46 results about "Comb generator" patented technology

A jammer for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are generated concurrently for the transmit band and the receive band and are transmitted as RF jamming signals to jam communications for mobile stations.

A vectorial network analyzer including n test ports. With the connection of several different calibration standards to the test ports, several calibration measurements are implemented. For the calibration, different measurements are implemented. Initially, in n calibration measurements, a comb-generator signal is supplied via a direct connection successively to all n test ports. Using a measuring point at the output of the comb generator and the measuring point associated with the respective test port, phase measurements are implemented at all of the frequencies forming the comb-generator signal. A frequency-dependent phase offset is determined from the phase measurements. Moreover, in at least one measurement, all n test ports are terminated successively in each case using known, input impedances, identical within one measurement, of arbitrary transmission properties, wherein successively, all n test ports are excited using a transmission oscillator successively with all frequencies of the comb-generator signal.

A scheme for reconstructing multiband signals that occupy a small part of a given broad frequency range under the constraint of a small number of sampling channels. The multirate sampling scheme (MRS) entails gathering samples at several different rates whose sum is significantly lower than the Nyquist sampling rate. The number of channels does not depend on any characteristics of a signal. The reconstruction method may or may not rely on the synchronization between different sampling channels. The scheme can be implemented easily with optical sampling systems. The optical pulses required for the under-sampling are generated by a combination of an electrical comb generator and an electro-absorption optical modulator

The invention discloses a method for generating a microwave frequency comb, which belongs to the technical field of microwave photons. First, inject the DC optical signal with adjustable amplitude into the semiconductor laser, so that the semiconductor laser works in a single-cycle oscillation state; then divide the output optical signal of the semiconductor laser into upper and lower paths, and the upper path undergoes photoelectric conversion, delay, and amplification. As a feedback signal, it is re-modulated to the semiconductor laser to form a photoelectric feedback loop; the downstream optical signal is sent to the photodetector for photoelectric conversion; the amplitude of the DC optical signal is modulated so that the amplitude of the DC optical signal is periodic The linear change of the property, and make the delay of the photoelectric feedback loop be an integer multiple of the linear change period of the amplitude of the DC optical signal. At this time, the output of the down channel photodetector is the microwave frequency comb signal. The invention also discloses a microwave frequency comb generating device. The invention can generate a microwave frequency comb signal with large bandwidth, high and fine comb-tooth spacing, and tunable bandwidth, center frequency and comb-tooth spacing.

The invention discloses a dual-channel microwave frequency comb generator which comprises a signal generator module, an optoelectronic feedback module and a control module. The signal generator module comprises a 850nm vertical cavity surface emitting laser VCSEL, a temperature controller, a current controller, an aspheric lens, an isolator, a half-wave piece and a polarization beam splitter. The optoelectronic feedback module comprises a photodetector, a power amplifier, a power attenuator and a radio frequency bias. The control module comprises a data acquisition card which is connected with the signal generator module and the optoelectronic feedback module and a computer, and is used for adjusting external parameters of a laser system and acquiring data. The microwave frequency comb generator uses the VCSEL as a core device, has the advantages of small whole system volume, easy integration and low cost, and can acquire dual-channel microwave frequency comb signals.

The invention provides a frequency mixer group delay measuring circuit which comprises a vector network analyzer and a comb generator. The vector network analyzer comprises a first frequency synthesizer, a second frequency synthesizer and a receiver. The output signals of the first frequency synthesizer are divided into two channels through a first coupler, one channel signals are coupled to the radio-frequency signal input end of a frequency mixer to be tested, and the other channel signals are coupled to the receiver. The output signals of the second frequency mixer are coupled to the local oscillating signal input end of the frequency mixer to be tested. The vector network analyzer further comprises a reference oscillator, the output end of the reference oscillator is coupled to the input end of the comb generator, the output end of the comb generator and the output end of the frequency mixer to be tested are coupled to the input end of a second coupler together, and the output end of the second coupler are coupled to the receiver. The frequency mixer group delay measuring circuit can achieve the measurement of the phase position of a measurement channel conveniently and fast, and achieve phase error correction accurately.

