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 direct conversion multi-band TV tuner includes: a plurality of RF (radio frequency) paths for processing the RF signal and for generating a plurality of processed RF signals, respectively; and a TSC (tri-state chopper) based quadrature frequency converter for receiving one of said processed RF signals and converting the received processed RF signal into a in-phase baseband signal and a quadrature baseband signals; wherein the TSC based quadrature frequency converter operates in accordance with a first set of periodic three-state control signals and a second set of periodic three-state control signals that are approximately 90 degrees offset from the first set of periodic three-state control signals.

Abstract: A radio frequency (RF) transceiver includes an RF transmitter that generates an outbound RF signal at a carrier frequency that is based on a transmitter local oscillation. An RF front-end receives an inbound RF signal that includes a desired signal component that is based on the outbound RF signal and that includes an undesired signal component. The RF front-end includes a first RF combiner module that attenuates the undesired signal component to produce a desired RF signal. A down conversion module generates a down converted signal from the desired RF signal based on a receiver local oscillation. A receiver processing module generates inbound data from the down converted signal. A frequency control module controls a frequency of the transmitter local oscillation and a frequency of the receiver local oscillation, based on an interference rejection signal, to control the attenuation of the undesired signal component.

Abstract: A dual conversion receiver selects and down-converts one channel from a plurality of channels in a received RF signal. The dual conversion receiver includes first and second mixer stages that are driven by first and second local oscillator signals. Channel selection is performed by tuning the first local oscillator signal so that a desired channel is up-converted to a first IF frequency, which defines the center of the passband of a first bandpass filter connected between the first and second mixer stages. The second mixer stage down-converts the output of the first bandpass filter to a second IF frequency, which is further filtered by a second bandpass filter. The first and second local oscillators can produce harmonics that mix in the second mixer stage, causing unwanted spurious signals that can fall in band with the second IF frequency.

Abstract: A system and method are disclosed for providing streaming data information to a receiver. The system accesses one or more information service providers for providing respective information signals, input buffers for storing portions of the streaming inforamtion, a digital broadcast transmitter for broadcasting the contents of the input buffers as transmission bursts, a digital broadcast receiver for receiving the transmission bursts for storage in a receiver input buffer, and an application processor for converting the transmission bursts to an information transmission stream. The digital broadcast receiver is synchronized with the transmitter broadcasts to allow for powering down between selected transmission bursts.

Abstract: An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit is described. A receiver front end provides programmable attenuation and a programmable gain low noise amplifier. Frequency conversion circuitry advantageously uses LC filters integrated onto the substrate in conjunction with image reject mixers to provide sufficient image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. The filters utilize multi track spiral inductors. The filters are tuned using local oscillators to tune a substitute filter, and frequency scaling during filter component values to those of the filter being tuned. In conjunction with filtering, frequency planning provides additional image rejection. The advantageous choice of local oscillator signal generation methods on chip is by PLL out of band local oscillation and by direct synthesis for in band local oscillator.

Abstract: A receiver includes a high-frequency filter which extracts, from a radio signal, a high-frequency signal, a first frequency converter which performs frequency conversion on the high-frequency signal using a first local signal, to obtain a first baseband signal, a second frequency converter which performs frequency conversion on the high-frequency signal using a second local signal, to obtain a second baseband signal, the second local signal having a frequency equal to an integral multiple of a frequency of the first local signal, and a subtraction processing unit configured to multiply the second baseband signal by a control coefficient for amplitude adjustment to obtain a product signal, and subtract the product signal from the first baseband signal to obtain a residual signal.

Abstract: The present invention is directed to a system and method of reducing frequency interference in a circuit when the harmonics of at least two frequencies could cause interference when such harmonics interact with each other. In one embodiment, a determination is made as to which harmonic could possibly support such interference, and based upon the determined harmonic, determining which combination within said determined harmonic is likely to cause the interference.

