Abstract: In one implementation, a power converter with over-voltage protection includes a power switch coupled to a power supply through a tank circuit, and a control circuit coupled to a gate of the power switch. The control circuit is configured to turn the power switch OFF based on a current from the tank circuit, thereby providing the over-voltage protection to the power converter. In one implementation, the power converter is a class-E power converter. In one implementation, the control circuit is configured to sense the current from the tank circuit based on a voltage drop across a sense resistor coupled to the power switch.

Abstract: A system and method to enable vibration mediated communication between electrical devices such as photovoltaic solar panel controllers. The electrical devices may be connected to a mesh network with individual router devices. The individual router devices will send and receive data packets by creating or detecting vibrations in a solid vibration conducting media (such as the solar power wiring) that connects the individual electrical devices. Often at least one centralized control device is used to periodically request sensor data packets from the individual router devices and electrical devices. When the electrical devices are photovoltaic solar arrays, the centralized control device may, for example, be used to compute the proper adjustments for the solar arrays that will optimize the overall power output from the photovoltaic solar array. The control device will then send adjustment data packets back to the individual router devices through the mesh network, thus optimizing overall power output.

Abstract: An oscillator which oscillates electromagnetic waves includes a negative differential resistance element, a resonator configured to prescribe oscillation frequencies of the electromagnetic waves, a voltage modulation unit configured to modulate the negative differential resistance element, a stabilizing circuit configured to suppress parasitic oscillation, and a bias circuit, including a power supply and a line, used to control an operating point voltage of the negative differential resistance element. The voltage modulation unit is connected to the bias circuit through the stabilizing circuit.

Abstract: Oscillators (10) which oscillate at a fundamental frequency also generate harmonics. The fundamental frequency or a lower harmonic is used for feedback purposes, and a harmonic higher than either the fundamental frequency or the lower harmonic is used for output purposes. As a result, the oscillators (10) operate at a lower frequency than an output frequency and are low cost. Synthesizers (20) coupled to the oscillators (10) also operate at this lower frequency, and modulators (5) comprising such oscillators (10) and synthesizers (20) are low cost. A lower power consumption and less sensitivity to disturbing fields are further advantages. Filtering has become less complicated, and a smaller number of components has resulted in smaller dimensions. The oscillators (10) comprise tuning circuits (11) and amplifiers (12), which amplifiers (12) are fed back via feedback circuits (13). Such an amplifier (12) may comprise just a single transistor (40).

Abstract: A variable capacitor modulator for use in a voltage controlled oscillator, includes a differential varactor block, coupling capacitors for connecting nodes of the varactor block to a tank circuit, and an element connected between the respective nodes and ground to trim the gain of the variable capacitor modulator.

Abstract: A dual-modulus prescaler circuit for a frequency synthesizer comprises a plurality of asynchronous dividers-by-two connected in series, a phase selector unit (11) between two dividers-by-two (10, 12) and a control unit (13) for supplying control signals (S0, S1, S2) to the selector unit as a function of a selected mode. Said selector unit receives four signals phase shifted by 90° in relation to each other from a master-slave first divider and supplies a selected one of the four phase shifted signals. The control signals (S0, S1, S2) are supplied to the selector unit for selecting one of the four phase shifted signals (F2) at the output in a particular division period. As a function of the control signals supplied by the control unit (13) in one selected of the modes, the selector unit effects phase switching in each division period between two phase shifted signals selected by each branch. The second phase shifted signal i in phase lead of 90° in relation to the first phase shifted signal.

Abstract: An FM signal oscillator circuit includes a resonator having a graded- or abrupt-junction variable capacitance diode that is producible through standard IC manufacturing processes but causes an inconstant modulation level. The FM signal oscillator circuit, therefore, is provided with a function of maintaining a constant modulation level irrespective of oscillation frequencies. Namely, to maintain a constant modulation level without regard to oscillation frequencies that change depending on a control voltage applied to the variable capacitance diode, the FM signal oscillator circuit employs a variable gain amplifier whose gain changes in response to the control voltage. The variable gain amplifier amplifies a modulating signal, and the amplified modulating signal is superimposed onto the control voltage.

Abstract: In a single-chip multistandard video modulator arrangement in which audio signals for transmission with video signals are first modulated onto a subcarrier and then combined with the video signals for modulation onto a VHF or UHF main carrier, the modulated subcarrier signals are passed through a high-pass filter before being combined with the video signals in order to reduce the amplitude of any audio frequency components, and the resulting variations in main carrier amplitude, which tend to produce "sound in vision" effects.