A frequency comb generator fabricated on a chip with elimination of a disadvantageous reflow process, includes an ultra-high Q disk resonator having a waveguide that is a part of a wedge structure fabricated from a silicon dioxide layer of the chip. The disk resonator allows generation of a frequency comb with a mode spacing as low as 2.6 GHz and up to 220 GHz. A surface-loss-limited behavior of the disk resonator decouples a strong dependence of pumping threshold on repetition rate.

Techniques are disclosed for eliminating or otherwise sufficiently suppressing spurious signals. The techniques are particularly useful in applications such as those that employ aggressor frequency sources along with a frequency conversion or mixing function, and especially applications implemented as a system-on-chip. In the spur-training mode, a spur-canceller circuit identifies spurious tones associated with the host system to neutralize those tones when running in a normal mode. The tones are neutralized using a comb generator with variable phase and gain by way of cancellation with comb output signals having substantially the same amplitude and a phase that is 180° out of phase with the aggressor tone to be cancelled.

The invention discloses an active resonant cavity based self-similarity ultrashort pulse amplification system and a working method therefor. The self-similarity ultrashort pulse amplification system is characterized by comprising an optical frequency comb-shaped generator, a pre-chirping management apparatus, an active optical resonant cavity and a dispersion compensation apparatus that are connected in sequence, wherein the active optical resonant cavity is also connected with an electronic control circuit and a pump laser. The active resonant cavity based self-similarity ultrashort pulse amplification system has the advantages that an outer cavity enhancement technique is adopted, so that the self-similarity amplification for the ultrashort pulse is realized by using solid gain mediums, and the gain narrowing is overcome; the nonlinear widening of spectrum in the amplification process is realized, the pulse contract ratio is improved, and the problems of unstable modes, self-focusing and the like existing in the high-power amplification process of an optical fiber amplifier are effectively restrained; and the self-similarity ultrashort pulse amplification system is used as a reliable scientific research tool for researching high-field laser physics and non-linear optics.

An optical comb generator includes frequency-shifting elements of a particular type that we refer to as a “frequency mirror.” A frequency mirror mixes input light at a signal frequency and a reference frequency to produce output light at a third frequency that lies in contraposition to the signal frequency relative to the reference frequency. The comb generator includes at least two frequency mirrors, having respective reference frequencies F1 and F2. At least some of the power of a light beam is shifted by the first frequency mirror from an input frequency to a frequency that lies in contraposition thereto relative to F1, and then light at the shifted frequency is shifted to yet a new frequency by the second frequency mirror. The resulting twice-shifted frequency lies in contraposition to the once-shifted frequency, relative to F2. The result is that a difference of 2(F2−F1) separates the twice-shifted frequency from the input frequency. This process is repeatable to generate a comb of equally spaced, shifted frequencies. In specific embodiments of the invention, the frequency mirror is a periodically poled lithium niobate (PPLN) device pumped by laser radiation at the pertinent reference frequency.

A variable frequency synthesizer and method of outputting the variable frequency is disclosed. The synthesizer comprises a first reference frequency, a direct digital synthesizer (DDS) receiving the first reference frequency and outputting a tuned frequency, a variable frequency comb generator receiving the tuned frequency and outputting a variable frequency comb comprised of a plurality of comb lines, a mixer receiving the variable frequency comb and a signal from an oscillator and outputting an intermediate frequency, a phase lock loop (PLL) receiving a second reference frequency and the intermediate frequency and outputting a phase lock signal, and the oscillator receiving the phase lock signal and outputting a variable synthesized frequency.

