Proximity sensing systems and methods

Abstract

An ultrasonic sensing system includes a comparator, an analog-to-digital converter (ADC) coupled to the comparator, and a processor coupled to the comparator and the ADC. The comparator is configured to compare an input signal with a triggering value and trigger proximity measurement in response to an amplitude of the input signal being greater than the triggering value. The ADC is configured to convert the input signal to a digital signal. The processor is configured to, in response to the proximity measurement being triggered, determine a peak time point when a peak amplitude is received based on the digital signal and calculate a distance based on the peak time point. The peak time point is different from a time point when the proximity measurement is triggered.

What is claimed is: 
     
         1 . An ultrasonic sensing system comprising:
 a comparator configured to:
 compare an input signal with a triggering value; and 
 trigger proximity measurement in response to an amplitude of the input signal being greater than the triggering value; 
   an analog-to-digital converter (ADC) coupled to the comparator and configured to convert the input signal to a digital signal; and   a processor coupled to the comparator and the ADC, the processor being configured to, in response to the proximity measurement being triggered:
 determine, based on the digital signal, a peak time point when a peak amplitude is received, the peak time point being different from a time point when the proximity measurement is triggered; and 
 calculate a distance based on the peak time point. 
   
     
     
         2 . The system of  claim 1 , further comprising:
 an ultrasonic transmitter configured to provide a transmission of a transmitting signal;   wherein the processor is further configured to calculate the distance based on the peak time point and a time point when the transmitting signal is transmitted.   
     
     
         3 . The system of  claim 2 , further comprising:
 a booster configured to increase an energy level associated with the transmission of the transmitting signal.   
     
     
         4 . The system of  claim 3 , further comprising:
 an ultrasonic receiver operably coupled to the comparator and the ADC and configured to receive an ultrasonic signal after the transmission of the transmitting signal.   
     
     
         5 . The system of  claim 4 , wherein the ultrasonic transmitter is the ultrasonic receiver. 
     
     
         6 . The system of  claim 4 , further comprising:
 a gain-adjustable amplifier coupled to the comparator and the ADC, the input signal being an output of the gain-adjustable amplifier.   
     
     
         7 . The system of  claim 6 , wherein the gain-adjustable amplifier is coupled to the ultrasonic receiver, and configured to amplify the ultrasonic signal according to a variable gain. 
     
     
         8 . The system of  claim 7 , wherein the gain-adjustable amplifier is further configured to adjust the variable gain based on at least one of previously measured data, a measuring distance, or a strength of the ultrasonic signal. 
     
     
         9 . The system of  claim 7 , wherein the gain-adjustable amplifier is further configured to adjust the variable gain according to an adjustable gain control (AGC) signal sent from the processor. 
     
     
         10 . The system of  claim 9 , wherein the processor is further configured to control the gain-adjustable amplifier based on at least one of an output of the comparator or an output of the ADC. 
     
     
         11 . The system of  claim 10 , wherein the processor is further configured to adjust the AGC signal based on at least one of the output of the comparator or the output of the ADC. 
     
     
         12 . The system of  claim 6 , further comprising:
 an attenuator circuit configured to attenuate the ultrasonic signal; and   a switch configured to:
 electrically couple the attenuator circuit to the ultrasonic receiver; and 
 decouple the attenuator circuit from the ultrasonic receiver. 
   
     
     
         13 . The system of  claim 12 , wherein the switch is further configured to:
 electrically couple the attenuator circuit to the ultrasonic receiver during a predetermined period of time after the transmission of the transmitting signal; and   decouple the attenuator circuit from the ultrasonic receiver prior to and after the predetermined period of time.   
     
     
         14 . The system of  claim 13 , wherein the predetermined period of time corresponds to a blind zone time period for the ultrasonic sensing system. 
     
     
         15 . The system of  claim 14 , wherein the ultrasonic signal received during the predetermined period of time includes a reverberation signal and an echo signal. 
     
     
         16 . The system of  claim 15 , wherein the attenuator circuit is configured to provide an amount of attenuation based at least in part on a previously-measured amplitude of a reverberation signal or an echo signal. 
     
     
         17 . The system of  claim 13 , wherein the switch is further configured to:
 electrically couple the gain-adjustable amplifier to the ultrasonic receiver through the attenuator circuit; and   electrically couple the gain-adjustable amplifier to the ultrasonic receiver without coupling the attenuator circuit.   
     
     
         18 . The system of  claim 1 , wherein at least one of the comparator or the ADC is integrated with the processor. 
     
     
         19 . A method for ultrasonic sensing comprising:
 comparing an input signal with a triggering value;   triggering proximity measurement in response to an amplitude of the input signal being greater than the triggering value;   converting the input signal to a digital signal; and   in response to the proximity measurement being triggered:
 determining, based on the digital signal, a peak time point when a peak amplitude is received, the peak time point being different from a time point when the proximity measurement is triggered; and 
 calculating a distance based on the peak time point. 
   
     
     
         20 . The method of  claim 19 , further comprising:
 providing a transmission of a transmitting signal;   receiving an ultrasonic signal after the transmission of the transmitting signal;   obtaining the input signal based on the ultrasonic signal prior to comparing the input signal with the triggering value, including:
 in response to the ultrasonic signal being received during a predetermined period of time after the transmission of the transmitting signal, controlling to attenuate the ultrasonic signal to obtain the input signal; and 
 in response to the ultrasonic signal being received prior to or after the predetermined period of time, controlling to not attenuate the ultrasonic signal to obtain the input signal; and 
   calculating the distance based on the peak time point and a time point when the transmitting signal is transmitted.