Abstract: Heretofore, a plurality of packages were used in a high frequency module in which a plurality of waveguide terminals were positioned resulting in problems, such as degradation of characteristics in the connection lines between packages, lower ease of assembly when mounting and connecting the connection lines, increased cost, and so forth. To solve these problems, a plurality of cavities having a part or the entire side metallized is formed in a multi-layer dielectric substrate. The multi-layer dielectric substrate is provided with a plurality of waveguide terminals, microstrip line-waveguide converters, RF lines, bias and control signal wiring, and bias and control signal pads. A high frequency circuit is mounted within the cavity and sealed with a seal and cover. This is intended to reduce the number of package, improve performance, improve fabrication, and lower the cost.

Abstract: In the radio-wave receiving apparatus according to the invention, a signal received by a receiving antenna is amplified and the amplified received signal is input into a multi-stage frequency conversion circuit including a plurality of basic circuits connected in series. The multi-stage frequency conversion circuit converts the frequency of the received signal from the antenna into frequencies based on signals input from the frequency divider circuit sequentially, thereby to output a signal “a” which is obtained by conversions into gradually lower frequencies. Detection is performed by a detection circuit on the basis of the signal. Thereby, a radio-wave receiving apparatus which requires no local oscillating circuit nor a PLL circuit and is also stable in operation and high in accuracy is realized.

Abstract: Frequency translation, such as frequency up conversion of a video baseband or intermediate frequency to a desired frequency division broadcast channel, is provided utilizing a single sideband or image reject mixer and filtering having relaxed selectivity requirements. According to a preferred embodiment, a first single sideband mixer accepts an input signal at an intermediate frequency and up converts this signal to a high intermediate frequency. The image rejection provided by the single sideband mixer in combination with simple filtering provide sufficient signal quality to achieve desired levels of desired signal isolation, such as on the order of 40 dB. Preferably, a second single sideband mixer accepts the high intermediate frequency signal and down converts this signal to a desired transmission or broadcast frequency.

Abstract: A radio frequency (RF) transceiver includes an RF transmitter that generates an outbound RF signal at a carrier frequency that is based on a transmitter local oscillation. An RF front-end receives an inbound RF signal that includes a desired signal component that is based on the outbound RF signal and that includes an undesired signal component. The RF front-end includes a first RF combiner module that attenuates the undesired signal component to produce a desired RF signal. A down conversion module generates a down converted signal from the desired RF signal based on a receiver local oscillation. A receiver processing module generates inbound data from the down converted signal. A frequency control module controls a frequency of the transmitter local oscillation and a frequency of the receiver local oscillation, based on an interference rejection signal, to control the attenuation of the undesired signal component.

Abstract: Receiver architectures and methods of processing harmonic rich input signals employing harmonic suppression mixers are disclosed herein. The disclosed receivers, mixers, and methods enable a receiver to achieve the advantages of switching mixers while greatly reducing the mixer response to the undesired harmonics. A harmonic mixer can include a plurality of mixers coupled to an input signal. A plurality of phases of a local oscillator signal can be generated from a single local oscillator output. Each of the phases can be used to drive an input of one of the mixers. The mixer outputs can be combined to generate a frequency converted output that has harmonic rejection.

Abstract: There is disclosed a radio frequency (RF) demodulation circuit comprising: 1) a first RF mixer having a first input port for receiving an in-phase RF signal having a frequency of RF and a second input port for receiving an in-phase local oscillator (LO) signal having a frequency of LO, wherein LO is approximately equal to one-half of RF, and wherein the first RF mixer generates a first intermediate frequency (IF) signal having a frequency of LO; 2) a second RF mixer having a first input port for receiving an out-of-phase RF signal having a frequency of RF and a second input port for receiving an out-of-phase local oscillator (LO) signal having a frequency of LO, and wherein the second RF mixer generates a second intermediate frequency (IF) signal having a frequency of LO; and 3) a first signal combiner for combining the first and second IF signals to generate a composite IF signal, wherein the first signal combiner combines a first leakage signal from the first RF mixer and a second leakage signal from the se

Abstract: A receiver, in particular for mobile radio, includes a receiver branch with a mixer, downstream of an analog/digital converter. A reference generator generates a reference clock, which is fed to the converters or PLL synthesizers of the mixer by integral multiplication or division. As a result, a particularly energy-saving and space-saving circuit configuration is realized, which has a low level of mutual interference between the signals and is suitable (in particular for Universal Mobile Telecommunication System, UMTS). In a preferred embodiment, the receiver is developed into a transceiver by providing a transmission path.