An optical comb generator for generating multiple optical wavelengths from a single source simultaneously for many optical channels on a semiconductor substrate. The comb generator provides narrow channel spacing using chirped Bragg grating with uniformly spaced grating pitches but with tapered waveguide to facilitate the fabrication process and generate laser comb channels with uniform line widths across all channels. The laser comb generator facilitates monolithic integration of many photonic integrated circuit elements.

Apparatus and methods are presented for enhancing the acquisition speed or performance of Fourier domain optical coherence tomography. In preferred embodiments a plurality of wavelength combs containing interleaved selections of wavelengths from a multi-wavelength optical source are generated and projected onto a sample. In certain embodiments the wavelength combs are projected simultaneously onto a plurality of regions of the sample, while in other embodiments the wavelength combs are projected sequentially onto the sample. Light in the wavelength combs reflected or scattered from the sample is detected in a single frame of a sensor array, and the detected light processed to obtain a tomographic profile of the sample. In preferred embodiments the wavelength comb generator comprises a wavelength interleaver in the form of a retro-reflective prism array for imparting different displacements to different selections of wavelengths from the optical source.

A comb frequency generator that is tunable to vary the width of the pulses in the output signal and achieve a maximum power output at different harmonic frequencies. A wavefront compression device receives a sinusoidal input signal and provides wavefront compression to create a compressed signal having a series of periodic fast edges. A delay device receives the fast-edge compressed signal and delays the fast-edge signal to create a delayed fast-edge signal. A combining device receives the original fast-edge compressed signal and the delayed fast-edge compressed signal to generate an output signal including a series of pulses having a width determined by the delay of the delayed signal. In one embodiment, the delay device is a shorted transmission line stub having a length selectively set by a series of MEM devices. In another embodiment, the delay device is an NLTL variable time delay device that delays the fast-edge signal.

The invention discloses a microwave frequency source component with low phase noise and high spurious suppression and a usage method thereof. The component comprises a crystal oscillator 1, a power splitter 2, a phase discriminator A3, a loop filter A4, a voltage controlled oscillator A5, a coupler A6, a filter A7, an amplifier A8, a filter B10, a filter C12, a phase discriminator B13, a loop filter B14, a voltage controlled oscillator B15, a coupler B16, an amplifier B17, a filter D18, a mixer 9 and a comb generator 11. The microwave frequency source component has the advantage of easiness inimplementation. A mixer phase-locked loop design technology is adopted, mixing processing is placed in a phase-locked loop, and feedback frequency is reduced by mixing, so that phase noise is reduced; mixing spuriousness is filtered by the phase-locked loop filter; and the microwave frequency source with low phase noise and high spurious suppression can be realized.

The invention discloses an all-optical broadband micro-wave frequency comb generator and relates to the technical field of coupling device of optical waveguide and a photoelectric element. The generator comprises a frequency comb seed resource generating module, an adjusting control module and a frequency spectrum expanding module. The frequency comb seed resource generating module comprises a first semiconductor laser, a first aspherical lens, a first beam splitter, a second beam splitter, a first Faraday rotator, a second Faraday rotator, a first plane mirror and a second plane mirror. The adjusting control module comprises a computer and a piezoceramics. The frequency spectrum expanding module comprises an adjustable attenuator, an opto-isolator, a second aspherical lens and a second semiconductor laser. The all-optical broadband micro-wave frequency comb generator has the advantages that electronic bottleneck is broken, comb distance adjustment is flexible, wide-broadband microwave frequency comb signal is further acquired, and comb lines are balanced in a certain degree.

