102 results about "Quadrature demodulation" patented technology

The invention relates to the technical field of ground resistance detection, in particular to a single-core cable ground resistance detection method capable of resisting strong power frequency interference. High-frequency signals are injected in a non-contact mode through a coupling type capacitor clamp, background voltage and current signals are collected firstly, and injection frequency far away from power frequency and harmonic waves is selected through Fourier analysis; cancelling background noise by adopting a normalized least mean square adaptive filter to generate an enhanced signal; the signal is down-converted to a base band through digital quadrature demodulation, a Kalman filter estimates the amplitude and the phase in real time, and the state and noise parameters are periodically calibrated through a compressed sensing algorithm; and finally, loop impedance is calculated according to the voltage and current amplitudes and the phase difference to obtain grounding resistance. The method has the advantages of being non-contact, high in safety, strong in anti-interference capability, high in measurement precision and the like, and is suitable for monitoring the grounding state of the cable in a complex electromagnetic environment.

The invention belongs to but is not limited to the technical field of signal extraction, and particularly relates to a gas storage wellbore leakage sound wave signal extraction method and system based on distributed optical fibers, and the method comprises the steps: S1, hardware platform construction: constructing a hardware platform based on a DAS technology; s2, data demodulation: a digital orthogonal demodulation technology is adopted in the demodulation process, and the collected data is decomposed into two mutually orthogonal components, so that phase information is extracted; and S3, shaft leakage sound wave signal extraction: performing algorithm processing according to the demodulated phase information. Compared with the originally collected wellbore leakage sound wave signal, the similarity between the extracted signal and the actual wellbore leakage sound wave signal is higher, and the similarity is mainly characterized in that the difference value of the average amplitude is reduced from 0.21 rad to 0.03 rad, the mean square error is reduced from 0.55 rad2 to 0.17 rad2, and the signal-to-noise ratio is increased by 16.9 dB.

The invention provides an anti-interference sound signal data extraction method based on energy data perception, and belongs to the technical field of underwater sound signal processing, and the method comprises the steps: carrying out the A / D sampling and digital orthogonal demodulation of a received sound signal, and obtaining a baseband signal; performing low-pass filtering and downsampling on the baseband signal to obtain a preprocessed signal; performing matched filtering on the pre-processed signal by using a reference signal; the key improvement lies in that a local energy estimation function of a preprocessed signal is calculated, and normalization processing is carried out on a matched filtering result and the energy estimation function to obtain a normalized detection signal. The method effectively suppresses the shielding effect of a strong interference signal on a weak target signal under a non-orthogonal reference signal and a strong near-end and weak far-end scene, remarkably reduces the misrecognition probability, and improves the accuracy and reliability of the extraction of a long-distance and low-signal-to-noise-ratio target beacon signal in a complex underwater acoustic environment. The method is suitable for underwater navigation, positioning and communication systems.

The invention discloses a non-intrusive permanent magnet synchronous servo motor bearing fault on-line diagnosis method and system, and the method comprises the steps: injecting a chirp current signal in a tuning stage, calculating a frequency response function through combining with a rotating speed feedback signal, and determining a resonant frequency according to the frequency response function; calculating a theoretical characteristic order according to the motor bearing size parameter; in a motor operation stage, collecting a motor rotating speed signal and determining a theoretical characteristic frequency according to the theoretical characteristic order; determining an optimal resonance demodulation frequency band according to the resonance frequency and the theoretical characteristic frequency, and performing band-pass filtering on the motor rotating speed signal according to the optimal resonance demodulation frequency band; an envelope signal of the filtered signal is calculated online through an orthogonal demodulation algorithm, the frequency spectrum of the envelope signal is obtained through FFT analysis, threshold comparison is conducted on the frequency spectrum of the envelope signal and the amplitude corresponding to the theoretical characteristic frequency, and fault diagnosis result judgment is completed. According to the invention, on-line diagnosis of the bearing fault of the permanent magnet synchronous servo motor under the condition of low-performance chip resources is realized.

