Abstract: A glass antenna system for an automobile comprises a T-shaped or pi-shaped dynamic impedance matching circuit. Another system comprises an integrated circuit consisting of T-shaped FM and AM matching circuits each connected to a common cable. The T-shaped or pi-shaped matching circuit comprises at least two varactor diodes each applied to a channel selection voltage to match the FM antenna impedance with that of the FM receiver including that of the transmission cable.

Abstract: For extending the dynamic range in measurements carried out with a directional coupler, such as antenna measurements, a signal is supplied to the object under analysis, such as an antenna, through a first port of the measuring directional coupler, part of the signal leaking as a leak signal through a second port of the measuring directional coupler directly towards a measuring device. The signal returning from the object under analysis is measured by the measuring device. To enable the measuring of signal levels lower than before, spurious signals, such as the leak signal, summing to the signal to be measured are eliminated by supplying a phased compensation signal through a second directional coupler to the measuring line.

Abstract: An arrangement for measuring the condition of a receiver antenna at a base station, utilizing an antenna amplifier positioned in connection with an antenna apart from other base station equipments, e.g., at a mast. A measuring signal is generated in connection with the other base station equipments at a frequency outside the frequency band used for radio traffic and applied through an antenna line to the antenna amplifier, in which the measuring signal is converted to the actual measuring frequency within the frequency band intended for the radio traffic.

Abstract: In a tuner for converting antenna input signal into audio signals, tuner circuit components are mounted on a tuner circuit substrate. Of the tuner circuit components, FM wave front end circuit components constituting a high-frequency amplifying circuit, a mixing circuit and a local oscillating circuit are surrounded by a shield case. An antenna jack including an earth tube and a signal terminal insulated from the earth tube is mounted on the tuner circuit substrate. The signal terminal of the antenna jack is connected to an antenna input signal pattern of the tuner circuit substrate. The earth tube of the antenna jack is forced in and supported by a jack attachment plate that is an extension of the shield case.

Abstract: A spatial combiner for connection to a receiver used in conjunction with a lurality of direction-sensitive antennas for receiving a spread-spectrum communication signal in the presence of interference includes a steering network, a plurality of normalizers, and a plurality of combiners. The steering network combines N inputs from N antennas and produces outputs J.sub.1, J.sub.2, . . . , J.sub.M, with M being a multiple of K and K a positive integer such that each M output is a weighted sum of N inputs from the antennas. The normalizers receive and normalize the M outputs to unit energy and produce normalized outputs J .sub.1, J .sub.2, . . . , J .sub.M. The combiners receive normalized outputs and sum the first K outputs to produce output C.sub.1, sum the next K outputs to produce output C.sub.2, and continuing summing outputs in the same manner until summing the last K outputs occurs to produce output C.sub.M/K. The outputs C.sub.1 through C.sub.

Abstract: An interference suppression system for cancelling undesired signals recei through the mainlobe of an antenna as well as its sidelobes. The interference suppression system has a main channel input having high gain for receiving desired signals and undesired signals and forming a main channel waveform, and an auxiliary channel input having low gain for receiving desired signals and undesired signals and forming an auxiliary channel waveform. A control circuit senses the relative undesired signal power in the two channels and responds by switching the waveforms in the two channels between two inputs of an interference-reducing circuit according to whether sidelobe or mainlobe interference is present in the main channel.

Abstract: Circuitry and concomitant methodology for demodulating Direct-Sequence, Spread-Spectrum Code-Division Multiple-Access (DS/SS CDMA) channel signal using multiple samples per transmitted symbol and a minimum mean squared error criterion to suppress interference. In one embodiment, a bank of cyclically shifted filters determined with reference to the conventional matched filter for CDMA is used to demodulate the channel signal. In another embodiment, a bank of sub-filters determined with reference to the conventional matched filter for CDMA is employed to demodulate the channel signal. In yet another embodiment, the output of a conventional matched filter is oversampled to demodulate the channel signal. Each embodiment utilizes a set of adaptive coefficients selected to minimize the mean square error between the transmitted symbol and detected symbol.

Abstract: The invention is directed to a wristwatch type paging device having a structure for preventing the intrusion of static electricity. The paging device is provided for receiving or transmitting signals. A pager circuit is provided for controlling and operating on the received or signals to be transmitted. A pager body, having a two part wrist band coupled thereto, houses the pager circuit. The body is formed with at least a conductive portion. The band fastens around the wrist of the user and carries antenna portions. A fastener mechanically couples the end portions and electronically couples the antenna portions. The conductive portion of the pager body is set to the AC ground potential (the potential of one of the positive or negative electrodes of the battery). A balanced varactor diode circuit is provided between the antenna portion ends defining an essentially neutral point coupled to one of its positive and negative electrodes.

