Digital range gated radio frequency sensor

Abstract

A digitally implemented radio frequency sensor for physiology sensing may be configured to generate oscillation signals for emitting radio frequency pulses for range gated sensing. The sensor may include a radio frequency transmitter configured to emit the pulses and a receiver configured to receive reflected ones of the emitted radio frequency pulses under control of a microcontroller. The received pulses may be processed by the microcontroller to detect physiology characteristics such as motion, sleep, respiration and/or heartbeat. The microcontroller may be configured to generate timing pulses such as with a pulse generator for transmission of radio frequency sensing pulses. The microprocessor may sample received signals, such as in phase and quadrature phase analogue signals, to implement digital demodulation and baseband filtering of the received signals.

1 . Digital radio frequency motion sensor apparatus comprising:
 a radio frequency transmitter, the transmitter configured to emit radio frequency signals, the radio frequency signals comprising pulses; and   a receiver configured to receive reflected ones of the emitted radio frequency signals,   a microcontroller configured to control a timing of the pulses;   a pulse generator configured to generate signal pulses in response to the timing;   an oscillator; and   a switched circuit coupled to the pulse generator and the oscillator,   wherein the microcontroller is configured to control digital filtering of one or more signals or baseband signals from the receiver, and   wherein the microcontroller is configured to detect movement of a user with a plurality of different sensing ranges.   
     
     
         2 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is further configured to control demodulating a combined signal of emitted and received signals to determine a baseband signal, and modulating the baseband signal to produce an intermediate frequency (IF) signal at the receiver. 
     
     
         3 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is further configured to control digital demodulation of an intermediate frequency (IF) signal after a stage of IF signal amplification to produce a baseband signal at the receiver. 
     
     
         4 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is further configured to control digital amplification of one or more baseband signals from the receiver. 
     
     
         5 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the pulse generator comprises a logic gate circuit configured to receive a timing signal generated by the microcontroller. 
     
     
         6 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is coupled with the receiver to sample a signal from the receiver representing phase and/or magnitude differences between received reflected ones of emitted radio frequency pulses and emitted radio frequency pulses. 
     
     
         7 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is configured to digitally demodulate the signal from the receiver. 
     
     
         8 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the receiver generates in phase and quadrature phase signals for sampling at inputs to the microcontroller. 
     
     
         9 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the receiver comprises a mixer, wherein the microcontroller controls timing of the mixer's operation. 
     
     
         10 . The digital radio frequency motion sensor apparatus of  claim 9  wherein the mixer comprises a switched magnitude detector. 
     
     
         11 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the microcontroller is configured to generate an indicator of any one or more of respiration, sleep and heart rate information from one or more digitally demodulated signals from the receiver. 
     
     
         12 . The digital radio frequency motion sensor apparatus of  claim 1 , wherein the microcontroller is configured to trigger sensor operation by turning the sensor apparatus on and off. 
     
     
         13 . The digital radio frequency motion sensor apparatus of any of  claim 1 , wherein the microcontroller is configured to control storing of data from received signals in epochs. 
     
     
         14 . The digital radio frequency motion sensor apparatus of  claim 13 , further comprising a memory, wherein the memory stores the epochs. 
     
     
         15 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the sensor apparatus is configured for wireless transmission from the sensor apparatus of data derived from received signals. 
     
     
         16 . The digital radio frequency motion sensor apparatus of  claim 1  further comprising a digital or analogue output connection. 
     
     
         17 . The digital radio frequency motion sensor apparatus of  claim 16 , wherein the digital or analogue output connection is a RS232, serial or USB connection. 
     
     
         18 . The digital radio frequency motion sensor apparatus of  claim 1  further comprising an analog output, and wherein the microcontroller is configured to convert digital signals received from the receiver into analogue signals for output via the analog output. 
     
     
         19 . The digital radio frequency motion sensor apparatus of  claim 18  wherein the analog signals comprise a pulse width modulated signal. 
     
     
         20 . The digital radio frequency motion sensor apparatus of  claim 1  further comprising a housing, wherein the sensor is contained within the housing. 
     
     
         21 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the transmitter and receiver comprise a single printed circuit board and wherein the microcontroller is a chip coupled to the single printed circuit board. 
     
     
         22 . The digital radio frequency motion sensor apparatus of  claim 1  wherein the receiver comprises two detectors for mixing emitted radio frequency (RF) pulses and received reflected ones of emitted radio frequency pulses, the two detectors including one magnitude detector for in-phase signals and one magnitude detector for quadrature phase signals, wherein each magnitude detector is configured to switch on, at a first defined point in time t1 and for a first defined time duration T1 within each one of a first number of RF pulses, to effect range gating. 
     
     
         23 . The digital radio frequency motion sensor apparatus of  claim 22 , wherein each detector is switched at a second defined point in time t0 for a second defined time duration T0 within each one of a second number of RF pulses, the first defined point in time t1 being different from the second defined point in time t0; and wherein each detector modulates the mixed pulses at an intermediate frequency that is higher than a baseband frequency. 
     
     
         24 . The digital radio frequency motion sensor apparatus of  claim 23 , wherein each detector alternates between being switched on at the first defined point in time t1, during the first number of RF pulses, and being switched on at the second defined point in time t0, during the second number of RF pulses. 
     
     
         25 . The digital radio frequency motion sensor apparatus of  claim 22 , wherein the detectors are magnitude detectors. 
     
     
         26 . The digital radio frequency motion sensor apparatus of  claim 23 , wherein the receiver further comprises, for each detector, a pre-amplifier or an amplifier for amplifying the modulated mixed pulses at the intermediate frequency. 
     
     
         27 . The digital radio frequency motion sensor apparatus of  claim 26 , wherein the microcontroller is further configured to demodulate the amplified modulated mixed pulses into baseband signals. 
     
     
         28 . The digital radio frequency motion sensor apparatus of  claim 1 , wherein the receiver and radio frequency transmitter are digitally controlled by the microcontroller, to automate changing of at least some of their parameters.