Abstract: A mixer apparatus (60), such as an integrated circuit (IC) mixer is provided for improving the physical layout of devices containing mixers. The mixer includes a multiplier (62) with an input port (64), an output port (66), a first switchable local oscillator input port (68) and a second switchable local oscillator input port (72). The dual switchable local oscillator ports are located on either side of the mixer, between the input side and the output side. The dual switchable local oscillator ports allow the mixer to provide more flexibility in integrated circuit and printed circuit board design layouts involving mixer apparatus. For example, in dual channel devices, a local oscillator can be coupled to a pair of the mixers using transmission lines that do not have to be routed around the integrated circuit, to a different level of the printed circuit board or underneath one of the mixers.

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 communications system includes a radio frequency (RF) element (104) for transforming an input RF signal into at least one of a first conditioned RF input signal associated with a first frequency range and a second conditioned RF input signal associated with a second frequency range higher than the first frequency range. The system also includes a local oscillator (LO) circuit (106) for generating at least a first LO signal, the LO circuit having an operating frequency range spanning at least a portion of a first inclusive frequency range defined by a lowest frequency of the first frequency range and a highest frequency of the second frequency range. The system further includes a mixer (108) for generating a first intermediate frequency (IF) signal based on one of the first and the second RF input signals and the first LO signal, and an IF element (110) for conditioning the first IF signal.

Abstract: A low-power receiver front-end includes a transconductance amplifier that produces a single-ended current signal in response to a single-ended voltage signal. An output of the transconductance amplifier is provided to an LC tuned circuit. At resonance, the LC tuned circuit generates a differential current signal in response to the single-ended current signal. Single-ended current signals corresponding to the resonant frequency of the LC tuned circuit are converted into differential signals. Further, the LC tuned circuit amplifies the differential current signals by an associated quality factor. Further, a mixer is coupled to an output of the LC tuned circuit. The mixer generates IF signals in response to the differential current signals.

Abstract: A calibration device is coupled to a balanced circuit device including first and second outputs provided with first and second load impedances. The calibration device includes an adjusting circuit to adjust the first and second load impedances into a load imbalance for linearization. A coupling circuit is inserted between the adjusting circuit and the first and second outputs to selectively couple the adjusting circuit to one of the first and second outputs, so that the adjusting circuit is coupled in parallel either to the first load impedance or to the second load impedance.

Abstract: A signal processing circuit having a modulator having frequency conversion circuits, each having a local oscillator and a mixer. The circuit multiplies a signal having a first frequency and a local oscillation signal from the local oscillator at the mixer to convert the frequency of the first frequency signal to a second frequency, outputs a current format frequency converted signal and a first gain control circuit amplifying the current format frequency converted signals from the frequency conversion circuits by a first gain in accordance with a first control voltage. The circuit also outputs the current format amplified signals and a second gain control circuit connected after the first gain control circuit and having at least one gain control circuit which amplifies a current format amplified signal output from the first gain control circuit by a second gain.

Abstract: The apparatus is a complete passive implementation of an image reject mixer (IRM) that is capable of operating at very high frequency. Using a hybrid as part of the IRM circuit enables operation at very high frequencies that also employs a high intermediate frequency (IF). All the components of the design are passive and implementable in MOS technologies providing significant cost and implementation advantages. Furthermore, the apparatus is operative at frequencies that are higher than several tens of GHz.

Abstract: A passive CMOS differential mixer circuit with a mismatch correction circuit for balancing the electrical characteristics of the two output paths. Once the output paths of the differential circuit are balanced, or matched as closely as possible, second order intermodulation product generation can be inhibited or at least reduced to acceptable levels. The mismatch correction circuit receives a digital offset signal, and generates one or more voltage signals to be selectively applied to the signal paths of the passive differential mixer circuit. The voltage signals can be adjusted back gate bias voltages applied to the bulk terminals of selected transistors to adjust their threshold voltages, or the voltage signals can be adjusted common mode voltages applied directly to a selected signal path. Since the differential mixer circuit is passive, no DC current contribution to noise is generated.

Abstract: Mixer topologies that have sufficiently high IIP2 and sufficiently low quadrature error to make zero IF receivers possible without special calibration techniques. This simplifies the receiver, avoids circuit startup delay and provides more stable performance over time and temperature. The methodology to achieve this performance in preferred embodiments consists of as many as three elements: (a) a high power local oscillator buffer circuit capable of driving low impedance loads coupled to the bases of the bipolar mixer transistors, (b) an optimized bias block for the mixer core and (c) incorporating two or more electronically programmable quad sections and selecting the best quad for use. Other types of transistors may also be used.

