In a method of a heterodyne FDD receiver for enabling reception of a multi-band RXRF signal spectrum, an RXRF signal spectrum is received, which comprises a lower frequency band and a higher frequency band. A Local Oscillator, LO, output frequency, f.sub.LO, is selected based on a frequency f.sub.A of the lower frequency band, and a frequency f.sub.B of the higher frequency band. Moreover, the RXRF signal spectrum is frequency shifted into an RXIF signal spectrum, by mixing the RXRF signal spectrum with the LO output frequency f.sub.LO. The LO frequency f.sub.LO is selected to satisfy f.sub.A<f.sub.LO<f.sub.B, where f.sub.A and f.sub.B are any frequency of the lower or higher frequency band, respectively.

The present invention discloses a multiband signal processing apparatus and method. The apparatus includes a multi-tone local oscillator signal generating unit and a multi-tone local oscillator signal transmission channel, where the multi-tone local oscillator signal transmission channel includes a band-pass filter and a frequency mixer. The multi-tone local oscillator signal generating unit is configured to generate a multi-tone local oscillator signal according to frequency response information of at least one device included in the multi-tone local oscillator signal transmission channel; the band-pass filter is configured to filter the received multi-tone local oscillator signal to obtain a filtered multi-tone local oscillator signal; and the frequency mixer is configured to perform frequency mixing on the multiband signal and the received multi-tone local oscillator signal.

Certain aspects of the present disclosure provide multi-way diversity receivers with multiple synthesizers. Such a multi-way diversity receiver may be implemented in a carrier aggregation (CA) transceiver. One example wireless reception diversity circuit generally includes three or more receive paths for processing received signals and two or more frequency synthesizing circuits configured to generate local oscillating signals to downconvert the received signals. Each of the frequency synthesizing circuits is shared by at most two of the receive paths, and each pair of the frequency synthesizing circuits may generate a pair of local oscillating signals having the same frequency.

Certain aspects of the present disclosure provide multi-way diversity receivers with multiple synthesizers. Such a multi-way diversity receiver may be implemented in a carrier aggregation (CA) transceiver. One example wireless reception diversity circuit generally includes three or more receive paths for processing received signals and two or more frequency synthesizing circuits configured to generate local oscillating signals to downconvert the received signals. Each of the frequency synthesizing circuits is shared by at most two of the receive paths, and each pair of the frequency synthesizing circuits may generate a pair of local oscillating signals having the same frequency.

Provided herein are oscillator paths between an oscillator and mixers. In an embodiment, the oscillator paths include a first path between an oscillator and a first mixer and a second path between the oscillator and the second mixer, in which the first path is enabled in a first state (e.g., a low band state) and the second path is enabled in a second state (e.g., a high band state). The first path can include a radio frequency divider configured to receive a signal having the oscillator frequency and to divide the signal in frequency by a positive odd integer divisor greater than one, and a duty cycle correction circuit configured to receive an output from the radio frequency divider and provide an output having a duty cycle that is closer to 50% than the output from the divider. Such separate oscillator paths can, for example, enhance receiver performance.

In a method of a heterodyne FDD receiver for enabling reception of a multi-band RXRF signal spectrum, an RXRF signal spectrum is received, which comprises a lower frequency band and a higher frequency band. A Local Oscillator, LO, output frequency, f.sub.LO, is selected based on a frequency f.sub.A of the lower frequency band, and a frequency f.sub.B of the higher frequency band. Moreover, the RXRF signal spectrum is frequency shifted into an RXIF signal spectrum, by mixing the RXRF signal spectrum with the LO output frequency f.sub.LO. The LO frequency f.sub.LO is selected to satisfy f.sub.A<f.sub.LO<f.sub.B, where f.sub.A and f.sub.B are any frequency of the lower or higher frequency band, respectively, such that when mixing the RXRF signal spectrum, one of the lower frequency band and the higher frequency band is frequency shifted into a first frequency band of the RXIF signal spectrum, and one another of the lower frequency band and the higher frequency band is frequency shifted folded into a second frequency band of the RXIF signal spectrum.

Provided herein are oscillator paths between an oscillator and mixers. In an embodiment, the oscillator paths include a first path between an oscillator and a first mixer and a second path between the oscillator and the second mixer, in which the first path is enabled in a first state (e.g., a low band state) and the second path is enabled in a second state (e.g., a high band state). The first path can include a radio frequency divider configured to receive a signal having the oscillator frequency and to divide the signal in frequency by a positive odd integer divisor greater than one, and a duty cycle correction circuit configured to receive an output from the radio frequency divider and provide an output having a duty cycle that is closer to 50% than the output from the divider. Such separate oscillator paths can, for example, enhance receiver performance.

The present invention discloses a multiband signal processing apparatus and method. The apparatus includes a multi-tone local oscillator signal generating unit and a multi-tone local oscillator signal transmission channel, where the multi-tone local oscillator signal transmission channel includes a band-pass filter and a frequency mixer. The multi-tone local oscillator signal generating unit is configured to generate a multi-tone local oscillator signal according to frequency response information of at least one device included in the multi-tone local oscillator signal transmission channel; the band-pass filter is configured to filter the received multi-tone local oscillator signal to obtain a filtered multi-tone local oscillator signal; and the frequency mixer is configured to perform frequency mixing on the multiband signal and the received multi-tone local oscillator signal.

In an embodiment, an apparatus includes a first baseband section to receive a calibration signal; a first radio frequency (RF) section configured to generate a RF calibration signal based on modulating the calibration signal. The calibration signal comprises an orthogonal code based signal. The apparatus includes a second RF section to receive the RF calibration signal and generate a received calibration signal based on demodulating the RF calibration signal; a calibration section; a first antenna electrically coupled to the first RF section and configured to transmit the RF calibration signal; and a second antenna electrically coupled to the second RF section and configured to receive the RF calibration signal. The calibration section is configured to determine one or more of gain, baseband delay, or RF delay to calibrate the first RF section; and the second antenna is switchable between receiving the RF calibration signal and transmitting an encoded data signal.

An on-off keying (OOK) transmitter and communication method are provided. The OOK transmitter may include a data encoder configured to encode input data into a transmission sequence, a pulse shaper configured to generate pulses based on the transmission sequence, a bi-phase controller configured to generate a control signal to control a random change in phase, between two phases, of a carrier based on the transmission sequence, a bi-phased switch configured to randomly change a phase of the carrier generated by a voltage-controlled oscillator (VCO), based on the control signal, and a power amplifier (PA) configured to generate a transmission signal based on the generated pulses and the carrier with the randomly changed phase. The PA may be a bi-phasing PA, and the bi-phased switch may be included in the bi-phasing PA.