Abstract: In a quadrature mixer circuit for receiving a radio frequency signal to generate first and second quadrature output signals, a first three-input mixer receives the radio frequency signal, a first local signal having a first frequency and a second local signal having a second frequency to generate the first quadrature output signal, and a second three-input mixer receives the radio frequency signal, the first local signal and the second local signal to generate the second quadrature output signal. The second local signal received by the first three-input mixer and the second local signal received by the second three-input mixer being out of phase by ?/2 from each other.

Abstract: A low power supply band-gap current reference includes a 1st P-N junction device, a 2nd and P-N junction device, a 1st current source, a 2nd current source, a 1st resistor, a 2nd resistor, a 3rd resistor, an operational amplifier, and a current mirror. The 1st and 2nd P-N junction devices are operably coupled to the 1st and 2nd current sources, respectively. The 2nd P-N junction device is a larger device than the 1st P-N junction device. The 2nd resistor is operably coupled in parallel with the 1st P-N junction device and the 2nd resistor is coupled in series with the 2nd P-N junction device. The 3rd resistor is coupled in parallel with the series combination of the 2nd resistor and 2nd P-N junction device. The operational amplifier is coupled to control the 1st and 2nd current sources based on the voltage imposed across the 1st and 2nd resistors. The current mirror is operably coupled to mirror the current of the 1st and/or 2nd current source to provide a band-gap reference current.

Abstract: The present invention relates to an I/Q demodulator (21) comprising a n-port structure (1,16) is provided, wherein n is an integer value of 4,5 or 6. The demodulator (21) is supplied at a first input (3) with a RF signal (2) which has to be demodulated. At a second input (5) it is supplied with a second RF signal (4). The n?2 output signals (6) are detected by power sensors (7). After low pass filtering (14) the output signals of the power sensors (7) are multiplexed by a multiplexing means (8).

Abstract: A system and method are provided for direct-conversion of a modulated radio-frequency (RF) signal. After receiving an RF signal, the RF signal is mixed with a plurality of oscillator signals with different phases in an interleaving manner.

Abstract: Techniques to reduce LO leakage by controlling the amplitude of LO signal based on the level of output signal after the frequency conversion process. An LO generator receives a VCO signal and generates an LO signal having a variable amplitude and a frequency that is related to the frequency of the VCO signal. A variable gain amplifier receives a control signal and adjusts the amplitude of the LO signal based on the control signal. The variable amplitude LO signal is used for frequency upconversion (e.g., direction upconversion) of an input signal (e.g., at baseband) to obtain an output signal (e.g., at RF). The relationship between LO signal amplitude and output signal level may be defined by a particular transfer function. In general, the LO signal is set higher for higher output signal level and is reduced proportionally for lower output signal level.

Abstract: A MMIC based superheterodyne receiver for converting at RF energy in an upper and a lower frequency band includes at least one attenuator for the RF energy input, a mixer for mixing the lower band input with a LO1 signal, another mixer for mixing the upper band input with the LO1 signal signal, a switch to direct the LO1 signal to the first mixer or to the second mixer, and a third mixer for mixing a LO2 signal with the first stage mixer output to produce a signal at the output frequency. Passband filters at the outputs of the mixers can reject interfering mixer-generated frequencies. Input frequency range can span 0.1 to 18 GHz with a 160 MHz or 1 GHz output. A modular receiver can have two or more converter modules for each LO module. The receiver can receive antenna input directly, without pre-mixing filtering or attenuating.

Abstract: GPS functionality is added to a wireless communication device in an efficient and cost effective manner. Briefly, the present invention has a common mixer constructed to be used for a GPS signal and another signal or a common IF filter constructed to be used for a GPS signal and another signal. In one embodiment, a common mixer and IF filter are used for both PCS and GPS signals. In another embodiment, a band select switch may be used to select either the PCS signal or the GPS signal. Alternatively, a duplexer or diplexer may couple the GPS signal and the PCS signal to the common mixer. In this way, a common mixer is enabled to be used for both GPS and PCS. A dual band local oscillator may be configured to output a local oscillator signal facilitating selection of a GPS IF signal, a PCS IF signal or a cellular CDMA IF signal, using a common IF filter.

