Abstract: An apparatus and method of accomplishing over-voltage protection for variable power levels and frequency applications including the microwave range. Clamping means are provided that instantaneously absorb over-voltage conditions for a brief period while simultaneously providing feedback control of a driver signal to reduce the source of the over-voltage condition.

Abstract: A composite signal recognizer separator, and PSK, AM, FM demodulator apparatus for processing received communication signals. The receiver utilizes N demodulators cascadely-coupled, where N is equal to or greater than the number of co-channel signals or perceived interference. Detailed in both dual and single stages cascaded fashion, the receiver first tracks to a predominant (stronger) signal, and regeneratively improves track on other (weaker) signals by subtracting predominant noise portion from the input of further demodulation stages. A unified approach to PSK carrier phase tracking, character data tracking, and recovery clock tracking is utilized.

Abstract: In a radio transmitter, a PM input signal is provided directly to a frequency synthesizer. The synthesizer includes a PLL having a reference frequency input signal and a controlled frequency output signal. The PLL includes a frequency divider which is directly connected in a feedback circuit path between the controlled frequency output signal and the PLL's phase-detector. The frequency divider has a frequency control input signal for setting a division ratio N for the divider, and a PM circuit has as input signal the PM input signal and the frequency control input signal. The PM circuit provides an offset signal to the phase detector output, so that the PLL creates a correcting phase signal resulting from the offset signal. The magnitude of the offset signal changes as a function of the change in the value of N.

Abstract: A bipolar modulator and its associated control devices for use with a high-efficiency amplifier in an RF transmitter. The modulator receives an inverted reference signal that has passed through at least two comparators. The modulator output is filtered and then rectified and coupled to a high-efficiency power amplifier.

Abstract: An adjustable digital synthesizer has frequency increments of a selected step size. The adjustable digital synthesizer includes a digital accumulator having N stages. The digital accumulator counts at a predetermined clock frequency such that, in response to each clock, the accumulator increments the step size determined by the digital input. The accumulator counts to 2.sup.Nth state and wraps around in response to an overflow. An adder, responsive to the overflow, adds an offset to the accumulator, the offset being a function of the difference between 2.sup.Nth times the minimum step size and the desired clock frequency.

Abstract: An RF voltage/current sensor apparatus comprising a plurality of transmission lines coupled through resistive means to voltage sense circuitry. The voltage sense circuitry utilizes transistor technology thereby reducing the use of switching relays, transformers and diodes thereby providing an apparatus operational over a frequency range from approximately two megahertz to two gigahertz.

Abstract: An apparatus and method of controlling the light intensity in a light source of variable emission affected by a drive signal. Spatial optical integration based upon light summation is incorporated into the accompanying encasement device at a backlight source by means of a light source support structure that allows light not directed toward a viewed surface, such as an LCD, to serve as a control input to the light drive signal.

Abstract: An apparatus and method for accomplishing DC-to-AC power conversion that combine the AC outputs of n interleaved, time division multiplexed inverters and steer the secondary pulses positively or negatively, as commanded by the time varying reference signal, such that the effective switching, or sampled-data, frequency of any of the inverter or pulse-steering transistors. The n interleaved inverter system can, in turn, be paralleled such that, relative to a single inverter supplying all the power, the losses for any inverter transistor are 1/np, n due to time multiplexing and p due to paralleling.

Abstract: An adjustable rugged antenna coupler assembly for primary use in portable radios. Connector means in combination with a pair of gasket means, signal carrying means and encasement means combine to provide an improved adjustable antenna coupler assembly. The connector means is mated with complementary threadings in the radio casing thereby providing an antenna coupler readily adjustable such that the antenna is always pointed in a desired direction, such as skyward.

Abstract: An apparatus for use as a connector in certain electronic applications. The disclosed apparatus teaches a connector assembly suitable for use in applications requiring minimal height restrictions while simultaneously affording a solderless, stackable, shielded connector assembly that may include a variety of electronic filtering. A described embodiment of the present invention includes a multi-walled encasement structure of electroplated construction housing a "pi" filter sandwiched between matching layers of resilient conductive layers, each layer having contact pads for coupling to contact pads of adjacent circuit board circuitry.

Abstract: An apparatus and method of using spatial nulling in antenna electronics to protect against interference signals. Nulling is achieved by computing and adjusting the computed complex weights values of "n" channels through the use of dithering of interfering signals of having power levels thereby allowing nulling of "n" minus one number of interfering signal. sources.

