Digital delta sigma modulator and applications thereof

Abstract

A digital delta sigma modulator includes an input integration stage, a resonating stage, a quantizer, and a plurality of feedback paths operably coupled to the quantizer, the input integration stage, and the resonating stage. The input integration stage is operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz. The resonating stage is operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz. The quantizer stage is operably coupled to produce a quantized signal from the resonating digital signal.

1 . A digital delta sigma modulator comprises: 
 an input integration stage operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz;    a resonating stage operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz; and    quantizer stage operably coupled to produce a quantized signal from the resonating digital signal.    
   
   
       2 . The digital delta sigma modulator of  claim 1 , wherein the input integration stage comprises: 
 a digital integrator operably coupled to integrate the digital input signal to produce an integration output; and    a gain module operably coupled to adjust magnitude of the integration output to produce the integrated digital signal.    
   
   
       3 . The digital delta sigma modulator of  claim 2  further comprises: 
 a feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal; and    subtraction module operably coupled to subtract the first feedback signal from an input to produce the digital input signal.    
   
   
       4 . The digital delta sigma modulator of  claim 1 , wherein the resonating stage comprises: 
 a subtraction module operably coupled to subtract a resonating feedback signal from the integrated digital signal to produce a first digital signal;    a first integration stage operably coupled to integrate the first resonating digital signal to produce a first integrated resonating digital signal;    a gain stage operably coupled to adjust magnitude of the first resonating integrated digital signal to produce a second resonating digital signal;    a second integration stage operably coupled to integrate the second resonating digital signal to produce the resonating digital signal; and    a resonating feedback gain module operably coupled to adjust magnitude of the resonating digital signal to produce the resonating feedback signal, wherein frequency of the poles of the resonating circuit is based on digital gain of the gain stage and the resonating feedback gain stage.    
   
   
       5 . The digital delta sigma modulator of  claim 4  further comprises: 
 a first feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal, wherein the subtraction module further subtracts the first back signal from the integrated digital signal to produce the first digital signal;    a second feedback gain module operably coupled to adjust the magnitude of the quantized signal to produce a second feedback signal; and    a second subtraction module operably coupled to subtract the second feedback signal from an output of the gain stage to produce the second resonating digital signal.    
   
   
       6 . The digital delta sigma modulator of  claim 1 , wherein the quantizer comprises: 
 a dither module operably coupled to generate a dither digital signal;    an addition module operably coupled to add the dither digital signal and the resonating digital signal to produce a dithered resonating digital signal; and    a single-bit quantizer operably coupled to produce the quantized signal from dithered resonating digital signal.    
   
   
       7 . The digital delta sigma modulator of  claim 1  further comprises: 
 a second resonating stage operably coupled to resonate the resonating digital signal to produce a second resonating digital signal, wherein the second resonating stage has poles at a frequency above zero Hertz and at different frequencies than the frequencies of the poles of the first resonating stage, and wherein the quantizer stage quantizes the second resonating digital signal to produce the quantized signal.    
   
   
       8 . A fractional-N frequency synthesizer comprises: 
 a phase and frequency detection module operably coupled to produce a difference signal from at least one of phase differences and frequency differences between a reference oscillation and a feedback oscillation;    a charge pump operably coupled to convert the difference signal into a current signal;    a loop filter operably coupled to convert the current signal into a control voltage;    a voltage controlled oscillation module operably coupled to convert the control voltage into an output oscillation;    a feedback module operably coupled to produce the feedback oscillation from the output oscillation, wherein the feedback module includes a multi-modulus divider module and a delta sigma control module, wherein the delta sigma control module includes: 
 an input integration stage operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz;  
 a resonating stage operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz; and  
 quantizer stage operably coupled to produce a quantized signal from the resonating digital signal.  
   
   
   
       9 . The fractional-N frequency synthesizer of  claim 8 , wherein the input integration stage comprises: 
 a digital integrator operably coupled to integrate the digital input signal to produce an integration output; and    a gain module operably coupled to adjust magnitude of the integration output to produce the integrated digital signal.    
   
   
       10 . The fractional-N frequency synthesizer of  claim 9  further comprises: 
 a feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal; and    subtraction module operably coupled to subtract the first feedback signal from an input to produce the digital input signal.    
   