Abstract: Disclosed are systems and methods which utilize a relatively low cost first IF filter in a dual conversion tuner circuit. A preferred embodiment first IF filter is provided using a filter arrangement having a relatively high tolerance. Accordingly, preferred embodiment systems are designed such that they can accommodate the range of first IF frequencies that the large tolerance filter may provide. One aspect of this accommodation may include providing a means by which the system may detect the location of the passband of the IF filter in the spectrum. Another aspect of the accommodation for the range of first IF frequencies may include adjusting the first IF frequency utilized by the dual conversion tuner to match the passband of the IF filter. Additionally or alternatively, the passband of the first IF filter itself may be tuned, such as to provide a passband more near a desired IF frequency.

Abstract: A digital intermediate frequency transmitter for a wireless communication is disclosed. In accordance with the present invention, an improvement of a modulation quality such as an EVM, a linearity and a power consumption is possible, and a main characteristic of a wireless communication transmitter may be embodied at a low cost through an integration such that a high frequency 90° phase shifter, a voltage controlled oscillator having a 2× frequency or higher and a high frequency I/Q local oscillated signals are not required and a side-band signal may be effectively removed.

Abstract: A frequency synthesizer with a single PLL and multiple SSB mixers is presented. The frequency synthesizer includes a single PLL outputting a reference signal that is fed to a plurality of dividers coupled in sequence. The outputs from the dividers are mixed by the SSB mixers to produce signals with different frequencies. These signals with different frequencies can be selected through use of multiple selectors.

Abstract: For the purpose of efficient transmission based on the UWB system, first and second baseband waveforms are generated at a cycle equivalent to an integral multiple of a carrier to have a specified phase difference from each other. The first baseband waveform is multiplied by the carrier and a first transmission data sequence to acquire a first transmission waveform. The second baseband waveform is multiplied by a phase shifted carrier and a second transmission data sequence to acquire a second transmission waveform. The first transmission waveform is mixed with the second transmission waveform to acquire a transmission signal. The transmission signal is transmitted as a ?/2 shift BPSK signal to transmit a UWB signal. Selecting the baseband waveforms and the carrier makes it possible to configure the transmission band and easily provide division multiplexing transmission.

Abstract: The invention relates to a connectivity box (1) and a method for connecting a mobile device (2), in particular an operator panel for an automation system, to a permanently installed infrastructure (3), the connectivity box (1) possessing an identity (ID) which is transmitted to the mobile device (2). The connection of the mobile device (2) is implemented for example via a cable which is plugged into the connectivity box (1). In this arrangement the existing signal lines (4) are used for transmitting the identity (ID) or, as the case may be, the box address. The lines are looped through for standard communication. However, when a mobile device (2) is connected, the lines are separated and connected to a control logic (5) on the mobile device side. By this means the identity (ID) of the connectivity box (1) is transmitted to the mobile device (2).

Abstract: A tracking filter for attenuating out-of-band signals and adjacent channel signals in a receiver is described. In one exemplary design, an apparatus includes a tracking filter, an LNA, and a downconverter. The tracking filter includes a summer, a filter, and an upconverter. The summer subtracts a feedback signal from an input signal and provides a first signal. The LNA amplifies the first signal and provides a second signal. The downconverter frequency downconverts the second signal and provides an output signal. The filter filters (e.g., differentiates) the output signal and provides a third signal. The filter blocks a desired signal and passes out-of-band signal components. The upconverter frequency upconverts the third signal and provides a fourth signal from which the feedback signal is derived. The tracking filter has an equivalent bandpass filter response and a variable center frequency determined based on the frequency of the desired signal.

