Abstract: A circuit for a large-signal electrical balance duplexer (EBD) may include a circulator that can be configured to couple an output node of a transmit (TX) path to an antenna. An EBD circuit may be coupled to the circulator, at a first port of the EBD circuit. The EBD circuit may be configured to isolate the circulator from one or more input nodes of a receive (RX) path. An attenuator may be coupled between the output node of the TX path and a second port of the EBD circuit. The attenuator may be configured to provide an attenuated signal to the EBD circuit.

Abstract: A circuit for a receiver with reconfigurable low-power or wideband operation may comprise one or more main signal paths each coupled to a first port and including a low-noise amplifier (LNA) configured to provide a radio frequency (RF) signal to a main mixer circuit. An auxiliary signal path may be coupled to a second port. The auxiliary signal path may include an auxiliary mixer configured to provide an on-chip matching input impedance that may match an impedance of the antenna. The first port may be coupled to an RF antenna through an off-chip matching circuit, when a low-power operation is desired. The first port may be coupled to the second port and to the RF antenna, when a wideband operation is desired.

Abstract: According to one embodiment, a compact low-power receiver comprises first and second analog circuits connected by a digitally controlled interface circuit. The first analog circuit has a first direct-current (DC) offset and a first common mode voltage at an output, and the second analog circuit has a second DC offset and a second common mode voltage at an input. The digitally controlled interface circuit connects the output to the input, and is configured to match the first and second DC offsets and to match the first and second common mode voltages. In one embodiment, the first analog circuit is a variable gain control transimpedance amplifier (TIA) implemented using a current mode buffer, the second analog circuit is a second-order adjustable low-pass filter, whereby a three-pole adjustable low-pass filter in the compact low-power receiver is effectively produced.

Abstract: A radio front end includes a power amplifier, a tone injection module, a duplexer, a balancing network, and a processor. The tone injection module is operable, in a first mode, to produce a tone having a carrier frequency that is substantially similar to a carrier frequency of an inbound wireless signal. The duplexer is operable, in the first mode, to provide electrical isolation between the outbound wireless signal and a combination signal of the tone and inbound wireless signal and is operable, in a second mode, to provide electrical isolation between the outbound wireless signal and the inbound wireless signal. The processor is operable to determine an amplitude of a tone component of the combination signal; correlate the amplitude of the tone component to an inbound frequency band isolation; and adjust baseband processing of a down converted representation of the combination signal based on the inbound frequency band isolation.

Abstract: A circuit for a low-loss duplexer with noise cancellation in a receive (RX) path of a transceiver includes a duplexer, a balancing network, and a noise cancellation circuit. The duplexer circuit is coupled to an antenna of the transceiver. The balancing network is coupled to the duplexer and provides an impedance matching an impedance associated with the antenna. The noise cancellation circuit senses a noise signal generated by the balancing network and uses the sensed noise signal to improve a signal-to-noise ratio (SNR) of the RX path.

Abstract: A circuit for a low-noise interface between an amplifier and an analog-to-digital converter (ADC) may comprise a capacitor element having a capacitance of C coupled between a first and second output node of the amplifier. A resistor circuit coupled between the capacitor element and input nodes of the ADC. A desired value RL for a load resistance of the amplifier is provided by selecting suitable initial values for resistances of the resistor circuit. A desired bandwidth for the at least one amplifier is achieved by selecting a value of the capacitance C based on the desired value RL for the load resistance.

Abstract: According to one embodiment, a compact low-power receiver comprises first and second analog circuits connected by a digitally controlled interface circuit. The first analog circuit has a first direct-current (DC) offset and a first common mode voltage at an output, and the second analog circuit has a second DC offset and a second common mode voltage at an input. The digitally controlled interface circuit connects the output to the input, and is configured to match the first and second DC offsets and to match the first and second common mode voltages. In one embodiment, the first analog circuit is a variable gain control transimpedance amplifier (TIA) implemented using a current mode buffer, the second analog circuit is a second-order adjustable low-pass filter, whereby a three-pole adjustable low-pass filter in the compact low-power receiver is effectively produced.