The invention discloses an in-phase and quadrature demodulation phase modulation optical heterodyne frequency stabilization system for inhibiting an RAM (Random Access Memory), which relates to the technical field of laser frequency stabilization and comprises a laser, an electro-optical modulator, a circulator, an optical resonant cavity, a photoelectric detector, a phase shifter, a frequency mixer, a summator, a low-pass filter, a signal generator and a signal acquisition and processing module. Laser emitted by the laser is modulated by the electro-optical modulator and then enters the circulator, the circulator receives reflected light of the optical resonant cavity and emits the reflected light to the photoelectric detector, and all error signals are obtained through the frequency mixer and the low-pass filter. All error signals are added through an adder and then are input into a signal acquisition and processing module for feedback, so that the frequency of laser emitted by the laser is locked to the resonant frequency of the optical resonant cavity; according to the frequency stabilization system, a plurality of modulation frequencies are introduced to modulate the laser phase in the electro-optical modulator, so that the influence of RAM noise on frequency stabilization is suppressed.

According to an embodiment, a circuit is proposed for generating rate and quadrature demodulation signals, incorporating unidirectional hysteresis for negative edges. The circuit features a preliminary stage that amplifies the differential sinusoidal signal from gyroscopic proof mass oscillations; a gain stage for boosting this signal with adjustable hysteresis levels; an output stage delivering a full-swing square wave output; and a customizable offset component to deepen the drop in the non-inverting compared to the inverting signal for the third signal's falling edge.

The invention provides an adaptive control method and system for an accelerator klystron, and electronic equipment, and the method comprises the steps: collecting a reverse wave signal in a microwave signal which is generated by an excitation source, is amplified by the klystron, and is inputted to an accelerating tube, and obtaining the current output frequency of the excitation source; performing I / Q orthogonal demodulation on the reverse wave signal to obtain an I / Q signal, and calculating the frequency deviation between the current resonant frequency of the accelerating tube and the current output frequency of the excitation source; and according to the frequency deviation, outputting a frequency control instruction to the excitation source so as to adjust the output frequency of the excitation source, and enabling the current output frequency of the excitation source to track the current resonant frequency of the accelerating tube. By calculating the frequency deviation and directly outputting the control instruction to adjust the output frequency of the excitation source, the technical problems of control object dislocation and response lag existing in a traditional automatic frequency control system are solved.

The invention relates to a permanent magnet synchronous motor rotor position estimation method based on high-frequency signal injection, and the method comprises the following steps: carrying out the amplitude modulation of a preset high-frequency voltage carrier signal through an orthogonal rotation modulator, and obtaining an injection signal vector; performing voltage excitation on a stator winding of the permanent magnet synchronous motor based on the injection signal vector to obtain a high-frequency current response signal; performing harmonic separation on the high-frequency current response signal through a comb filter bank to obtain a rotor position modulation current component; orthogonal demodulation is carried out on the rotor position modulation current component through a complex demodulator, and a position-dependent phase difference value is obtained; non-linear mapping processing is carried out on the position-dependent phase difference value through an adaptive state observer, a real-time rotor position angle value is obtained, and the key problem of how to effectively extract information related to the rotor position from a high-frequency current response signal is solved.

The invention discloses an optical fiber sensor high-speed demodulation device based on a cascaded Mach-Zehnder interferometer, which adopts a two-stage cascaded Mach-Zehnder interferometer structure, and obtains four-channel output with equal central wavelength intervals by accurately aligning two-stage central wavelengths. And the four-channel signal is utilized to carry out orthogonal demultiplexing on a spectral signal of the optical fiber sensor. In a digital domain, an orthogonal demodulation algorithm for phase demodulation of an optical fiber sensor is provided, and the demodulation speed is only limited by a digital sampling rate. Compared with a traditional spectrum demodulation algorithm, the scheme has the advantages of being high in demodulation speed, wide in working frequency band, easy to implement and the like.

The invention provides a breast cancer tissue anomaly detection method based on multi-frequency electrical impedance dynamic analysis, and the method comprises the steps: generating a multi-frequency electrical excitation signal covering a preset low frequency to a high frequency, applying the multi-frequency electrical excitation signal to a to-be-detected breast tissue through an electrode array, and synchronously collecting a response voltage signal. Orthogonal demodulation is carried out on the collected voltage signals, real and imaginary components of each frequency point are separated, a complex impedance value is calculated, and a multi-frequency impedance spectrum is generated. Feature vectors including amplitude-frequency characteristic slope, phase-frequency characteristic extreme point position, high-frequency-band impedance attenuation rate and the like are extracted from the impedance spectrum, a pre-trained dynamic judgment model is input to calculate a tissue anomaly index, and finally whether the mammary gland tissue is abnormal or not is judged according to a comparison result of the anomaly index and a preset threshold value. The accuracy of early detection of breast cancer can be improved, and the stability and reliability of detection are enhanced.

