System and method for dynamic amplitude adjustment of modulating signal in frequency modulated transceivers

Abstract

A system and method for dynamically optimizing occupied bandwidth of a direct modulated FM radio is disclosed, in which a remote receiver periodically monitors the received output of a local transmitter and compares the received output occupied bandwidth to a reference level. If the monitored level of the demodulated signal unacceptably exceeds the reference level an error message is developed and sent back to the local transmitter to cause the output of the local transmitter to be adjusted to more closely conform to the desired spectrum output mask. An alternative embodiment is also disclosed in which temperature and operating frequency are monitored at the local transmitter and a correction factor appropriate for that operating temperature and frequency are applied.

What is claimed is:  
     
         1 . A method for optimizing transmitter output of a digital microwave radio including the steps of 
 monitoring the output of the transmitter,    generating a correction signal in response to the monitored output,    summing the correction signal with a conventional signal to conform the transmitter output to a predetermined mask, and    repeating the monitoring, generating and adding steps periodically.    
     
     
         2 . A method for optimizing transmitter output of a digital microwave radio including the steps of 
 monitoring a characteristic of the transmitter,    generating a correction signal in response to the monitored characteristic,    summing the correction signal with a conventional signal to conform the transmitter output to a predetermined mask, and    repeating the monitoring, generating and adding steps periodically.    
     
     
         3 . The method of    claim 2    in which the monitored characteristic is temperature.  
     
     
         4 . The method of    claim 2    in which the monitored characteristic is the transmitter output occupied bandwidth.  
     
     
         5 . A method for optimizing transmitter output of a digital microwave radio including the steps of 
 monitoring at a remote receiver the output of the transmitter,    generating an error message in response to the monitoring step,    developing a correction signal in accordance with the error message, and    adding the correction signal to the transmitter FM modulator occupied bandwidth to conform the transmitter occupied bandwidth to a predetermined mask.    repeating the monitoring, generating, developing and adding steps periodically.    
     
     
         6 . In a digital microwave radio having an outdoor unit and operating at a preselected frequency band, a method for optimizing transmitter output including the steps of 
 monitoring the temperature of the outdoor unit,    selecting, from a lookup table, a correction factor corresponding to the monitored temperature and operating frequency band,    generating a correction signal in response to the correction factor, and    adding the correction signal into the transmitter to optimize transmitter output occupied bandwidth.    
     
     
         7 . A digital microwave radio having transmitter and receiver portions comprising 
 a bandwidth monitoring circuit for detecting the bandwidth transmitted from a remote radio,    error logic for developing a digital error message representative of the difference between the monitored bandwidth and a reference value,    a feedback circuit for providing the digital error message to the remote radio, and    amplifier means for adjusting the output bandwidth in response to the digital error message.