Abstract: An electrical power supply system for an aircraft includes a plurality of generators, each being couplable to and rotatable by an aircraft engine. and a plurality of electrical conversion units, each having a plurality of inputs and at least one output. Each generator includes at least four AC phases. The inputs of each individual electrical conversion unit are connected to a plurality of phases of at least two of the plurality of generators. The electrical conversion units each includes a rectification and conversion device for providing an output voltage having a predeterminable frequency and voltage level at the output.

Abstract: A modulation circuit includes a load and a transistor serving as a switch. The transistor has an oxide semiconductor layer in which hydrogen concentration is 5×1019/cm3 or less. The off-state current of the transistor is 1×10?13 A or less. A modulation circuit includes a load, a transistor serving as a switch, and a diode. The load, the transistor, and the diode are connected in series between the terminals of an antenna. The transistor has an oxide semiconductor layer in which hydrogen concentration is 5×1019/cm3 or less. An off-state current of the transistor is 1×10?13 A or less. On/off of the transistor is controlled in accordance with a signal inputted to a gate of the transistor. The load is a resistor, a capacitor, or a combination of a resistor and a capacitor.

Abstract: An apparatus for coding a signal by means of amplitude shift keying comprises a class E amplifier including a switching transistor, to whose gate is supplied a voltage having an operating frequency for operating the class E amplifier. For achieving an amplitude shift keying in the output signal of the class E amplifier, a circuit for switching the operating frequency of the voltage supplied to the gate of the switching transistor, or the resonance frequency of the class E amplifier, between a first value and a second value is provided and in order to switch a deviation degree between the operating frequency and the resonance frequency between a first value and a second value.

Abstract: A modulation circuit that can improve an on/off ratio or increase short pulses, and a wireless communication apparatus are provided. The modulation circuit includes a first transistor in which a first signal is input to a gate terminal; a second transistor that is cascode-connected to the first transistor by connecting a source terminal to a drain terminal of the first transistor, that receives an input of a second signal having a frequency lower than the first signal at a gate terminal, and that modulates the second signal by the first signal and outputs the modulated second signal; and a switch circuit that is formed on the output side of the second transistor. The switch circuit is turned on in synch with a switching of the second transistor to an off state, and turned off in synch with a switching of the second transistor to an on state.

Abstract: A modulator which has a first terminal to receive a carrier signal, a second terminal to receive a first control signal to control a frequency band of the carrier signal and a third terminal to receive a second control signal to control a modulation depth of the carrier signal.

Abstract: An amplitude modulated pulse transmitter designed to operate across a multi MHz range of modulation frequencies. A wire wound rare earth magnet is to be utilized instead of the typical modulation transformer. Additionally, a plurality of electrolytic capacitors are also employed in the transmitter.

Abstract: A low noise RF driver circuit including at least two series-coupled driver stages which receive a frequency modulated signal and an amplitude modulated signal that is applied to the supply voltage input of the driver stages, and provide a combined output signal. The RF driver circuit can be implemented in CMOS technology and integrated with other components of an RF communication subsystem, such as an RF transceiver circuit and power amplifier. Each driver stage includes a complementary pair of transistors with source degeneration resistors for linearity and gain control.

Abstract: Modulators for amplitude-modulating signals defined by phase information and envelope codes are provided with first transistors for receiving the phase information and second transistors for receiving the envelope codes. The first main electrode of one transistor is coupled to the second main electrode of the other transistor and the other second main electrode constitutes an output of the modulator. This modulator can be used in any kind of transistor environment and is simple and low cost. The doped areas of the coupled first and second main electrodes comprise an overlap to reduce cross-talk and to reduce silicon area. Polar transmitters are provided with this modulator and with a circuit for generating a phase/frequency code and the envelope code and with an oscillator for receiving the phase/frequency code and for generating the phase information. A phase shift between the phase information and the envelope code reduce aliases.

Abstract: A modulation method according to the invention is applied to a modulation device in which a light source is driven by a differential signal while a modulation circuit and the light source are capacitively coupled. In the modulation method of the invention, when an average potential fluctuates at an input terminal of the light source, a potential fluctuation is externally provided using a control circuit such that a normal phase side and a reverse phase side become equal to each other in a time constant of the fluctuation in average potential, and transient states of the average potentials at the normal phase side and reverse phase side are equalized and cancel each other as in-phase components of a signal input to the light source, which allows an optical signal to be normally transmitted from the light source.