Abstract: Methods, systems, and apparatuses for down-converting and up-converting an electromagnetic signal. In embodiments, the invention operates by receiving an electromagnetic signal and recursively operating on approximate half cycles of a carrier signal. The recursive operations can be performed at a sub-harmonic rate of the carrier signal. The invention accumulates the results of the recursive operations and uses the accumulated results to form a down-converted signal. In embodiments, up-conversion is accomplished by controlling a switch with an oscillating signal, the frequency of the oscillating signal being selected as a sub-harmonic of the desired output frequency. When the invention is being used in the frequency modulation or phase modulation implementations, the oscillating signal is modulated by an information signal before it causes the switch to gate a bias signal. The output of the switch is filtered, and the desired harmonic is output.

Abstract: Disclosed is a quadrature signal generator for generating an in-phase signal and a quadrature-phase signal, which is capable of generating a quadrature signal having the same frequency as a differential oscillating frequency, using a feedback control system.

Abstract: A frequency plan is provided for particular use in a transceiver. Advantageously, a single oscillator may be used to generate desired frequency signal. One or more power splitters receive the signal and equally divide the signal into first and second signals having a frequency substantially equal to the original. Multipliers on each arm of the transceiver receive a signal and increase the frequency of the signal. Ultimately, multiple signals having different frequencies may be transmitted over the same cable due in part to the generated frequency separation between the signals. In one particular aspect, the frequency plan provides a two-thirds relationship between the frequencies of the multiple signals.

Abstract: In a PLL circuit, the number of LPFs is reduced to one to reduce mounting area and pin number, and to simplify design. In one embodiment, the PLL circuit includes a variable-gain phase comparator, a mixer, an LPF, VCOs, couplers, and a control circuit to controlling the on/off operation of the VCOs. The variable-gain phase comparator is capable of varying a phase difference gain. The on/off of the operation of the VCOs is controlled by the control circuit so that one of the VCOs is turned off. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs so the number of LPFs required for the PLL circuit can be reduced to only one.

Abstract: An oscillator that provides a quadrature output and has a cross-coupled configuration is disclosed. The oscillator generates an output signal having a frequency. Two phase shift circuits, or stages, are activated by a control signal to provide phase shifts within the oscillator. Each phase shift circuit includes poles to provide the phase shift. A pole includes a varactor to tune, adjust or vary the phase shift accordingly.

Abstract: A microwave oscillator for inducing parallel feedback from collector to base and obtaining a stabilized oscillation output is realized by connecting MSL A with released end to a base terminal of a transistor, connecting MSL B to its collector terminal, and disposing a DR closely to the MSL A and B to couple them electromagnetically. The length between the released end and the position of MSL A which is closest to the center of DR is set to ?g1/4 (?g1 is the guide wavelength in the MSL A), and HIL is merely connected to this position as a bias supply line to the base terminal. This structure does not require the choke circuits which occupied a relatively wide area on the conventional circuit board, and a small and stable microwave oscillator having excellent phase noise characteristics, and a low-noise converter for receiving satellite signal by using the same are realized.

Abstract: There is disclosed a frequency synthesizer having an HF synthesizer for generating a first reference frequency signal having a variable frequency in a high-frequency band as a unit synthesizer, an LF synthesizer for generating a second reference frequency signal in a low-frequency band as another unit synthesizer, and an arithmetic circuit including a mixer for receiving the first and second reference frequency signals, a divider for receiving the second reference frequency signal, a mixer for receiving the first reference frequency signal and an output signal from the divider, a divider for receiving an output signal from the mixer, a divider for receiving an output signal from the mixer and capable of switching a division ratio, and a switch for switching and outputting output signals from the dividers, wherein an output signal of the switch is outputted as a first local signal, and an output signal from the divider is outputted as a second local signal.

Abstract: A ring oscillator produces an in-phase and quadrature phase radio frequency signal. A first mixer mixes the in-phase signal with a received signal. A second mixer mixes the quadrature phase signal with the received signal. A combiner, operatively coupled to the first and second mixers, produces an image cancelled signal.