This invention discloses a global phase quadrature demodulation method and apparatus for fiber optic sensing data. The method includes: acquiring initial fiber optic sensing IQ data; determining the corresponding direct phase value based on the initial fiber optic sensing IQ data; performing a light source phase correction operation on the direct phase to obtain first processed data; performing a receiver point initial phase correction operation on the first processed data to obtain second processed data; performing a light source linear phase correction operation on the second processed data to obtain third processed data; performing a receiver point linear phase correction operation on the third processed data to obtain fourth processed data; and performing phase dewinding processing and near-DC component removal processing on the fourth processed data to obtain globally phase demodulated data. By analyzing various influencing factors of the initial fiber optic sensing IQ data and adopting corresponding data optimization processing methods, the problems existing in the acquisition process of fiber optic sensing data are overcome, and the accuracy of fiber optic sensing data is improved.

According to an embodiment, a circuit is proposed for generating rate and quadrature demodulation signals, incorporating unidirectional hysteresis for negative edges. The circuit features a preliminary stage that amplifies the differential sinusoidal signal from gyroscopic proof mass oscillations; a gain stage for boosting this signal with adjustable hysteresis levels; an output stage delivering a full-swing square wave output; and a customizable offset component to deepen the drop in the non-inverting compared to the inverting signal for the third signal's falling edge.

The invention relates to the technical field of microscopic imaging, and particularly provides a stimulated Raman scattering microscopic imaging system capable of simultaneously scanning double Raman frequency shift spectrums, which comprises a laser light source driving and modulating unit and a signal detecting and data processing unit, the laser light source driving and modulating unit comprises a dual-channel laser synchronous excitation module, a light beam polarization regulation and power distribution module, a pulse broadening and spectrum focusing module, a dual-channel dual-phase modulation module, a common-path different-time dual-frequency difference module and a laser scanning and telecentric focusing module; and the signal detection and data processing unit comprises a dual-channel orthogonal demodulation module and a scanning driving and signal synchronous acquisition module. Compared with the prior art, the dual-Raman frequency shift spectrum scanning stimulated Raman microimaging device has the advantages that dual-Raman frequency shift spectrum scanning stimulated Raman microimaging with higher acquisition speed, high resolution and wide spectrum coverage range is realized, and the problem of long time consumption for acquiring the complete spectrum of the to-be-tested sample by the traditional single-frequency resonance spectrum scanning stimulated Raman microimaging is solved.

The application discloses a kind of digital frequency tracking and synchronous sampling control system for resonant gyro, including self-excitation oscillation and automatic gain control device, preamplifier circuit and digital signal processor, digital signal processor includes first A / D conversion unit, second A / D conversion unit, frequency error detection unit FD, phase error detection unit PD, digital control oscillator NCO, sampling frequency generator and quadrature demodulation unit, the vibration signal of drive channel is handled after device output to first A / D conversion unit, conversion obtains the vibration signal after conversion, FD obtains frequency difference by frequency error detection, PD obtains phase difference by phase error detection, NCO is adjusted the frequency and phase of sampling frequency generator according to frequency difference and phase difference in real time, until the resonant frequency and phase of drive channel are tracked;The vibration signal of detection channel is handled after circuit output to second A / D conversion unit, obtains the vibration signal after conversion, and quadrature demodulation unit carries out quadrature demodulation and obtains speed signal.

The application discloses a laser phase noise measurement method based on delay self-heterodyne and digital demodulation, and relates to the technical field of laser measurement, and comprises the following contents: after being adjusted by a variable optical attenuator, to-be-measured laser is divided into a frequency shift arm and a delay arm, the frequency shift arm is frequency-shifted by an acousto-optic modulator, the delay arm is delayed by a delay optical fiber, and original electric beat frequency signals are obtained by a balanced photoelectric detector after the two arms are coupled; homologous and synchronous quadrature demodulation is carried out on the original electric beat frequency signals, envelope credibility judgment and abnormal sample repair are combined, and a continuous differential phase sequence is obtained; actual optical time delay is determined according to the beat frequency spectrum characteristics and the continuous differential phase sequence, and a differential phase power spectral density is formed; then, transmission relationship conversion is carried out according to the actual optical time delay, bounded spectrum compensation is implemented on a zero point neighborhood and a low credibility frequency point, and an intrinsic phase noise power spectral density is obtained. The application can improve the stability, continuity and result credibility of phase noise measurement under the condition of short delay.