Abstract: An apparatus for coding a signal by means of amplitude shift keying comprises a class E amplifier including a switching transistor, to whose gate is supplied a voltage having an operating frequency for operating the class E amplifier. For achieving an amplitude shift keying in the output signal of the class E amplifier, a circuit for switching the operating frequency of the voltage supplied to the gate of the switching transistor, or the resonance frequency of the class E amplifier, between a first value and a second value is provided and in order to switch a deviation degree between the operating frequency and the resonance frequency between a first value and a second value.

Abstract: Modulators for amplitude-modulating signals defined by phase information and envelope codes are provided with first transistors for receiving the phase information and second transistors for receiving the envelope codes. The first main electrode of one transistor is coupled to the second main electrode of the other transistor and the other second main electrode constitutes an output of the modulator. This modulator can be used in any kind of transistor environment and is simple and low cost. The doped areas of the coupled first and second main electrodes comprise an overlap to reduce cross-talk and to reduce silicon area. Polar transmitters are provided with this modulator and with a circuit for generating a phase/frequency code and the envelope code and with an oscillator for receiving the phase/frequency code and for generating the phase information. A phase shift between the phase information and the envelope code reduce aliases.

Abstract: A power management device providing a power amplifier with power supply voltage is provided. The power management unit includes a parallel-hybrid amplitude modulator apparatus having a linear part configured to track frequency components of an input signal above a determined threshold frequency and a switching part arranged in parallel with the linear part and configured to track frequency components of the input signal below the determined threshold frequency. Additionally, the power management unit includes a current sensing and controlling part configured to determine the level of a direct current component at an output of the linear part and control the switching part to produce an output signal compensating for the direct current component at the output of the linear part to decrease the absolute level of the direct current at the output of the linear part.

Abstract: A phase modulation circuit for outputting a modulated signal of an input signal which has been modulated to a desired phase. The circuit includes a light emitting element for emitting light according to an input signal and outputting a modulated signal, a bias current source for supplying in advance to a light emitting element a bias current smaller than the light emitting threshold current of the light emitting element, a bias current control unit for controlling the bias current according to a desired phase for supplying to the light emitting element a modulation current for causing the light emitting element to emit light according to the input signal, and a modulation current control unit for controlling the modulation current according to the phase shift resolution in the phase modulation circuit. The modulation current control unit controls modulation current further according to the phase range in the phase modulation circuit.

Abstract: Polar modulators include a phase splitter, a controller, variable current sources, transistor circuits, and a combiner. The phase splitter splits a RF carrier signal into quadrature component signals that are 90 degrees out of phase with each other. The controller generates modulation control signals based on information that is to be transmitted. The variable current sources each generate a variable amplitude current signal based on a different one of the modulation control signals. Each of the transistor circuits amplify a different one of the quadrature component signals with a variable amplification based on the variable amplitude current signal from a different one of the variable current sources to generate an amplitude adjusted quadrature component signal. The combiner combines the amplitude adjusted quadrature component signals from each of the transistor circuits to generate a phase-modulated RF carrier output signal.

Abstract: A non-radiative dielectric (NRD) waveguide modulator is provided having a waveguide type hybrid coupler, in which by forming a waveguide type 180° hybrid coupler and waveguide as a single body, the structure is simplified and manufacturing processes are reduced. The NRD waveguide modulator includes a conducting housing having a lower conducting plate and an upper conducting plate; a hybrid coupler which is processed in the form of conduit lines inside the conducting housing and includes a ring portion and a plurality of waveguides extended from the ring portion in the radial direction, in modulator, and a termination which is connected to an isolation port that is an end of any one waveguide of the hybrid coupler and terminates a signal reflected by the modulator by consuming the signal internally.

Abstract: A device for providing the functionality of an oscillator and mixer is disclosed herein. The device uses a differential pair to provide first and second filter networks with a time varying signal. The first filer network generates an oscillating signal through the use of a generated negative resistance and provides the oscillating signal while filtering out unwanted signals. The second filter network receives the time varying input signal and the oscillating signal and provides a mixed output while preventing the transmission of oscillations at the oscillating signal frequency. A double balanced embodiment is also disclosed.