Abstract: An HF radio transceiving apparatus that maintains communication integrity by employing a plurality of receivers, each capable of operating in separate and independent communication modes. One embodiment of the apparatus includes an antenna, a programmed controller having a plurality of control signals, first and second receivers and a transmitter section. The receivers receive and demodulate radio signals transmitted from external radios in common or mutually exclusive communication modes, and provide link-data information to the programmed controller. The transmitter, responsive to the programmed controller and coupled to the antenna, transmits modulated data in one of the common or mutually exclusive communication modes.

Abstract: A stabilized oscillation circuit includes a bias circuit which controllably biases a bipolar-transistor-driven crystal oscillator circuit. The bipolar-transistor-driven crystal oscillator circuit is a modified version of a conventional transistor-driven oscillator, such as a Hartley, Pierce or Colpitts-type circuit. The bias circuit includes a first current providing a reference current through a Schottky diode and a pair of bipolar transistors. The bipolar-transistor-driven crystal oscillator circuit includes an input and an output, where the input of the bipolar-transistor-driven crystal oscillator circuit is coupled to the bias circuit. The bipolar-transistor-driven crystal oscillator circuit includes a second current through a second bipolar transistor. The second current tracks the reference current so that the output of the bipolar-transistor-driven oscillator circuit is substantially constant over variations in ambient temperature.

Abstract: An amplitude modulated (AM) radio receiver uses a digital signal processor, responsive to in-phase (I) and quadrature-phase (Q) component signals, to compensate for carrier energy removed by a capacitive coupling circuit. A quadrature mixer converts the received AM signal to the I and Q component signals representative of the AM signal, and a signal filter passes a desired frequency segment of the I and Q component signals. A capacitive coupling circuit couples the I and Q component signals to provide representative I and Q signals with no DC bias to the input of an analog-to-digital converter. The analog-to-digital converter converts the representative unbiased I and Q signals to digital I and Q signals for processing by the digital signal processor.

Abstract: A frequency modulation circuit includes a phase-locked loop having a reference frequency input and a controlled frequency output. The phase-locked loop has a phase detector, a filter and a voltage-controlled oscillator and, in a feedback path between the output and the phase detector, a frequency divider. Also included is a converter converting an input signal to a digital modulation signal M, and an adder inverting the most significant bit of the digital modulation signal and adding it to a digital word representing a selected frequency. The frequency divider divides a fractional number (N.F).+-.M, where N is an integer, F is a fraction and M is the digital value of modulation data.

Abstract: An apparatus and method of processing transmitted signals through the use of correlator means and RAM means thereby accomplishing synchronization and data interpretation. Specifically, a plurality of correlators are coupled to RAM means which cooperate to store and subsequently read transmitted data. Clocking means used in conjunction with a programmed delay period provides segments of the received and stored data to a plurality of correlators and on to logic means for further processing.

Abstract: A digitally switched gain amplifier designed for use in binary controlled systems. The amplifier is designed for fabrication as a monolithic integrated circuit. The amplifier provides gain that varies in discrete levels in a binary manner under direct control of a digital word. The smallest resolution, or distance between gain steps, is one decibel and the maximum amount of gain reduction is determined by the number of stages included in the amplifier. The incremental resolution of the amplifier allows for the amplifier to keep a received signal at a constant level with a digital word. Thus, eliminating the need for digital to analog conversion.

Abstract: A four way 2:1 bandwidth RF splitter/combiner is described. When used as a splitter, the splitter/combiner provides equal amplitude output signals while maintaining quadrature phase over the entire bandwidth of the input signal. This splitter/combiner also maintains a one to one VSWR and eliminates back door intermodulation. When used as a combiner, the splitter/combiner losslessly combines four equal amplitude quadrature phase signals.

Abstract: A variety of embodiments of varactor diodes are disclosed ranging from an N.times.N matrix assembly of individually packaged diodes arranged in N rows and columns to a multi-continuous layered varactor. The matrix assembly varactor has N rows of discrete devices electrically coupled in parallel and multiple rows vertically aligned and electrically coupled in series to each other. The overall matrix assembly capacitance equals the individual diode capacitance of such assembly. When used as a tuning component across a tank coil transmission line, the RF voltage across any device in the matrix assembly is equal to the tank voltage divided by N.

Abstract: A Q multiplier circuit which is automatically feedback stabilized through the use of phase and gain control loops and thereby adapted for use as an amplifier and filter. In a typical embodiment, a variable gain amplifier and band pass filter are provided in a forward signal path while a phase shifter is provided in a feedback signal path. The output of the circuit is sampled and compared to a fixed reference in order to generate a gain control signal for application to the variable gain amplifier. The input signal on the forward signal path is sampled along with the signal on the feedback signal path and the phases of these samples are compared in order to generate a phase control signal for application to the phase shifter. The variable gain amplifier is controlled to maintain a predetermined power output level while the phase shifter is controlled to maintain positive feed back.