Abstract: An RF transmitter having two digital to RF-conversion devices that combine the D/A conversion function and the upconversion function by a RF-carrier or IF-signal. The device comprises a plurality of parallel unit cells, each of which is a mixer cell type converter having a differential data switch section connected in series to a differential LO-switch pair. The differential LO-switch is further connected in series to a current source. Each unit cell is adapted to receive a control voltage indicative of a data signal value.

Abstract: This patent describes a method of removing the LO-leakage and 1/f noise problems associated with direct conversion RF receivers and other demodulators. In order to solve this problem a virtual LO™ signal is generated within the RF signal path which is tuned to the incoming RF signal. The virtual local oscillator (VLO) signal is constructed using signals that do not contain a significant amount of power (or no power at all) at the LO frequency. Any errors in generating the virtual LO signal are minimized using a closed loop correction scheme.

Abstract: A rat race circuit has an annular transmission line formed on a microstrip dielectric substrate. A terminal for port 1 is formed at any given position of the annular transmission line. Respective terminals for port 2 and port 3 are formed at respective positions distant from the position of port 1 in the counter-clockwise and clockwise directions each by a distance of ?g/4 (?g: effective wavelength). Moreover, at the position distant from the position of port 2 in the counter-clockwise direction by the distance of ?g/4, a terminator resistor (R=50?) is formed. A local oscillator signal is supplied to port 1, and first and second mixer inputs are connected respectively to port 2 and port 3. The local oscillator signal divider and a low noise converter using the divider are thus provided that are scarcely influenced by matching with respect to mixers and provide stable performance and high isolation.

Abstract: In a PLL circuit, the number of LPFs is reduced to one to reduce mounting area and pin number, and to simplify design. In one embodiment, the PLL circuit includes a variable-gain phase comparator, a mixer, an LPF, VCOs, couplers, and a control circuit to controlling the on/off operation of the VCOs. The variable-gain phase comparator is capable of varying a phase difference gain. The on/off of the operation of the VCOs is controlled by the control circuit so that one of the VCOs is turned off. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs so the number of LPFs required for the PLL circuit can be reduced to only one.

Abstract: The frequency conversion circuit 30 as an element of a radio communication device, the frequency conversion circuit for converting by using a local oscillator 32 the frequency of a signal which is modulated with a reference oscillation signal from a reference oscillator 31. The frequency conversion circuit 30 is provided with a first mixer 36, a change-over switch 35, and a second mixer 33. The first mixer 36 mixes the reference oscillation signal from the reference oscillator 31 and a local oscillation signal from the local oscillator. The change-over switch 35 selects one of a mixed signal from the first mixer 36 and the local oscillation signal from the local oscillator 32. The second mixer 33 mixes the signal modulated with the reference oscillation signal with an output from the change-over switch 35.

Abstract: An image rejection mixer includes first and second mixers, a phase shift circuit and a summer. The first mixer receives an RF input signal and a first local oscillator (LO) signal and generates a first intermediate frequency (IF) output signal. The second mixer receives the RF input signal and a second LO signal and generates a second IF output signal. The first LO signal is a phase lag signal (sin ?lot) and the second LO signal is a phase lead signal (?cos ?lot), where ?lot is a frequency signal generated by a local oscillator. The phase shift circuit is connected between the summer and the first mixer, receives the first IF output signal and generates a phase lag signal. The phase shift circuit causes the phase lag signal to lag the first IF output signal by about 90 degrees. The summer is connected to the phase shift circuit and the second mixer, receives the second IF output signal and the phase lag signal, and generates a combined IF output signal.

Abstract: A local oscillator for use in an optoelectronic distance measurement system for generating a narrow-band HF signal for direct signal mixing with a reception signal generated by an avalanche photodiode (2) from a light signal impinging on the latter, with the depletion layer capacitance (CAPD) of the avalanche photodiode (2), which varies due to different influences and specimen scatter, is incorporated, as an element which (co-)determines the oscillator frequency, in a controllable HF resonant circuit whose HF resonant frequency is determined, for example, by the adjustable divider ratio of a PLL-circuit (1) which is acted upon by a phase-locked reference oscillator (6) and which controls the capacitance (C) of a capacitance diode (3) connected in parallel with the depletion layer capacitance.

