Detector system with adjustable phase stage

Abstract

A detector system has a local oscillator port, a radio frequency port, and an oscillator providing a local oscillator signal having amplitude-modulated (“AM”) noise coupled. A first detector detects the local oscillator signal and produces a first detected signal having a first detected AM noise signal component and a demodulated signal component at a first phase. A second detector detects a second high-frequency signal to produce a second detected signal having a second detected AM noise signal component at a second phase. An algebraic combining network combines the first detected signal and the second detected signal to produce a demodulated signal component at an output. A phase delay disposed between the local oscillator and the output of the algebraic combining network is calibrated to offset the first phase from the second phase to improve signal-to-noise ratio at the output.

1 . A detector system comprising:
 a local oscillator port;   a radio frequency port;   an oscillator providing a local oscillator signal having amplitude-modulated (“AM”) noise coupled to the local oscillator port;   a first detector configured to detect at least the local oscillator signal to produce a first detected signal having at least a first detected AM noise signal component and a demodulated signal component at a first phase;   a second detector configured to detect a second high-frequency signal having the AM noise to produce a second detected signal having at least a second detected AM noise signal component at a second phase;   an algebraic combining network combining the first detected signal and the second detected signal to produce an output signal including the demodulated signal component at an output; and   a phase delay disposed between one of the local oscillator port and the radio frequency port and the output of the algebraic combining network calibrated to offset the first phase from the second phase to improve signal-to-noise ratio at the output.   
     
     
         2 . The detector system of  claim 1  wherein the local oscillator signal is at a selected local oscillator signal level and the phase delay is calibrated at the selected local oscillator signal level. 
     
     
         3 . The detector system of  claim 1  further comprising a high-frequency combining network, wherein the phase delay is disposed in a radio frequency path of the high-frequency combining network. 
     
     
         4 . The detector system of  claim 1  further comprising a high-frequency combining network, wherein the phase delay is disposed in a local oscillator path of a high-frequency combining network. 
     
     
         5 . The detector system of  claim 1  wherein the phase delay is disposed between the first detector and the output of the algebraic combining network. 
     
     
         6 . The detector system of  claim 1  wherein the phase delay is disposed between the second detector and the output of the algebraic combining network. 
     
     
         7 . The detector system of  claim 1  further comprising a second phase delay calibrated to improve signal-to-noise ratio at the output