Abstract: A transceiver includes a local oscillation module, a transmitter section, and a receiver section. The local oscillation module is operable to generate a transmit local oscillation and a receive oscillation. The transmitter section includes a transmit mixing module and a transmit weaved connection that is operable to high frequency filter the transmit location oscillation. The transmit mixing module mixes the filtered transmit location oscillation with a transmit signal to produce an up-converted signal. The receiver section includes a receive mixing module and a receive weaved connection that is operable to high frequency filter the receive location oscillation. The receive mixing module mixes the filtered receive location oscillation with an RF received signal to produce a down-converted signal.

Abstract: Aspects of a method and system for a low-noise, highly-linear receiver front-end are provided. In this regard, a received signal may be processed via one or more transconductances, one or more transimpedance amplifiers (TIAs), and one or more mixers to generate a first baseband signal corresponding to a voltage at a node of the receiver, and a second baseband signal corresponding to a current at the node of the receiver. The first signal and the second signal may be processed to recover information from the received signal. The first signal may be generated via a first one or more signal paths of the receiver and the second signal may be generated via a second one or more signal paths of the receiver.

Abstract: A circuit for a low-loss electrical balance duplexer (EBD) with noise cancellation may include an EBD circuit. The EBD circuit may be coupled to one or more output nodes of a transmit (TX) path, an antenna, and a one or more input nodes of a receive (RX) path. The EBD circuit may be configured to isolate the TX path from the RX path, and to provide low-loss signal paths between the one or more output nodes of the TX path and the antenna. A balancing network may be coupled to the EBD circuit and configured to provide an impedance that matches an impedance associated with the antenna. A noise cancellation circuit may be configured to sense a noise signal generated by the balancing network, and to use the sensed noise signal to improve a signal-to-noise ratio (SNR) of the RX path.

Abstract: A circuit for a low-noise interface between an amplifier and an analog-to-digital converter (ADC) may comprise a capacitor element having a capacitance of C coupled between a first and second output node of the amplifier. A first resistor R1 may be coupled in parallel with the capacitor. A second resistor R2 may be coupled between the first output node of the amplifier and a first input node of the ADC. A third resistor R3 may be coupled between the second output node of the amplifier and a second input node of the ADC. Initial values of the resistances R1, R2, and R3 may be selected to provide a desired value RL for a load resistance of the amplifier. A value of the capacitance C may be selected so that, in combination with the desired value RL, a desired bandwidth for the amplifier is achieved.

Abstract: Embodiments of a four-port isolation module are presented herein. In an embodiment, the isolation module includes a step-up autotransformer comprising a first and second winding that are electrically coupled in series at a center node. The first port of the isolation module is configured to couple an antenna to a first end node of the series coupled windings. The second port of the isolation module is configured to couple a balancing network to a second end node of the series coupled windings. The third port is configured to couple a transmit path to the center node. The fourth port is configured to couple a differential receive path across the first end node and the second end node. The isolation module effectively isolates the third port from the fourth port to prevent strong outbound signals received at the third port from saturating an LNA coupled to the fourth port.

Abstract: A circuit for measurement of a phase noise of an oscillator may include the oscillator to generate a first signal having the same oscillation frequency as an instantaneous oscillation frequency of the oscillator. The circuit may include a first circuit that is configured to generate a second signal from the first signal. An instantaneous amplitude of the second signal may be related to the oscillation frequency of the first signal. A second circuit may be configured to integrate the second signal to generate a third signal. The third signal can be a measure of the phase noise of the oscillator. The third signal can be used to cancel some or all of the phase noise of the oscillator.

Abstract: A radio front end includes an antenna tuning unit, a duplexer, a balancing network, and a processing module. The antenna tuning unit is operably coupled to an antenna and operable to tune an operational characteristic of the antenna based on an antenna tuning signal. The duplexer is operably coupled to the antenna tuning unit and operable to provide electrical isolation between an outbound wireless signal and an inbound wireless signal. The balancing network is operably coupled to the duplexer and operable to establish an impedance that substantially matches an impedance of the antenna. The processing module is operable to estimate the impedance of the antenna to produce an estimated antenna impedance and to generate the antenna tuning signal based on the estimated antenna impedance.