Abstract: A device for providing the functionality of an oscillator and mixer is disclosed herein. The device uses a differential pair to provide first and second filter networks with a time varying signal. The first filter network generates an oscillating signal through the use of a generated negative resistance and provides the oscillating signal while filtering out unwanted signals. The second filter network receives the time varying input signal and the oscillating signal and provides a mixed output while preventing the transmission of oscillations at the oscillating signal frequency. A double balanced embodiment is also disclosed.

Abstract: A transmission front-end processor modulates the amplitude of a carrier wave with baseband data, and sets the power of the resultant modulated wave at a required value while controlling power leakage to adjoining channel to thereby output transmission data. The processor includes a first filter connected to an input terminal to which the baseband data are applied, for removing frequency components which would otherwise cause the power of the baseband data to leak to adjoining channels. The carrier wave and the baseband data passed through the first filter are applied to a power modulator. The power modulator controls the amplitude of the carrier wave with the baseband data, sets the power of the result of the control at the required value, and then outputs the power. A second filter removes higher order components from the carrier wave included in the output of the power modulator to thereby output the transmission data.

Abstract: A low voltage, current-folded signal modulator that reduces distortion in the output signal is provided. The signal modulator has a differential amplifier that receives a first input signal and converts it to a current, a current amplifier that has a low impedance input and provides an amplified current signal, and a differential pair circuit that receives a second input signal and modulates the amplified current signal by the second signal.

Abstract: An ASK modulator can be operated with only a positive-voltage power source. A source-voltage switching circuit that applies a positive voltage to the source of a FET when a data signal is at an L level in relation to the source of the FET is connected to the source of the FET which has a negative pinch-off voltage. Since the L level of the data signal can be set to 0 V, the ASK modulator can be configured only with the positive-voltage power source. This allows miniaturization and cost reduction to be implemented.

Abstract: A transistor commuted double balanced mixer that uses a Gilbert cell mixer quad transistor core. The RF input differential pair is deleted from the standard Gilbert cell mixer configuration. A transformer is used to apply the RF input through resistors to the Gilbert cell mixer quad transistor core.

Abstract: The present invention provides a modulation circuit that has excellent modulation characteristics and can be designed as an MMIC. Consequently, this modulation circuit is such that the modulating wave input means is composed of a capacitor 21 and an inductor 22, the carrier input means is composed of a capacitor 23 and a resistance element 24, the self-bias means is composed of a resistance element 26 and a capacitor 27, the carrier selection means is composed of an inductor 22 and a capacitor 28, and the modulated wave output means is composed of a capacitor 28.

Abstract: A low-powered mixer that is operable at a low voltage by a single positive power supply. A predetermined voltage and a first data signal Ss1 superimposed on the predetermined voltage are input into the drain D of an FET Q1, while a first carrier signal Sc1 is input into the FET Q1's gate G. The FET Q1 thus generates a first mixed signal So1 by mixing the first data signal Ss1 and the first carrier signal Sc1. A predetermined voltage and a second data signal Ss2 superimposed on the predetermined voltage are input into the FET Q2's drain D, while a second carrier signal Sc2 is input into the FET Q2's gate G. The FET Q2 thus generates a second mixed signal So2 by mixing the second data signal Ss2 and the second carrier signal Sc2. A capacitor C5 causes the sources S of the FETs Q1 and Q2 to float for DC and to be grounded for AC.

Abstract: The present invention relates to a power supply modulator for a radio transmitter having apportioned input impedance and buffered switching of power modules. A series arrangement of power supply modules, conventionally disposed in a diode cascade, includes individual inductors to apportion the input impedance of the switching power supplies. The switching sequence of the power supplies is controlled by a FIFO buffer, with the sequentially adjacent power supplies being disposed physically remote so that current transients and thermal loads are more uniformly distributed.