Abstract: Methods, systems, and apparatuses for filtering received radio frequency signals are provided. A first RF communication signal is received that includes a desired information signal portion and an undesired blocker signal portion that is offset in frequency from the desired portion. The first RF communication signal is amplified in a first signal path and is filtered in a second signal path. The filtering of the first RF communication signal in the second signal path includes: down-converting the first RF communication signal to a down-converted signal, high pass filtering the down-converted signal, and up-converting the high pass filtered down-converted signal to a second RF communication signal. The filtering of the first RF communication signal filters out the desired information signal portion from the second signal path. A signal phase is adjusted in the second signal path to match phase shifts between the first and second signal paths.

Abstract: A receiver includes a static I/Q calibration block and a correlation/integration block. The static I/Q calibration block is configured to substantially eliminate mismatches between in-phase and quadrature components of a portion of the spectrum having associated I/Q mismatches that are relatively frequency-independent. The correlation/integration block is configured to substantially eliminate mismatches between the in-phase and quadrature components of portions of the spectrum having associated I/Q mismatches that are relatively frequency-dependent in accordance with a pair of signals generated by the static I/C calibration block.

Abstract: A single chip integrated circuit wireless data processor demodulates N separate data signals from M separate antennas simultaneously. The multi-antenna processor can be coupled to a baseband processor on the IC, so that it responds to changing channel conditions between two access points, and selectively kicks in if there is noise, interference, frequency fading, a need for an enhanced data rate, a need for an increased operating range, etc. to improve a performance of the baseband processor.

Abstract: Aspects of a method and system for a distributed transceiver for high frequency applications may include generating a second signal from a first signal by frequency-translating the first signal via a plurality of conversion stages. Each of the plurality of conversion stages may frequency-translate a corresponding input signal by a local oscillator frequency or by a fraction of said local oscillator frequency. The first signal may be the corresponding input signal to an initial stage of a the plurality of conversion stages, an output signal of a previous one of the plurality of conversion stages may be the corresponding input signal to a subsequent one of the plurality of conversion stages, and the second signal may be an output signal of a final stage of the plurality of conversion stages.

Abstract: Aspects of a method and system for a distributed quadrature transceiver for high frequency applications may include frequency-translating a first signal to generate a second signal utilizing a plurality of conversion stages. The frequency-translating may comprise receiving in each one of the plurality of conversion stages, a local oscillator signal or a fractional local oscillator signal which may be utilized for mixing a corresponding input signal to each one of the plurality of conversion stages, wherein the first signal may be the corresponding input signal to an initial stage of the plurality of conversion stages. An output signal from a prior one of the plurality of conversion stages may be the corresponding input signal to a successive one of the plurality of conversion stages, and the second signal may be an output signal of a final stage of the plurality of conversion stages.

Abstract: In a receiver, a mixer portion provided in a front-end portion thereof is built with two mixers with different input/output linearity characteristics and different current consumption. According to the electric-field strength of a received signal, or manually, one of the mixers is chosen to operate so that, when the electric-field strength is in an ordinary range, the mixer with a better input/output linearity characteristic is chosen to operate with lower current consumption and, when the electric-field strength is in a high range, the mixer that, despite operating with higher current consumption, exhibits a still better input/output linearity characteristic is chosen. The receiver thus operates with lower current consumption and lower signal distortion.

Abstract: A frequency separating system is described utilising tuneable frequency shifting complex converters in which the centre frequency of the band extracted and the bandwidth extracted can be varied depending upon the parameters chosen by the user. A single output band may contain multiple target carrier signals for separation using fine-tuning shaping filters. The local oscillators provide a stream of coefficient values for multiplying the digital signal sample values to perform part of the frequency extraction operation. These local oscillators may be numerically controlled oscillators with the stream of generated co-efficient values being selected from different sets of such coefficient values depending upon the desired frequency extraction.

