Abstract: A radio frequency rectifier circuit may include a resistive termination to circuit ground, a plurality of inductors, and at least a first pair of rectifier components. The plurality of inductors may be connected electrically in series between an input node for receiving an input RF signal and the resistive termination. Each pair of electrically adjacent inductors of the plurality of inductors may be connected together at a respective in-line node. The first pair of rectifier components may electrically couple a first one of the in-line nodes to a respective direct current output node. Each rectifier component may have a cathode and an anode. A first rectifier component of the first pair of rectifier components may have the cathode electrically connected to the first in-line node and a second rectifier component of the first pair of rectifier components may have the anode electrically connected to the first in-line node.

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: The present invention is a high power direct transmitter with frequency-shift keying (FSK) modulation. The transmitter implements a high power, high efficiency power voltage-controlled oscillator (VCO) which allows for production of a modulated RF signal at the final stage (ex.—right at the antenna), thereby eliminating all driving stage power amplification and frequency translation. The transmitter further provides a low SWAP-C alternative to currently available solutions.

Abstract: With some embodiments, a VCO (voltage controlled oscillator) operates at an integer multiple (N) above a desired transmission frequency. In accordance with one embodiment, a chip is provided with a VCO to generate a signal and a frequency dividing circuit to provide a reduced frequency version of the signal to a transmit mixer. The transmit mixer is followed by a power amplifier that is on the same die as the VCO. The power amplifier is to generate an OFDM output transmission.

Abstract: A semiconductor element for macro and micro frequency tuning, and an antenna and a frequency tuning circuit having the semiconductor element, are provided. The semiconductor element includes first and second semiconductors which have a same polarity, a third semiconductor which has a polarity opposite to the polarity of the first and second semiconductors and is interposed between the first and the second semiconductors, a first intrinsic semiconductor which is interposed between the first and the third semiconductors, and a second intrinsic semiconductor which is interposed between the third and the second semiconductors.

Abstract: A charge pump-based frequency modulator is provided. The charge pump-based frequency modulator comprises an analog phase correction path comprising a varactor and a charge pump. The varactor is coupled to an output of the charge pump-based frequency modulator. The charge pump is coupled to a node between the varactor and the output and receives a signal containing the modulated data.

Abstract: A circuit arrangement for frequency modulation is provided, which includes a voltage-controlled oscillator having at least one varactor diode that is driven by a drive signal, wherein a capacitance of the varactor diode depends on the drive signal, includes a modulating unit that creates a modulation signal for frequency modulation of the voltage-controlled oscillator, and includes a drive unit that generates the drive signal for the at least one varactor diode from the modulation signal, wherein the drive unit generates the drive signal from the modulation signal in such a manner that a linear relationship results between the modulation signal and the capacitance of the varactor diode.

Abstract: A modulation-signal generating circuit includes a temperature monitoring unit that detects a casing temperature of the circuit, a voltage control oscillator including two variable impedance circuits that independently control oscillation frequency based on an input control voltage, a frequency-correction-voltage generating unit that outputs a voltage for compensating for a temperature drift of an oscillation frequency according to the casing temperature detected by the temperature monitoring unit, to one of the variable impedance circuits, and an FM-modulation-voltage generating unit that outputs a modulation voltage containing a constant DC component not depending on temperature and a predetermined AC component, to the other variable impedance circuit, under a temperature drift compensation condition of the frequency-correction-voltage generating unit.

Abstract: Transistors M11 and M12 are cross-coupled to each other so as to form a negative resistance circuit. First and second variable capacitor sections 10 and 20 are connected in parallel with an inductor circuit so as to form a parallel resonant circuit. A first reference voltage Vref1 and a control voltage VT1 corresponding to a carrier wave component are fed to both terminals, respectively, of each of variable capacitors VC11 and VC12 included in the first variable capacitor section 10. A second reference voltage Vref2 and a control voltage VT2 corresponding to a modulated wave component are fed to both terminals, respectively, of each of variable capacitors VC21 and VC22 included in the second variable capacitor section 20.

Abstract: To avoid intermodulation interferences, a varactor diode alternative circuit has at least three varactor diodes connected in series alternatingly opposite to one another and a resistor and/or inductor network. At each of the varactor diodes, a control voltage supplied to the circuit for adjusting capacitance is at least approximately at full extent. An alternating voltage applied at the series connection, which is at a higher frequency than the control voltage, is distributed at least approximately uniformly to the varacter diodes. Even for an at least not substantially larger tuning voltage than the amplitude of a signal voltage to be processed in the oscillator circuit that has the alternative circuit, reactions of the signal voltage on the set capacitance of the varactor diode alternative circuit remain negligible, or at least low. The circuit may be used in an electrical, e.g., battery-operated, unit in which only one small operating voltage is available.

