Low power radio transmitter using pulse transmissions

Abstract

A radio receiver includes a low-noise amplifier, pulse-to-signal conversion module, and intermediate frequency stage. The low-noise amplifier is operably coupled to receive and amplify an M-bit signal at a radio frequency. The M-bit signal at a radio frequency is representative of a pulse signal that is carried on a radio frequency. The pulse-to-signal conversion module demodulates the M-bit signal to produce an N-bit signal at an intermediate frequency. For example, the pulse-to-signal conversion module performs pulse-width demodulation, pulse-density demodulation, or pulse-position demodulation to recapture the N-bit signal. The intermediate frequency stage steps down the frequency of the N-bit signal to produce a base-band digital signal.

1 . A radio receiver comprises:
 low noise amplifier operably coupled to amplify an M-bit signal at a radio frequency to produce an amplified M-bit signal at the radio frequency;   pulse to signal conversion module operably coupled to convert the amplified M-bit signal at a radio frequency into an N-bit signal at an intermediate frequency, wherein N is greater than M; and   intermediate frequency stage operably coupled to down-convert frequency of the N-bit signal at the intermediate frequency into a baseband digital signal.   
   
   
       2 . The radio receiver of  claim 1 , wherein the intermediate frequency stage further comprises:
 first mixing module operably coupled to mix the N-bit signal at the intermediate frequency with an in-phase intermediate frequency signal to produce a first mixed signal;   second mixing module operably coupled to mix the N-bit signal at the intermediate frequency with a quadrature intermediate frequency signal to produce a second mixed signal; and   bandpass filter module operably coupled to filter the first and second mixed signals to produce the baseband digital signal.   
   
   
       3 . The radio receiver of  claim 1 , wherein the pulse to signal conversion module further comprises:
 radio frequency module operably coupled to decrease frequency of the M-bit signal at the radio frequency to produce an M-bit pulse density signal at the intermediate frequency;   pulse density demodulator operably coupled to demodulate the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   rate converter operably coupled to decrease rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       4 . The radio receiver of  claim 1 , wherein the pulse to signal conversion module further comprises:
 radio frequency module operably coupled to decrease frequency of the M-bit signal at the radio frequency to produce a rate increased M-bit pulse density signal at the intermediate frequency;   rate converter operably coupled to decrease rate of the rate increased M-bit pulse density signal at the intermediate frequency to produce an M-bit pulse density signal at the intermediate frequency;   pulse density demodulator operably coupled to demodulate the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   second rate converter operably coupled to decrease rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       5 . The radio receiver of  claim 4  further comprises:
 the rate converter including:
 first sample and hold module operably coupled to sample and hold, at a first decreased rate, the rate increased M-bit pulse density signal at the intermediate frequency to produce the M-bit pulse density signal at the intermediate frequency; and 
   the second rate converter including:
 second sample and hold module operably coupled to sample and hold, at a second decreased rate, the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency. 
   
   
   
       6 . The radio receiver of  claim 4 , wherein the pulse density demodulator further comprises:
 decimation filter operably coupled to filter the M-bit pulse density signal at the intermediate frequency to produce the rate increased N-bit signal at the intermediate frequency.   
   
   
       7 . The radio receiver of  claim 1 , wherein the pulse to signal conversion module further comprises:
 pulse width demodulator operably coupled to demodulate the amplified M-bit signal at the radio frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       8 . The radio receiver of  claim 7 , wherein the pulse width demodulator further comprises:
 an integrator operably coupled to integrate the amplified M-bit signal at the radio frequency to produce an integrated signal;   sample and hold module operably coupled to sample and hold a value of the integrated signal at falling edges of the amplified M-bit signal at the radio frequency to produce sampled values;   analog to digital converter operably coupled to convert the sampled values into digital samples; and   a compiler operably coupled to convert the digital samples into the N-bit signal at the intermediate frequency.   
   
   
       9 . The radio receiver of  claim 1 , wherein the pulse to signal conversion module further comprises:
 pulse position demodulator operably coupled to demodulate the amplified M-bit signal at the radio frequency with respect to a reference signal to produce the N-bit signal at the intermediate frequency.   
   
   
       10 . A method for receiving a radio frequency signal, the method comprises:
 amplifying a received M-bit signal at a radio frequency to produce an amplified M-bit signal at the radio frequency;   pulse to signal converting the amplified M-bit signal at a radio frequency into an N-bit signal at an intermediate frequency, wherein N is greater than M; and   down-converting frequency of the N-bit signal at the intermediate frequency into a baseband digital signal.   
   
   
       11 . The method of  claim 10 , wherein the down-converting the frequency of the N-bit signal at the intermediate frequency further comprises:
 mixing the N-bit signal at the intermediate frequency with an in-phase intermediate frequency signal to produce a first mixed signal;   mixing the N-bit signal at the intermediate frequency with a quadrature intermediate frequency signal to produce a second mixed signal; and   bandpass filtering the first and second mixed signals to produce the baseband digital signal.   
   