This invention provides a low-crosstalk signal demodulation device and method for fiber optic laser communication, belonging to the field of fiber optic communication technology. The device includes a fiber optic signal input port, an optical circulator, a polarization beam splitter / combiner module, a balanced photodetector unit, a low-noise amplification and quadrature demodulation module, an adaptive crosstalk cancellation unit, a MIMO equalization and decision unit, and a digital signal output port, connected in series according to the signal flow direction. It also includes a crosstalk monitoring and feedback unit bidirectionally connected to the low-noise amplification and quadrature demodulation module, the adaptive crosstalk cancellation unit, and the MIMO equalization and decision unit. This invention, employing the aforementioned low-crosstalk signal demodulation device and method for fiber optic laser communication, overcomes the limitations of traditional single-domain crosstalk suppression. Through the synergistic effect of optical path, circuit, and algorithm layers, it effectively suppresses crosstalk caused by multi-channel multiplexing, polarization mode dispersion, and backscattering, significantly improving demodulation accuracy, anti-interference capability, and system stability.

According to the fast full-channel power detection circuit structure for adaptive channel selection described in the present invention, a quadrature demodulation chip containing a fast-jumping local oscillator (a phase-locked loop (PLL) with an integrated voltage-controlled oscillator (VCO)) is used to directly orthogonally demodulate the RF signal to the baseband, and one of the output signals is used for baseband power detection. The circuit structure of the present invention uses a coupler to couple a portion of the signal processed by the RF front end to form a relatively independent channel detection link for fast channel scanning, which can avoid the error and cost increase caused by the independent detection link and make the design of the fast channel detection link very flexible.

A system and method for using quadrature demodulation to detect an event associated with a substrate. The method includes receiving an ultrasound signal associated with a substrate. The method includes performing quadrature demodulation of the ultrasound signal to generate an in-phase signal and a quadrature signal. The method includes detecting an event associated with the substrate based on the in-phase signal and the quadrature signal. The method includes providing a notification indicating the event.

A system and method for using quadrature demodulation to detect an event associated with a substrate. The method includes receiving an ultrasonic signal associated with a substrate. The method includes performing quadrature demodulation of the ultrasonic signal to generate an in-phase signal and a quadrature signal. The method includes detecting an event associated with the substrate based on the in-phase signal and the quadrature signal. The method includes providing a notification indicating the event.

The application discloses a kind of dual-frequency modulation transfer spectroscopy laser frequency stabilization device and method, construct the dual-frequency modulation signal including first frequency component and second frequency component, according to dual-frequency modulation signal driving fiber electro-optic phase modulator to laser is carried out dual-frequency electro-optic phase modulation;Photoelectric detector carries out detection to the polarized beam splitter output light and obtains saturated absorption signal, to saturated absorption signal in turn carries out quadrature demodulation and low-pass filter processing and obtains first error signal and second error signal, first error signal and second error signal are superimposed to obtain dual-frequency error signal;Further, tunable laser is carried out closed-loop feedback control, realizes laser frequency stabilization.The application obtains two different frequency components error signal using dual-frequency modulation transfer spectroscopy detection technology, improves slope and intensity by adding operation, improves frequency discrimination sensitivity and anti-interference ability, is conducive to peak search determination and realizes the precision locking of laser frequency to rubidium absorption peak, with good practicability.

The invention discloses an in-phase and quadrature demodulation phase modulation optical heterodyne frequency stabilization system for suppressing RAM, and relates to the technical field of laser frequency stabilization, comprising a laser, an electro-optic modulator, a circulator, an optical resonant cavity, a photodetector, a phase shifter, a mixer, an adder, a low-pass filter, a signal generator and a signal acquisition and processing module; laser light emitted by the laser enters the circulator after being modulated by the electro-optic modulator, the circulator receives the reflected light of the optical resonant cavity and emits it into the photodetector, and all error signals are obtained through the mixer and the low-pass filter, all error signals are added through the adder, and then input into the signal acquisition and processing module and fed back, so that the frequency of the laser light emitted by the laser is locked to the resonant frequency of the optical resonant cavity; the frequency stabilization system modulates the laser phase in the electro-optic modulator by introducing multiple modulation frequencies, so as to suppress the influence of RAM noise on the frequency stabilization.