Abstract: Integrated balun and coupler is described. In one example, a radio frequency (RF) device includes a balun and coupler. The balun includes a first winding and a second winding arranged on a magnetic core. Respective inputs of the first winding and the second winding are configured to receive a balanced RF input and respective outputs of the first winding and the second winding are configured to provide a first unbalanced RF output. The coupler includes a third winding arranged on the magnetic core. The third winding is configured to provide a second unbalanced RF output, where the second unbalanced RF output is a fraction of the first unbalanced RF output.

Abstract: An embodiment is directed to a zero IF down converter circuit. The circuit comprises a voltage-to-current converter, a mixer, and a suppression circuit. The voltage-to-current converter converts an RF voltage signal to an RF current signal. The mixer changes the frequency of the current signal to a lower frequency current signal. The suppression circuit removes a lower frequency distortion component from the RF current signal before sending the RF current signal to the mixer.

Abstract: A circuit arrangement for signal mixing. One embodiment provides a circuit arrangement for mixing an input signal with at least one carrier signal. The circuit arrangement includes a current source and a current sink. The current source and the current sink have a mixer core coupled between them which provides cross-coupling between mixer input connections and mixer output connections.

Abstract: A broadband balanced frequency converter (“BBFC”) in signal communication with a frequency source is disclosed. The BBFC may include a mixer and an active balancing element in signal communication with the mixer.

Abstract: A variable transconductance device for a mixer apparatus is provided. The apparatus includes at least one variable current source circuit having a plurality of selectively enabled current source stages. Each of the current source stages, when enabled, is actuable to establish a conductive path between a first supply level and an output terminal. The device further includes at least one variable transconductance circuit having a plurality of selectively enabled transconductance stages. Each transconductance stage, when enabled, is actuable to establish a conductive path between a second supply level and the output terminal. An output current signal is generated at the output terminal responsive to actuation of the variable transconductance circuit by an input voltage signal, whereby the output current signal exhibits a power gain adjustably determined responsive to the numbers of current source and transconductance stages selectively enabled.

Abstract: A frequency mixing apparatus with improved voltage gain and linearity is provided. The frequency mixing apparatus includes a transconductor, a separator, and a switching unit. A voltage gain of the transconductor is controllable, and the transconductor converts a Radio Frequency (RF) signal into a current signal under control of a self bias. The separator transfers the current signal to the switching unit. The switching unit outputs a signal having a frequency corresponding to one of a sum and a difference of a frequency of the RF signal and a frequency of a Local Oscillation (LO) signal by performing a switching operation according to the LO signal.

Abstract: A compensating circuit for a mixer stage is provided, wherein the mixer stage has an input stage to which an input signal for mixing can be applied and has, following the input stage, a switching stage for mixing a differential input signal—obtained from the input stage as a function of the input signal—with an oscillator signal, wherein the input of the compensating circuit can be connected to an input signal terminal of the input stage and the output of the compensating circuit can be connected to an input signal terminal of the switching circuit at which the differential input signal obtained by means of the input stage is present, and wherein a compensating signal obtained by means of a compensating stage of the compensating circuit, in particular for compensating intermodulation products, can be produced by the compensating circuit at its output.

Abstract: A modulation circuit is provided that generates an output signal obtained by modulating an input signal with a local signal and includes a local input section that receives the local signal and generates the local signal and an inverted local signal obtained by inverting the local signal, a signal input section that receives the input signal and generates the input signal and an inverted input signal obtained by inverting the input signal, a first multiplying section that outputs from a terminal that receives the input signal a first multiplied signal obtained by multiplying the local signal with the input signal, a second multiplying section that outputs from a terminal that receives the inverted input signal a second multiplied signal obtained by multiplying the inverted local signal with the inverted input signal, an output section that adds the first multiplied signal to the second multiplied signal and generates the output signal, and a transmission line that sends to the output section the first multipl

Abstract: An apparatus adapted for measuring the properties of periodic signals and a method for making such measurements is disclosed. The apparatus includes a LO signal generator, a mixer, a low pass filter and an output device. The LO signal generator generates an LO signal comprising a fundamental frequency ?LO and one or more higher harmonics with arbitrary amplitudes and phases. The mixer receives a periodic input signal having harmonics including a highest harmonic of interest, N, and a fundamental frequency, ?in. The mixer outputs an IF signal that is filtered. The filtered IF signal includes a frequency-compressed signal having M harmonics including a fundamental characterized by a frequency ?c<?in. Each of the harmonics in the frequency-compressed signal corresponds to one of the harmonics in the input signal and has an amplitude related to the amplitude of the corresponding harmonic in the input signal.

