Abstract: The present invention provides a synthesizer having an efficient lock detect signal generator, an extended range VCO that can operate within any one of a plurality of adjacent characteristic curves defined by a plurality of adjacent regions, and a divide circuit implemented using only a single counter along with a decoder. This allows for a method of operating the synthesizer, methods of establishing or reestablishing a lock condition using the extended range VCO, and a method of designing a plurality of divide circuits which each use the same single counter and each use a different decoder.

Abstract: A printed balun satisfies performance requirements for operation at a desired operational frequency (e.g., ƒ=5.3 GHz) while minimizing space requirements on a circuit board. Segments of microstrip are connected at right angles that define fingers whose dimensions can be tailored for operation at a desired operational frequency while minimizing the corresponding space required on a circuit board. Minimal separation between the fingers avoids undesirable internal interference. Mounted at the edges of distinct fingers are the necessary ports for operation of the balun including a single-ended port, an isolation port, and two differential ports.

Abstract: A radio-frequency (RF) front-end is described. In one embodiment, the RF front-end comprises a low noise amplifier (LNA), a first mixer and an I/Q quadrature mixer. The LNA amplifies a received signal at a carrier frequency, the LNA having inductive loads. The first mixer is coupled to the low noise amplifier and mixes an amplified received signal with a first local oscillator (LO) signal to down convert the amplified received signal to an intermediate frequency (IF). The first mixer has inductive loads. The first frequency is related to the carrier frequency such that an image channel associated with the carrier and the LO frequency is outside the bandwidth of the inductive loads of the LNA. The I/Q quadrature mixer stage has a second mixer and a third mixer coupled to the first mixer. The I/Q quadrature mixer converts the amplified received signal at the IF to I and Q signals using a second LO signal related to the first LO signal.

Abstract: A calibration method and apparatus are described. In one embodiment, the method includes a pair of transceivers performing a loop back test to determine a relationship between transmit and receive gain for each transceiver. A path loss between the first transceiver and a second transceiver is computed. The computation is made by transmitting a pair of signals in opposite directions between the first and second transceivers to determine a relationship between transmit path gain of the first transceiver and receive path gain of the second transceiver and a relationship between the transmit path gain of the second transceiver and receive path of the first transceiver. The transmit and receive path gains are generated for the first transceivers based on the path loss and the relationship.

Abstract: A mixing apparatus includes a Gilbert cell connected to a first load and a second load. In one embodiment each load contains transistors that are configured as a diode and a triode, where these circuits are additively combined to achieve substantially linear voltage-current characteristics over a predetermined range. The mixing apparatus takes two pairs of differential inputs and produces a pair of differential outputs. Because of the substantial linearity of the loads, the inputs and outputs of the mixing apparatus are acceptable over a relatively large range of input settings. In other embodiments each load may contain a transistor configured as a triode and a resistor, where these circuits are likewise additively combined to achieve substantially linear voltage-current characteristics over a predetermined range.