   
       11 . The fractional-N frequency synthesizer of  claim 8 , wherein the resonating stage comprises: 
 a subtraction module operably coupled to subtract a resonating feedback signal from the integrated digital signal to produce a first digital signal;    a first integration stage operably coupled to integrate the first resonating digital signal to produce a first integrated resonating digital signal;    a gain stage operably coupled to adjust magnitude of the first resonating integrated digital signal to produce a second resonating digital signal;    a second integration stage operably coupled to integrate the second resonating digital signal to produce the resonating digital signal; and    a resonating feedback gain module operably coupled to adjust magnitude of the resonating digital signal to produce the resonating feedback signal, wherein frequency of the poles of the resonating circuit is based on digital gain of the gain stage and the resonating feedback gain stage.    
   
   
       12 . The fractional-N frequency synthesizer of  claim 11  further comprises: 
 a first feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal, wherein the subtraction module further subtracts the first back signal from the integrated digital signal to produce the first digital signal;    a second feedback gain module operably coupled to adjust the magnitude of the quantized signal to produce a second feedback signal; and    a second subtraction module operably coupled to subtract the second feedback signal from an output of the gain stage to produce the second resonating digital signal.    
   
   
       13 . The fractional-N frequency synthesizer of  claim 8 , wherein the quantizer comprises: 
 a dither module operably coupled to generate a dither digital signal;    an addition module operably coupled to add the dither digital signal and the resonating digital signal to produce a dithered resonating digital signal; and    a single-bit quantizer operably coupled to produce the quantized signal from dithered resonating digital signal.    
   
   
       14 . The fractional-N frequency synthesizer of  claim 8  further comprises: 
 a second resonating stage operably coupled to resonate the resonating digital signal to produce a second resonating digital signal, wherein the second resonating stage has poles at a frequency above zero Hertz and at different frequencies than the frequencies of the poles of the first resonating stage, and wherein the quantizer stage quantizes the second resonating digital signal to produce the quantized signal.    
   
   
       15 . An integrated radio circuit comprises: 
 a transmitter section operably coupled to convert outbound baseband signals into outbound radio frequency (RF) signals based on a transmit local oscillation;    a receiver section operably coupled to convert inbound RF signals into inbound baseband signals based on a receive local oscillation; and    a local oscillation generation module operably coupled to produce the transmit local oscillation and the receive local oscillation, wherein the local oscillation generation module includes: 
 a phase and frequency detection module operably coupled to produce a difference signal from at least one of phase differences and frequency differences between a reference oscillation and a feedback oscillation;  
 a charge pump operably coupled to convert the difference signal into a current signal;  
 a loop filter operably coupled to convert the current signal into a control voltage;  
 a voltage controlled oscillation module operably coupled to convert the control voltage into an output oscillation, wherein the transmit and receive local oscillations are derived from the output oscillation;  
 a feedback module operably coupled to produce the feedback oscillation from the output oscillation, wherein the feedback module includes a multi-modulus divider module and a delta sigma control module, wherein the delta sigma control module includes: 
 an input integration stage operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz;  
 a resonating stage operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz; and  
 quantizer stage operably coupled to produce a quantized signal from the resonating digital signal.  
 
   
   
   
       16 . The integrated radio circuit of  claim 15 , wherein the input integration stage comprises: 
 a digital integrator operably coupled to integrate the digital input signal to produce an integration output; and    a gain module operably coupled to adjust magnitude of the integration output to produce the integrated digital signal.    
   
   
       17 . The integrated radio circuit of  claim 16  further comprises: 
 a feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal; and    subtraction module operably coupled to subtract the first feedback signal from an input to produce the digital input signal.    
   
   
       18 . The integrated radio circuit of  claim 15 , wherein the resonating stage comprises: 
 a subtraction module operably coupled to subtract a resonating feedback signal from the integrated digital signal to produce a first digital signal;    a first integration stage operably coupled to integrate the first resonating digital signal to produce a first integrated resonating digital signal;    a gain stage operably coupled to adjust magnitude of the first resonating integrated digital signal to produce a second resonating digital signal;    a second integration stage operably coupled to integrate the second resonating digital signal to produce the resonating digital signal; and    a resonating feedback gain module operably coupled to adjust magnitude of the resonating digital signal to produce the resonating feedback signal, wherein frequency of the poles of the resonating circuit is based on digital gain of the gain stage and the resonating feedback gain stage.    
   
