Texas Instruments Corporation

Cirrus Logic Inc.

Lei Ding

Rahmi Hezar

Baher S Haroun

Srinath Mathur Ramaswamy

Joonhoi Hur

Nathan Richard Schemm

Aritra Banerjee

Anand Ganesh Dabak

Fernando Alberto Mujica

Zigang Yang

Anand Gopalan

John L Melanson

Roland Sperlich

Hardik Prakash Gandhi

Vaibhav Garg

Lars Jorgensen

Milind Anil Borkar

Sujeet Milind Patole

Xaiofan Fei

Murtaza Ali

Xiaofan Fei

Johann Guy Gaboriau

Bruce Eliot Duewer

Dok Won Lee

William Louis Abbott

Wai Lee

Carson Arthur Wick

Steven Loveless

Michael John Zroka

Brian Burk

Ultrasonic ranging systems and methods that use coding to distinguish emitted bursts from multiple transducers temporally stagger the bursts emitted from the transducers. The stagger delay between bursts from different transducers in a sensing frame can be randomized between different sensing frames to prevent blind zones. The stagger delay can be relatively small (e.g., between 3 ms and 10 ms) as compared to delays required between bursts in a single-tone ranging system (which would need to be more on the order of between 30 ms and 40 ms, depending on the maximum detecting range of the ranging system). The coding of bursts can be selected to utilize the entire bandwidth of the bursting transducer so as to preserve short-range sensitivity over transducer ringing. Schemes in which some transducers in a system only listen for bursts from other transducers but do not themselves burst within a sensing frame are also described.

Coded ultrasonic sensing with staggered bursts

Ultrasonic audio processing circuitry and a method useful in ultrasonic presence detection. An ultrasonic burst generator produces an ultrasonic burst signal at one or more ultrasonic frequencies, and an equalizer equalizes that ultrasonic burst signal according to frequency response characteristics of the speaker and microphone at those ultrasonic frequencies. Driver circuitry drives a speaker with the ultrasonic burst signal, which may be combined with an audible audio signal. An ultrasonic separation filter separates an ultrasonic portion from a signal received at a microphone, and processing circuitry is provided to determine a delay time of an echo corresponding to the ultrasonic burst signal in that separated ultrasonic portion of the received signal. In another aspect, the equalizer equalizes an ultrasonic portion of the signal received at a microphone, according to frequency response characteristics of the speaker and microphone at the ultrasonic frequencies of the burst.

Ultrasonic equalization and gain control for smart speakers

In a described example, a circuit includes a sensor circuit including multiple magnetic field sensors having respective sensor outputs. The magnetic field sensors are configured to provide magnetic field sensor signals at the respective sensor outputs representative of a measure of current flow through a conductive structure. A combiner interface has combiner inputs and a combiner output. The combiner inputs are coupled to the respective sensor outputs. The combiner interface is configured to provide an aggregate sensor measurement at the combiner output responsive to the magnetic field sensor signals, in which the aggregate sensor measurement is decoupled from magnetic fields generated responsive to the current flow through the conductive structure.

Magnetic current sensing

In an ultrasonic detection system that uses frequency-modulation or phase-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses peak search, peak buffer, and peak rank stages in one or more receiver signal processing paths to identify valid received ultrasonic signal envelope peaks in correlator outputs. The peak rank stage can support different modes respectively designed to handle one code, two or more codes, or two or more codes with support for Doppler frequency shift detection. Valid peak information (e.g., amplitude and time) can be reported to a central controller and/or stored locally in a fusion stage to generate more intelligent information for targets or obstacles using peaks from multiple bursts.

Time of flight and code signature detection for coded ultrasonic transmission

In an ultrasonic detection system that uses frequency-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses dynamic thresholding to discriminate valid echoes from system and environmental noise in multiple envelope signals produced by multiple correlators. The time-varying dynamic thresholds are generated from the mean of noise in a respective envelope derived from the output of a respective correlator. Multiple thresholds can be combined together such that a single time-varying threshold is applied to all correlators' envelopes. Such thresholding has the benefits of a constant false-alarm rate with regard to detection of echoes (as opposed to false triggering from noise), and, owing to finer-resolution and adaptive thresholds, can detect targets or obstacles as further distances and with greater time responsiveness.

Threshold generation for coded ultrasonic sensing

An ultrasound detect circuit includes a decimator that decimates a transmit signal to be transmitted through an ultrasonic transducer. The transmit signal is decimated to generate first and second template signals. The decimator uses a different decimation ratio to generate the first template signal than the second template signal. The circuit also includes a first correlator to correlate a signal derived from the ultrasonic transducer with the first template signal, aa second correlator to correlate the signal derived from the ultrasonic transducer with the second template signal, and a Doppler shift determination circuit to determine a Doppler frequency shift based on an output from the first correlator and an output from the second correlator.

Ultrasonic echo processing in presence of Doppler shift

Ultrasonic sensing systems and associated methods provide side-lobe reduction to improve the acoustic detection of small objects, the signature envelope peaks of which can otherwise be obscured by subsidiary envelope peaks in side lobes that result from residual correlation between a signal received by an ultrasonic transducer and a template signal corresponding to a burst signal emitted by the ultrasonic transducer. A shaping signal by which the amplitude of the burst signal can be varied with respect to time is taken into account in the template signal, and correlator circuitry correlates a signal derived from the ultrasonic transducer with the template signal to produce a correlated output exhibiting the desired side-lobe reduction. The distance from the transducer to the detected object can thereby be determined with enhanced accuracy and responsiveness.

