Abstract: A power management central controller is operable to transmit a sequential two tone load shed command to a plurality of power loads should power consumption become excessive. An improved detector at the load site detects the presence of the two tone signal and initiates the load shedding interval.

Abstract: The inventive lens focuses a plurality of radio frequency signals received by a multi-element antenna array into a coherent signal.A circular transmission cavity has probe sites located therein. The probe sites are located on radii of the circular cavity approximately one quarter wavelength of the radio frequency of interest from the cavity's perimeter. A probe pair is positioned at each probe site. The signal from each antenna element is coupled through a three port circulator to a particular probe pair via a 180.degree. coupler. Incoherent images received at the probe pair are dumped in a load resistor, whereas the focused image of the received signal is routed through the circulator and to a receiver.

Abstract: A radiated signal, received by each one of a plurality of spatially separated antennas, forming a directive array, is coherently recovered by the lens. The lens is comprised of a plurality of vertically standing and circularly arranged printed circuit panels, each of which includes a conductive strip connected at one end to each antenna. A plurality of semi-elliptical circuit panels are affixed to the vertical panels at a predetermined angle with respect thereto. Plated on the semi-elliptical panels are metal strips of predetermined length to provide the desired time delay to the antenna signals. A combining strip couples to the time delay strips and provides a combined output signal at one end of the semi-elliptical panel. The angle at which the semi-elliptical boards are affixed to the vertical boards corrects for time delay distortion caused by the placement of the combining strip.

Abstract: The encoder processes M information characters, each of bit length m, followed by k-1 flush out bits, through an (n,k) convolutional encoder. Each resulting output character is stored as one row of an output register matrix. A transmission bit stream is formed by extracting bits from the register on a column by column basis, thereby interleaving the characters.The decoder fills an input storage basis on a column by column basis, thereby restoring each character in its appropriate row. The characters are sequentially switched to an (n,k) convolutional decoder which outputs the original m bit information character. The characters are, in turn, stored in corresponding rows of an output register matrix, where they are available as recovered data.

Abstract: An antenna for a hand-held radio transceiver includes first and second elements extending from the radio's case. The first element is comprised of a pair of series coupled members having electrical lengths of one-half and one-quarter wavelength, respectively, with the free end of the second member being coupled to the transmitter output. The second element couples to the radio's electrical ground and is configured to form a transmission line with the second member. The effective electrical length of the second element, including the influence of the elements parasitic coupling to the radio, is adjusted to be one-quarter wavelength.The resulting antenna structure minimizes surface currents across the radio's body, thereby substantially eliminating power loss caused by absorption in the user's body.

Abstract: There is disclosed an electronic steering circuit suitable to be utilized in scanning antenna array systems for automatically steering receive and transmit signals between particular antenna elements and a plurality of transceivers. In the preferred form, the electronic steering circuit is coupled between each one of a plurality of antenna elements and a lens, such as a Luneberg lens. Each steering circuit is adapted to be connected to a particular transceiver. Transmitted signals from the transceiver are routed through the steering circuit to the lens and cumulated receive signals from the lens are routed through the steering circuit to the transceiver.

Abstract: Selected radio circuits are fabricated on modules which plug into a "mother" board located in the radio chassis. The circuitry includes a plurality of RF front ends (including at least one AM and one FM front end), each tunable over a selected radio band by tuner circuitry. The AM front end includes a saturable core reactor whose tuning inductance varies as a function of the tuning current provided to it by a voltage-to-current converter in the tuner.Both AM and FM signals are translated by a frequency synthesizer to a common IF frequency, namely 10.7 MHz. The synthesizer employs a quartz crystal controlled oscillator feeding a phase lock loop whose frequency is varied via the tuning control. Quartz crystal filters for AM, and ceramic filters for FM provide required selectivity. As all signals are at the same IF, a common IF amplifier is employed. Further, a single phase lock loop is adapted to demodulate both AM and FM signals.The resultant demodulated signals are amplified, and tone shaped, via D. C.

Abstract: The improved gain control circuit is comprised of an amplifier, a semiconductor device attenuator at the amplifier input, and unique control circuitry for controlling the attenuation factor of the semiconductor device. The amplifier is designed for low phase shift to minimize the time delay of its transfer function. The control circuitry responds to both positive and negative a.c. signal transitions at the amplifier output to initiate attenuator gain reduction. As with the amplifier, the control circuitry is designed for minimum response time. The combination results in an extremely fast a.g.c. attack time.

Abstract: A plurality of horizontally directive antenna sectors are arranged in configuration to receive signals from remote transmitters over a given angle in the horizontal plane. A scanning system is operative in one of several modes to sequentially couple each sector to a receiver. In its first mode, each sector is sequentially scanned with the output signal level therefrom being compared to a reference level. If the signal level on any sector exceeds the reference level the scanner activates to its second mode wherein scanning continues for a predetermined interval. At the end of the interval, scanning is inhibited and the receiver is coupled to that sector which produced the strongest signal level during the second mode scanning cycle. In the inhibit scan mode, if the signal level from the sector falls to a minimum level for a given time period the system reverts to the first scanning mode.