Abstract: A first printed circuit board is attached to an upper surface of a chassis, and a second printed circuit board is attached to a lower surface of the chassis. The chassis has a thickness of a certain degree, which can reduce a mutual effect of first and second local oscillators, and can suppress occurrence of a spurious signal. Thus, a satellite broadcast receiving device can be provided in which the mutual effect of two local oscillating circuits can be reduced and thus occurrence of a spurious signal is suppressed.

Abstract: A data-pattern feedback mechanism is introduced into the peak detection process of an automatic frequency compensation system in a Gaussian Frequency Shift Keying (GFSK) modulated system, providing fast and accurate fine-stage automatic frequency compensation (AFC). Maximum positive and negative peak registers are updated with new values as necessary based on detection during a sequence of identical binary bit values (e.g., during a “00” for detection of maximum negative peak frequency, or during a “11” for detection of maximum positive peak frequency), in a particular data frame. As soon as an initial value is determined for both the maximum positive and negative peak frequencies (e.g., after the first occurrence of a “11” and a “00”, in any order), fine-stage automatic frequency compensation can be initiated. Subsequent adjustments to the VCO of the local oscillator will further refine the frequency offset towards the ideal of zero.

Abstract: A communication apparatus is provided which employs two oscillators to generate a transmission signal and a reception signal, and prevents harmful spurious components from being produced. As shown in FIGS. 9A and 9B, the oscillation frequency fVCO2 of a VCO 2 is given by fVCO2=N×(2×fDD), where fDD is the difference between the transmit frequency fT and receive frequency fR. A 3/(2×N) frequency multiplier outputs a signal with a frequency 3×fDD, and a divide-by-N circuit (2/(2×N) frequency multiplier) outputs a signal with a frequency 2×fDD. Thus the transmit intermediate frequency fTIF is given by fTIF=3×fDD, and the receive intermediate frequency fRIF is given by fRIF=2×fDD. The oscillation frequency fVCO1 of a VCO 1 is fCH. The transmit frequency fT is given by fT=fCH+fTIF=fCH+3×fDD. The circuit can prevent a transmission spurious problem to its own reception band.

Abstract: A single conversion frequency converter comprises an image reject mixer and a local oscillator. The local oscillator comprises a variable frequency oscillator and a variable divider. The variable divider supplies to the mixer a local oscillator signal whose frequency is a sub-multiple of the frequency of the variable frequency oscillator.

Abstract: A receiver for a digital beamforming radar system includes a plurality of antenna elements, low-noise block converters, one or more analog-to-digital converters, and a processor. The antenna elements receive a radar signal and output a received signal. The low-noise block converters are modified commercially available components used in satellite television systems, respond to the received signal from a corresponding antenna element, and output an intermediate frequency signal. The low-noise block converters include at least one amplifier, a mixer, and a local oscillator input. The local oscillator input enables an external local oscillator signal to be inputted to the mixer. The analog-to-digital converters are responsive to the intermediate frequency signal of a corresponding low-noise block converter. The processor is responsive to the digital signals output by the analog-to-digital converters.

Abstract: Disclosed is a NRD waveguide mixer adopting a ring hybrid coupler applicable to a small-sized and high functional millimeter wave receiving/transmitting device. The NRD waveguide has a housing including two parallel conductive plates. The ring hybrid coupler is installed in the housing and has an annular ring formed with first to fourth ports which are radially extended about the annular ring. An oscillating device is connected to the first port so as to generate a local oscillating signal. A rod antenna is connected to the second port so as to receive/transmit a radio frequency signal. A first balanced mixer mount is connected to the third port and is provided with a first Schottky diode. A second balanced mixer mount is connected to the fourth port and is provided with a second Schottky diode. The radio frequency signal and the oscillating signal inputted from the first and second ports are mixed in the ring hybrid coupler to be transformed into an addition signal and a subtraction signal.

Abstract: A local oscillator architecture provides a signal at an output frequency with reduced pulling effect. A voltage controlled oscillator (VCO) generates a first signal having a frequency that is a fraction of the output frequency. A frequency shifter generates a second signal with a frequency substantially equal to the difference between the VCO frequency and the output frequency. Single-sideband mixers are used to produce output signals at the sum of the VCO frequency and the shifted frequency while suppressing an unwanted sideband at the difference of the two frequencies.