   
       19 . The integrated radio circuit of  claim 18  further comprises: 
 a first feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal, wherein the subtraction module further subtracts the first back signal from the integrated digital signal to produce the first digital signal;    a second feedback gain module operably coupled to adjust the magnitude of the quantized signal to produce a second feedback signal; and    a second subtraction module operably coupled to subtract the second feedback signal from an output of the gain stage to produce the second resonating digital signal.    
   
   
       20 . The integrated radio circuit of  claim 15 , wherein the quantizer comprises: 
 a dither module operably coupled to generate a dither digital signal;    an addition module operably coupled to add the dither digital signal and the resonating digital signal to produce a dithered resonating digital signal; and    a single-bit quantizer operably coupled to produce the quantized signal from dithered resonating digital signal.    
   
   
       21 . The integrated radio circuit of  claim 15  further comprises: 
 a second resonating stage operably coupled to resonate the resonating digital signal to produce a second resonating digital signal, wherein the second resonating stage has poles at a frequency above zero Hertz and at different frequencies than the frequencies of the poles of the first resonating stage, and wherein the quantizer stage quantizes the second resonating digital signal to produce the quantized signal.    
   
   
       22 . A radio frequency (RF) transmitter comprises: 
 a phase and frequency detection module operably coupled to produce a difference signal from at least one of phase differences and frequency differences between a modulated input signal and a feedback oscillation;    a charge pump operably coupled to convert the difference signal into a current signal;    a loop filter operably coupled to convert the current signal into a control voltage;    a voltage controlled oscillation module operably coupled to convert the control voltage into radio frequency (RF) signals;    a feedback module operably coupled to produce the feedback oscillation from the RF signals, wherein the feedback module includes a multi-modulus divider module and a delta sigma control module, wherein the delta sigma control module includes: 
 an input integration stage operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz;  
 a resonating stage operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz; and  
 quantizer stage operably coupled to produce a quantized signal from the resonating digital signal.  
   
   
   
       23 . The RF transmitter of  claim 22 , wherein the input integration stage comprises: 
 a digital integrator operably coupled to integrate the digital input signal to produce an integration output; and    a gain module operably coupled to adjust magnitude of the integration output to produce the integrated digital signal.    
   
   
       24 . The RF transmitter of  claim 23  further comprises: 
 a feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal; and    subtraction module operably coupled to subtract the first feedback signal from an input to produce the digital input signal.    
   
   
       25 . The RF transmitter of  claim 22 , wherein the resonating stage comprises: 
 a subtraction module operably coupled to subtract a resonating feedback signal from the integrated digital signal to produce a first digital signal;    a first integration stage operably coupled to integrate the first resonating digital signal to produce a first integrated resonating digital signal;    a gain stage operably coupled to adjust magnitude of the first resonating integrated digital signal to produce a second resonating digital signal;    a second integration stage operably coupled to integrate the second resonating digital signal to produce the resonating digital signal; and    a resonating feedback gain module operably coupled to adjust magnitude of the resonating digital signal to produce the resonating feedback signal, wherein frequency of the poles of the resonating circuit is based on digital gain of the gain stage and the resonating feedback gain stage.    
   
   
       26 . The RF transmitter of  claim 25  further comprises: 
 a first feedback gain module operably coupled to adjust magnitude of the quantized signal to produce a first feedback signal, wherein the subtraction module further subtracts the first back signal from the integrated digital signal to produce the first digital signal;    a second feedback gain module operably coupled to adjust the magnitude of the quantized signal to produce a second feedback signal; and    a second subtraction module operably coupled to subtract the second feedback signal from an output of the gain stage to produce the second resonating digital signal.    
   
   
       27 . The RF transmitter of  claim 22 , wherein the quantizer comprises: 
 a dither module operably coupled to generate a dither digital signal;    an addition module operably coupled to add the dither digital signal and the resonating digital signal to produce a dithered resonating digital signal; and    a single-bit quantizer operably coupled to produce the quantized signal from dithered resonating digital signal.    
   
   
       28 . The RF transmitter of  claim 22  further comprises: 
 a second resonating stage operably coupled to resonate the resonating digital signal to produce a second resonating digital signal, wherein the second resonating stage has poles at a frequency above zero Hertz and at different frequencies than the frequencies of the poles of the first resonating stage, and wherein the quantizer stage quantizes the second resonating digital signal to produce the quantized signal.