Abstract:
Exemplary embodiments are related to digital pre-distortion in envelope tracking systems. A device may include an amplitude modulation-to-phase modulation (AM-PM) distortion unit configured to generate an AM-PM distortion component in response to receipt of phase data of an input transmit signal. The device may also include a local oscillator (LO) path coupled to the distortion unit and configured to convey a local oscillator (LO) signal that varies based on the AM-PM distortion component.
Abstract:
Certain aspects of the present disclosure provide techniques and apparatus for generating multiple oscillating signals. One example circuit generally includes a first voltage-controlled oscillator (VCO) having a first inductor and a second VCO having a second inductor in parallel with a third inductor, wherein the second and third inductors are disposed inside a loop of the first inductor and may behave as a magnetic dipole. The loop of the first inductor may be symmetrical, and a combined geometry of loops of the second and third inductors may be symmetrical. The coupling coefficient (k) between the first inductor and a combination of the second and third inductors may be small (e.g., k
Abstract:
Certain aspects provide a circuit for generating an oscillating signal. The circuit generally includes a voltage-controlled oscillator (VCO) having cross-coupled transistors, a first capacitive element and a second capacitive element coupled to the cross-coupled transistors, and a first inductive element and a second inductive element coupled to the cross-coupled transistors. First terminals of the first inductive element and the second inductive element are coupled to first terminals of the first capacitive element and the second capacitive element, respectively. The circuit also includes a control circuit having an output coupled to a supply voltage node at second terminals of the first inductive element and the second inductive element, and a feedback path coupled between the VCO and an input of the control circuit.
Abstract:
Certain aspects of the present disclosure generally relate to a voltage-controlled oscillator (VCO) that is configurable (e.g., in a dynamic manner) in multiple modes of operation (e.g., low/high-band modes). The VCO may include a resonant circuit coupled to a plurality of switches that may be used to adjust current flow within one or more inductive elements of the resonant circuit. By adjusting the current flow within the inductive elements, an inductance of the resonant circuit may be adjusted, which in turn adjusts a band of the VCO.
Abstract:
Certain aspects of the present disclosure provide methods and apparatus for generating multiple oscillating signals having different phases. One example multiphase generating circuit generally includes a first phase shifting circuit configured to phase shift an input signal having an input frequency, such that an output signal of the first phase shifting circuit has a first phase difference with respect to the input signal; a first frequency dividing circuit configured to receive the input signal and output a first set of signals having a first frequency less than the input frequency of the input signal; and a second frequency dividing circuit configured to receive the output signal of the first phase shifting circuit and output a second set of signals having a second frequency less than the input frequency of the input signal. The multiphase signals may be used for fast frequency estimation of the input signal or in N-path filters.