Abstract: Certain aspects of the present disclosure generally relate to an amplifier configured to process signals received in different frequency bands, where at least a portion of the amplifier is shared between different modes corresponding to the different frequency bands. One example circuit generally includes an amplifier having at least one first transistor configured to amplify a first signal received in a first mode of operation (e.g., associated with a particular frequency band), and at least one second transistor configured to amplify a second signal received in a second mode of operation. The amplifier may also include a transformer comprising a primary winding and a secondary winding, and one or more switches configured to selectively couple the primary winding to the first transistor or the second transistor based on the first mode or the second mode of operation, respectively. In certain aspects, the transformer may be coupled to a transconductance circuit.

Abstract: Generally described, the devices and methods provided herein are directed to wearables having a spectrometer for analyzing a chemical composition of a substance. The substance can be a solid, liquid, or gas. Spectrometer readings can be matched against known chemical compositions that are stored locally or remotely. After a spectrometer reading, a notification mechanism can be activated. The notification mechanism can activate when the composition of the substance has been determined or the substance is determined to be harmful and/or safe.

Abstract: Techniques for providing voltage-controlled oscillator circuits having improved phase noise performance and lower power consumption. In an exemplary embodiment, a voltage controlled oscillator (VCO) is coupled to a mixer or a frequency divider such as a divide-by-two circuit. The VCO includes a transistor pair with magnetically cross-coupled inductors, and variable capacitance coupled to the gates of the transistor pair. In an exemplary embodiment, a frequency divider is configured to divide the frequency of the differential current flowing through the transistor pair to generate the LO output. In an alternative exemplary embodiment, a mixer is configured to mix the differential current flowing through the transistor pair with another signal. The VCO and mixer or frequency divider share common bias currents, thereby reducing power consumption. Various exemplary apparatuses and methods utilizing these techniques are disclosed.

Abstract: Techniques for providing voltage-controlled oscillator circuits having improved phase noise performance and lower power consumption. In an exemplary embodiment, a voltage controlled oscillator (VCO) is coupled to a mixer or a frequency divider such as a divide-by-two circuit. The VCO includes a transistor pair with magnetically cross-coupled inductors, and variable capacitance coupled to the gates of the transistor pair. In an exemplary embodiment, a frequency divider is configured to divide the frequency of the differential current flowing through the transistor pair to generate the LO output. In an alternative exemplary embodiment, a mixer is configured to mix the differential current flowing through the transistor pair with another signal. The VCO and mixer or frequency divider share common bias currents, thereby reducing power consumption. Various exemplary apparatuses and methods utilizing these techniques are disclosed.