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 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:
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 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:
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.
Abstract:
A method for reciprocal-mixing noise cancellation may include receiving, from a first mixer, a first signal comprising a wanted signal at a first frequency and a modulated signal at a second frequency. The modulated signal may be a product of a reciprocal-mixing of an unwanted signal with a phase noise. The second frequency may be greater than the first frequency, and at least a portion of the modulated signal may overlap the wanted signal, adding a reciprocal-mixing noise to the wanted signal. Using the first signal, a narrow second signal may be generated at a third frequency, twice the second frequency. At a second mixer, the second signal may be mixed with the first signal to generate a third signal. The third signal may be subtracted from the first signal to remove a reciprocal-mixing noise and to generate the wanted signal at the first frequency without the reciprocal-mixing noise.
Abstract:
A circuit for a low-power and blocker-tolerant mixer-amplifier stage may include a complementary mixer formed by transmission gates having complementary structures. The complementary mixer may be configured to receive one or more radio-frequency (RF) signals and to convert the one or more RF signals to intermediate frequency (IF) current signals. A complementary TIA may be coupled to the complementary mixer and may be configured to receive the IF current signals and provide IF voltage signals. The complementary TIA may be formed by coupling an NMOS-TIA and a PMOS-TIA to a common load. A first portion of the complementary mixer may be coupled to the NMOS-TIA and a second portion of the complementary mixer may be coupled to the PMOS-TIA.
Abstract:
A circuit for a wideband electrical balance duplexer (EBD) may include a first impedance element and a second impedance coupled between a first and a second node and a second and a third node of the bridge circuit, respectively. An antenna may be coupled between the first and a fourth node of the bridge circuit to receive and transmit RF signals. A balancing network may provide an impedance substantially matching an impedance of the antenna. The balancing network may be coupled between the third and the fourth node of the bridge circuit. The first or the second impedance elements may facilitate balancing the bridge circuit. One or more output nodes of a transmit path may be coupled to an input node of the bridge circuit. One or more input nodes of a receive path may be coupled between the second and the fourth node of the bridge circuit.
Abstract:
A transceiver circuit including a digital-to-analog converter, a filter coupled to the digital-to-analog converter, a passive mixer coupled to the filter, via a buffer and a multi-stage power amplifier coupled to the passive mixer via a passive amplifier. A transmitter and method for amplifying a RF signal for transmission are also provided.
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.