Shaped ultrasonic transmission and echo processing with coding

Ultrasonic ranging systems and methods that emit coded bursts and correlate transduced acoustical echoes of the bursts with a receive template characterizing a burst code to determine time-of-flight information use receive templates of time-variable length to improve short-range object detection. The template length is based on a time index measured from the start of the burst emission. The detection can account for a dead zone of transducer ringing following a burst. A time-variable gain that is also based on the time index can be applied to the correlated signal. The length and gain can be adjusted with reduced temporal frequency to reduce computation cost.

Time-varying template for improved short-distance performance in coded ultrasonic ranging

A first branch group circuit includes a first branch circuit receiving a first RF input signal and first control information; and a second branch circuit receiving the first input signal and second control information. Each of the first and second branch circuits includes a power amplifier. The second control information enables the second branch circuit to be switched on or off while the first branch circuit remains on. A second branch group circuit includes: a third branch circuit receiving a second RF input signal and third control information; and a fourth branch circuit receiving the second input signal and fourth control information. Each of the third and fourth branch circuits includes a power amplifier. The fourth control information enables the fourth branch circuit to be switched on or off while the third branch circuit remains on. A combiner combines output signals of the power amplifiers to produce an output signal.

Multi-branch outphasing system and method

An ultrasonic sensing system includes: an amplifier including an input and an output; and an n-level comparator, coupled to the output of the amplifier, to compare an adjustable threshold voltage to an output signal from the output of the amplifier. N is greater than or equal to 1. The system also includes a noise power estimator, coupled to an output of the n-level comparator, to generate a noise power signal indicative of noise power of an input signal at the input of the amplifier. The system further includes a time-varying threshold circuit, coupled to the noise power estimator and the n-level comparator, to adjust the adjustable threshold voltage based on the noise power signal.

Sound sensing with time-varying thresholds

A frequency modulated continuous wave (FMCW) radar system that includes a transceiver coupled to an analog to digital converter (ADC), and a digital signal processor (DSP) coupled to the ADC. The transceiver is configured to transmit a plurality of FMCW chirps, receive a plurality of reflected FMCW chirps, and mix the plurality of reflected FMCW chirps with at least one of the FMCW chirps to generate a plurality of beat signals. The reflected FMCW chirps are the FMCW chirps after being reflected off of a target object. The ADC is configured to convert the beat signals into a plurality of digital chirps. The DSP is configured to receive the digital chirps and quantify a plurality of vibration parameters for the target object based on a comparison of phase information in a frequency domain between one of the plurality of FMCW chirps and one of the plurality of digital chirps.

Vibration parameters monitoring using FMCW radar

An ultrasonic detection circuit includes a transmitter circuit that provides excitation signals to an ultrasonic transducer during an excitation interval. A control circuit includes a port to receive a command. The control circuit controls the frequency and the duty cycle of the excitation signals of the transmitter circuit during the excitation interval. The control circuit generates a first excitation signal sequence of the excitation interval followed by a first monitoring period to receive a first echo signal in response to the command. The control circuit generates a second excitation signal sequence of the excitation interval followed by a second monitoring period to receive a second echo signal in response to the command. The control circuit outputs results via the port based on at least one of the first or second echo signals received.

Excitation signal sequences for ultrasonic transducer

An ultrasonic detection circuit includes a transmitter circuit that provides excitation signals to a terminal of an ultrasonic transducer to drive the ultrasonic transducer during an excitation interval. The excitation signals provided during the excitation interval include a first excitation signal at a first resonant frequency of the ultrasonic transducer followed by a second excitation signal at a second resonant frequency of the ultrasonic transducer. The first resonant frequency is different from the second resonant frequency.

Excitation interval for ultrasonic transducer

A circuit includes an amplifier to amplify an input signal and generate an output signal. The circuit also includes a tuning network to tune frequency response of the amplifier. The tuning network includes at least one tunable capacitor, which includes at least one micro-electro mechanical system (MEMS) capacitor. The amplifier could include a first die, the at least one MEMS capacitor could include a second die, and the first die and the second die could be integrated in a single package. The at least one MEMS capacitor could include a MEMS superstructure over a control structure, which is to control the MEMS superstructure and tune the capacitance of the at least one MEMS capacitor.

Tunable power amplifier with wide frequency range

A circuit includes an ultrasonic transducer having a first terminal and a second terminal. The first terminal receives an electrical drive signal and excites the ultrasonic transducer during an excitation interval to provide an ultrasound signal. The first terminal also provides an electrical receive signal in response to the ultrasonic transducer receiving a reflected ultrasound signal. The circuit includes a capacitor having one terminal connected to the first terminal of the ultrasonic transducer. A resistor is connected to another terminal of the capacitor to form a resistor-capacitor (RC) network. At least one of resistor and the capacitor have a variable resistance or capacitance value that is set to tune the RC network to mitigate ringing of the ultrasonic transducer following the excitation interval.

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Plano, TX, United States of America

Lei Ding