Abstract: An antenna system of the type wherein the radiating pattern may be controlled to direct the radiation of a signal in a selected direction. The system includes a plurality of radiating elements which are affixed to a coplanar in planes which are equiangular from each other. In response to a selected direction of radiation, control circuitry applies the signal to the coplanar antenna elements which are in a plane perpendicular to the selected radiating direction. Further, the control circuitry varies the electrical length of the remaining elements such that some act to direct, and other reflect the radiated signal.

Abstract: The housing includes a casting formed with a provided cavity for receiving and supporting therein a high frequency circuit fabricated on a ceramic substrate. A cover portion is adapted to be affixed to the casting to seal off the cavity. Both the cover and casting are made from an electrical conducting but acoustically dampening material. Rigid standoffs with rubber bumpers at one end extend from the cover portion into the cavity such that when the cover is affixed to the casting the bumpers forcibly engage and compress against the circuit substrate thereby constraining the substrate against the casting. The amount of compression of the bumpers is controlled to minimize circuit microphonics caused by external mechanical shock.

Abstract: An improved synchronizer for recovering the clock signal in split phase encoded data. The synchronizer includes a phase locked loop (PLL) which locks in phase with the encoded data at twice the data clock frequency. The output from the PLL is divided by two in a flip flop which is triggerable to produce an output at either 0.degree. or 180.degree. relative phase. The encoded data is detected in synchronism with the output of the flip flop and the resultant is integrated over each cycle of the flip flop signal. Comparator circuitry produces an error signal if the integrated value is within predetermined limits. A counter receives the error signals and, in response to a significant number thereof, activates the flip flop to produce its alternate phase output. In this manner, the flip flop output recovers the clock signal in proper phase.The synchronizer may be used in combination with additionally disclosed circuitry for use as a full demodulator.

Abstract: A woven mesh of conductively coated stiff filaments is affixed between a first element deformable in response to an applied electronic signal and a second element which has substantially the same configuration as the first element and which may be electrically deformable also. The mesh serves as a center vane between two elements which allows the bender elements to move relative to each other. The bender is supported by peripheral tabs extending from the mesh. A bender structure is produced by coating a woven mesh of conductively coated filaments with an uncured solid epoxy. The mesh and two transducer elements are assembled together and heat and pressure applied to melt and then cure the epoxy, causing the conductive mesh material to make contact with and adhere to the faces of the transducer elements.

Abstract: The coupler accepts four independent RF input signals, divides each input into four equal parts, and applies each part to one of four adjoining output ports. Each input signal divided part is phase shifted a multiple of 90.degree. whereby the output ports, taken in the proper order, are in phase quadrature.The novel coupler comprises four hybrid couplers, all of which are fabricated on a dielectric substrate. The hybrid couplers are located on the substrate in a unique interleaved configuration whereby intercouplings are formed between selected hybrid couplers. The interleaved construction results in the electrical length of all intercouplings being controlled and, preferably, all are the same length.

Abstract: A precisely controlled bandpass/bandstop filter is fabricated by coupling open circuit stubs to a transmission line. The first and second stubs are designed to resonate with the third stub at the center frequency of the passband. Both the first and third stubs are one quarter wavelength long at the center frequency of the stopband, thereby attenuating transmission line signals within this band. The second stub is of a predetermined dimension to attenuate signals at a flyback frequency which occurs within the stopband as a result of interreaction between the stubs.In a particular application, the filter may be used to significantly enhance the signal to noise characteristic of the mixer portion of a radio receiver.

Abstract: The synthesizer uses phase lock loop techniques to generate either the carrier signal for an associated transmitter or the injection signal for an associated receiver. A programmable divider controls the specific channel to which the synthesizer tunes the transmitter or receiver whereas operation in the transmit or receive mode is dependent upon which of two oscillators is coupled in the synthesizer circuit. The oscillators are designed to run at two frequencies having a difference equal to the intermediate frequency of the receiver. This allows the one output from the synthesizer to be used in both the transmit and receive modes.

Abstract: A bimorph bender is comprised of a pair of piezoelectric circular discs having diametrically opposed surface portions. Signal carrying electrodes are formed contiguous with each surface portion. A center vane is sandwiched between the discs maintaining them in a fixed spaced relation. The bender dishes in response to the electrical signals appearing at the electrodes.Mechanical coupling to the bender is provided by a washer which is affixed in the central portion of the bender. The washer is made of a high specific stiffness material for maintaining a high electro-mechanical coupling factor. The resulting structure provides a highly reliable and efficient power transducer.

Abstract: A compression amplifier processes both the audio modulating signal to the transmitter, and the audio output from the receiver, in a conventional amplitude modulated transceiver. Unique switching circuitry provides isolation between transmitter and receiver inputs to, and outputs from, the compression amplifier.

Abstract: An improved repeater adds on to each mobile transceiver of a radio wave communication system for selectively controlling rebroadcasts to an associated portable station. Novel circuitry within each associated repeater eliminates rebroadcast interference among local units, while keeping retransmission delay at an optimized minimum.At turn on, detector circuitry senses if a nearby repeater is broadcasting. In response thereto, programmable delay circuitry is activated to a high incremental state. Where no repeater broadcast is sensed, a program signal is transmitted which increments all nearby repeaters to their next higher delay state. On reception of a signal to be rebroadcast, the repeater whose delay circuitry is in the lowest incremental state initiates rebroadcast, thereby inhibiting the remaining units.A special feature of the programmable delay circuitry is that each repeater is automatically assigned a unique incremental delay time whereby repeater prioritization is positively established.