Abstract: A receiver apparatus coupled to receive an RF signal having frequency components in a desired band and an image band, includes: an image rejection filter; a local oscillator to produce a first signal; a frequency divider to produce a plurality of second signals; a first mixer, coupled to receive the RF signal and the first signal, to produce an intermediate signal; and a frequency translation filter including a plurality of mixers each coupled to receive the intermediate signal and a different one of the plurality of second signals; and at least one impedance coupled as a load to each of the plurality of mixers, wherein: the image rejection filter and the frequency translation filter are configured to operate in conjunction to form a band-pass filter in the desired band and a band-stop filter in the image band and to apply the band-pass filter and band-stop filter to the RF signal.

Abstract: A signal generation device for generating radio frequency, RF, signals, the signal generation device comprising a waveform input for receiving a number of basic waveforms, a control command input for receiving control commands each comprising control information for modifying a respective basic waveform, a RF frontend for transmitting RF signals, and a waveform processor, which based on the control commands modifies the respective basic waveforms and transmits the resulting modified waveforms through the RF frontend.

Abstract: Systems and methods for selecting, combining and duplexing signals in a communications network. Several configurations of diplexers and channel selectors are disclosed which use filters, combiners and splitters to select and combine which the signals to be either received or transmitted.

Abstract: The invention concerns an oscillator generating a wave composed of a frequency of on the order of terahertz from a beat of two optical waves generated by a dual-frequency optical source. The oscillator includes a modulator the transfer function of which is non-linear for generating harmonics with a frequency of less than one terahertz for each of the optical waves generated by the dual-frequency optical source, an optical detector able to detect at least one harmonic for each of the optical waves generated by the dual-frequency optical source and transforming the harmonics detected into an electrical signal, a phase comparator for comparing the electrical signal with a reference electrical signal, and a module for controlling at least one element of the dual-frequency optical source with a signal obtained from the signal resulting from the comparison.

Abstract: Techniques for detecting and mitigating interference are described. A device (e.g., a cellular phone) senses interference levels and digitally reconstructs the expected interference in the received signal. The device may correlate the reconstructed interference with the received signal and determine interference in the received signal based on correlation results. The device may adjust the operation of one or more circuit blocks (e.g., a mixer, an LNA, etc.) in a receiver based on the detected interference in the received signal. Alternatively or additionally, the device may condition the digital interference to obtain conditioned reconstructed interference matching the interference in the received signal and may then subtract the conditioned interference from the received signal.

Abstract: The present invention relates to an atomic frequency acquisition device comprising a gas cell (400) filled with an atomic gas, a laser light source (100) emitting a laser beam which enters the gas cell (40) and excites a first energy transition of the atomic gas, a local oscillator (700) for generating an oscillator frequency in a frequency range including a frequency of a HFS transition of the atomic gas, and a modulator (600) modulating the laser light source (100) so as to emit laser radiation modulated with the oscillator frequency. An optical reflector (500) is arranged behind the gas cell (400) to reflect the laser beam after passage through the atomic gas so as to re-enter the laser cavity. A photodetector (200) detects beat frequencies caused by self-mixing interference within the laser cavity.

Abstract: A local oscillator circuit for a signal transmitter or receiver, the circuit comprising: an input for receiving a master oscillating signal from a master oscillator; and signal processing circuitry configured to be clocked by the master oscillating signal to generate a local oscillator signal, the signal processing circuitry being such that the local oscillator signal has substantially no harmonic content at any integer multiple of the frequency of the master oscillator signal, which oscillates at (2n+1)/2 times the frequency of the generated local oscillator signal, with n being a positive integer.

Abstract: The present invention provides an array of tunable, injection-locking oscillators which are scalable to higher frequencies and measure the entire relevant frequency space simultaneously. The scalable, highly-parallelized, adaptive receiver architecture uses arrays of tunable, injection-locking nonlinear oscillator rings for broad spectrum RF analysis. Three separate and different microelectronic circuit configurations, each having a different type of readout, are described. The embodiments are designed to be incorporated as a subsystem in any type of powered system in which a fast image of the broader spectrum is valuable, when no information about the location of signals in the frequency space is predictable or forthcoming.