Abstract: A receiving apparatus includes an analog demodulation unit, a digital demodulation/decoding unit, a delay unit, a reception state detecting unit, first/second processing units, and a mixing processing unit. The analog demodulation unit demodulates a first audio signal. The digital demodulation/decoding unit demodulates and decodes a second audio signal. The delay unit delays at least one of the first and second audio signals, to be outputted as third and fourth audio signals. The reception state detecting unit outputs an analog reception state signal. The first/second audio processing units control at least one of volume and quality of the third/fourth audio signals, to be outputted as fifth and sixth audio signals. The mixing processing unit mixes the fifth and sixth audio signal at a predetermined ratio, outputted according to a reception state of at least one of a broadcast wave of analog broadcasting and the broadcast wave of digital broadcasting.

Abstract: An integrated circuit (IC) low noise amplifier includes an on-chip balun and an on-chip differential amplifier. The on-chip balun is coupled to convert a single-ended signal into a differential signal. The on-chip differential amplifier is coupled to amplify the differential signal.

Abstract: A frequency conversion circuit comprises an input stage composed of one or more transistors, the input stage outputting a current corresponding to a voltage-type RF signal which is input to the gate of the transistor; a frequency conversion stage receiving an LO signal, causing the output RF signal to transit by the frequency of the LO signal so as to output an IF signal, and detecting an output voltage of the IF signal; a bleeding transistor connected to the input stage, supplying a current corresponding to a DC voltage, applied to a gate-source stage thereof, as a bleeding current to the transistor of the input stage, and in an AC manner, operating complementarily with the input stage to control a current flowing in the frequency conversion stage; a common mode feedback circuit comparing an output voltage provided from the frequency conversion stage with a preset reference voltage, adjusting the output voltage such that the output voltage is equalized to the reference voltage, and directly feeding the adjus

Abstract: A high frequency module includes: a line substrate having a first high-frequency signal line on a first surface thereof and a second high-frequency signal line on a second surface being a surface on the opposite side of the first surface, the second high-frequency signal line being electrically connected with the first high-frequency signal line; and a base substrate which is provided to the second surface of the line substrate, and which is formed in a manner that the base substrate is located away from the second high-frequency signal line.

Abstract: There is provided a transceiver comprising a first node for receiving a received signal and transmitting a transmitted signal; a receiver, connected between a first voltage and the first node, for processing the received signal; a transmitter, connected between a second voltage and the first node, for generating the transmitted signal; and a DC voltage controller for selecting a DC component of a voltage of the first node to at least one of: selectively activate at least one of the transmitter and the receiver; and selectively substantially deactivate at least one of the transmitter and receiver.

Abstract: A chopped intermediate frequency (IF) wireless receiver is disclosed. The wireless receiver includes a local oscillator (LO), a first and a second mixers, an LO frequency control module, an IF filter, a digital down converter and a down conversion controller. The LO provides a local oscillating signal to the first and second mixers. The first and second mixers converts a received radio frequency signal to an in-phase IF signal and a quadrature IF signal, respectively. The LO frequency control module alternately down converts a channel frequency by changing an oscillation frequency of the LO. Coupled to the digital down converter, the down conversion controller adjusts a complex sine wave within the digital down converter while the in-phase IF signal and the quadrature IF signal are being down-converted by the digital down converter to a baseband signal.

Abstract: A circuit and method for tracking a local oscillator signal frequency in an RF tuner, for tuning input RF signals. The RF tuner includes a frequency-dependent impedance generator that generates a frequency-dependent impedance at the input by rejecting unwanted input RF signals and shunt feeding back the desired signal to the input. The desired signal frequency is centered at the local oscillator signal frequency. The frequency-dependent impedance generator is used with an amplifier circuit to generate a tracking amplifier, the frequency-dependent amplifier gain of which tracks the local oscillator signal frequency.

