Radio frequency transmitter noise cancellation

    公开(公告)号:US09831898B2

    公开(公告)日:2017-11-28

    申请号:US13801130

    申请日:2013-03-13

    CPC classification number: H04B1/0475 H04B1/525

    Abstract: Transmitter noise cancellation may be applied on a channel by channel basis to active channels of an incoming radio frequency signal received at a receiver. A noise cancellation filter may be provided for each active channel in a predetermined signal band. Applying noise cancellation on a per active channel basis instead of to the entire receive band may substantially reduce the filtering requirement and number of filter coefficients or taps to save power and reduce manufacturing costs. Channelized transmitter noise cancellers, multi transmitter-receiver cross coupling cancellers, and hybrid full signal band and channelized transmitter noise cancellers are also provided.

    Low power bias current generator and voltage reference

    公开(公告)号:US09811107B2

    公开(公告)日:2017-11-07

    申请号:US14789477

    申请日:2015-07-01

    Inventor: Stefan Marinca

    CPC classification number: G05F3/267

    Abstract: A bias current generators that may be implemented in low power environments is described. The current generator can be implemented without using resistors and may be used to generate reference currents and voltages. It may also be used to generate voltage references where the output of the circuit is to at least a first order temperature independent.

    BLOOD OXYGENATION SENSOR WITH LED CURRENT MODULATION

    公开(公告)号:US20170265794A1

    公开(公告)日:2017-09-21

    申请号:US15072961

    申请日:2016-03-17

    CPC classification number: A61B5/14552 A61B5/0402 A61B5/7292 A61B2562/0238

    Abstract: A blood oxygenation sensor is provided comprising: a first current-powered light source to produce light having a first wavelength; a second current-powered light source to produce light having a second wavelength; a light sensor to produce a current signal having a magnitude that is indicative of intensity of light incident upon it; a current level driver circuit that includes a current source configured to couple the current source to alternatively provide current to one of the first current-powered light source and the second light current-powered light source; a processor configured to predict times of occurrence of one or more first time intervals in which arterial volume at a tissue site is at one of a maximum and a minimum; wherein the processor is configured to control the current source, to provide a first pattern of higher power-dissipation current pulses to the first and second current-powered light sources during the first time intervals, and to provide a second pattern of lower power-dissipation current pulses to at least one of the first and second current-powered light sources during second time intervals.

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