Abstract: Provided are a multi-output oscillator using a single oscillator, and a method of generating multiple outputs. The multi-output oscillator includes: an oscillator outputting the single frequency; a multiplier multiplying the single frequency to output a first frequency; a first frequency divider dividing the single frequency by a first division factor; a first mixer outputting a second frequency by mixing an output of the first frequency divider and an output of the multiplier; a second frequency divider dividing the single frequency by a second division factor; a second mixer mixing the output of the second frequency divider and the output of the first mixer to output a third frequency; and a third mixer mixing the output of the second frequency divider and the output of the multiplier to output a fourth frequency.

Abstract: A first and a second resonator are fabricated monolithically adjacent to one another. The first resonator is the reference resonator. The resonant frequency of the second resonator is offset by a difference frequency Fo from the first resonator. Each resonator is included within an oscillator. A mixer receives the output of both oscillators. A low pass filter receives the mixer output and generates a clock signal whose frequency is equal to the difference frequency Fo.

Abstract: A nonlinear solid-state device useful for frequency conversion of electromagnetic radiation and in particular for harmonic generation, comprising a waveguiding electromagnetically distributed structure (WEDS) which includes monolithically a synthetic nonlinear material (SNM). Input radiation coupled into the WEDS is converted into a higher frequency output radiation through a constricted oscillatory motion of charge carriers and phase matched harmonic frequency generation of radiation which builds up coherently over an interaction length many time larger than the radiation wavelengths. In one embodiment, microwave radiation is converted into terahertz radiation. In other embodiments, SNM based WEDS devices are adapted for frequency mixing and parametric oscillation.

Abstract: Provided are a harmonic rejection mixer and a harmonic rejection mixing method. A plurality of oscillator signals having a ? duty cycle and uniform phase differences may be generated and a differential or quadrature mixer with harmonic rejection may be realized by using the oscillator signals.

Abstract: The present invention provides a frequency synthesizer for a wireless communication system. The synthesizer includes an oscillator that generates an electronic signal as well as frequency dividers, frequency selectors and mixers. The signal generated by the oscillator is sequentially divided by the frequency dividers to produce a first group of frequencies, and the selectors and mixers are then capable of mixing the first group of frequencies according to instructions from control bits to produce a second group of frequencies which constitute UWB band frequencies. In this manner, the synthesizer can generate all 14 UWB band frequencies or particular UWB band groups using a single oscillator. One of the frequencies generated by the dividers can also be used as the baseband clock signal without requiring an additional frequency source.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. An input baseband signal is interpolated and upconverted in the digital domain to an IF. The LO operates at a frequency which is a n/m division of the target RF frequency fRF. The IF frequency is configured to ½ of the LO frequency. The upconverted IF signal is then converted to the analog domain via digital power amplifiers followed by voltage combiners. The output of the combiners is band pass filtered to extract the desired replica.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The signal is input to a synthesizer timed to a rational multiplier of the RF frequency fRF. The signal is then divided to generate a plurality of phases of the divided signal. A plurality of combination signals are generated which are then multiplied by a set of weights and summed to cancel out some undersired products. The result is filtered to generate the LO output signal.

Abstract: There is provided a feedback circuit including: an oscillator generating an oscillation frequency signal; a mixer unit having an input terminal, a feedback terminal, and an output terminal and outputting a frequency signal through the output terminal, the frequency signal obtained by adding or subtracting frequency of a feedback signal, input through the feedback terminal, to or from frequency of the oscillation frequency signal input through the input terminal from the oscillator; a first frequency divider dividing the frequency signal output from the mixer unit at a division ratio of N (N is a multiple of 2) to generate an output signal; and a feedback circuit adjusting the output signal of the first frequency divider for the first frequency divider to output a frequency signal in a desired band and feeding back the adjusted signal to the feedback terminal of the mixer unit.

