Abstract: An apparatus is disclosed for injecting a frequency-modulated signal into a receiver. In an example aspect, the apparatus includes a receiver, a local oscillator circuit, and an injection circuit. The receiver comprises a signal propagation path. The local oscillator circuit is configured to generate a frequency-modulated signal. The injection circuit is coupled to the receiver and the local oscillator circuit. The injection circuit is configured to selectively connect the local oscillator circuit to the signal propagation path of the receiver to inject the frequency-modulated signal into the signal propagation path of the receiver. The injection circuit is also configured to disconnect the local oscillator circuit from the signal propagation path of the receiver.

Abstract: A frequency divider with duty cycle adjustment within a feedback loop is disclosed. In an exemplary design, an apparatus includes at least one divider circuit and at least one duty cycle adjustment circuit coupled in a feedback loop. The divider circuit(s) receive a clock signal at a first frequency and provide at least one divided signal at a second frequency, which is a fraction of the first frequency. The duty cycle adjustment circuit(s) adjust the duty cycle of the at least one divided signal and provide at least one duty cycle adjusted signal to the divider circuit(s). The divider circuit(s) may include first and second latches, and the duty cycle adjustment circuit(s) may include first and second duty cycle adjustment circuits. The first and second latches and the first and second duty cycle adjustment circuits may be coupled in a feedback loop and may perform divide-by-2.

Abstract: Selectable sizes for a local oscillator (LO) buffer and mixer are disclosed. In an exemplary embodiment, LO buffer and/or mixer size may be increased when a receiver or transmitter operates in a high gain mode, while LO buffer and/or mixer size may be decreased when the receiver or transmitter operates in a low gain mode. In an exemplary embodiment, LO buffer and mixer sizes are increased and decreased in lock step. Circuit topologies and control schemes for specific exemplary embodiments of LO buffers and mixers having adjustable size are disclosed.

Abstract: A frequency divider with duty cycle adjustment within a feedback loop is disclosed. In an exemplary design, an apparatus includes at least one divider circuit and at least one duty cycle adjustment circuit coupled in a feedback loop. The divider circuit(s) receive a clock signal at a first frequency and provide at least one divided signal at a second frequency, which is a fraction of the first frequency. The duty cycle adjustment circuit(s) adjust the duty cycle of the at least one divided signal and provide at least one duty cycle adjusted signal to the divider circuit(s). The divider circuit(s) may include first and second latches, and the duty cycle adjustment circuit(s) may include first and second duty cycle adjustment circuits. The first and second latches and the first and second duty cycle adjustment circuits may be coupled in a feedback loop and may perform divide-by-2.

Abstract: A method an apparatus for synchronizing phases of one or more divider units comprise powering on a master divider unit to provide a reference signal. A phase of a slave divider unit is synchronized to the reference signal from the master divider unit by providing a power on pulse at the slave divider unit, synchronizing the phase of the slave divider unit to the reference signal using a digitally controlled oscillator, and powering on the slave divider unit after a first predetermined delay period following a rising edge of the power on pulse. By synchronizing a slave divider unit to the reference signal from the master divider unit, any number of slave divider units may be powered on and in-phase with each other.

Abstract: A method an apparatus for synchronizing phases of one or more divider units comprise powering on a master divider unit to provide a reference signal. A phase of a slave divider unit is synchronized to the reference signal from the master divider unit by providing a power on pulse at the slave divider unit, synchronizing the phase of the slave divider unit to the reference signal using a digitally controlled oscillator, and powering on the slave divider unit after a first predetermined delay period following a rising edge of the power on pulse. By synchronizing a slave divider unit to the reference signal from the master divider unit, any number of slave divider units may be powered on and in-phase with each other.

Abstract: Selectable sizes for a local oscillator (LO) buffer and mixer are disclosed. In an exemplary embodiment, LO buffer and/or mixer size may be increased when a receiver or transmitter operates in a high gain mode, while LO buffer and/or mixer size may be decreased when the receiver or transmitter operates in a low gain mode. In an exemplary embodiment, LO buffer and mixer sizes are increased and decreased in lock step. Circuit topologies and control schemes for specific exemplary embodiments of LO buffers and mixers having adjustable size are disclosed.