Abstract: A radio frequency (RF) demodulation circuit comprising: 1) a radio frequency (RF) mixer having a first input port capable of receiving an incoming RF signal having a frequency of RF and a second input port capable of receiving a first local oscillator (LO) signal having a frequency of LO, wherein the RF mixer generates a first intermediate frequency (IF) signal having a frequency of IF; 2) a frequency divider circuit capable of receiving the first LO signal having the frequency of LO and generating therefrom a second local oscillator (LO) signal having a frequency of LO/N and synchronized with the first LO signal; and 3) an intermediate frequency (IF) mixer having a first input port capable of receiving the first IF signal and a second input port capable of receiving the second LO signal having the frequency of LO/N, and wherein the IF mixer generates a baseband output signal.

Abstract: A baseband signal processing method includes reducing a frequency of an intermediate-frequency signal using a first oscillation signal, the intermediate-frequency signal being a signal that has been converted by an RF circuit that converts a received signal into the intermediate-frequency signal using a local oscillation signal, mixing the reduced signal with a second oscillation signal to obtain a baseband signal, and changing the first oscillation signal and the second oscillation signal corresponding to an oscillation frequency of the local oscillation signal.

Abstract: A receiver system design and architecture that implements a 3-step gain LNA and an analog VGA for a WCDMA handsets and local area base stations, providing a wireless device eliminating the use of external bandpass filter between low-noise amplifier and first mixer.

Abstract: A television tuner system includes a low noise amplifier (LNA) for receiving and amplifying television signals, a quadrature mixer coupled to receive the amplified television signals and generate first intermediate frequency (IF1) quadrature signals, a complex mixer coupled to receive the IF1 quadrature signals and generate second intermediate frequency (IF2) quadrature signals, a polyphase filter coupled to receive the IF2 quadrature signals and generate IF2 real signals, a channel select filter (CSF) coupled to receive the IF2 real signals and select signals within a desired channel, and an IF variable-gain amplifier (VGA) for amplifying the signals within the desired channel selected by the CSF.

Abstract: An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit is described. A receiver front end provides programable attenuation and a programable gain low noise amplifier. Frequency conversion circuitry advantageously uses LC filters integrated onto the substrate in conjunction with image reject mixers to provide sufficient image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. The filters utilize multi track spiral inductors. The filters are tuned using local oscillators to tune a substitute filter, and frequency scaling during filter component values to those of the filter being tuned. In conjunction with filtering, frequency planning provides additional image rejection. The advantageous choice of local oscillator signal generation methods on chip is by PLL out of band local oscillation and by direct synthesis for in band local oscillator.

Abstract: Frequency translation, such as frequency up conversion of a video baseband or intermediate frequency to a desired frequency division broadcast channel, is provided utilizing a single sideband or image reject mixer and filtering having relaxed selectivity requirements. According to a preferred embodiment, a first single sideband mixer accepts an input signal at an intermediate frequency and up converts this signal to a high intermediate frequency. The image rejection provided by the single sideband mixer in combination with simple filtering provide sufficient signal quality to achieve desired levels of desired signal isolation, such as on the order of 40 dB. Preferably, a second single sideband mixer accepts the high intermediate frequency signal and down converts this signal to a desired transmission or broadcast frequency.

Abstract: According to the radio receiver, a first path P1 included in a frequency conversion circuit 12 does not have a filter, and a filter 171 for extracting a reference signal 74c is provided in a second path P2 so that a second IF multiple signal 74 and the reference signal 74c are multiplied together in a mixer section 12a. Consequently, by extracting the reference signal 74c, the filter 171 in the second path P2 operates as a local oscillation signal source synchronized with the second IF multiple signal 74. Therefore, according to the signal obtained by down-conversion of the second IF multiple signal 74 with use of the reference signal 74c in the mixer section 12a, signals identical in quality to input signals inputted on the transmission side can be reproduced.

Abstract: An off-chip signal is provided to a differential branch-line directional coupler implemented entirely on-chip. The coupler produces differential quadrature signals, which are then buffered and applied to a quadrature mixer. The coupler is implemented entirely on-chip using microstrip transmission lines. The coupler is made up of a plurality of rings and a plurality of underpasses connecting ports of the rings, wherein each of the plurality of rings is made up of four branch lines, and each branch line having an electrical length of one-quarter wavelength at the center design frequency. Coupling between the plurality of branch lines of the rings may be varied.