Abstract: A frequency modulation circuit includes an emitter-follower connection transistor (2), having a base supplied with a modulation signal, for generating an emitter voltage which is in proportion to a modulation signal level; and an integrated mono-stable multi-vibrator (1) having an inversion trigger terminal ((A*)), a non-inversion trigger terminal (B), a resister/capacitor terminal (R.sub.X /C.sub.X), a capacitor terminal (C.sub.X), complementary output terminals (Q, (Q*)), and the like. The inversion trigger terminal ((A*)) is connected to the complementary output terminal (Q), the non-inversion trigger terminal (B) is connected to a partial voltage point of partial voltage resistors (10, 11), the capacitor/resistor terminal (R.sub.X /C.sub.X) is connected to the emitter of the transistor (2) through a resistor (3) and connected to the capacitor terminal (C.sub.

Abstract: A frequency modulator controls the center frequency and modulation factor at the same time with one control signal. The frequency modulator includes a voltage-to-current converter that receives an input voltage signal to be modulated, a reference voltage signal, and a control voltage signal, and generates an output current signal by combining the input voltage signal and the control voltage signal. The input voltage signal is amplified by a transconductance amplifier. The control voltage signal is converted into a gain signal which is used to vary the transconductance of the amplifier. A voltage controlled oscillator generates a frequency modulated signal responsive to the output current signal. The center frequency and modulation factor can be controlled by adjusting the value of a resistor in the current-to-voltage converter, a capacitor in the voltage control oscillator, or the control voltage signal.

Abstract: The high frequency circuit includes an oscillator connected in a Colpitts configuration. Negative feedback to the oscillator is applied through an amplifier, both to stabilize the circuit and to permit frequency modulation of the carrier signal generated by the circuit. This feedback incorporates a capacitance to neutralize the Miller effect, thereby enabling it to operate at exceedingly high carrier frequencies. A variation of the circuit permits it to be simultaneously controlled by both a voltage and a current control signal. Also, by applying a frequency modulated carrier signal at a particular node of the oscillator, a demodulated output signal may be obtained.

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 relaxation oscillator of reduced complexity is described which can be constructed as part of a silicon integrated circuit. The current controlled oscillator includes complementary field effect transistors operating in enhancement mode. The drain of one FET is connected to the gate of the other FET and vice versa. The resulting CMOS circuit functions as a four-layer diode. A resistor is connected between the drains of both transistors. A storage capacitor is connected between the sources of both transistors. A current source is connected to charge the storage capacitor such that the frequency of an oscillator output signal is determined by the current generated by the current source.

Abstract: A frequency control circuit of an FM modulator with a small number of external parts and a low number of IC pins, including a non-linear D/A converter, a current generator circuit and an emitter-coupled multivibrator. The non-linear D/A converter for giving an analog optimum resistance value depending on digital frequency control signals includes a plurality of resistors weighted by K.sup.n (1<K<2 and n is a sequential natural number). The current generator generates a current .DELTA.I depending on the output resistance value of the non-linear D/A converter. An oscillating frequency of the multivibrator is determined in proportional to I.sub.o /4CF.DELTA.I (I.sub.o represents a current value of an operational current source, C represents a capacitance of a capacitor, R represents a resistance value of a resistor and .DELTA.I represents a current flowing in the resistor). When the oscillating frequency is controlled depending on .DELTA.

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: A frequency modulation circuit which varies the resonance frequency of an LC resonance circuit, and which corresponds to the frequency modulation conversions of all TV methods with a simple constitution. Each of a plurality of passive element series circuits for varying a time constant of the LC resonance circuit is composed of, for instance, a capacitor and a resistor, which is switched and controlled by connecting to or separating from the LC resonance circuit by a switching circuit such as a transistor. Thereby, the oscillation frequency of the LC resonance circuit can be easily converted to a predetermined frequency.

Abstract: A voltage controlled oscillator apparatus for generating a desired frequency, set by a tuning voltage, toward modulating a transmission signal on the desired frequency. The voltage controlled oscillator apparatus includes an oscillator transistor the base of which is RF live so as to destabilize the transistor such that it oscillates. The oscillator transistor emitter is operably connected through a capacitor to a tank circuit, which stores RF energy at the desired frequency, based on the tuning voltage, to set the oscillator transistor frequency. The inherent collector-base junction capacitance serves to provide voltage variable capacitance resulting in the generation of a carrier signal. The oscillator transistor collector is electrically connected to an amplifier transistor's emitter, such that the amplified transistor and oscillator transistor are in cascode configuration. The amplifier transistor amplifies the transmission signal input at its base and presents a signal output on its collector.

Abstract: An integrated circuit is provided with particular application for high frequency modulation circuits, such as a mixer circuit, with reduced noise and gain. The circuit provides a novel application of a single device comprising a 4 or 5 terminal, gate controlled lateral bipolar junction transistor device, in the form of a merged MOS and lateral bipolar transistor. In a grounded base configuration, RF and LO signals are applied to the gate and emitter terminals respectively and provide for modulated output at the collector, and provides signal modulation with reduced noise compared with multi-device implementations of known mixer circuits using a summation circuit, diodes and FETs. Advantageously, operation of the device in the grounded base or grounded emitter configuration provides for strong modulation of the DC current gain, i.e. over 4 decades, as a function of gate voltage.