Abstract: According to one embodiment, an input control unit to provide isolation and electrostatic discharge (ESD) protection for a circuit in an RF transceiver comprises a switching device coupled between an input of the circuit and ground. The switching device is configured to provide ESD protection while the circuit is activated. The switching device is further configured to ground the input while the circuit is non-activated, thereby concurrently isolating the input and providing ESD protection. A method for providing isolation and ESD protection for a circuit in an RF transceiver comprises activating the circuit, providing ESD protection while the circuit is activated, deactivating the circuit, and coupling an input of the circuit to ground, thereby concurrently isolating the input and providing ESD protection while the circuit is non-activated. The method and switching device can be used to provide isolation and ESD protection to receive bands in the RF transceiver.

Abstract: Embodiments of a four-port isolation module are presented herein. In an embodiment, the isolation module includes a step-up autotransformer comprising a first and second winding that are electrically coupled in series at a center node. The first port of the isolation module is configured to couple an antenna to a first end node of the series coupled windings. The second port of the isolation module is configured to couple a balancing network to a second end node of the series coupled windings. The third port is configured to couple a transmit path to the center node. The fourth port is configured to couple a differential receive path across the first end node and the second end node. The isolation module effectively isolates the third port from the fourth port to prevent strong outbound signals received at the third port from saturating an LNA coupled to the fourth port.

Abstract: According to one embodiment, a concurrent impedance and noise matching transconductance amplifier designed for implementation in a receiver comprises an input device configured to couple to a matching network of the receiver, and a boost capacitor connected to the input device to increase an input capacitance of the transconductance amplifier. The boost capacitor is selected to substantially minimize the receiver noise and to enable the concurrent impedance and noise matching of the receiver and the matching network. In one embodiment, the receiver comprises the transconductance amplifier to provide an amplified receive signal, and a mixer to produce a down-converted signal corresponding to the amplified receive signal, wherein the mixer is coupled to the transconductance amplifier by a blocking capacitor. The blocking capacitor is selected to substantially increase an amplitude ratio of the down-converted signal to the amplified receive signal to substantially increase the front-end gain of the receiver.

Abstract: A technique for calibration of on-chip resistance (R) and capacitance (C) values using an on-board bypass capacitor may include configuring an on-chip switch to selectively couple an on-chip calibration circuit to an on-chip port. The on-chip calibration circuit may include an RC oscillator having an RC time constant (RCTC). The on-board bypass capacitor may be coupled to the on-chip calibration circuit, by using the on-chip port. The on-chip R and C values may be calibrated using the on-chip calibration circuit and the on-board bypass capacitor.

Abstract: According to one embodiment, a compact low-power receiver comprises a front-end producing a front-end gain and a back-end producing a back-end gain. The front-end includes a transconductance amplifier providing digital gain control and outputting an amplified receive signal, a mixer for generating a down-converted signal from the amplified receive signal, and a transimpedance amplifier (TIA) including a current mode buffer. The TIA provides gain control for amplifying the down-converted signal to produce a front-end output signal. In one embodiment, the back end includes a second-order low-pass filter to produce a filtered signal from the front-end output signal and an analog-to-digital converter (ADC), wherein the filtered signal is fed directly to the ADC without direct-current (DC) offset cancellation being performed. In various embodiments, the front-end gain is substantially greater than the back-end gain.

Abstract: A system for cancellation of a reciprocal-mixing noise may comprise a down-converter mixer that may be configured to down convert a radio-frequency (RF) signal and to generate a baseband signal. The RF signal may include a desired signal and a blocker signal. A first signal path may be configured to receive the baseband signal and to generate a first signal. A second signal path may be configured to receive the baseband signal and to generate a second signal. A subtraction module may be configured to subtract the second signal from the first signal and to generate an output signal. The second signal may comprise the reciprocal-mixing noise, and the output signal may comprise the desired signal substantially free from the reciprocal-mixing noise.