A broadband sender system is provided. The broadband sender system comprises a radio frequency digital-to-analog converter. In this context, the radio frequency digital-to-analog converter is adapted to emit a baseband signal modulated on a carrier signal with a first intermediate frequency and a second intermediate frequency. In addition to this, the first intermediate frequency is higher than the second intermediate frequency.

An RF frontend IC device includes an RF transceiver to transmit and receive RF signals and a frequency synthesizer to perform frequency synthetization to operate within a predetermined frequency band. The frequency synthesizer generates an LO signal to the RF transceiver to enable the RF transceiver to transmit and receive RF signals within the predetermined frequency band. The frequency synthesizer includes a QPG circuit to generate signals shifted in phases based on the LO signal and a phase shifting circuit to generate quadrant signals based on the signals shifted in phases. Each of the quadrant signals corresponds to one of the four quadrants in phases in the respective quadrant spaces. The phase shifting circuit includes multiple phase switches operable in a collaboration manner to further shift in phase based on the signal shifted in phases to generate the quadrant signals in proper quadrant spaces.

Systems and methods are disclosed herein that relate to a wireless device that intelligently uses different reference crystal oscillators (XOs) for a PhaseLocked Loop(s) (PLL(s)) in a transceiver of the wireless device. Embodiments of a method of operation of a wireless device comprising a first XO that operates at a first reference frequency and a second XO that operates at a second reference frequency that is greater than the first reference frequency are disclosed. In some embodiments, the method of operation of the wireless devices comprises making a decision as to whether to configure a receiver of the wireless device to use the first XO or the second XO and configuring the receiver of the wireless device to use the first XO or the second XO in accordance with the decision.

A multi-radio access technology (RAT) circuit is provided. The multi-RAT circuit includes a radio frequency (RF) circuit(s) coupled to an interconnect medium(s). The RF circuit(s) includes a power head circuit configured to receive a local oscillation (LO) pilot and an RF signal via the interconnect medium(s). The power head circuit generates an LO signal based on the LO pilot without requiring a synthesizer. Accordingly, the power head circuit modulates the RF signal to a carrier band based on the LO signal for transmission in a millimeter wave (mmWave) spectrum. By generating the LO signal and modulating the RF signal to the carrier band in the power head circuit, it may be possible to minimize attenuation and/or interference to the RF signal. Further, it may also be possible to share the interconnect medium(s) with existing RATs, thus helping to reduce size, power, and cost impacts associated with supporting an mmWave RAT.

We disclose multiband receivers for millimeter-wave devices, which may have reduced size and/or reduced power consumption. One multiband receiver comprises a first band path comprising a first passive mixer configured to receive a first input RF signal having a first frequency and to be driven by a first local oscillator signal having a frequency about the first frequency; a second band path comprising a second passive mixer configured to receive a second input RF signal having a second frequency and to be driven by a second local oscillator signal having a frequency about the second frequency; and a base band path comprising a third passive mixer configured to receive intermediate RF signals during a duty cycle and to be driven by a third local oscillator signal having a frequency about the first frequency or about the second frequency during the duty cycle.

A method of transmitting a signal using carrier aggregation, the method comprising providing at least two component carriers, combining the at least two component carriers in the digital domain, converting the combined component carriers to the analog domain with a DAC, passing the combined component carriers through an up conversion mixer to convert each combined component carrier to within a predetermined bandwidth centred on a conversion intermediate frequency to provide a signal for transmission comprising the combined component carriers, transmitting the signal.

An amplifier for a receiver circuit is disclosed. The amplifier has an input node (V.sub.in) and an output node (V.sub.out). It comprises a tunable tank circuit connected to the output node (V.sub.out), a feedback circuit path connected between the output node (V.sub.out) and the input node (V.sub.in), and a tunable capacitor connected between an internal node of the feedback circuit path and a reference-voltage node. A receiver circuit and a communication apparatus is disclosed as well.

An amplifier for a receiver circuit is disclosed. The amplifier has an input node (V.sub.in) and an output node (V.sub.out). It comprises a tunable tank circuit connected to the output node (V.sub.out), a feedback circuit path connected between the output node (V.sub.out) and the input node (V.sub.in), and a tunable capacitor connected between an internal node of the feedback circuit path and a reference-voltage node. A receiver circuit and a communication apparatus is disclosed as well.

Techniques for mitigating interference between coexisting Bluetooth baseband processing circuitry and Wireless Local Area Network (WLAN) baseband processing circuitry are disclosed. In some implementations, an oscillator control circuit may determine a first operating frequency associated with the WLAN baseband processing circuitry. The oscillator control circuit may determine a second operating frequency associated with the Bluetooth baseband processing circuitry. The oscillator control circuit may detect overlap between the first operating frequency and the second operating frequency. The oscillator control circuit may adjust an oscillator sideband for an oscillator of the Bluetooth baseband processing circuitry based on the detected overlap to mitigate interference between signals generated by the oscillator of the Bluetooth baseband processing circuitry and the first operating frequency associated with the WLAN baseband processing circuitry.

A radio frequency (RF) device includes a plurality of mixers, each of the plurality of mixers having a first input terminal, a second input terminal, and an output terminal; and a self-test circuit. The self-test circuit includes a buffer having an input terminal and an output terminal, the buffer configured to buffer a reference signal from a local oscillator (LO) to produce a first RF signal at a first frequency; and a plurality of delay elements having different respective transmission delays, the delay elements each having a first end coupled to the output terminal of the buffer and a second end configured to provide a respective delayed signal based on the first RF signal, where the self-test circuit is configured to, in a test mode, couple the second ends of the delay elements to respective first input terminals of the plurality of mixers to provide each mixer with the respective delayed signal, and where the second input terminals of the mixer are configured to receive a second RF signal having the first frequency.