Reference signal distribution in multi-module systems

Abstract

Methods and systems for reducing and eliminating the effects of reference signal leakage in multi-module radio-frequency systems, particularly for radio-frequency integrated-circuit devices. Isolation is provided by frequency shifting, by binary phase-shift keying of reference signals to furnish different reference signals with unique signatures to enable separation and discrimination, and by backwards sending of reference signals from receiver to transmitter to avoid contamination of receiver signals by leakage of transmitter reference signals. In addition to improving calibration, methods of the present invention also provide noise reduction in certain multiple-module radio frequency systems.

What is claimed is: 
     
         1 . A method for calibrating a radio-frequency transmitter-receiver system having a transmitter with a transmitted signal, a receiver with a receiver intermediate frequency signal and a local oscillator signal as a reference signal, and a transmitter downconverter, the method comprising:
 downconverting the transmitted signal via the downconverter to a transmitter intermediate frequency signal according to the local oscillator signal;   furnishing the reference signal with a unique signature, allowing the reference signal to be identified;   measuring a phase difference between the receiver intermediate frequency signal and the transmitter intermediate frequency signal; and   calibrating the transmitter-receiver system according to the phase difference.   
     
     
         2 . The method of  claim 1 , wherein the unique signature is applied via frequency-shifting. 
     
     
         3 . The method of  claim 1 , wherein the unique signature is applied via binary phase-shift encoding. 
     
     
         4 . A radio-frequency transmitter-receiver system comprising:
 at least one transmitting module for transmitting a transmitted signal at a shared transmission frequency, and including a transmitter downconverter for downconverting the transmitted signal to a transmitter intermediate frequency signal;   at least one receiving module for receiving the transmitted signal as a received transmitted signal, each at least one receiving module including a local oscillator having a local oscillator signal at a shared local oscillator frequency, for downconverting the received transmitted signal from the shared transmission frequency to an intermediate frequency as a receiver intermediate frequency signal; and   a radio-frequency integrated circuit;   wherein:   each local oscillator signal of the at least one receiving module has a unique signature;   the radio-frequency integrated circuit is operative to:
 identify a local oscillator signal according to the unique signature thereof; 
 measure a phase difference between a receiver intermediate frequency signal and a transmitter intermediate frequency signal according to the unique signature thereof; and 
 calibrate the radio-frequency transmitter-receiver system according to the phase difference. 
   
     
     
         5 . The radio-frequency transmitter-receiver system of  claim 4 , comprising a plurality of transmitting modules and a plurality of receiving modules, wherein the radio-frequency integrated circuit is further operative to separating local oscillator signals according to the respective unique signatures thereof. 
     
     
         6 . The radio-frequency transmitter-receiver system of  claim 4 , wherein a unique signature is applied via frequency-shifting. 
     
     
         7 . The radio-frequency transmitter-receiver system of  claim 4 , wherein a unique signature is applied via binary phase-shift encoding.