Abstract: The invention is directed to a receiver arrangement, for example, in a mobile radio, which allows the use of slowly locking phase locked loops for a point-to-point connection between two transceivers, even in the case of a heterodyne receiver structure. The need to change channels between a transmission slot and a reception slot is avoided by virtue of a changeover device being provided for the purpose of interchanging the in-phase and quadrature components at the input side on a down-conversion frequency mixer. This advantageously allows either the upper sideband or the lower sideband of a useful signal to be down-converted without the need to change channel.

Abstract: A unique ultra wide band receiver is provided that blends together RF and photonic technologies. The receiver has application as a steering mechanism (600) for a much higher resolution receiver. Some implementations can provide at least four times shorter scanning and processing time than current technology using Bragg-cell technology as a direct replacement for state of the art A/D technology at a high IF frequency conversion rate. The dynamic range offered through use of Bragg-cell processor technology, as used in this IF application, provides greater bandwidth than comparable A/D technology.

Abstract: A frequency synthesizer with a single PLL and multiple SSB mixers is presented. The frequency synthesizer includes a single PLL outputting a reference signal that is fed to a plurality of dividers coupled in sequence. The outputs from the dividers are mixed by the SSB mixers to produce signals with different frequencies. These signals with different frequencies can be selected through use of multiple selectors.

Abstract: A frequency synthesizer in an ultra wide band (UWB) wireless communication system which transmits and receives data through multiband includes a frequency generation means which generates a plurality of frequency signals; and a frequency adjustment means which receives the plurality of frequency signals from the frequency generation means and generates center frequencies of all or part of sub-bands within the UWB through the frequency adjustment. Since all of the center frequencies of the sub-bands are generated, the utilization of the sub-bands can be enhanced for the wideband wireless communication. Furthermore, it is possible to enable the stable UWB communications by flexibly utilizing all of fourteen sub-bands since the sub-bands suffer less from the frequency interference in a complicated and variable wireless frequency environment.

Abstract: The invention proposes a repeater designed for indoor transmissions. The useful frequency band is split into two frequency bands and the repeater amplifies the signals from one of the bands and translates them to the other band. The transposition of frequency bands results in preventing creating significant interference effects on the signal to be amplified. A management circuit is used to address, at lower cost, interference problems between the bands.

Abstract: A mixer arrangement includes a first mixer having at least one signal input for receiving a first signal the frequency of which is to be changed. The mixer arrangement also includes at least one frequency input for receiving an input frequency and at least one output. The first mixer is configured to mix a first signal with an input frequency to provide an output which is output by the at least one output. A second mixer has at least one frequency input for receiving an input frequency and at least one output. At least one output of the first mixer and at least one output of the second mixer are combined to cancel unwanted components from the input frequency in the outputs of the mixers.

Abstract: An automatic gain control (AGC) and DC estimation and correction technique for wireless communication devices is provided. An AGC signal, which controls a gain applied to a received signal by a gain stage to generate a scaled signal, is assigned one of a relatively small number of values in accordance with the amplitude of the scaled signal. An estimate of a DC offset in the scaled signal corresponding to each value of the AGC signal is stored in a memory. A DC estimation arrangement then reads the stored estimate associated with the particular value of the AGC signal from the memory and generates a current DC estimate based thereon. The current estimate is then used to correct the scaled signal for DC offset and to update the stored estimate.

Abstract: A wireless receiver includes a local oscillator, a mixer, a band pass filter, a DC offset determination module, a DC offset correction module, a subtraction module, and a down converter. The local oscillator produces a local oscillation that a mixer uses to down convert the RF information signal to produce a Very Low Intermediate Frequency (VLIF) information signal at a VLIF and having a DC offset. The band pass filter band pass filters the VLIF information signal. The DC offset determination module produces a DC offset indication for the VLIF information signal. The DC offset correction module generates a DC offset correction based upon the DC offset indication. The subtraction module subtracts the DC offset correction from the VLIF information signal to substantially remove a DC offset of the post-filtered VLIF information signal. The down converter down converts the VLIF information signal to a baseband information signal.