Abstract: A bit error rate of the reception signal is detected on the reception side, such that an n optimal modulation method and LO output power are determined in accordance with this bit error rate, and an LO output changing instruction is sent to an image signal rejection mixer on the transmission side. The image signal rejection mixer changes the phase X=?+? in response to the LO output changing instruction when power splitter (201) splits the LO into two components with equal amplitude and phase difference ?, power splitter (202) splits the IF signal into two components with equal amplitude and phase difference ?, and power combiner (205) combines RF signals with equal amplitude and phase difference ?. By changing the X, the LO output power is controlled and the back-off amount of a transmission amplifier is changed in accordance with an optimal modulation scheme. In this event, ???+?=2n? (n is an integer) is set so as to maximize the image signal rejection amount.

Abstract: A method and apparatus is provided for use in power amplifiers for reducing the peak voltage that transistors are subjected to. A power amplifier is provided with first and second switching devices and an inductor connected between the switching devices. The switching devices are driven such that the switching devices are turned on and off during the same time intervals. Differential RF power amplifiers are also provided with inductive networks coupled at various nodes of the power amplifiers. In some examples, techniques are used to stabilize differential power amplifiers by stabilizing common-mode feedback loops.

Abstract: A very low intermediate frequency (VLIF) receiver comprising a first and second mixer circuits, characterised in that receiver comprises a means of estimating the energy in a desired signal band; a means of estimating the energy in a band of frequencies comprising the desired signal band; and a means of altering a VLIF of the receiver according to the ratio of the energy in a desired signal band and the energy in the band of frequencies comprising the desired signal band.

Abstract: Transmission of a high frequency signal is provided by a passive mixer. The passive mixer receives a low frequency signal as an input. The passive mixer includes a plurality of transistors each with a gate, a source, and a drain. The passive mixer also includes a local oscillator connected to the gates of the transistors. The gates of the transistors are also connected to a DC bias proportional to the threshold voltage of the transistors. In addition, an output of the passive mixer may be attenuated by a passive attenuator wherein both the passive attenuator and passive mixer are substantially free of quiescent current.

Abstract: A switching circuit comprising: first and second steering switches operable to make or break a path between first and second terminals thereof, and each steering switch further having a control terminal for controlling the switch, the first and second steering switches having their control terminals driven by first and second switching signals, the first and second switching signals having a first frequency and the second switching signal being in anti-phase with the first switching signal and a first chopping switch operable to make or break a path between first and second terminals thereof and being connected in series with at least one of the first and second steering switches and receiving at its first terminal an input to be modulated, wherein the control terminal of the chopping switch is driven by a first switching control signal such that the chopping switch is non-conducting while the first and second steering switches are changing between being conducting and being non-conducting.

Abstract: An integrated circuit including a structure of inductances on a semiconductor substrate, intended for operating at frequencies greater than several hundreds of MHz, including a first inductance formed by a conductive track and having first and second terminals respectively connected to each of the two ends of the conductive track, including a second inductance formed by the conductive track between the second terminal and any intermediary point of the conductive track connected to a third terminal, said second and third terminals forming the two terminals of the second inductance, and means for setting the third terminal to high impedance when the first inductance is used.

Abstract: An apparatus and method for local oscillator calibration compensates for filter passband variation in a mixer circuit, such as a receiver circuit. The receiver includes at least a mixer circuit and a filter coupled to the output of the mixer. During operation, the mixer mixes an RF input signal with a first local oscillator (LO) signal to frequency translate a selected channel in the RF input signal into the passband of the filter. During a calibration mode, the RF input signal is disabled, and the first LO signal is injected into the filter input by leaking the first LO signal through the mixer circuit. The frequency of the LO signal is then swept over a frequency bandwidth that is sufficiently wide so that the actual passband is detected by measuring the signal amplitude at the output of the bandpass filter, thereby determining any variation in the passband of the filter from the expected passband.

Abstract: A system for single path processing identical, substantially identical, close or interfering frequencies with a single analog-to-digital converter. The system receives a plurality of input signals at various frequencies and front end circuits filter out first and second frequencies. A mixer and a front end oscillator are in communication with one of the front end circuits for mixing a front end frequency with one of the first and second frequencies prior to the analog-to-digital converter. A summer combines the output of the mixer with the output of one of the front end circuits. An analog-to-digital converter is connected to the summer for converting the analog input signal to a digital output signal. The first and second frequencies may be separately processed after they have been combined, even if they were identical frequencies.