Abstract: According to one exemplary embodiment, a local oscillation generator includes a mixing stage for receiving a primary frequency and one of a number of related frequencies. The local oscillation generator further includes a first transconductance stage to provide a first related frequency to the mixing stage when a first switch selectably enables a first power path in the first transconductance stage. The local oscillation generator further includes a second transconductance stage to provide a second related frequency to the mixing stage when a second switch selectably enables a second power path in the second transconductance stage. The local oscillation generator further includes a number of dividers, where an output of a first divider provides the first related frequency to an input of the first transconductance stage, and where an output of a second divider provides the second related frequency to an input of the second transconductance stage.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The input signal is fed to a synthesizer timed to a rational multiplier of the RF frequency L/N fRF. The clock signal generated is divided by a factor Q to form 2Q phases of the clock at a frequency of L(N*Q)fRF, wherein each phase undergoes division by L. The phase signals are input to a pulse generator which outputs a plurality of pulses. The pulses are input to a selector which selects which signal to output at any point in time. By controlling the selector, the output clock is generated as a TDM based signal. Any spurs are removed by an optional filter.

Abstract: A mixer is provided. The mixer comprises a Gilbert cell mixer core, a pair of load devices, a transconductor cell, and a current injection branch. The Gilbert cell mixer core has first and second nodes, receives a first differential input signal, and provides a differential output signal at the first nodes. The load devices are respectively coupled between the first nodes of the Gilbert cell mixer core and a first fixed voltage. The transconductor cell is coupled between the second nodes and a second fixed voltage and receives a second differential input signal. The dynamic current injection branch comprises first and second pairs of MOS transistors each connected in parallel and having drains commonly coupled to a corresponding second node and gates receiving a third differential input signal. There is a phase difference of 90° between the first and third differential input signals.

Abstract: Whispering-gallery-mode (WGM) optical resonators made of crystal materials to achieve high quality factors at or above 1010.

Abstract: An oscillator circuit, a transceiver, and a method for generating an oscillatory signal are provided to avoid the VCO pulling effect. The oscillator circuit includes an oscillator, a frequency multiplier, a frequency divider, and a mixer module. The oscillator is utilized for generating a first signal having a first frequency. The frequency multiplier is coupled to the oscillator, and utilized for generating a second signal according to the first signal, wherein the second signal has a second frequency. The frequency divider is coupled to the oscillator, and utilized for generating a third signal according to the first signal, wherein the third signal has a third frequency. The mixer module is coupled to the frequency multiplier and the frequency divider, and utilized for mixing the second signal and the third signal to generate the oscillatory signal having an output frequency being not a harmonic of the first frequency.

Abstract: The embodiments of the present invention provide a configurable homodyne/heterodyne RF receiver including first and second mixers. The configurable homodyne/heterodyne RF receiver functions as a homodyne receiver when the first and second mixers are configured to operate in parallel, and as a heterodyne receiver when the first and second mixers are configured to operate in series. The embodiments of the present invention further provides an RFID reader employing the configurable homodyne/heterodyne RF receiver to facilitate a listen-before-talk function.

Abstract: A control loop (10) for producing an output signal with a stable nominal frequency is provided. The control loop includes inputs for reference (11) and oscillator (25) output signals, a beat frequency generator (12) for producing a signal with a frequency that is the difference between the oscillator and reference signal frequencies, an ADC (14) to convert the beat frequency to a digital beat frequency signal, an estimator (17) for estimating the frequency or phase of the beat signal, an adder (18) for combining an offset and modulation signal and the estimated frequency or phase of the beat signal into an added signal, and a DAC (23) for generating an analogue control signal for controlling the oscillator output frequency.

Abstract: An IF input signal corresponding to a selected reception channel is applied through an SAW filter to an IF-AGC circuit, the amplitude of the signal is adjusted to a prescribed level, and the signal is thereafter supplied to a down converter unit. The down converter unit selectively outputs a Low-IF signal provided by down-converting the IF input signal and the High-IF signal amplified without frequency conversion, in accordance with an external instruction. A filter circuit has its cut off frequency selectively set to pass the Low-IF signal only, or both the Low-IF and High-IF signals.

