A mixer includes a load portion connected between an input terminal of a first power voltage and an output terminal of the radio frequency transmit signal and configured to adjust a magnitude of the radio frequency transmit signal, a first switching unit connected to an output terminal of the radio frequency transmit signal, and configured to perform a first switching operation in response to a plurality of local oscillation signals, and a second switching unit connected between the first switching unit and an input terminal of a second power voltage, lower than the first power voltage, and configured to perform a second switching operation in response to a plurality of baseband signals, the plurality of local oscillation signals include an I+ baseband signal, an I− baseband signal, a Q+ baseband signal, and a Q− baseband signal, and the second switching unit includes a first branch performing a switching operation under control of the I+ baseband signal and the Q+ baseband signal, a second branch performing a switching operation under control of the I− baseband signal and the Q− baseband signal, a third branch performing a switching operation under control of the Q+ baseband signal and the I− baseband signal, and a fourth branch performing a switching operation under control of the Q− baseband signal and the I+ baseband signal.

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM) may include sending a signal through an up-converter of a transmit path to provide an up-converted signal, determining the up-converted signal, determining one or more IQMM parameters for the transmit path based on the determined up-converted signal, and determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal may be determined through a receive feedback path. In some embodiments, the up-converted signal may be determined through an envelope detector.

An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

A mobile terminal including an up-converter converting a baseband (BB) signal into a radio frequency (RF) signal and a controller controlling a voltage applied to the up-converter is provided. The up-converter includes a first transistor and a second transistor each having a gate to which a baseband voltage is applied, a third transistor having a drain connected in parallel to a drain of the first transistor, and a fourth transistor having a drain connected in parallel to a drain of the second transistor, and the up-converter and the mobile terminal with improved phase linearity characteristics may be provided.

An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

The disclosed embodiments provide an absorptive coupled-line bandpass filter. This bandpass filter includes a first port, which is coupled to a first absorptive stub, and a second port, which is coupled to a second absorptive stub. The bandpass filter also includes a coupled-line bandpass section coupled between the first and second ports, wherein the coupled-line bandpass section comprises a set of one or more parallel strip line resonators, which are coupled together in series and are coupled to the first and second ports through overlapping coupled-line sections, wherein at a center frequency of a passband for the absorptive coupled-line bandpass filter, the first and second absorptive stubs appear as open circuits, and outside of the passband, the first and second absorptive stubs appear as matched loads to ground and contribute to absorption of out-of-band signals.

The disclosed embodiments provide an absorptive coupled-line bandpass filter. This bandpass filter includes a first port, which is coupled to a first absorptive stub, and a second port, which is coupled to a second absorptive stub. The bandpass filter also includes a coupled-line bandpass section coupled between the first and second ports, wherein the coupled-line bandpass section comprises a set of one or more parallel strip line resonators, which are coupled together in series and are coupled to the first and second ports through overlapping coupled-line sections, wherein at a center frequency of a passband for the absorptive coupled-line bandpass filter, the first and second absorptive stubs appear as open circuits, and outside of the passband, the first and second absorptive stubs appear as matched loads to ground and contribute to absorption of out-of-band signals.

A radio frequency, RF, receiver circuit is configured to simultaneously monitor a two or more different RF frequencies. The RF receiver circuit uses a sub-sampler to sub-sample an RF signal that is at any of the monitored RF frequencies, and the sub-sampled signal is then demodulated and a digital code that was encoded in the RF signal is recovered. The RF receiver circuit may be particularly low power, in part owing to using the same sub-sampler for each of the two or more monitored RF frequencies, and not relying on superheterodyning. Furthermore, monitoring two or more different RF frequencies simultaneously means that signals received on the monitored RF frequencies may be acted on very quickly. These characteristics make the RF receiver circuit particularly suitable for use in low-power wake-up receivers, such as Bluetooth Low Energy (BLE) wake-up receivers.

The invention discloses a power mixer, radio frequency circuit, device and equipment, and belongs to the technical field of electronics and communication. The power mixer includes a mixer module, which amplifies an analog baseband current signal by a silicon germanium heterojunction bipolar transistor amplifying circuit, and converts a local oscillator voltage signal into a local oscillator current signal by a silicon germanium heterojunction bipolar transistor switching circuit. The silicon germanium heterojunction bipolar transistor switching circuit receives an amplified analog baseband current signal, and mixes the amplified analog baseband current signal and the local oscillator current signal into a radio frequency current signal; and a transformer module, which converts the radio frequency current signal into a radio frequency power signal and then outputs the radio frequency power signal from the power mixer.

The invention discloses a power mixer, radio frequency circuit, device and equipment, and belongs to the technical field of electronics and communication. The power mixer includes a mixer module, which amplifies an analog baseband current signal by a silicon germanium heterojunction bipolar transistor amplifying circuit, and converts a local oscillator voltage signal into a local oscillator current signal by a silicon germanium heterojunction bipolar transistor switching circuit. The silicon germanium heterojunction bipolar transistor switching circuit receives an amplified analog baseband current signal, and mixes the amplified analog baseband current signal and the local oscillator current signal into a radio frequency current signal; and a transformer module, which converts the radio frequency current signal into a radio frequency power signal and then outputs the radio frequency power signal from the power mixer.