to detection capabilities far below optimum. Calculations are presented for the use and operation of a three-frequency nonlinear heterodyne system that eliminates many of the stringent conditions required for conventional heterodyne detection, while maintaining its near-ideal SNR. The technique, which is similar in principle to heterodyne radiometry, makes use of a two-frequency transmitter and a nonlinear second detector and is particularly useful for signal acquisition; for signals of unknown Doppler shift, in fact, performance is generally superior to that of the conventional system. Although primary emphasis is on the ir and optical because of the large Doppler shifts encoun...Continue Reading

References

Jul 1, 1972·Applied Optics·J H McElroy

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.