Device comprising: a quadrature demodulator configured to receive an input signal, a first reference signal, and a second reference signal in quadrature with the first reference signal, the quadrature demodulator further configured to produce a plurality of output signals from the input signal and the first and second reference signals, the plurality of output signals indicative of the amplitude and phase of the input signal; one or more inverting circuits, the inverting circuits having a first and a second programmable output polarity, the plurality of output signals being output by the quadrature demodulator when the inverting circuits are set to the first programmable output polarity, the plurality of output signals being inverted and output by the quadrature demodulator when the inverting circuits are set to the second programmable output polarity, and a controller (508) coupled to the quadrature demodulator, the controller (508) being configured to determine the amplitude and phase of the input signal according to the plurality of output signals, the one or more inverting circuits being configured to be coupled to the controller (508), the controller (508) further being configured to set the inverting circuits to the first programmable output polarity while determining first values ​​of the plurality of output signals, set the inverting circuits to the second programmable output polarity while determining second values ​​of the plurality of output signals, and determine one or more error values ​​from the first and second values ​​of the plurality of output signals, the controller (508) further being configured toto determine the error values ​​by subtracting the first values ​​of the plurality of output signals from the second values ​​of the plurality of output signals, wherein determining comprises subtracting the second values ​​of the plurality of output signals from respective ones of the first values ​​of the plurality of output signals to produce the one or more error values.

The present application relates to the technical field of precision phase measurement and digital signal processing, and particularly relates to a method and system for suppressing spectral aliasing and nonlinear distortion. The beat frequency signal is preprocessed and spectrum is constructed to obtain a normalized spectrum; peak value search is performed in a preset target frequency range to identify beat frequency, side frequency and pilot frequency signals to form an effective spectrum line set; nonlinear parasitic components are calculated to obtain folded parasitic spectrum lines, and the parasitic spectrum lines to be evaluated are obtained through constraint screening; branch processing is realized through suppression standard judgment, and selective narrowband notch suppression is performed on the parasitic spectrum lines meeting the conditions; digital heterodyne quadrature demodulation and low-pass filtering are performed on the signals before and after processing; and the suppression effect quantitative evaluation is completed according to the phase error and phase noise index, and the parameters are dynamically adjusted to realize the working condition adaptive optimization. The advantage lies in: accurately predicting and suppressing the composite interference, protecting the integrity of the effective signal, significantly improving the phase measurement accuracy and robustness, and widely applying to various scenes.

Method and system for automatic modulation classification (AMC) use time-series voltage signals representative of radio frequency (RF) signal envelope and frequency components as input features to a deep learning-based neural network, which enables classification of both modulation type and symbol rate without requiring in-phase and quadrature (IQ) demodulation. A feature extraction circuit captures RF signal envelope amplitude and frequency using stub-based sensing, and a Long Short-Term Memory (LSTM) neural network processes these features in a digitized form to classify the modulation and symbol rate with high accuracy and minimal latency.

The application provides an anti-interference acoustic signal data extraction method based on energy data sensing, and belongs to the technical field of underwater acoustic signal processing. The method comprises the following steps: A / D sampling and digital quadrature demodulation are performed on a received acoustic signal to obtain a baseband signal; low-pass filtering and down-sampling are performed on the baseband signal to obtain a pretreated signal; the pretreated signal is matched filtered by using a reference signal; a key improvement lies in that a local energy estimation function of the pretreated signal is calculated, and the matched filtering result is normalized with the energy estimation function to obtain a normalized detection signal. Through energy sensing normalization, the application effectively suppresses the shielding effect of strong interference signals on weak target signals due to non-quadrature reference signals and the "near-end strong and far-end weak" scene, significantly reduces the false recognition probability, and improves the accuracy and reliability of extracting a long-distance and low signal-to-noise ratio target beacon signal in a complex underwater acoustic environment. The application is suitable for underwater navigation, positioning and communication systems.