Abstract: A Gilbert Multiplier Cell includes an emitter-coupled transistor pair and a pair of cross-coupled emitter-coupled transistor pairs. A filter couples the emitter-coupled transistor pair to the pair of the cross-coupled emitter-coupled transistor pairs. The filter may include a pair of inductors or resistors, a respective one of which serially couples a respective one of the emitter-coupled transistor pair to a respective one of the pair of cross-coupled emitter-coupled transistor pairs, and a capacitor connected between the pair of inductors or resistors. A local oscillator is coupled to the pair of cross-coupled emitter-coupled transistor pairs and a data input is coupled to the emitter-coupled transistor pair. By low pass filtering the output of the emitter-coupled transistor pair that is applied to the pair of cross-coupled emitter-coupled transistor pairs, low noise floor Gilbert Multiplier Cells and quadraphase modulators may be provided.

Abstract: The present invention relates to a power supply modulator for a radio transmitter having apportioned input impedance and buffered switching of power modules. A series arrangement of power supply modules, conventionally disposed in a diode cascade, includes individual inductors to apportion the input impedance of the switching power supplies. The switching sequence of the power supplies is controlled by a FIFO buffer, with the sequentially adjacent power supplies being disposed physically remote so that current transients and thermal loads are more uniformly distributed.

Abstract: A small and inexpensive mixer that does not require a choke inductor and a large-capacitance capacitor. The mixer has a FET. The FET's source is grounded via a capacitor and is also connected to a power-supply terminal. The FET's gate is coupled to a bias voltage and also connected to a gate input terminal via a capacitor. The FET's drain is connected to an output terminal via a capacitor. A modulating signal is input into the power-supply terminal, and a local signal is input into the gate input terminal, so that a modulated signal is output from the output terminal.

Abstract: A low-powered mixer that is operable at a low voltage by a single positive power supply. A predetermined voltage and a first data signal Ss1 superimposed on the predetermined voltage are input into the drain D of an FET Q1, while a first carrier signal Sc1 is input into the FET Q1's gate G. The FET Q1 thus generates a first mixed signal So1 by mixing the first data signal Ss1 and the first carrier signal Sc1. A predetermined voltage and a second data signal Ss2 superimposed on the predetermined voltage are input into the FET Q2's drain D, while a second carrier signal Sc2 is input into the FET Q2's gate G. The FET Q2 thus generates a second mixed signal So2 by mixing the second data signal Ss2 and the second carrier signal Sc2. A capacitor C5 causes the sources S of the FETs Q1 and Q2 to float for DC and to be grounded for AC.

Abstract: A voltage and a data signal superimposed on the voltage are input to the drain of an FET and a carrier signal is input to the gate of the FET. The FET mixes the data signal and the carrier signal to generate the mixed signal. Two capacitors are connected between the source and ground for blocking direct current and passing alternating current.

Abstract: The invention concerns multipliers used to modulate a carrier by a signal. The signal is delivered by a Surface Acoustic Wave (SAW) filter, which requires a load impedance of low value, in the range of tens of ohms, and almost certainly less than 200 ohms. The invention modifies a Gilbert multiplier such that its signal-input stage presents the required load impedance to the SAW. The input impedance of the signal-input stage is adjustable.

Abstract: An I/Q-modulator or I/Q demodulator circuit in which the modulating signals (2, 3) are input through the output phase transfer branches of the circuit. In relation to the RF-characteristics, a series resistor (16) and a series inductance (20) in the phase transfer circuits are grounded with small capacitors (23, 25). A capacitor (17) having a high impedance at the modulating frequency is located between the branches. Tho modulating signals are not summed through the capacitor (17), and, thus, their phase difference is not weakened.

Abstract: A method for simultaneously imposing a single modulating signal on a number of constant frequency carriers includes applying the single modulating signal and all of the carriers to a doubly-balanced mixer circuit that produces sideband signals that are uncontaminated by the carriers. The sideband signals thus produced are then combined with signals proportional to the carriers in a linear circuit to obtain an output signal equivalent to a signal that would result from combining separately modulated carriers.

Abstract: The universally-applicable circuit arrangement of the invention makes possible an adjustment procedure for holding emitted optical power of a laser constant independent of temperature and aging. This circuit arrangement may be carried out as a three-stage cascade circuit supplied with operating voltages greater than 5 V. In accordance with the purpose of the invention, a circuit arrangement is provided which is universally applicable in a temperature range T=-40.degree. C. to 100.degree. C. for commercially available lasers and can be supplied by a standard 5 V source. In order to accomplish this as per the invention, differential amplifiers acting as current switches are arranged in a first cascade stage and the current sources feeding the differential amplifiers arranged in a second cascade stage. A data signal (D) serving to control the modulating current (I.sub.mod) is logically combined with a pilot signal (P) serving to control the pilot currents (I.sub.P1, I.sub.P2) in at least one cascade stage.

