Abstract: A frequency reference device that includes a frequency reference generation unit to generate a frequency reference signal based on an absorption line of a gas.

Abstract: An apparatus and method for reducing interference signals using multiphase clocks. An integrated circuit includes a digital circuit and an analog circuit. The digital circuit includes a derived clock circuit configured to receive a root clock having a frequency D*f, D being a divide factor, to divide the root clock by D, and generate multiphase clocks having N phases. N circuits of the digital circuit are configured to receive a corresponding one of the N phases, with edges of the multiphase clocks being spread over the N phases. The multiphase clocks cause a frequency shift in interference signals generated by reduced periodic peak currents drawn by the N circuits from f to N*f and harmonics thereof. The analog circuit receives an in-band range of signals. A value of N is configured to shift the interference signals outside the in-band range of signals.

Abstract: Various apparatuses and methods for varying segment activation in a segmented power amplifier are disclosed herein. For example, some embodiments provide a power amplifier including an input, an output, a plurality of amplifier segments and a controller. The amplifier segments are connected in parallel between the input and the output and are adapted to be activated and inactivated. The power level at the output may be controlled by changing a number of the amplifier segments that are activated concurrently. The controller is connected to the amplifier segments and is adapted to vary which of the amplifier segments are activated to arrive at a selected number of activated amplifier segments.

Abstract: Various apparatuses and methods for varying segment activation in a segmented power amplifier are disclosed herein. For example, some embodiments provide a power amplifier including an input, an output, a plurality of amplifier segments and a controller. The amplifier segments are connected in parallel between the input and the output and are adapted to be activated and inactivated. The power level at the output may be controlled by changing a number of the amplifier segments that are activated concurrently. The controller is connected to the amplifier segments and is adapted to vary which of the amplifier segments are activated to arrive at a selected number of activated amplifier segments.

Abstract: An apparatus and method for reducing interference signals using multiphase clocks. An integrated circuit includes a digital circuit and an analog circuit. The digital circuit includes a derived clock circuit configured to receive a root clock having a frequency D*f, D being a divide factor, to divide the root clock by D, and generate multiphase clocks having N phases. N circuits of the digital circuit are configured to receive a corresponding one of the N phases, with edges of the multiphase clocks being spread over the N phases. The multiphase clocks cause a frequency shift in interference signals generated by reduced periodic peak currents drawn by the N circuits from f to N*f and harmonics thereof. The analog circuit receives an in-band range of signals. A value of N is configured to shift the interference signals outside the in-band range of signals.

Abstract: An adaptive digital pre-distortion block is used to cancel device nonlinearities to improve the overall linearity of a Delta-Sigma DAC system. In particular, the pre-distortion block may be implemented all in digital components and utilize programmable registers that change the pre-distortion transfer function either statically or dynamically, or both. Static changes can be for variation in process corners during production, whereas, dynamic changes can be used to correct nonlinear changes that can occur from environmental reasons such as voltage, temperature, aging and device stress.

Abstract: An adaptive digital pre-distortion block is used to cancel device nonlinearities to improve the overall linearity of a Delta-Sigma DAC system. In particular, the pre-distortion block may be implemented all in digital components and utilize programmable registers that change the pre-distortion transfer function either statically or dynamically, or both. Static changes can be for variation in process corners during production, whereas, dynamic changes can be used to correct nonlinear changes that can occur from environmental reasons such as voltage, temperature, aging and device stress.

Abstract: An amplifier system in accordance with an aspect of the present invention comprises a switching amplifier that drives a load with a pulse-width modulated (PWM) output signal that varies between first and second rails based on a first control input signal, and a common mode supply that provides a switching signal that varies between third and fourth rails to maintain a common mode voltage of the load at a level that is between the first and second rails.

Abstract: A Class-D amplifier system may include an input stage that includes an Nth order filter, where N>1. The input stage filters an input signal to provide a filtered output signal, an input of the input stage being configured to receive the input signal as a digital pulse-width-modulated (PWM) signal. A comparator provides a quantized output signal based on the filtered output signal. An output stage is connected between a first voltage rail and a second voltage rail. The output stage provides a switching output signal at an output that varies between the first voltage rail and the second voltage rail based on the quantized output signal. A feedback path connects the output of the output stage with the input of the input stage, such that the Nth order filter compensates for variations in at least one of the first voltage rail and the second voltage rail.