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: The present invention relates generally to the field of frequency modulation, and in particular to dual port frequency modulators. The present invention provides a frequency modulator comprising a phase lock loop circuit (108) for receiving and modulating a carrier signal according to the low frequency component of a modulating signal, the phase lock loop circuit comprising a voltage controlled oscillator (118) for outputting a modulated carrier signal and a loop filter (116) for outputting a steering voltage to the VCO, the VCO having a tank circuit (120) comprising a voltage controlled capacitance (VAR1). The frequency modulator also comprises an external voltage controlled capacitance (122) which is arranged to modulate its capacitance according to a high frequency component of the modulating signal, the second voltage controlled capacitance being coupled to the tank circuit.

Abstract: A system for synchronizing a portable transceiver to a network is disclosed. Embodiments of the system for synchronizing a portable transceiver to a network include a crystal oscillator, a frequency synthesizer adapted to receive an output of the crystal oscillator, logic coupled to the crystal oscillator, the logic configured to estimate a frequency error of a received signal; and a first control signal supplied from the logic to the frequency synthesizer, the first control signal configured to adjust the frequency synthesizer to compensate for the error.

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: A method and apparatus for modulation of a voltage-controlled oscillator (VCO). The VCO receives a tuning control voltage for adjusting a center frequency of an output periodic signal formed by the VCO. In addition, the VCO receives a modulation control voltage for modulating the output periodic signal by a content-carrying signal according to frequency modulation techniques. A frequency deviation obtained in the output periodic signal in response to changes in the modulation control voltage is linearized by forming the modulation control voltage as the result of a linear correction polynomial. A linear correction circuit forms the modulation control voltage. More particularly, a first amplifier having a gain of K1 receives the tuning control voltage. A first summing block then receives the output of the first amplifier and adds the constant K0. A second amplifier having a gain of m receives the content-carrying signal.

Abstract: A voltage controlled oscillator circuit (58) having a modulation input port (60) for receiving a modulation input signal through modulation circuit (62, 64, 66, 68) and a frequency resonator circuit (28, 74, 76, 80, 82, 84) operable coupled to the modulation input port (60) for providing a modulation dependent impedance. A semiconductor element (90) has three ports, a gate port (98), a source port (96) and a drain port (92), and the modulation circuit is operably coupled to the gate port (98) of the field effect transistor (90) via a first capacitance (70) and the source port (96) of the field effect transistor (90) via a second capacitance (71). This enables the modulation sensitivity to be substantially independent of temperature variations of circuit elements.

Abstract: A voltage controlled oscillator having a reduced oscillation frequency-modulation sensitivity variation and having a positive modulation function is designed to: (a) reduce the modulation variation by making the rate of change in oscillation frequency with a certain change in a modulation signal generally constant with respect to a wide range of oscillation frequencies; (b) reduce the manufacturing cost by using only one varactor diode; and (c) reduce the cost of a system using the voltage controlled oscillator by eliminating the need for correction of the modulation variation on the side of a system using the oscillator. In a variable capacitance circuit of the voltage controlled oscillator, the cathode of a varactor diode is connected to a control voltage terminal and is also connected to a modulation signal input terminal by a coupling resistor and a voltage dividing resistor.

Abstract: A low-noise oscillator circuit with an amplifier element for negative feedback, specifically a transistor. In addition to a positive feedback of the oscillator transistor, provision is made for a negative-feedback loop with a pass band of 0 (thus DC coupling) to 1/4 to 1/100 of the oscillation frequency of the oscillator, in order to regulate out fluctuations of the current of the amplifier element.

Abstract: A broadcast transmitter for generating low power modulated signals, especially for a wireless speaker system. A signal source such as a source of composite audio signals including left and right audio signals and a pilot signal are applied to a radio frequency signal oscillator. The radio frequency signal oscillator includes a bipolar transistor connected in a common base configuration, and having a stripline element as a frequency determinative component in the collector circuit of the bipolar transistor. The modulating signal is applied to the base of the bipolar transistor which modulates the collector junction capacitance of the transistor thereby frequency modulating the signal produced by the oscillator. Varactor tuning is provided for setting a nominal frequency of oscillation.