Abstract: A differential RF input signal drives the plus and minus terminals of a center tapped primary winding, which couples the differential RF input signal to the plus and minus terminals of a center tapped secondary winding. From the secondary winding, the coupled, differential RF signal drives a double-balanced mixer core operating in response to a differential local oscillator signal. The output of the mixer core is a differential IF signal representative of the differential RF input signal down-converted at the local oscillator frequency. A step reduction in gain associated with the RF input signal may be implemented using bypass circuitry coupled across the primary of the transformer, wherein a relatively small resistance or impedance is coupled across the primary to effectively reduce the load of the differential amplifiers driving the primary.

Abstract: A wireless communications device includes an antenna that receives a first signal at a first frequency and a second signal at a second frequency and converts the first and second signals into a composite signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second frequencies are different.

Abstract: A multiple channel receiver (200) includes a communications receiver synthesizer (204) and at least one numerically controlled oscillator (NCO) (406) that produce local oscillator signals that are derived from a common reference oscillator (202). A DSP (212) and CPU (214) perform automatic frequency control (AFC) by adjustment of the reference oscillator (202) based upon a signal received by a receive channel using the local oscillator signal produced by the communications receiver synthesizer (204). The CPU (214) also provides a synchronous indication of adjustments to the reference oscillator (202) to control circuitry for the at least one NCO (406) so that the configuration of the NCO (406) can be altered so as to maintain a substantially constant frequency output during the adjustment of the reference oscillator (202).

Abstract: A multi-stage channel select filter and associated methods are disclosed that can be used, for example, with receiver architectures and associated methods that are also described herein. The multi-stage channel select filter can include a plurality of cascaded stages including at least one tunable stage. Each stage can include a digital mixer, a low pass filter and a decimator, with the decimator for each tunable stage including a tunable decimator having a decimation rate selection signal as an input. In addition, each non-tunable stage, if any are utilized, can include a decimator having a fixed decimation rate. In operation, the first cascaded stage is configured to receive a digitized channel signal spectrum, and the last cascaded change is configured to output a baseband signal representative of a desired channel within the digitized channel spectrum.

Abstract: Disclosed is a quadrature signal generator for generating an in-phase signal and a quadrature-phase signal, which is capable of generating a quadrature signal having the same frequency as a differential oscillating frequency, using a feedback control system.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A double balanced mixer with improved isolation between the LO and RF frequency signals. The mixer has a local oscillator balun, an intermediate frequency balun and an RF balun. The baluns are located on inner layers of a substrate comprised of low temperature co-fired ceramic. The baluns are formed from spiral lines that form windings. The windings are coupled between adjacent layers. The local oscillator balun is connected to the intermediate frequency balun. A diode ring is connected between the RF balun and the intermediate frequency balun. The diode ring is mounted to a top layer. Several vias extend through the substrate. The vias provide an electrical connection between the baluns and the diode ring.

Abstract: A frequency scalable, low self-generated noise frequency source generates coherent or mostly-coherent local oscillator signals and includes a common reference, a coherent set of high frequency references and specific local oscillators which may be non-coherent for each specific output frequency. Delay lines may be included in the paths to ensure time delay alignment. The use of these elements with this modular design allows the generation of multiple coherent local oscillators via replication of the modular design elements.

Abstract: An LO leakage canceller for a direct conversion receiver is disclosed. The canceller includes an RF input stage operating to provide at least two input signals, a local oscillator, an in-phase processor, and a quadrature processor. The local oscillator is configured to produce at least two reference signals for modulating the two input signals. Each of the in-phase and quadrature processors includes two consecutive quadrature splitters operating to substantially reduce leakage of the reference signal from the local oscillator to the RF input stage.

Abstract: A subharmonic mixer design is described that permits greater integration on standard silicon chips with an improvement in power and linearity compared to previous mixer designs, enabling low-power, high performance RF reception.

Abstract: A frequency converter comprises an impedance matching unit connected to a current switching stage and a transconductance amplifier stage. The impedance matching unit has an impedance for conjugate power match. For example, the impedance matching unit is a parallel resonant circuit that includes an inductor and a capacitor that are formed as an integrated circuit. Thus, the frequency converter that has high conversion gain and low noise is obtained.

