Abstract: A system for generating amplitude matched 45 degree phase separated signals is disclosed. Embodiments of the system for generating amplitude matched 45 degree phase separated signals include a filter arrangement including a plurality of nodes, an adjustable element associated with each node, the adjustable element configured to substantially equalize an amplitude of each vector associated with each node. The adjustable element may be an adjustable resistance or an adjustable capacitance associated with each node.

Abstract: A phase-locked loop (PLL) is disclosed. One embodiment, among others, includes a PLL that provides a control signal and a square root module configured to receive state information, the state information corresponding to tuning information, the square root module further configured to multiply the control signal by a square root of the state information to provide a tuning signal.

Abstract: A phase-locked loop (PLL) is disclosed. One embodiment, among others, includes a PLL that provides a control current and varies the control current in proportion to an inverse of N squared. N is the ratio of the output frequency of the PLL system to the reference frequency of the PLL system. The varying of the control current compensates for bandwidth changes of the PLL system.

Abstract: A tuning circuit for use in tuning multiple voltage-controlled oscillators (VCOs) of a phase-locked loop (PLL) is provided. A search algorithm is used to determine which VCO to use for a given frequency to be synthesized by the PLL. The tuning circuit provides a binary representation, associated with the frequency to synthesize, to the PLL. The PLL responds to this representation by attempting to synthesize the associated frequency. New binary representations are provided until an indication of a threshold frequency between multiple VCOs is determined. A record of the threshold frequency is stored. The binary representation of a frequency to be synthesized and the stored record of the threshold frequency are used to provide an indication of which VCO of the PLL to use to synthesize the desired frequency.