Abstract: The present invention relates to a power supply modulator for a radio transmitter having apportioned input impedance and buffered switching of power modules. A series arrangement of power supply modules, conventionally disposed in a diode cascade, includes individual inductors to apportion the input impedance of the switching power supplies. The switching sequence of the power supplies is controlled by a FIFO buffer, with the sequentially adjacent power supplies being disposed physically remote so that current transients and thermal loads are more uniformly distributed.

Abstract: Disclosed herein is a synchronous single cycle sample and control amplitude modulator for use with any carrier frequency. The modulator includes both a data input and a sine wave generator coupled with a sample and hold device. The sample and hold device synchronizes the data and the sine wave signal and then transmits the synchronized signal to a modulator. The modulator modulates the synchronized data and the sine wave signal such that a sampled and controlled, synchronous single cycle amplitude modulated signal is produced.

Abstract: An amplitude modulator circuit, having an input for receiving an input information signal and an output for providing an output signal, which is proportional to the input signal. The amplitude modulator circuit comprises at least two pass devices for amplifying the input information signal to produce the output signal and applying it to a load. The amplitude modulator circuit further comprises at least two voltage supplies for applying a plurality of supply voltages (at least some of which have different voltages) to the pass devices. The amplitude modulator circuit also includes a driver circuit having an input for receiving the input signal, and at least two driver outputs for driving the pass devices. The driver circuit activates the pass device having the lowest supply voltage that is sufficient to supply the required voltage to the load.

Abstract: An improved short distance, battery powered, amplitude modulated RF transmitter for transmitting encoded security data. An oscillator stage provides a control crystal and filter which are feedback coupled between the emitter and base of a transistor to oscillate at the fifth overtone of the fundamental crystal frequency. A filter tuned to the third harmonic of the overtone frequency selects the carrier frequency which is coupled via a resistive attenuator to an amplifier/filter stage, before the carrier is amplitude modulated with encoded security data. The improved transmitter circuit compensates for crystals exhibiting variations in series resistance and provides increased output power and improved frequency stability to temperature and over time. A foil antenna stage is augmented with the plates of the battery power supply to further improve performance.

Abstract: A balanced modulation circuit includes first, second, and third differential amplifiers. The first differential amplifier includes first and second transistors (Q11, Q12) having the emitters connected to first and second constant-current sources (CS11, CS12) and also connected with each other through a resistor, the collectors connected to the power supply line through respective base-collector-coupled transistors (Q13, Q14) used as diodes, and the bases connected to a first voltage source (V11) through respective resistors (R11, R12).

Abstract: Modulator circuit (MOD) with a modulator proper and a correction signal generator. The modulator proper comprises the cascade connection of an amplifier (T11, T21, CS11, T12, T22, CS12) and a first switching circuit (R11, T31, T51, R12, T32, T52), while the generator comprises the cascade connection of the same amplifier and a second switching circuit (R21, T61, T42, R22, T62, T41) having a correction output (P11, P12) coupled to a feedback input (P21, P22) of the amplifier via a feedback circuit (T71, R31, CS21, T72, R32, CS22). The amplifier and the switching circuits are controlled by a modulating signal and a carrier signal respectively and the first and second switching circuits provide a modulated output signal and a correction signal substantially equal to the envelope of the modulated output signal and used to decrease the modulator distortion.

Abstract: A microwave amplitude modulation system maintains constant amplitude attenuation at very high modulation rates over a broad range of microwave frequencies in response to voltage driving signals derived from modulation signals. In the system, the video input of a shunt-type PIN diode microwave amplitude modulation system is driven by a logarithmic voltage amplifier circuit which receives the modulation signals as an input.

Abstract: A method and apparatus for modulating or demodulating a radio frequency (RF) signal which incorporates a pair of quadrature couplers. In demodulating an RF signal, an LO signal and the RF signal are each phase shifted -90 degrees by the couplers. The RF and LO signals are mixed as are the phase-shifted RF and LO signals. Each mixed signal is low-pass filtered and the filtered signals are added thereby producing an intermediate frequency signal.