   
       12 . The method of  claim 10 , wherein the pulse to signal converting further comprises:
 decreasing frequency of the M-bit signal at the radio frequency to produce an M-bit pulse density signal at the intermediate frequency;   pulse density demodulating the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   decreasing rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       13 . The method of  claim 10 , wherein the pulse to signal converting further comprises:
 decreasing frequency of the M-bit signal at the radio frequency to produce a rate increased M-bit pulse density signal at the intermediate frequency;   decreasing rate of the rate increased M-bit pulse density signal at the intermediate frequency to produce an M-bit signal at the intermediate frequency;   pulse density demodulating the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   decreasing rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       14 . The method of  claim 13  further comprises:
 decreasing rate of the rate increased M-bit pulse density signal at the intermediate frequency including:
 sample and holding, at a first decreased rate, the rate increased M-bit pulse density signal at the intermediate frequency to produce the M-bit signal at the intermediate frequency; and 
   decreasing rate of the rated increased N-bit signal at the intermediate frequency including:
 sample and holding, at a second decreased rate, the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency. 
   
   
   
       15 . The method of  claim 13 , wherein the pulse density demodulating further comprises:
 decimation filtering the rate decreased M-bit pulse density signal at the intermediate frequency to produce the rate increased N-bit signal at the intermediate frequency.   
   
   
       16 . The method of  claim 10 , wherein the pulse to signal converting further comprises:
 pulse width demodulating the amplified M-bit signal at the radio frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       17 . The method of  claim 16 , wherein the pulse width demodulating further comprises:
 integrating the amplified M-bit signal at the radio frequency to produce an integrated signal;   sample and holding a value of the integrated signal at falling edges of the amplified M-bit signal at the radio frequency to produce sampled values;   converting the sampled values into digital samples; and   compiling the digital samples to produce the N-bit signal at the intermediate frequency.   
   
   
       18 . The method of  claim 10 , wherein the pulse to signal converting further comprises:
 pulse position demodulating the amplified M-bit signal at the radio frequency with respect to a reference signal to produce the N-bit signal at the intermediate frequency.   
   
   
       19 . An apparatus for receiving a radio frequency signal, the apparatus comprises:
 processing module; and   memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:   amplify a received M-bit signal at a radio frequency to produce an amplified M-bit signal at the radio frequency;   pulse to signal convert the amplified M-bit signal at a radio frequency into an N-bit signal at an intermediate frequency, wherein N is greater than M; and   down-convert frequency of the N-bit signal at the intermediate frequency into a baseband digital signal.   
   
   
       20 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to down-convert the frequency of the N-bit signal at the intermediate frequency by:
 mixing the N-bit signal at the intermediate frequency with an in-phase intermediate frequency signal to produce a first mixed signal;   mixing the N-bit signal at the intermediate frequency with a quadrature intermediate frequency signal to produce a second mixed signal; and   bandpass filtering the first and second mixed signals to produce the baseband digital signal.   
   
   
       21 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to pulse to signal convert the M-bit signal at the radio frequency by:
 decreasing frequency of the M-bit signal at the radio frequency to produce an M-bit pulse density signal at the intermediate frequency;   pulse density demodulating the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   decreasing rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       22 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to pulse to signal convert the M-bit signal at the radio frequency by:
 decreasing frequency of the M-bit signal at the radio frequency to produce a rate increased M-bit pulse density signal at the intermediate frequency;   decreasing rate of the rate increased M-bit pulse density signal at the intermediate frequency to produce an M-bit pulse density signal at the intermediate frequency;   pulse density demodulating the M-bit pulse density signal at the intermediate frequency to produce a rate increased N-bit signal at the intermediate frequency; and   decreasing rate of the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       23 . The apparatus of  claim 22 , wherein the memory further comprises operational instructions that cause the processing module to:
 decrease rate of the rate increased M-bit pulse density signal at the intermediate frequency by:
 sample and holding, at a first decreased rate, the rate increased M-bit pulse density signal at the intermediate frequency to produce the M-bit pulse density signal at the intermediate frequency; and 
   decrease rate of the rated increased N-bit signal at the intermediate frequency by:
 sample and holding, at a second decreased rate, the rated increased N-bit signal at the intermediate frequency to produce the N-bit signal at the intermediate frequency. 
   
   
   
       24 . The apparatus of  claim 22 , wherein the memory further comprises operational instructions that cause the processing module to pulse density demodulate the rate decreased M-bit pulse density signal at the intermediate frequency by:
 decimation filtering the rate decreased M-bit pulse density signal at the intermediate frequency to produce the rate increased N-bit signal at the intermediate frequency.   
   
   
       25 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to pulse to signal convert the amplified M-bit signal at the radio frequency by:
 pulse width demodulating the amplified M-bit signal at the radio frequency to produce the N-bit signal at the intermediate frequency.   
   
   
       26 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to pulse width demodulate the amplified M-bit signal at the radio frequency by:
 integrating the amplified M-bit signal at the radio frequency to produce an integrated signal;   sample and holding a value of the integrated signal at falling edges of the amplified M-bit signal at the radio frequency to produce sampled values;   convert the sampled values into digital samples; and   compile the digital samples to produce the N-bit signal at the intermediate frequency.   
   
   
       27 . The apparatus of  claim 19 , wherein the memory further comprises operational instructions that cause the processing module to pulse to signal convert the amplified M-bit signal at the radio frequency by:
 pulse position demodulating the amplified M-bit signal at the radio frequency with respect to a reference signal to produce the N-bit signal at the intermediate frequency.