Abstract: A frequency generation apparatus and a method are provided. The frequency generation apparatus for generating a plurality of center frequencies for use in multi-band hopping communication, includes: an oscillator generating an oscillation frequency; a reference frequency generator multiplying the oscillation frequency by a first multiplication rate to generate a reference frequency; a compensation frequency generator multiplying the oscillation frequency by a second multiplication rate to generate a compensation frequency for compensating for the influence of a frequency offset of the oscillation frequency; and a center frequency generator generating the plurality of center frequencies using the reference frequency and the compensation frequency. Therefore, by compensating for the influence of a frequency offset of an oscillation frequency on the generation of center frequencies, it is possible to generate stable center frequencies.

Abstract: A method of determining the number of magnetic particles within a sample using a tuned circuit having a capacitor and a coil. The method comprises: a. determining the difference in the resonant frequency of the tuned circuit when the sample is exposed to a magnetic field generated by the coil and when the sample is not exposed to the magnetic field generated by the coil; and b. using the difference in the resonant frequency to determine the number of magnetic particles within the sample.

Abstract: In a signal generating circuit SG1, a 90 -degree divider 3 generates, from a local oscillation signal SLO supplied through an input terminal 1, an intermediate reference phase signal ISREF and an intermediate quadrature signal ISQR orthogonal in phase to the intermediate reference phase signal ISREF for output to mixers 6 and 7, respectively. A shifter 4 shifts the phase of the local oscillation signal supplied through an input terminal 2 by a predetermined amount to generate a shift signal SSFT for output through a divider 5 to the mixers 6 and 7. The mixer 6 mixes the input intermediate reference phase signal ISREF and the input shift signal SSFT to generate a reference phase signal SREF. The mixer 7 mixes intermediate quadrature signal ISQR and the input shift signal SSFT to generate a quadrature signal SQR. With this, it is possible to provide a signal generator capable of generating highly-accurate, high-frequency reference phase signals and quadrature signals.

Abstract: A digital signal to pulse converter including a spectral spreader which provides an adjusted clock signal that does not cycle during selected cycles. The adjusted clock signal is written into a multi-port content addressable memory which, as a function of the current count, provides output signals that determine a beginning or an end of a pulse within a frame. The spectral spreader varies the number of selected cycles to adjust the frame rate as desired, linearly or nonlinearly.

Abstract: A microwave synthesizer includes a drift-cancel loop having a narrow-band input, a low-frequency comb input, a wide-band input, and an output for providing an adjustable-frequency output signal. A narrow-band synthesizer is coupled to the narrow-band input, and a comb generator is coupled to the low-frequency comb input. Instead of using a wide-band synthesizer to drive the wide-band input, as conventional topologies have done, the instant invention employs a highly stable, low noise high frequency oscillator. The output of the oscillator is mixed with the output of the comb generator to produce low-noise, high frequency combs. The low-noise, high frequency combs are then used to drive the wide-band input of the drift-cancel loop. Significant reductions in phase noise can be achieved as compared with conventional designs.

Abstract: The invention provides a high-speed PLL frequency synthesizer in which the frequency of a reference signal can be made larger than a frequency interval of an external output with a simple configuration. An n-th harmonic of an output of a voltage-controlled oscillator is caused to pass through a band pass filter. The frequency of an output of the band pass filter is divided by M in a variable frequency divider. The phase of an output of the variable frequency divider is compared with that of the reference signal in a phase comparator. An output of the phase comparator is smoothed by a loop filter. The output of the voltage-controlled oscillator is controlled by an output of the loop filter. The fundamental wave of the output of the voltage-controlled oscillator is caused to pass through another band pass filter, and then output to the outside. At this time, the frequency of the reference signal is n times a frequency interval of the fundamental wave of the output of the voltage-controlled oscillator.

