A transceiver circuit is disclosed. The transceiver circuit includes an antenna, a receiver RF chain configured to receive a receiver RF signal from the antenna, a transmitter RF chain configured to transmit a transmitter RF signal to the antenna, a frequency synthesizer configured to generate an oscillator signal, and a controller configured to cause the receiver RF chain to receive a first reflection signal from the antenna, down convert the first reflection signal to a non-zero intermediate frequency, and determine a range estimate to another transceiver circuit based on a phase of the first reflection signal.

A transceiver circuit is disclosed. The transceiver circuit includes an antenna, a receiver RF chain configured to receive a receiver RF signal from the antenna, a transmitter RF chain configured to transmit a transmitter RF signal to the antenna, a frequency synthesizer configured to generate an oscillator signal, and a controller configured to cause the receiver RF chain to receive a first reflection signal from the antenna, down convert the first reflection signal to a non-zero intermediate frequency, and determine a range estimate to another transceiver circuit based on a phase of the first reflection signal.

An apparatus includes a transformer including a first inductor, a second inductor, and a third inductor. The apparatus also includes a power amplifier having an output coupled to the first inductor, a low-noise amplifier having an input coupled to a first terminal of the third inductor, and a fourth inductor having a first terminal and a second terminal, wherein the second terminal of the fourth inductor is coupled to a second terminal of the third inductor. The apparatus also includes a switch coupled between the first terminal of the third inductor and the first terminal of the fourth inductor.

An apparatus for detecting difference in operating characteristics of a main circuit by using a replica circuit is presented. In one exemplary case, a sensed difference in operating characteristics of the two circuits is used to drive a tuning control loop to minimize the sensed difference. In another exemplary case, several replica circuits of the main circuit are used, where each is isolated from one or more operating variables that affect the operating characteristic of the main circuit. Each replica circuit can be used for sensing a different operating characteristic, or, two replica circuits can be combined to sense a same operating characteristic.

An apparatus for detecting difference in operating characteristics of a main circuit by using a replica circuit is presented. In one exemplary case, a sensed difference in operating characteristics of the two circuits is used to drive a tuning control loop to minimize the sensed difference. In another exemplary case, several replica circuits of the main circuit are used, where each is isolated from one or more operating variables that affect the operating characteristic of the main circuit. Each replica circuit can be used for sensing a different operating characteristic, or, two replica circuits can be combined to sense a same operating characteristic.

A transmission filter is arranged in a first filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. A reception filter is arranged in a second filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. The first filter region and the second filter region are arranged adjacently to each other and have at least sides constituting a pair and opposing to each other. At least either one of the first filter region and the second filter region has no wire extending along one side in a forbidden region that is defined by a width including a terminal electrode nearest to the one side, along the one side and over the one side opposing to the other filter region.

A transmission filter is arranged in a first filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. A reception filter is arranged in a second filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. The first filter region and the second filter region are arranged adjacently to each other and have at least sides constituting a pair and opposing to each other. At least either one of the first filter region and the second filter region has no wire extending along one side in a forbidden region that is defined by a width including a terminal electrode nearest to the one side, along the one side and over the one side opposing to the other filter region.

A transceiver is disclosed. The transceiver accesses a CFO (carrier frequency offset) estimate, and, for each of one or more working frequencies: transmits a transmitter RF signal at each working frequency, receives a receiver RF signal at each working frequency, and generates first I/Q measurement data based at least in part on the received receiver RF signal and the CFO estimate. In some embodiments, the transceiver receives I/Q measurement information for each working frequency. In some embodiments, the transceiver generates second I/Q measurement data based at least in part on the received I/Q measurement information. In some embodiments, the transceiver estimates a distance between the antenna and an antenna of another device based at least in part on the first and second I/Q measurement data.

A transceiver is disclosed. The transceiver accesses a CFO (carrier frequency offset) estimate, and, for each of one or more working frequencies: transmits a transmitter RF signal at each working frequency, receives a receiver RF signal at each working frequency, and generates first I/Q measurement data based at least in part on the received receiver RF signal and the CFO estimate. In some embodiments, the transceiver receives I/Q measurement information for each working frequency. In some embodiments, the transceiver generates second I/Q measurement data based at least in part on the received I/Q measurement information. In some embodiments, the transceiver estimates a distance between the antenna and an antenna of another device based at least in part on the first and second I/Q measurement data.

Apparatus and methods for signal conditioning of radio frequency signals are provided. In certain embodiments, a mobile device includes a transceiver configured to output a differential transmit signal and to receive a single-ended receive signal, and a front end system. The front end system includes a transmit balun, a differential transmit amplifier configured to amplify the differential transmit signal to generate an amplified differential transmit signal provided to a first winding of the transmit balun, a differential receive amplifier configured to amplify a differential receive signal received from the first winding to generate an amplified differential receive signal, and a receive balun configured to convert the amplified differential receive signal into the single-ended receive signal.