The invention provides a method for automatically acquiring YIG tuned filter compensation data and specifically relates to the technical field of signal analyzer dynamic non-linear compensation data acquisition. The method for automatically acquiring YIG tuned filter compensation data is applied to production debugging and calibration of signal analyzers and can achieve high-speed and high-precision linear tuning of a YIG tuned filter. In a production debugging or calibration process, a comb generator embedded in the front end of a radio frequency channel of a signal analyzer provides inspection input signals as a signal source. When YIG filter tuning is performed under a linear voltage or linear current (main tuning drive) , lag offsets vary with tuning frequency points, so that different comb wave signals with the same power do not have the same testing power after passing the a YIG filter. Proper compensation drive is provided for different tuning frequency points by invoking compensation data, so that a transient position of the YIG filter in a dynamic tuning process is consistent with that in static tuning and signal power testing is not influenced by a tuning process of the YIG filter.

An integrated electro-optic frequency comb generator based on ultralow loss integrated, e.g. thin-film lithium niobate, platform, which enables low power consumption comb generation spanning over a wider range of optical frequencies. The comb generator includes an intensity modulator, and at least one phase modulator, which provides a powerful technique to generate a broad high power comb, without using an optical resonator. A compact integrated electro-optic modulator based frequency comb generator, provides the benefits of integrated, e.g. lithium niobate, platform including low waveguide loss, high electro-optic modulation efficiency, small bending radius and flexible microwave design.

The present invention provides a method and device for determining the sideband ratio of a superconducting mixer using a comb generator. The method includes the steps of: (a) tentatively adjusting the sideband ratio of a mixer for calibration of an output of the comb generator; (b) determining the signal intensity of a pseudo-celestial signal oscillator for calibration of the output of the comb generator; (c) repeating the steps (a) and (b) to derive the relation between the sideband radio of the mixer for the comb-generator output calibration and the intensity of a pseudo-celestial signal; (d) calibrating the output of the comb generator; and (e) obtaining the sideband ratio of the mixer to be measured.

An integrated electro-optic frequency comb generator based on ultralow loss integrated, e.g. thin-film lithium niobate, platform, which enables low power consumption comb generation spanning over a wider range of optical frequencies. The comb generator includes an intensity modulator, and at least one phase modulator, which provides a powerful technique to generate a broad high power comb, without using an optical resonator. A compact integrated electro-optic modulator based frequency comb generator, provides the benefits of integrated, e.g. lithium niobate, platform including low waveguide loss, high electro-optic modulation efficiency, small bending radius and flexible microwave design.

The current comb generator periodically applies current spikes to a power supply signal in the time domain to produce a series of current spikes at different frequencies in the frequency domain.

An optical comb generator for generating multiple optical wavelengths from a single source simultaneously for many optical channels on a semiconductor substrate. The comb generator provides narrow channel spacing using chirped Bragg grating with uniformly spaced grating pitches but with tapered waveguide to facilitate the fabrication process and generate laser comb channels with uniform line widths across all channels. The laser comb generator facilitates monolithic integration of many photonic integrated circuit elements.

System and methods for the sampling of an optical signal by generating a plurality of copies of the spectrum of the said optical signal including at least one sampling block for the convolution between the optical input spectrum and an optical comb; wherein the said sampling block includes a modulator, and a bias voltage generator, the said sampling block is driven by an electrical comb generator and a phase shifter, the said electrical comb generator being configured to generate a number of N lines, with N from one to infinity, in the radio frequency domain, equally spaced in frequency and locked in phase, the said modulator being configured to generate a plurality of 2N+1 copies of the input spectrum from (i) the signal spectrum and (ii) a number of N lines provided by the said electrical comb generator.

A multi-tone multi-band tunable millimeter-wave synthesizer is provided. In some embodiments, the multi-tone multi-band tunable millimeter-wave synthesizer is configured to simultaneously generate multiple frequency tones for space-borne beacon transmitter for atmospheric radio wave propagation studies. The apparatus includes a comb generator, which puts out evenly spaced harmonic frequencies of the input signal, which are coherent, tunable, and the number of tones or combs is scalable over a wide range of frequencies. These harmonics or tones are amplified to the power level needed for radio wave propagation studies. The amplified signals are transmitted as beacon signals from a satellite to a ground receiving station.