Showing papers on "Feed line published in 1970"

Apparatus for cryosurgery

Abstract: An apparatus for cryosurgery wherein the probe includes a grip member having a hollow cryogenic coolant feed line supported by said grip member open at the tip thereof and connected at one end to the cryogenic coolant supply for transmitting coolant to impinge directly upon the tissue to be frozen. A return line open at the tip thereof and concentrically disposed around the feed line forms a space therebetween, with means communicating said space to suction means for returning vaporized coolant from the feed supply line. The open end of the feed supply line is recessed with respect to the corresponding open end of the return line, allowing a cryogenic coolant to impinge directly upon the tissue to be frozen, while vaporized coolant is returned through the return line.

Broadband discone antenna having auxiliary cone

Abstract: A broadband discone antenna arrangement for improving the elevation pattern of the basic discone antenna at frequencies many times the antenna cutoff frequency. An auxiliary conical element is added to the basic discone arrangement coaxially positioned between the main cone and the disc element. The inner surface of the outer conductor of the coaxial transmission feed line, which line passes through the main cone, is continuous with the outer surface of the auxiliary cone at its apex; while the outer surface of the coaxial line''s outer conductor is continuous with the inner surface of the main cone. The auxiliary cone slant height is chosen just above cutoff at the frequency where pattern improvement is desired. The flair angle of the auxiliary cone is chosen greater than 60* while the main cone flair angle is less than 60* in order to minimize antenna size and optimize the pattern at the higher frequencies.

Simultaneous digital transmission in both directions over one line

Abstract: A duplex digital signalling system includes a transmission line having characteristic impedance terminations, a transmitter at each end of the transmission line for supplying digital signals through the characteristic impedance termination to the transmission line, and a differential receiver at each end of the transmission line. A resistor network couples each receiver across the local characteristic impedance termination, so that each receiver responds only to the distant transmitter, and digital information may be simultaneously transmitted in both directions through the transmission line.

Antenna system with ferrite radiation suppressors mounted on feed line

Abstract: A high frequency antenna system comprises an antenna, a transmission line such as a coaxial cable electrically connected to the antenna, and a magnetic member surrounding the outer conductor of the coaxial cable. The magnetic member suppresses extraneous currents that are induced in the outer conductor of the coaxial cable by radiations from the antenna. By suppressing the extraneous current in the outer conductor distortion of radiations is prevented. In the preferred embodiment, the magnetic member comprises a plurality of ferrite toroids which collectively form a cylindrical covering on the conductor. Several antenna systems of this type may be closely spaced in a compact array, and each system may operate independently of the others in the array without interference between antennas.

Wired or circuit

Abstract: WIRED OR circuit arrangement in which a transmission line is used as the OR''ING media. The transmission line is driven from a source of substantially constant current having a source impedance which is substantially equal to the characteristic impedance of the line. Changes in line current are sensed by a current sensing device which also maintains a constant voltage between the line and circuit ground.

Duplexed antenna for retransmission devices

Abstract: A dual antenna system formed on a common structure includes two antennas operating within different frequency ranges. In one embodiment of the invention the central conductor of a coaxial line defines the receiving element of one antenna and the shield of the coaxial line is employed as the receiving element of the second antenna. A ground plane for the first antenna is coupled to the coaxial shield. In a second embodiment of the invention the central conductor of the coaxial line is electrically divided to serve as the receiving element of both antennas, and the shield of the coaxial line forms a part of the ground element of one of the antennas. Duplexing circuitry connected to the antenna separates the signals received at the two antennas and applies the separated signals to the appropriate receiver or transmitter.

Corona Location in Transformers by Radio Frequency Spectrum Analysis, Part I: Theory

Abstract: After discussing transformer types, ?values, and location of voltage generators in capacitive ladder networks and equivalent transmission lines, a new electrical technique for locating transformer partial discharges or corona is described. It is based on the measurement of the radio frequency spectra at the transformer terminals. Provided the transforner winding can be approximated to a uniform transmission line for the frequency range considered, the method is shown to be theoretically sound. Measurements on model networks and actual transformers suggest that, at least over certain frequency ranges, the winding can be regarded as a uniform transmission line. Apart from locating corona, the method provides a quick and accurate means of measuring actual transformer ?values.

Wireless communication system for railway vehicle including an open type transmission line mounted on a radiowave absorbent support

Abstract: A communication system for eliminating interference in communications between a fixed station and a mobile vehicle. The fixed station includes a support base for supporting an open type transmission line, along the path of the mobile vehicle. The transmission line transmits radio waves from the fixed station and receives radio waves from the mobile vehicle. The mobile vehicle includes an antenna positioned to transmit radio waves from said mobile vehicle and to receive radio waves from the fixed station. The support base is positioned relative to the transmission line and the antenna, such that radio waves from the antenna not received by the transmission line and radio waves from the transmission line not received by the antenna and radio waves from other communication systems, are absorbed by the support base. The system may also include wave absorbing means positioned on the mobile vehicle to further reduce interference.

Adapter for converting an am radio receiver into a citizens band channel 9 transceiver

Abstract: This adapter circuit comprises a microphone, a transmitter operating only at 27.065 MHz, and a down converter. It can be used with any conventional amplitude modulated (AM) radio set in an automobile without necessitating any physical change in the car radio. It is connected between the existing cable plug on the antenna and the antenna jack on the radio. During normal operation, signals received by the antenna are directly connected to the radio which is responsive only to signals having frequencies in the AM radio broadcast band. Emergency messages are transmitted at 27.065 MHz by actuating a switch that connects the antenna to the output of the transmitter, and talking into the microphone. Received signals having frequencies of 27.065 MHz are reproduced by down converting such signals to approximately 1,600 kHz signals that are coupled to the radio, the radio being manually tuned to the latter frequency.

Adjustable center loaded antenna arrangement

Abstract: A center-loaded antenna arrangement having a fixed loading coil in a whip antenna, and a tuning core mounted for movement through and out of the coil, said core having a ferrous section and an inductor ring section. Suitable connecting means connects an end of the coil to a radio ground and to a radio transmitter or receiver through a R.F. transmission line. This connecting means is preferably connected to the radio ground through an impedance matching device which couples the coil to the transmitter or receiver.

Microwave limiter that suppresses leading edge spike of radiofrequency signal

Abstract: An RF limiter includes a section of transmission line having ferrite material so arranged therewith and biased as to act as a reciprocal limiter An RF signal passing in one direction through the transmission line is reflected so that the signal passes back through the transmission line in the opposite direction The reflected signal is delayed at least a time period approximately equal to the fall time of a leading edge spike such that, when the delayed RF reflected signal reaches the transmission line section, the ferrite material in the transmission line section is in its nonlinear operating condition

TV Antenna Performance Evaluation with RF Pulse Techniques

Abstract: One of the most critical performance characteristics of a TV antenna system is its ability to transmit a ghost-free picture. RF pulse techniques have been developed to evaluate this performance characteristic. Such measurements can be made to simulate the actual operational conditions of the antenna system very closely. During the past years, several RF pulse-measuring methods have gained acceptance here and abroad. The principles of some of these techniques are presented here and their advantages and limitations are evaluated. Additionally, some instrumentation problems are presented and precautionary steps indicated.

Feed-line radiation of the center-fed dipole antenna with feed points displaced transverse to dipole axis

Abstract: The effect of displacement of the feed points of a center-fed dipole antenna upon radiation from a feed line connecting the dipole arms to a small generator is discussed.