Abstract: A mixer has a controllable load, a signal mixing module, and a controller. The controllable load is controlled by a control signal to change an equivalent load value thereof. The signal mixing module has an output port coupled to the controllable load and an input port coupled to an input signal, and is used for mixing the input signal with a local oscillation signal. The controller is coupled to the controllable load, and is used for generating the control signal to reduce the equivalent load value of the controllable load during switching transients of the local oscillation signal.

Abstract: Disclosed is a mixer comprising: a switching circuit, having a first pair of differential signal nodes and a second pair of differential signal nodes, for switching according to a local oscillation signal; an amplifying stage circuit, for receiving an input signal and amplifying the input signal; a load circuit, for serving as the loading of the mixer and generating an output signal of the mixer; a common-mode feedback circuit, for receiving the output signal and generating a feedback signal according to the output signal; a first current source, for receiving the feedback signal and generating a first current according to the feedback signal; and a second current source, for receiving the feedback signal and generating a second current according to the feedback signal.

Abstract: A method (1100, 1200) of generating a composite mitigation signal (216, 902, 1002) is presented. The composite mitigation signal includes an odd integer (N) of transitions (310, 312) between a first amplitude and a second amplitude of the composite mitigation signal. Successive sets of the transition bursts are separated by a desired phase delay or time delay (330), or such separations are defined by a base signal (416) having a frequency equal to a fundamental frequency of the composite mitigation signal. The composite signal generators (222, 900, 1000) that generate the composite mitigation signal are also presented.

Abstract: Provided is a mixer including: an amplifier amplifying an input signal using at least one amplifier element; a mixing unit mixing the input signal amplified by the amplifier with a local oscillator signal output from a local oscillator. The mixing unit includes at least one pair of switching elements switching the amplifier, and the switching elements are MOSFETs having gates and body nodes to which a same local oscillator signal is applied. Thus, a time required for turning on the switching elements can be reduced, and 1/f noise is also reduced. Also, an overdrive voltage can be increased with respect to local oscillator signals having an identical intensity. Thus, a relatively low voltage operation can be performed.

Abstract: The system and method of the present invention provide a single mixer (200-400) with significantly reduced noise performance at a low cost by adding a current control circuit (109) that reduces the current in at least the switching stage (103, 303, 403) during polarity changes of the local oscillator (LO) signal (104). Alternative embodiments (300-400) are provided for a single mixer having significantly reduced noise wherein the low-noise characteristic is enhanced by a further modification to the switching stage (303-403).

Abstract: A mixer for down-converting an input signal to an output signal is disclosed. The mixer includes an amplifying circuit and a down-converting circuit. The amplifying circuit is utilized for amplifying the input signal to generate an amplified signal. The down-converting circuit includes a filtering module, a loading module, and a down-converting module. The filtering module is coupled to the amplifying circuit, and is utilized for filtering low-frequency components in the amplified signal. The loading module is coupled to the amplifying circuit and a predetermined voltage level, and is utilized for providing a DC bias voltage to the amplifying circuit. The down-converting module is coupled to the filtering module and the predetermined voltage level, and is utilized for generating the output signal according to a local oscillating signal.

Abstract: A miniaturized dual-balanced mixer circuit based on a multilayer double spiral layout architecture is proposed, which is designed for use to provide a frequency mixing function for millimeter wave (MMW) signals, and which features a downsized circuit layout architecture that allows IC implementation to be more miniaturized than the conventional star-type dual-balanced mixer (DBM). The proposed miniaturized dual-balanced mixer circuit is distinguished from the conventional star-type DBM particularly in the use of a 3-dimensional double-spiral circuit layout architecture for the layout of two balun circuit units. This feature allows the required layout area to be only about 15% of that of the conventional star-type DBM.

Abstract: A configurable passive mixer is described herein. According to one exemplary embodiment, the passive mixer comprises a clock generator, a controller, and a plurality of passive mixer cores connected in parallel. The clock generator comprises a local oscillator drive unit for each passive mixer core. The controller varies an effective transistor size of the passive mixer by separately configuring each of the passive mixer cores to enable/disable each passive mixer core. For example, the controller may selectively enable one or more of the passive mixer cores to vary the effective transistor width of the passive mixer. As the performance requirements and/or the operating communication standard change, the controller may re-configure each passive mixer core.

Abstract: The present invention relates to a balanced circuit arrangement and methods for linearizing and calibrating such a circuit arrangement, wherein linearization is obtained by introducing a load imbalance between the output branches of the balanced circuit arrangement. Thus, a controllable extraneous imbalance is created between the output loads of the balanced circuit arrangement to thereby obtain a linearization by means of even-order non-linearity.

