Abstract: This disclosure describes designs for a digitally controlled oscillator (DCO). The DCO can overcome many of the shortcomings associated with conventional voltage controlled oscillators (VCOs), and may improve wireless communication devices. The described DCO may improve the frequency synthesis process, reduce noise in a wireless communication device, and allow for simplification of various components of the device.

Abstract: A method according to one embodiment includes using a quadrature set of local oscillator signals having duty cycles of substantially less than fifty percent to perform a mixing operation on a radio-frequency current signal. Other embodiments include using a quadrature set of local oscillator signals having duty cycles of less than twenty-five percent.

Abstract: Techniques to linearly (in dB) adjust the gains of variable gain elements (i.e., variable gain amplifiers or VGAs) in a receiver or transmitter. An input control signal is provided to a conditioning circuit that conditions the control signal to achieve various signal characteristics. The input control signal is limited to within a particular range of values, temperature compensated, scaled (or normalized) to the supply voltages, shifted with an offset, or manipulated in other fashions. The conditioned signal is then provided to an input stage of a linearizer that generates a set of exponentially related signals. This is achieved using, for example, a differential amplifier in which the conditioned control signal is applied to the inputs of the differential amplifier and the collector currents from the differential amplifier comprises the exponentially related signals. An output stage within the linearizer receives the exponentially related signals and, in response, generates a gain control signal.

Abstract: A multi-stage low power, high dynamic range variable gain amplifier comprises an input stage cascaded with one or more current amplifier stages, whereby the gain of each stage may be independently controlled. The input stage may be comprised of a variable transconductance amplifier using variable emitter degeneration. The current amplifier may be comprised of a differential Darlington amplifier coupled to a differential cascode amplifier. The transconductance amplifier converts an input voltage signal to a current signal. The variable gain amplifier is designed for efficient low power operation.