Abstract: A device that frequency up-shifts an impinging electromagnetic wave, facilitating signal pulse compression, consisting of a semiconductor block or waveguide containing an optically induced relativistic plasma wave which interacts with an applied or self generated electromagnetic signal.

Abstract: A device that frequency up-shifts an impinging electromagnetic wave, facilitating signal pulse compression, consisting of a semiconductor block or waveguide with an optically-induced relativistic plasma wave which interacts with an applied or self generated electromagnetic signal.

Abstract: A frequency modulation oscillator circuit includes an oscillator stage having two emitter-coupled transistor pairs, each being fed from at least one controllable current source, and at least one trigger stage for triggering the controllable current sources for the two transistor pairs.

Abstract: For realizing a highly sensitive and favorably linear frequency modulator stably operating with a small-sized and readily manufactured arrangement, input and output strip electrodes are disposed in face on both ends of a ferri-magnetic film deposited on a magnetic substrate and applied with a DC magnetic field perpendicular thereto, a high frequency electro-magnetic wave being applied through the input electrode, so as to generate a magneto-static forward volume wave propagating through the magnetic film, the propagation phase of which is modulated in response to the intensity variation of the applied magnetic field modulated by a signal, so as to derive a frequency modulated electro-magnetic wave from the output electrode.

Abstract: A modulator circuit comprises an input for receiving an audio frequency (AF) signal, an oscillator circuit for providing a carrier wave signal, a mixer circuit for mixing the AF input signal with the carrier wave signal to provide an AM modulated signal, a switch having a first position in which the AM modulated signal is provided to an output and the switch having a second position in which the AM modulated signal is provided to a vector adding circuit where the AM modulated signal is vector added to the carrier wave signal, and the circuit including phase shift circuitry for shifting the phase of the AM modulated signal prior to vector adding with the carrier wave signal whereby to provide an FM modulated version of the AF input signal on the oscillator carrier wave.

Abstract: A voltage controlled oscillator circuit including an oscillator circuit having first and second terminals to which an external inductance is connected. A frequency control voltage (V.sub.F) is applied through a bias circuit to the second terminal for varying the center frequency. The oscillator circuit may have an AGC circuit or a modulation circuit connected to it. An output amplifier is connected with the first terminal and has an adjustable output impedance for matching the input impedance of a load circuit.

Abstract: An oscillator circuit is tunable by a tuning circuit which includes a spiral inductor disposed on a ferrite substrate. The oscillator circuit is tuned or modulated by varying a current through the spiral inductor.

Abstract: An improved frequency modulation apparatus (100) is provided comprising a generator (102), a biasing voltage line (116), and an interface circuit (110). The generator (102) is utilized to generate a carrier signal. A control line input (104) on the generator (102) adjusts the frequency of the carrier signal. The biasing voltage line (116) provides DC power in order to DC bias the generator (102). The interface circuit (110) couples an information signal (114) to the biasing voltage line (116) for altering the biasing of the generator (102) in response to the information signal (114). The alteration of the biasing of the generator (102) results in the carrier signal being frequency modulated by the information signal (114).

Abstract: A frequency modulation circuit includes a VCO which constitutes a PLL along with a loop filter which is operated by a current source. Such a frequency modulation circuit is formed in monolithic IC. When a power source of the IC is turned-on, a capacitor included in the loop filter is biased by an output voltage of a voltage follower which receives Vcc/2. Since this output voltage rises in the same manner as Vcc, a center frequency of the VCO can be rapidly pulled into a phase-locked state of the PLL. In addition, the frequency modulation circuit is provided with a voltage-to-current conversion circuit which increases a charging current for the capacitor in response to a mute signal generated when the power source is turned-on, whereby the time constant of the loop filter is decreased substantially.

Abstract: A signal delay device comprises a CMOS gate circuit having an input terminal to which a binary input signal to be delayed is applied, an output terminal from which a delayed signal is derived and power voltage supply terminals to which operation power voltages are applied. The delay time of the CMOS gate circuit depends upon voltage applied to it and, utilizing this phenomenon, voltage control means is provided in a power supplying path for the CMOS gate circuit for controlling voltage applied to the CMOS gate circuit. The signal delay device using the CMOS gate circuit is applied to various circuits including a FM modulator or FM demodulator. The signal delay device will assure undistorted signals.

Abstract: A frequency modulator is provided, in which, for instance, a video signal is used as a modulation signal. A differential amplifier is formed by first and second transistors. First and second load resistors are connected between respective collectors of the first and second transistors and a power supply terminal (A). A series circuit of first and second feedback capacitors is inserted between the collector of the first transistor and a base of the second transistor. A series circuit of third and fourth feedback capacitors is inserted between the collector of the second transistor and a base of the first transistor. The respective same electrodes of first and second variable capacitance diodes are connected with each other and the other electrodes thereof are connected respectively to a junction point of the first and second feedback capacitors and to a junction point of the third and fourth feedback capacitors.