Reliable through-the-earth communications (tec) are needed for command and control of deep-based icbm sites. the required data rates can be achieved by using both signal coding and signal-tonoise-ratio (snr) enhancement techniques. the key signal-processing elements ofjsuchasystem are: nolinear… More

The proposed program is a feasibility study and system design for an innovative power-amplifier system for the adaptive-jammer application. this system operates over the entire hf and vhf range (3 - 300 mhz), produces signals with various types of modulation, and can concentrate all of its power on… More

A variety of advanced-basing concepts enhance survivability by combining missile mobility with fixed protective structures (tunnels, garages, etc.). providing communication connectivity by installing variety of hardened antennas is, however, quite expensive. a completely portable communication… More

A variety of advanced-basing concepts enhance survivability by combining missile mobility with fixed protective structures (tunnels, garages, etc.). providing communication connectivity by installing variety of hardened antennas is, however, quite expensive. a completely portable, communication… More

Maintaining command-and-control communications connectivity continuously through pre-, trans-, and post-attack periods is essential. communication links for this application should be nondeniable (by nuclear detonation) and noninterruptable, and should also allow communications while in motion and… More

Operation of a jammer transmitter from a small platform (rpv or jeep) necessitates the use of electrically short antennas such as short whips and small loops. the conventional approach uses a power amplifier designed for a 50-ohm load and an antenna tuner that matches the antenna-input impedance to… More

Modern hf/vhf jammers employ power combiners and multiple power-amplifier (pa) modules to achieve a high power output, cancellation of harmonics, and gradual degradation of performance due to module failure. power combiners can be a significant source of power loss because of resistive losses,… More

The RF transmitter/locator (TL) concept presented in this proposal enables the location and recovery of a canister such as a nose cone, artillery shell, buoy, or instrument package. The system operates over a distance of 5 mi on the surface and several hundred feet through soil, sand, or fresh… More

Tunable HF/VHF filters capable of operating at high power levels are needed for preventing a jammer from interfering with nearby friendly communications, high-speed antenna tuners, and output filters for high-efficiency power amplifiers (PAS). Filter systems presently employ either relays or… More

This Phase-I SBIR program will investigate novel techniques for the efficient delivery of signal power to reactive loads such as are required in sonar systems. Class-D and class-S power amplifiers with very fast switching offer a theoretical efficiency of100 percent. Maintaining high efficiency… More

This Small Business Innovation Research (SBIR) Phase I project will investigate techniques for low-cost, high-efficiency, wide-bandwidth power amplifiers for magnetic-resonance-imaging (MRI) systems. To date, MRI transmitters have been based upon broadband linear power amplifiers, which are… More

70034 Accelerators for nuclear physics research currently use vacuum-tube devices (klystrons) to generate high-power signals at 1500 MHz. As a result, they are subject to low efficiency, aging effects, low reliability, short life, and high operating expense. This project will develop… More

"Modern phased-array transmitters employ a separate power-amplifier (PA) module for each antenna element. The transmitted signals have time-varying envelopes and peak amplitudes that vary over a large dynamic range, resulting in inefficient amplificationby the conventional linear PAs that are… More

There is a need for a portable command-post transmitter that can be deployed in an emergency situation. Interoperability among the different military services and civilian agencies is required. Consequently, the transmitter must operate at allfrequencies from 200 MHz to 3 GHz. It must also be… More

This Small Business Innovation Research Phase II will develop and test a prototype low-cost, high-efficiency transmitter for magnetic-resonance-imaging (MRI) systems. Existing MRI transmitters use conventional power amplifiers (PAs), which makes them inefficient and consequently large, heavy, and… More

This Small Business Innovation Research Phase II will develop and test a prototype low-cost, high-efficiency transmitter for magnetic-resonance-imaging (MRI) systems. Existing MRI transmitters use conventional power amplifiers (PAs), which makes them inefficient and consequently large, heavy, and… More

The military makes extensive use of high-power signals at frequencies from 1.5 MHz to 3 GHz for communication, jamming, and other applications. The proposed ultra-wideband high-efficiency power amplifier is based upon a combination of a high-efficiency RFpower amplifier (PA) and electronic tuning. … More

Space-based radar (SBR) requires multiple RF power amplifiers (PAs) to drive phased-arrays antennas. Control of the beam direction requires an amplitude range of 22 dB, and coupling between elements results in load impedances with significant mismatch. Both factors make conventional linear RF PAs… More

The military makes extensive use of high-power signals at frequencies from 1.5 MHz to 3 GHz for communication, jamming, and other applications. The proposed ultra-wideband high-efficiency power amplifier is based upon a combination of a high-efficiency RF power amplifier (PA) and electronic tuning.… More

UHF radar is used for surveillance from unmanned aerial vehicles (UAVs). A typical transmitter must produce multi-kilowatt pulses, but the efficiency of existing transmitters is only 20 to 30 percent. Low efficiency results in transmitters that are unnecessarily large and heavy. It also taxes the… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. These accelerators currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power. This project will review… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. These accelerators currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power. This project will review… More

Accelerators used for nuclear physics research require megawatts of radio-frequency energy. These accelerators currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power. This project will involve a… More

Accelerators used in synchrotron light sources require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime electrical power. We will review available… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime electrical power. We will review available… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime electrical power. We will review available… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power. Many other applications including… More

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that areinefficient and therefore consume a great deal of prime power. Many other applications including semiconductor… More