Abstract: A transmultiplexer for use in a telephone system is disclosed. The transmultiplexer includes a programmable virtual distribution frame feature which provides for information traffic to be switched from one digital group facility to another analog facility in both time division multiplexed and frequency division multiplexed directions.

Abstract: A dual mode broadband antenna especially designed to provide an omni-directional low angle or high angle radiation pattern which is predominately horizontally polarized is disclosed herein. This antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to alternatively operate the antenna in its high and low angle modes, first and second oppositely phased AC currents are applied to the radiators in two different ways using a simple switching device rather than a more complicated network of four hybrid circuits.

Abstract: A dual mode broad band antenna especially designed to provide simultaneously high and low angle radiation patterns relative to a horizontal ground plane is disclosed herein. This particular antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to operate the antenna in its high and low angle modes simultaneously, first and second oppositely phased AC currents are applied to the radiators in two different ways through specifically connected hybrid isolating transformers.

Abstract: A dual mode broadband antenna especially designed to provide an omni-directional low angle or high angle radiation pattern which is predominately horizontally polarized is disclosed herein. This antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to alternatively operate the antenna in its high and low angle modes, first and second oppositely phased AC currents are applied to the radiators in two different ways using a simple switching device rather than a more complicated network of four hybrid circuits.

Abstract: A collapsible apparatus for supporting an antenna or other such device at a predetermined orientation with the horizontal is disclosed herein along with a kit for and method of assembling the apparatus. This apparatus is made up of a number of straight structural members interconnected in a specific way to form a matrix which is movable between a first collapsed position and a second extended position. In this way, with the matrix in its collapsed position, an antenna can be assembled and mounted thereto and thereafter raised to a higher location by moving the matrix to its extended position. When the particular matrix disclosed herein is in its extended position it is combined with three additional structural members to form an octahedron pair for supporting the assembled and mounted antenna.

Abstract: A transmultiplexer and method for use in a telephone system for translating information between time division and frequency division multiplexed formats. The transmultiplexer includes discrete cosine transform processor means connected to receive a linearly coded time division multiplexed signal representing a plurality of information channels for transforming the time division signal into a frequency division multiplexed signal and also includes weighting network means for weighting the transformed signal with predetermined real coefficients thereby forming a frequency division multiplexed signal corresponding to said time division multiplexed signal. The weighting network means are connected to receive a second multi-channel frequency division multiplexed signal for weighting the frequency signal with predetermined real coefficients thereby forming a weighted signal.

Abstract: Disclosed is a digital filter for modulating and demodulating in frequency division multiplexing systems. For modulating a number of voice channels, a Fourier transform processor computes the discrete Fourier transform of a first series of data samples representative of the number of voice channels in time division multiplex format. A weighting network weights the transformed samples with predetermined weighting coefficients to form a frequency division multiplexed signal with proper passband characteristics. For demodulating a frequency division multiplexed signal the weighting network weights the samples with predetermined weighting coefficients and the Fourier transform processor computes a discrete Fourier transform of the weighted samples to form a time division multiplexed signal representative of the number of voice channels.