Abstract: A three port structure for the down conversion demodulation of a digitally modulated RF signal is proposed, wherein no RF switches are provided. The three port structure (1) has a first input (2) for the RF signal to be down converted and a second input (3) for a RF signal originating from a local oscillator (8). An output (4) of the three port structure (1) is supplied to a power sensor unit (5). The RF signal from the local oscillator (8) is modulated (7) before it is supplied to the three port structure (1).

Abstract: A wide band mixer is provided that mitigates local oscillator leakage. A LO signal is provided to a 180 degree splitter that provides a first intermediate LO signal and a second intermediate LO signal 180° out of phase from one another. Since both the first and second intermediate LO signals are 180° out of phase, the fundamental LO leakage is mitigated at the RF port by the in-phase combination of the 180° out of phase LO tones canceling one another out and providing strong LO/RF rejection. An RF or microwave input signal is provided to a power splitter to provide a first intermediate RF signal and a second intermediate RF signal. The first intermediate LO signal is mixed with the first intermediate RF signal and the second intermediate LO signal is mixed with the second intermediate RF signal to provide an intermediate frequency signal at the output of the mixer.

Abstract: A receiver (10) for a wireless telecommunications system that provides relatively wideband signal processing of received signals without increased signal distortion so that multiple received signals can be simultaneously processed. The receiver (10) includes a specialized LNA (16), frequency down-converter (18) and ADC (20) to perform the wideband signal processing while maintaining receiver performance. The frequency down-converter (18) employs a suitable mixer (28), BPA (32), attenuator (34), and transformer (36) that are tuned to provide the desired frequency down-conversion and amplitude control over the desired wideband. The down-converter devices are selected depending on the particular performance criteria of the ADC (20). A specialized digital channelizer (22) is included in the receiver (10) that receives the digital signal from the ADC (20), and separates the signals into the multiple channels.

Abstract: Disclosed is an amplifier apparatus that corrects mismatching of the filter transmission characteristic due to a change in the temperature of the amplifier apparatus itself and thereby stably amplifies the high-frequency signal. The amplifier apparatus converts a signal to be processed into one having an intermediate frequency band to thereby execute amplification processing.

Abstract: A mixer circuit has an additional capacitance connected between the emitters of the input transistor pair to which the RF input signal is applied.

Abstract: A wireless communications device includes an antenna that receives a first signal at a first radio frequency and a second signal at a second radio frequency and converts the first and second signals into a composite radio frequency (RF) signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite RF signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second radio frequencies are different.

Abstract: Frequency modification circuitry may be employed as part of a crystal oscillator circuit to generate a reference signal with adjustable frequency. The frequency modification circuitry may be implemented as part of a crystal oscillator circuit that includes digitally controlled crystal oscillator (“DCXO”) circuitry and a crystal. The frequency modification circuitry may adjust the frequency of the reference signal in response to one or more frequency control signals. In one example, the frequency modification circuitry may include variable capacitors such as one or more continuously variable and/or discretely variable capacitors for providing coarse and/or fine adjustment of the reference signal frequency.

Abstract: A method and apparatus for offsetting the frequency of a local oscillator in a receiver are disclosed. The local oscillator frequency is offset with an offset frequency that depends on the training sequence used. Training symbols are inputted to the control unit. The control unit then provides an offset frequency depending on the training symbol received. A rotation of the baseband signal, proportional to the offset frequency, is introduced which later is digitally compensated for. Upon reception of the signal, a DC offset is introduced in the radio part. The digital compensation transforms this DC offset, in the baseband signal, to a rotating signal. The rotating DC offset signal is then subtracted in the baseband processing.

Abstract: A subharmonic mixer and a method of downconverting a received radio frequency signal is described. The subharmonic mixer of the present invention uses two stacks of switching cores with high order symmetry to reduce unwanted harmonic generation and uses transistors to improve headroom.

Abstract: In a radio receiver, clock distribution changes, that is, enabling or disabling the clock signals to specific circuit blocks at specific times to reduce power consumption, can cause changes in the DC offset level. Knowledge about clock distribution changes can be used to improve receiver performance. Specifically, information about clock distribution changes is stored during signal reception, and used to predict the presence of DC offset step changes.