Abstract: A receiver includes a processor and an RF bridge. The RF bridge is coupled to the processor to receive a reference signal from the processor. The RF bridge includes first and second frequency converters coupled to respective first and second antennas. The RF bridge also includes a third frequency converter coupled to outputs of the first and second frequency converters. In an alternative receiver the processor is coupled to receive an information signal from the RF bridge. The processor includes a digital frequency source to generate the reference signal based on a signal from a clock source and circuitry to detect a frequency difference from the information signal based on the signal from the clock source. In a variant, the circuitry to detect includes a first Fourier transformer having a first center frequency and a second Fourier transformer having a second center frequency different than the first center frequency.

Abstract: A method and circuit to eliminate an offset noise, which may be produced at or near DC (zero Hertz) in an analog, linear multiplier, is described. An input signal is chopped (converted to another frequency) by a first chopper, shifting a frequency of the input signal such that the multiplier output signal is shifted away from DC. An output signal of the multiplier is subsequently chopped again by a second chopper employing the same chopping frequency as the first chopper. This converts a frequency of the output signal to a desired frequency at or near DC. The double chopping also shifts the offset noise produced by the multiplier to a frequency, that is higher than the frequency of the output signal. The offset noise can then be removed by a low-pass filter leaving the output signal without the offset noise.

Abstract: There is disclosed a receiver which solves such a problem as to strictly realize channel selection filter characteristics in extracting a narrow band signal from a broad band signal by digital signal processing in a conventional direct conversion circuit and which improves an image rejection ratio and which can reduce a load of hardware or processing to realize a channel selection filter for extracting the narrow band signal. In a digital signal processing section, one set or a plurality of sets of an image rejection section, a frequency conversion section, and a rate conversion section are continuously connected. A narrow band signal of a desired wave is extracted from a broad band signal whose sampling frequency is lowered, and an offset provided at a local oscillator at the time of quadrature detection is removed in the receiver.

Abstract: An ultra-wideband receiver system includes an intelligent-preselector stage to up-convert received signals to signals within a first IF frequency-range with stepped first oscillation signals, a first down-converting stage to down-convert the signals within the first IF frequency-range to signals within a second IF frequency-range with a fixed second oscillation signal, and a second down-converting stage to down-convert the signals within the second IF frequency-range to signals within a third IF frequency-range with stepped third oscillation signals. The center frequency of the first IF frequency-range may be at least 30% to 35% higher than a highest frequency in the receive-frequency range to provide an image frequency far from (e.g., more than twice) the highest frequency in the receive-frequency range. The receiver may also include a synthesizer to generate the first, second and third oscillation signals with half-integer frequency dividers based on a master reference signal.

Abstract: A digital down-converter having a low spurious level and a high frequency precision without increasing power consumption of a local oscillator. A first mixer receives, as a first IF input signal, a digital signal obtained by sampling a received signal with an RF signal or an IF signal, and converts the first IF input signal to a second IF signal using the first local oscillator. A digital filter suppresses an outband signal of the second IF signal provided from the first mixer. A second mixer converts an output of the digital filter to a detection process frequency using the second local oscillator. An available frequency step of the first local oscillator is larger than an available frequency step of the second local oscillator.

Abstract: A multiband receiver and associated method are provided for simultaneous reception of a number of RF signals with partially different carrier frequencies. An RF/IF converter is provided with a number of local oscillators corresponding to a number of RF signals in order to produce L0 in phase components corresponding to the carrier frequencies and quadrature components; in addition to an in-phase mixer and a quadrature mixer for mixing the respective L0 in-phase and quadrature components with the RF signals in order to produce intermediate frequency signals with IF in-phse components and IF quadrature components. A complex fiber carries out complex filtering on the basis of the intermediate frequency signals in order to suppress reflected intermediate frequency signals.