A transmitter/receiver (1) up-converts, using an LO signal as a local oscillation signal, an IF signal having a predetermined frequency band, thereby generating a transmission signal RF.sub.TX. Moreover, the transmitter/receiver (1) generates a (LO+IF).sup.2 signal and a (LO−IF).sup.2 signal based on the IF signal and the LO signal. Using the LO signal obtained by adding-up of the (LO+IF).sup.2 signal and the (LO−IF).sup.2 signal, a reception signal RF.sub.RX is down-converted. Thus, a local oscillation signal generation unit of a receiving unit is not necessary.

A transmitter/receiver (1) up-converts, using an LO signal as a local oscillation signal, an IF signal having a predetermined frequency band, thereby generating a transmission signal RF.sub.TX. Moreover, the transmitter/receiver (1) generates a (LO+IF).sup.2 signal and a (LO−IF).sup.2 signal based on the IF signal and the LO signal. Using the LO signal obtained by adding-up of the (LO+IF).sup.2 signal and the (LO−IF).sup.2 signal, a reception signal RF.sub.RX is down-converted. Thus, a local oscillation signal generation unit of a receiving unit is not necessary.

Apparatuses and methods are disclosed regarding a multiband transmitter. In an example aspect, an apparatus for processing signals for wireless transmission includes a wireless interface device. The wireless interface device includes an upconverter, a tunable filter, and a driver amplifier. The upconverter has an output and is configured to upconvert a baseband frequency to a radio frequency based on a local oscillator signal. The tunable filter has an input and an output; the input of the tunable filter is coupled to the output of the upconverter. The driver amplifier has an input; the input of the driver amplifier is coupled to the output of the tunable filter.

The present disclosure provides a mixer circuit, a transmitter, and a communication device. The mixer circuit comprises an I-channel digital-to-analog converter, a Q-channel digital-to-analog converter, a low-pass filter, and a passive quadrature mixer, wherein the low-pass filter comprises an active device, so that an output admittance of the mixer circuit contains conductance dependent of frequency. The consistency between the gains of the mixer circuit at the upper sideband and the lower sideband can be improved.

An integrated amplifier device includes a main amplifier configured to be coupled to an input source. A replica amplifier is coupled to the main amplifier to provide a bias to the main amplifier. A transconductance biasing cell to the main amplifier and the replica amplifier. The transconductance biasing cell is configured to bias both the main amplifier and the replica amplifier. A method of making an integrated amplifier device is also disclosed.

This disclosure describes apparatuses, methods, and techniques for implementing a multimode frequency multiplier. In example implementations, an apparatus for generating a frequency includes a multimode frequency multiplier. The multimode frequency multiplier includes a multiphase generator and a reconfigurable frequency multiplier. The multiphase generator is configured to produce a first signal including multiple phase components and having a first frequency. The reconfigurable frequency multiplier is coupled in series with the multiphase generator. The reconfigurable frequency multiplier is configured to produce a second signal based on the first signal and having a second frequency that is a multiple of the first frequency.

Radio frequency (RF) mixer circuits having a complementary frequency multiplier module that requires no balun to multiply a lower frequency base oscillator signal to a higher frequency local oscillator (LO) signal, and which has a significantly reduced IC area compared to balun-based frequency multipliers. In one embodiment, the complementary frequency multiplier module includes a complementary pair of FETs controlled by an applied base oscillator signal. The complementary FETs are coupled to a common-gate FET amplifier and alternate becoming conductive in response to the base oscillator signal. The alternating switching of the complementary FETs in response to the opposing phases of the base oscillator signal cause the common-gate FET amplifier to output a higher frequency local oscillator (LO) signal. The LO signal is coupled to the LO input of a mixer or mixer core of a type suitable for use in conjunction with a frequency multiplier.

An electronic device may include wireless circuitry with a baseband processor, a transceiver, a front-end module, and an antenna. The transceiver may include mixer circuitry. The mixer circuitry may include switches controlled by oscillator signals. The mixer circuitry may also include oscillator phase noise cancelling capacitors controlled by inverted oscillator signals. Operated in this way, the mixer circuitry exhibits improved noise figure performance.

A circuit for subharmonic detection includes in-phase and quadrature mixers, first and second filters, and a processing circuit. The in-phase mixer has a first mixer input and a first mixer output. The quadrature mixer has a second mixer input and a second mixer output, the first mixer input coupled to the second mixer input. The first filter circuit has a first filter input and a first filter output, the first filter input coupled to the first mixer output. The second filter circuit has a second filter input and a second filter output, the second filter input coupled to the second mixer output. The processing circuit has a first input and a second input, the first input of the processing circuit coupled to the first filter output, the second input of the processing circuit coupled to the second filter output. The processing circuit is configured to detect a subharmonic component of a wave at the first mixer input and the second mixer input using a first direct current (DC) component at the first input of the processing circuit and a second DC component at the second input of the processing circuit.

A method and apparatus for input matching of a passive mixer are disclosed. The passive mixer includes a differential transistor pair including a first transistor and a second transistor, a first inductor having one end connected to the first transistor and another end connected to a ground, a second inductor having one end connected to the second transistor and another end connected to a ground, and a third inductor having one end for receiving a radio frequency (RF) signal and another end connected to a ground.