Abstract: The invention relates to a communications system suitable for application directly to a national electricity grid and comprising a transmitter for transmitting data over a plurality of transmission frequency bands, a receiver for receiving messages over any one of the frequency bands, means for evaluating the transmission quality of each of the frequency bands, and a way to adapt the system for transmitting and receiving over the frequency band that has optimum transmission quality. The system of the invention may be applied, in particular, to remote reading of electricity meters.

Abstract: A radio frequency limiter having a radio frequency power divider having an input and a plurality of outputs; at least one diode connected in shunt with each one of the outputs of the power divider; and, a power combiner having an output and a plurality of inputs, each one of such inputs being connected to a corresponding one of the outputs of the power divider. With such arrangement, the insertion loss of such limiter is reduced compared to a limiter having a like number of diodes connected in shunt at a common point of a single transmission line. Therefore, the reduced insertion loss means that the impedance matching circuit required will not limit the maximum operating frequency to the degree an impedance matching circuit of similar complexity will limit the maximum operating frequency required for a limiter having the same number of diodes but using a single transmission line.

Abstract: The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.

Abstract: A noise trap circuit particularly suitable for use in an electro-acoustic system, operates to suppress low level signals or noise while allowing a relatively large signal to pass unattenuated between input and output terminals of the circuit. Blocking elements between the input and output terminals establish a high impedance path to the noise but switch to a conductive state when the large signals are present at the input terminals. Shunt elements across the output terminals provide a low resistance path or "crowbar" when only the noise is present at the input terminals, but switch to a non-conductive state when the large signals are sensed at the circuit input.

Abstract: The effects of multipath and other interference signals in communication receivers are reduced by implementing an adaptive array. The invention addresses a signal environment in which the directions of arrival and the time of arrival of the signal of interest and the unwanted multipath or interference signals are unknown. The feedback equation of the LMS adaptive array is changed so that a reference signal is not needed. The system uses the strongest received signal as the signal of interest and rejects the other received signals.

Abstract: An automatic AC protection circuit protects a radio receiver from RF overload by shortcircuiting the overload power to ground. The circuit includes a transistor having its collector coupled to the RF input and its emitter coupled to ground and the base coupled through an inductive impedance to ground. The value of inductive impedance in parallel with the base to emitter impedance of the transistor determines the RF input level at which the transistor turns on and clamps the RF to ground to protect a receiver from overload.

Abstract: An overload protector, using a power-dissipating element for receiving and dissipating excessive radio-frequency power, can safely transfer a signal from an input to an output. The protector also has a detector coupled to the input for providing a bias current in response to an input signal in excess of a predetermined magnitude. Also included in a diverter coupled to the input, the output, the power-dissipating element and the detector. This diverter can receive the bias current and can, in response, redirect power at the input from the output to the power-dissipating element.

Abstract: An automatic tuning receiver having an automatic tuning system which comprises an antenna input attenuator for attenuating antenna inputs and a sensitivity switching device, the sensitivity switching device having two positions, one controlling the attenuator to a high continuation condition for local station searching and alternatively to a low attenuation condition for distant station searches. In the high attenuation condition a switching means is further responsive to muting signals derived from the receiver so as to maintain the attenuator in a high attenuation condition during search, at the end of which time the search ceases, the receiver locks on the desired signal, and the disappearance of the muting signal causes the attenuator to revert to a low attenuation condition, thereby preserving an improved signal to noise condition in the receiver.

Abstract: To suppress a fluctuation in resonance frequency caused by an input signal voltage in a tunable circuit, a respective capacitor is connected to each of two variable capacitance diodes connected in series-opposition.

Abstract: The present invention relates to an adaptive cross-polarization cancellation arrangement where a first desired polarized signal and a second interfering orthogonally polarized signal, including cross-polarization components, are concurrently received at an antenna. In the present arrangement, the orthogonally polarized components of the received signal are separated and transmitted along separate paths and recombined after the phase and amplitude of the separated polarized interfering signal sample has been appropriately adjusted for maximally cancelling cross-polarization components thereof in the other path.

Abstract: The described system utilizes the interference cancelation technique disced in my pending U.S. Pat. application Ser. No. 114,547, filed Jan. 23, 1980, with narrow-band orthogonal addressing in providing improved system performance, but only with modest equipment requirements. Orthogonal narrow-band frequency division multiple access signaling is employed to initially accomplish call-up, with interference then being adaptively suppressed and an available voice channel selected for accomplishing the communication requirements.

Abstract: A microwave receiver is constituted by an antenna having a reflector and a primary radiator, and a converter having an unbalanced input terminal. A core conductor projected from the unbalanced terminal of the converter is extended inside the reflector through a bore formed therein so as to function as the primary radiator of the antenna. The converter is fixed directly to the wall of the reflector.