Abstract: Apparatus and methods for switch-coupled oscillators are disclosed. In certain implementations, an oscillator system includes a primary oscillator, one or more auxiliary oscillators, one or more switching circuits, and an oscillator control circuit. The oscillator control circuit can be used to control the one or more switching circuits to selectively couple the primary oscillator to all or a portion of the one or more auxiliary oscillators. The oscillator control circuit can also disable any auxiliary oscillators that are decoupled from the primary oscillator to reduce power consumption. By selecting a number of auxiliary oscillators to couple to the primary oscillator, the oscillator system can have a configurable phase noise versus power consumption profile.

Abstract: Apparatus and methods for switch-coupled oscillators are disclosed. In certain implementations, an oscillator system includes a primary oscillator, one or more auxiliary oscillators, one or more switching circuits, and an oscillator control circuit. The oscillator control circuit can be used to control the one or more switching circuits to selectively couple the primary oscillator to all or a portion of the one or more auxiliary oscillators. The oscillator control circuit can also disable any auxiliary oscillators that are decoupled from the primary oscillator to reduce power consumption. By selecting a number of auxiliary oscillators to couple to the primary oscillator, the oscillator system can have a configurable phase noise versus power consumption profile.

Abstract: A transceiver circuit is disclosed for use in radio frequency communication systems. The circuit includes a transmitter circuit, a receiver circuit and a local oscillator circuit. The local oscillator circuit includes at least one oscillator input signal having a frequency that is a non-integer multiple of the transmission frequency of the radio frequency communication system. The oscillator input signal is used to produce a transmitter local oscillator signal and a receiver local oscillator signal.

Abstract: A rejection converter is disclosed for use in a transmitter for operating in at least either of a first mode for transmitting signals within a first frequency range, and a second mode for transmitting signals within a second frequency range. The rejection converter includes an input unit for receiving an input signal in at least either of the first or second frequency ranges. The rejection converter also includes a rejection unit for rejecting at least one spurious harmonic signal associated with the first frequency range that falls within the second frequency range. The rejection converter permits signals in the second frequency range to be passed when the output signal is within the second frequency range.

Abstract: A transceiver circuit is disclosed for use in radio frequency communication systems. The circuit includes a transmitter circuit, a receiver circuit and a local oscillator circuit. The local oscillator circuit includes at least one oscillator input signal having a frequency that is a non-integer multiple of the transmission frequency of the radio frequency communication system. The oscillator input signal is used to produce a transmitter local oscillator signal and a receiver local oscillator signal.