Abstract: The resonant circuit has at least one resonant body of a semiconductor material anchored on the surface of a semiconductor substrate, at least one first electrode being arranged at said semiconductor material, and at least one second electrode. The first and second electrode are arranged lying opposite one another. When an AC-superimposed DC voltage is applied between the first and the second electrode, the resonant body is excited to mechanical oscillation by the DC voltage. In particular, the resonant circuit can be monoically integrated in electronic circuits.

Abstract: A delay-locked loop includes a phase detection circuit, a charge pump circuit and a phase shift circuit. The phase detection circuit is coupled to receive a first signal and a second signal. The phase detection circuit generates a phase-error output signal indicative of whether the first signal is ahead of or behind the second signal in phase responsive to receiving the first and second signals. The charge pump circuit is coupled to receive a phase-error signal derived from the phase-error output signal. The charge pump circuit generates a plurality of control output signals. Each of the control output signals are based upon the phase-error signal and by at least one signal derived from one other of the control output signals. The phase shift circuit is coupled to receive a plurality of control input signals and a plurality of periodic input signals. The control input signals are derived from the control output signals. Each of the periodic input signals have a different phase.

Abstract: There is provided an image rejection mixer for downconversion of an incoming signal to a lower intermediate frequency signal, using the absolute difference of frequencies between the incoming signal and the local oscillator signal. The image rejection mixer is set up to accept and downconvert incoming signals at two discrete frequencies f.sub.h and f.sub.l, where the local oscillator frequency is positioned mid-way between those frequencies f.sub.h and f.sub.l. There are two signal paths in the image rejection mixer, either one or the other of which is chosen by positioning a controllable single pole, double throw switch into one of its two switch positions. The output of the switch is led to a mixing element, from which an intermediate frequency signal is derived.

Abstract: A signal generator comprises a number of independent signal sources each of which can be controlled to generate predetermined frequencies and modulation. The outputs of these signal sources can be made available separately at output ports or can be combined within the signal generator to provide a combined output signal. The output signals are sensed at the output ports, and are calibrated against a stored correction tabulation to ensure that they have the correct signal level at the output ports. Such a signal generator is useful for the measurement and testing of complex electrical and electronic products.

Abstract: A four terminal multiplication circuit capable of mixing up to three input signals. The circuit includes a MOS transistor having gate, source, drain and back-gate terminals. When the circuit is used as an RF mixer or downconverter, an RF signal is provided to the gate terminal and a local oscillator signal is provided to the back-gate terminal. A DC voltage is applied to the source terminal for biasing the transistor and the mixed/downconverted output (IF) signal is obtained from the drain terminal. A single balanced and a double balanced mixer circuit are also disclosed. In the single balanced circuit, two MOS transistors are used; the RF signal is applied to the gate terminals with the positive phase LO component applied to one back-gate terminal and the negative phase local oscillator (LO) component applied to the other back-gate terminal for producing a positive phase and a negative phase IF signal.

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 dual-gate self-oscillating mixer FET that is injection-locked from a remote LO frequency source. The dual-gate FET having a feedback circuit connected between the first gate port and the drain port that is tuned so that the FET can oscillate within a frequency range including a predetermined LO frequency. The FET having a remote synchronization circuit electrically connected to the FET first gate port to inject the predetermined LO frequency therein and lock the FET oscillation to that LO. Accordingly, the dual-gate FET mixes RF energy input to the second gate port with the locked LO injected in the first gate port and outputs the desired intermediate frequency through the drain port.

Abstract: A frequency mixer circuit uses an impedance transforming power combiner to sum the power levels of RF and LO input signals and drive an output field effect transistor (FET). The nonlinear transconductance in the FET creates the sum and difference mixing products for providing an IF output signal operating at a frequency equal to the difference between the frequencies of the RF and LO input signals. The power combiner is impedance matched to the gate of the FET in order to minimize reflections back into the power combiner. The impedance transforming power combiner reduces component count and associated physical space requirements of the frequency mixing circuit.