This application discloses a fully digital magnetic field measurement device and method, relating to the field of magnetic field measurement technology. The device generates a constant AC-DC superimposed current signal with adjustable frequency and amplitude, and outputs it to a Hall sensor placed in the magnetic field to be measured. It acquires the Hall voltage generated by the Hall sensor and performs analog-to-digital conversion to obtain a digital Hall signal. The digital Hall signal is quadrature demodulated to extract the in-phase and quadrature components. The magnetic field strength amplitude and phase are calculated based on the in-phase and quadrature components. The current is sampled in real time, and a closed-loop control signal is generated based on the deviation between a preset target current value and the actual sampled value to adjust the AC-DC superimposed current amplitude. Through a fully digital signal processing architecture and closed-loop control and output, high-precision, high-speed, and low-noise measurement of magnetic field strength and direction is achieved.

The utility model provides a frequency hopping zero intermediate frequency receiver circuit, which is characterized in that a radio frequency amplification circuit is connected with the input end of a power distribution circuit through a controllable attenuation circuit, the output end of the power distribution circuit is respectively connected with the input ends of two orthogonal demodulation circuits, the output end of a first PLL circuit is connected with the local oscillation end of a first orthogonal demodulation circuit, and the output end of a second PLL circuit is connected with the local oscillation end of a second orthogonal demodulation circuit. The output end of the second PLL circuit is connected with the local oscillation end of the second orthogonal demodulation circuit; two outputs of the first orthogonal demodulation circuit are respectively connected with the input end of the first baseband pre-amplification circuit, and two outputs of the second orthogonal demodulation circuit are respectively connected with the input end of the second baseband pre-amplification circuit; the two output ends of each baseband pre-amplification circuit are respectively connected with the input end of the electronic switch circuit, and the output end of the electronic switch circuit is connected with the final-stage amplification circuit through the baseband filter circuit. The PLL load is not changed at the switching moment of the electronic switch, the influence of PLL load traction can be obviously relieved, and the frequency switching time is reduced by more than 80% compared with that of a traditional ping-pong phase-locked loop.

An amplitude demodulation implementation method applied to a secondary radar, the method comprising: performing frequency mixing on a reply signal to obtain an intermediate frequency signal; quantizing the intermediate frequency signal; performing quadrature demodulation on the quantized intermediate frequency signal to obtain a digital amplitude value, and using a piecewise linear calculation method to obtain a logarithmic digital amplitude. The logarithmic compression processing function of the secondary radar for a reply signal is implemented by an FPGA; after intermediate frequency digitization of the reply signal, a digital amplitude value is obtained via quadrature demodulation; and the digital amplitude value is processed in the FPGA by using a piecewise linear calculation method to approximate a logarithmic conversion characteristic, so as to obtain a logarithmic digital amplitude, which is very simple.

The invention discloses a high-precision capacitive displacement sensor based on double ADC switch proportional demodulation. According to the high-precision capacitance displacement sensor based on double-ADC switch proportional demodulation, the analog front-end circuit is used, a refined circuit model is established, modulation noise can be reduced, and the capacitance resolution of analog modulation can be improved; by using the double-ADC switch proportion measurement circuit, secondary alternate acquisition and reconstruction of modulation signals and carrier signals can be realized, so that gain fluctuation caused by carrier generation modules such as ADCs and DACs is inhibited; by using the digital quadrature demodulation circuit, the phase error introduced in the demodulation process can be reduced or eliminated; the bad influence of the DAC carrier gain and the ADC gain on the finally output baseband signal is small, the included phase error introduced in the demodulation process is small, and high-precision displacement detection can be achieved. The displacement sensor is widely applied to the technical field of displacement sensors.

An apparatus for detecting real-time phase and offset errors of a Q demodulator includes: an RF signal path configured to receive an RF signal from an RF component; a first chopper for chopping the RF signal at a first frequency to generate a chopped RF signal; an LO signal path configured to receive an LO signal; a second chopper for chopping the LO signal at a second frequency to generate a chopped LO signal; and a summing mechanism for combining the chopped LO signal and the chopped RF signal into a combined signal. The apparatus further comprises a Q demodulator and at least two filters, the Q demodulator comprising: a phase shifter configured to shift a phase of the combined signal and a phase of the LO signal; and a mixer configured to multiply the shifted combined signal with the shifted LO signal to generate a baseband signal, and the at least two filters configured to extract different signals included in the baseband signal for analysis.