Abstract: A mixer which has an enhanced frequency selection characteristic and generates no pass loss is realized without using an operation control signal having a frequency higher than a sampling frequency. Provided are a time control section 102 for supplying control signals, a first switched capacitor circuit 100 for outputting a discrete time sample stream of the input signal 107 in accordance with integration operation control signals Lo1 and Lo2, and a second switched capacitor circuit 104 functioning as a high-order IIR filter by sharing a charge, and a frequency of each of the integration operation control signals Lo1 and Lo2 is higher than frequencies of other control signals.

Abstract: A method and system for increasing the compression point of a receiver by deriving a feedback signal from mixer output signals. The feedback signal prevents the receiver from going into compression on strong out-of-band or blocking signals, while enhancing the receiver gain at the desired frequency. The desired frequency coincides with the local oscillator (LO) signal and is therefore particularly applicable for, but not limited to, homodyne receivers where selectivity can be made quite narrowband. Since the selectivity is coupled to the LO, a tunable receiver may be achieved that enables selectivity over a wide range of input frequencies.

Abstract: An orthogonal signal output circuit having an error correction function for correcting an orthogonal error, including: first and second differential circuits; and first to fourth variable resistors, wherein the first variable resistor is connected to a positive output of the first differential circuit and a positive output of the second differential circuit; the second variable resistor is connected to the positive output of the first differential circuit and a negative output of the second differential circuit; the third variable resistor is connected to a negative output of the first differential circuit and the positive output of the second differential circuit; and the fourth variable resistor is connected to the negative output of the first differential circuit and the negative output of the second differential circuit.

Abstract: A Gilbert cell mixer for a wireless transceiver includes a first stage that performs voltage to current conversions and that includes first and second transistors that are operated in a saturation region and third and fourth transistors that are operated in a triode region. A second stage communicates with the first stage and that performs frequency conversion. A biasing circuit communicates with the first stage to maintain a substantially constant input linear range over temperature and process variations.

Abstract: Mixer circuits (1) comprise mixers (2) for receiving input signals and oscillation signals and for outputting output signals. By providing the mixers (2) with loads (3) having adjustable load values and by introducing adjustors (4) for adjusting and sweeping the loads (3), which adjusted loads (3) have different load values at different moments in time, and by introducing detectors (5) for detecting components such as second order intermodulation products of the output signal per load value and selectors (6) for selecting detection results and for instructing the adjustors (4) to set the loads (3) in response to the selected detection result, the mixer (2) is calibrated. The detectors (5) comprise filtering circuitry (52) for filtering the components and comprising slope detection circuitry (53) and the electors (6) comprise comparison circuitry (61) for comparing slope values with each other for finding an extreme slope value that defines the detection result to be selected.

Abstract: A frequency-mixing device performing voltage multiplying and low-pass filtering operations in addition to frequency mixing is provided. The three operations may be carried out with the same components by designing the frequency mixer appropriately. The frequency mixer comprises a first capacitance connected in series to the input of the frequency-mixing device, a first switch connected in parallel to the first capacitance, a second switch connected in series to the first capacitance, and a second capacitance connected in parallel to the second switching means. The switches are controlled by a local oscillator signal to close and open alternately according to a change in the voltage level of the first oscillator signal.

Abstract: A calibration device is coupled to a balanced circuit device including first and second outputs provided with first and second load impedances. The calibration device includes an adjusting circuit to adjust the first and second load impedances into a load imbalance for linearization. A coupling circuit is inserted between the adjusting circuit and the first and second outputs to selectively couple the adjusting circuit to one of the first and second outputs, so that the adjusting circuit is coupled in parallel either to the first load impedance or to the second load impedance.

Abstract: A semiconductor integrated circuit including: a mixer circuit which includes a first MOS transistor a second MOS transistor; a third MOS transistor whose drain is connected to a first potential, and which has a conductivity type and a threshold value which are the same as those of the first MOS transistor and the second MOS transistor; a current source connected between the source of the third MOS transistor and a second potential; a voltage dividing circuit which is connected between the first potential and the second potential, and divides a voltage between the first potential and the second potential to output a divided voltage as a reference voltage; and a differential amplifier circuit whose in-phase input receives the reference voltage, whose anti-phase input receives a source potential of the third MOS transistor, and whose output is connected to a gate of the third MOS transistor.