Abstract: A digitally controlled oscillator (100) having a first oscillator circuit (108) for providing an oscillator signal F.sub.o of a defined frequency and a digital divider (110) for dividing the oscillator signal F.sub.o by a selectable number controlled by a digital word for providing a clock signal F.sub.clk. A second oscillator circuit (104) receives the clock signal F.sub.clk and provides a low frequency signal F.sub.c. The second oscillator circuit includes a digitally controlled resonator element (112) for determining the frequency of the low frequency signal and has a center frequency dependent upon the clock signal. Circuitry (118, 120, 138) is included for providing first and second pairs of quadrature phase shifted signals derived from the clock signal F.sub.clk and the low frequency signal F.sub.c and from the oscillator signal F.sub.o, respectively.

Abstract: Disclosed is a low noise microwave frequency synthesizer having a plurality of rapidly switchable output frequencies. Two banks of oscillators are selectively mixed to yield a range of output signals of low phase noise and low spurious noise. The first bank of oscillators comprises low noise, highly stable oscillators of a frequency range below the desired synthesized output signal. The second bank of oscillators comprises low noise, highly stable oscillators of a frequency range lower than the first bank. The signal from the second bank of oscillators is frequency multiplied to a desired frequency range by a low multiplication factor and then mixed with the signal from the first bank of oscillators. Multiplied phase noise is reduced by using a low multiplication factor. The upper sideband of the mixed signals is output as the synthesized output signal. Rapid switching between oscillators in both banks provides a frequency range of synthesized output signals which may be rapidly stepped through as desired.

Abstract: A transducer for converting a pressure variation to a variation in the frequency of a periodic function includes a reference oscillator and a sensor oscillator coupled to a digital mixer. The reference oscillator includes a reference capacitor and reference resistor for providing a reference periodic electrical signal having a frequency which is a function of the reference timing capacitor and reference resistor. Similarly, the sensor oscillator has a variable sensor timing capacitor and a sensor resistor for providing a sensor periodic electrical signal having a frequency which is a function of the variable sensor timing capacitor and sensor resistor. The digital mixer generates a mixed periodic electrical signal having a frequency proportional to the difference between the reference and sensor electrical signals. The transfer function of the transducer relates pressure and frequency and is adjustable by adjustment of the magnitude of the reference and sensor resistors.

Abstract: The invention aims at obtaining an intermediate beat frequency from two millimeter wave frequencies by attenuating as much as possible the amplitude variations of the frequency coming from the local oscillator.The mixer of the invention comprises two modules each containing a diode, one electrode of which is grounded to a conducting support. The modules are face to face. The diodes detect the electric field of the wave of the signal to be processed reigning in a cavity, and through conducting strips serving as outputs for the mixer and extending into a cavity where the electric field radiated by the local oscillator reigns, each module also detects a part of this electric field. The output terminals of the intermediate frequency are connected to an operational amplifier.

Abstract: A system is disclosed for synchronizing a free-swinging oscillator to a reference signal of a substantially lower frequency. A regulating circuit connects to the oscillator to control the frequency thereof. A quartz oscillator is provided for producing the reference signal. The reference signal is subsequently connected to a frequency multiplier and/or frequency divider, an amplifier and a pass band filter. An output signal from the pass band filter is fed to a harmonics mixer connected to the free-swinging oscillator and which produces a pattern of harmonics. A selective amplifier feeds an intermediate frequency obtained from the harmonics mixer to the regulator circuit. A filter also connected to the quartz oscillator produces harmonics which are also coupled to the regulating circuit. By phase or frequency comparison the regulating circuit adjusts the running frequency of the free-swinging oscillator.

Abstract: A harmonic mixer utilizing an anti-parallel configuration of two diodes which, when excited by a voltage waveform V.sub.LO sin .omega..sub.LO t + V.sub.s sin .omega..sub.s t where V.sub.LO is much greater than V.sub.s, yields a terminal current having angular frequency components m .omega..sub.LO .+-. n .omega..sub.s with the restriction that m + n is an odd integer. The diode configuration results in low conversion loss mixing when the local oscillator frequency is a subharmonic of the usually required local oscillator frequency, suppression of local oscillator noise sideband effects without the use of filters or hybrid junctions, and suppression of direct video detection.