Abstract: An oscillator circuit is provided for stabilizing the amplitude of a HF oscillation of an audio signal. In such an oscillator circuit, an audio signal having a frequency in the range of 20 Hz . . . 20 kHz is coupled into the oscillator circuit, is modulated with a high frequency and is emitted in the form of an RF audio signal having a frequency of more than 2 MHz. Such an oscillator circuit is used for instance in an infrared transmitting unit, wherein a low frequency audio signal is transformed into a higher frequency infrared signal. The higher frequency audio signals are transmitted via infrared channel to an appropriate receiving unit--for instance to infrared head phones--which comprises a receiving unit having an appropriate demodulator and preferably also a stereo-decoder in order to reproduce the low frequency audio signals.

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: In a structure adopted for an FM-CW radar, a corner waveguide for connecting each of transmission and reception antennas to a sensor unit is integrated with a sensor unit case. In a waveguide/strip line converter for converting the transmission mode between the waveguide and the strip lines in the circuits of the sensor unit, a ditch is dug in the inner wall of an opening of the waveguide in order to prevent oozing of conductive adhesive. The strip line board is abutted on the inner wall of the waveguide in order to restrict a length of a projecting portion of a line conductor on the strip line board. By employing an oscillator mixer or a multiplier mixer, the circuitry in the sensor unit can be simplified without using lots of expensive millimeter wave devices. Furthermore, power can be utilized effectively even when a switching radar is off, which enables measurement of an absolute speed. Moreover, cost reduction can be achieved.

Abstract: A VCO circuit has a voltage variable capacitance CVD2 connected in series with or in parallel to a condenser C3 connected in series with an inductance L1, which constitutes a resonator of the VCO circuit. An adjustment voltage VD2 is applied to a cathode of the voltage variable capacitance CVD2, such that the relation between a control voltage VD1 and an oscillation frequency f0 of the VCO circuit is electrically adjusted to improve the fabrication yield.

Abstract: A pullable overtone crystal oscillator (201) includes an impedance buffer (217) for buffering an input impedance (109) to an amplifier stage (203). This structure enables construction of an overtone oscillator with increased pullability because a drive level of a crystal (221) can be set independent of the input impedance (109) of the amplifier stage (203).

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: A tuning circuit for a reference oscillator (200) including voltage variable capacitors (222, 224) in a back to back configuration and providing a control terminal for voltage controlled tuning of the reference oscillator (200). Also included in the tuning circuit is a modulation bias circuit for modulating the reference oscillator (200).

Abstract: An apparatus and method for demodulating and remodulating a transmitted signal prior to presentation to a television receiver, the transmitted signal comprising a video signal, a first channel signal, and a second channel signal, wherein one of the two channel signals is selected, demodulated and remodulated with the video signal prior to presentation to the television receiver. The apparatus allows the viewer of a television receiver which accepts a single channel signal to select between one of two alternate channel signals associated with a video broadcast without the need to modify the television receiver. The apparatus is particularly well suited for television broadcasts using a dual carrier transmission format. A novel varactor diode tuning means is used in one embodiment for changing the center frequency of a frequency modulation demodulator. The disclosed apparatus also transparently allows stereo demodulation for television receivers which are capable of such stereo demodulation.

Abstract: The invention relates to a biased electronic circuit in which a voltage-controlled component has a characteristic with a non-linear portion and a substantially linear portion. The circuit is biased by a voltage being applied to one terminal of the component thereby shifting the operation of the component to the linear portion.

Abstract: A fundamental or subharmonic optically injection locked oscillator is coupled to a phase locked loop circuit. The injection locked oscillator has two single stage HEMT amplifiers with parallel feedback from the drain of a second transistor to a gate of a first transistor. A feedback resonant network controls the oscillator frequency. A microwave/millimeter wave source modulates a laser diode and the signal from the laser diode is then transmitted via an optical fiber to a PIN photodetector diode. The signal from the photodetector diode is injected into the oscillator at an nth subharmonic of the oscillator frequency. The feedback network may consist of a microstrip gap resonator with two tuning varactors at the ends of the resonator. The phase locked loop includes a balanced mixer used as a phase detector to compare the nth harmonic of the signal from the photodetector diode to the sampled output of the oscillator.

Abstract: Biomedical information is directly digitally telemetered from the patient through a frequency modulated transmitter to a remote receiver and computer station. A phase-lock-loop circuit in the digital transmitter compensates for DC data bias by averaging and generating a scaled measure of the DC content of the digital data fed into the phase-lock-loop circuit. The average signal is then provided as a control signal to a first voltage controlled crystal oscillator, the output of which is then used as a reference frequency for the phase-lock-loop circuit. Frequency modulation of the digital data is provided by coupling the digital data directly into the voltage control input of the voltage controlled oscillator which generates the output frequency. Further control of the phase-lock-loop circuit in the transmitter is achieved by prepositioning the operating frequency of the voltage controlled oscillator by means of a microcontroller.

Abstract: For minimization of a microstrip line and improvement of a Q value, the line length and width of the microstrip line are minimized, and the high frequency trend of the resulting resonant frequency is lowered and corrected to the resonant frequency near the oscillation frequency of an oscillator by connecting an additional capacitance component to the microstrip line. Thereby, the minimization of the microstrip line or the minimization of an oscillation circuit and characteristics equivalent to a dielectric coaxial resonator may be readily obtained. The strip line and the additional capacitance component are made as one piece circuit elements. The microstrip line is connected with a stub such that the stub may be trimmed to adjust the oscillation frequency. A cascode connecting amplifier which lessens the oscillation frequency fluctuation due to load variations is used.

Abstract: A frequency-modulation modulator in a cellular wireless telephone for modulating frequency after uniformly and linearly compensating for frequency characteristics to be suitable for each engaged channel in a cellular wireless telephone. Since frequency modulation characteristics are compensated uniformly and linearly according to each one of a plurality of channels, an error due to the frequency distorted modulation can be prevented and the cellular wireless telephone becomes more reliable.

Abstract: A diode circuit in which the flicker noise generated by the diode is reduced comprises a diode (D1) connected in series with a resistor (R2) having a by-pass capacitor (C1) in parallel therewith. In one embodiment the side of the diode remote from this resistor (R2) is connected to one input of a DC differential inverting amplifier (A1) via a low pass filter (L1, C2). The amplifier's output is negatively fed back to the junction of the diode (D1) and the resistor (R2) so that the latter forms the amplifier load. A control voltage is applied to the other input of the amplifier of such value as to produce the required diode bias. The basic diode circuit can be extended to perform functions such as amplitude limiting, frequency control and modulation.

Abstract: Voltage controlled oscillator provided with a resonant network, an amplifier and a reactive network, all incorporated in an oscillator loop, the reactive network having one or more reactive components whose values depend on a control signal fed to a control input, so that the oscillator frequency can be regulated with said control signal. A control loop is provided between the resonant network and the reactive network, with which control loop the difference is determined between a measure of the imaginary part of the impedance or admittance of the resonant network and the control signal acting as reference quantity. The imaginary part of the impedance or admittance of the reactive network is regulated with said difference. The control loop contains a derivation circuit for deriving said measure and a differential amplifier, to one input of which the output signal of the derivation circuit is fed and to the other input of which the control signal is fed.

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: Briefly, according to the invention, a voltage controlled oscillator 200 having a control input, an information signal input, and an output is disclosed. The voltage controlled oscillator 200 comprises a tank circuit 202 for generating a carrier signal and a modulator 206 for modulating the carrier signal in response to the information signal 210 at the information signal input of the voltage controlled oscillator 200. The voltage controlled oscillator 200 includes a filter 208 coupling the modulator 206 to the tank circuit 202 for rejecting out of band signals from altering the bias point of the modulator 206.

Abstract: A method and apparatus for modulating a radio frequency signal with digital data including: a variable oscillator, a modulator for varying the oscillator's output, a network for detecting when the oscillator's output crosses its zero axis, a storage device for storing an applied data bit, and wherein the storage device applies the data bit to the modulator when the oscillator's output is at its zero crossing point.

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.

Abstract: A circuit for use in conjunction with a voltage controlled oscillator (VCO). The circuit introduces modulation into a radio system (to create a substantially flat frequency response) at the same VCO port at which VCO frequency centering and negative bias control signals are introduced. A potentiometer is utilized both for providing an adjustable negative bias to the varactor in the VCO resonant circuit and for setting the VCO to the appropriate center frequency. Modulation compensation circuitry is coupled to the control arm of the potentiometer and to the anode of the varactor (via a choke 4). The modulation compensating circuitry is preferably designed to have a transfer function that is substantially the inverse of the closed loop transfer function of the phase locked loop system with respect to the frequency modulation of the VCO.