Wireless communication receiver

Abstract

A wireless communication receiver that is able to lessen the effect of noise that accompanies gain change by programmable gain amplifiers. The receiver includes an AGC controller which controls the timing at which the programmable gain amplifiers make gain change, using a terminal counter and a sequencer. The receiver prevents gain change noise signals during the reception of control signals and other signals that are susceptible to noise. By the timing control feature, the programmable gain amplifiers make gain change while reducing noise impact.

1 . A method for controlling gain change timing of a programmable gain amplifier for a wireless communication receiver, the method comprising steps of: 
 detecting slot synchronization at a start of speech or a data flow;    sending a synchronization signal to a sequencer; and    controlling a timing at which a portion including the programmable gain amplifier makes gain change with using a terminal counter.    
     
     
         2 . The method for controlling gain change timing according to  claim 1 , wherein, if slot synchronization is detected, then the terminal counter starts via the sequencer and counts time elapse from a beginning of a slot format, and the sequencer gets information about the slot format to select the gain change timing corresponding to the slot format in which the wireless communication receiver is receiving.  
     
     
         3 . The method for controlling gain change timing according to  claim 2 , wherein the wireless communication receiver comprises: 
 a first mixer for converting received signals to a predetermined baseband frequency by down converting the signals once; and    a first programmable gain amplifier, which is connected in series to the first mixer at the following stage, and has a gain adjustment function that enables gain change in discrete gains.    
     
     
         4 . The method for controlling gain change timing according to  claim 3 , wherein said wireless communication receiver includes a circuit for reducing noise that is generated by discrete gain changing in said first programmable gain amplifier because of their DC offsets.  
     
     
         5 . The method for controlling gain change timing according to  claim 4 , wherein said circuit for reducing noise is a timing control circuit which controls gain change timing for reducing noise that is generated by discrete gain changing in said first programmable gain amplifier because of their DC offsets.  
     
     
         6 . The method for controlling gain change timing according to  claim 5 , wherein said first programmable gain amplifier is connected to a mixer at the following stage amplifier has a function of suppressing noise that accompanies gain change.  
     
     
         7 . The method for controlling gain change timing according to  claim 5 , wherein said received signals are formatted in a predetermined frame structure and received without intermittence and said timing control circuit exerts control so that said programmable gain amplifier makes a gain change at timing when a specific signal that is strong to noise impact by being error corrected in said frame structure is received.  
     
     
         8 . The method for controlling gain change timing according to  claim 5 , wherein said received signals are formatted in a predetermined frame structure and received without intermittence and said timing control circuit exerts control so that said programmable gain amplifier makes a gain change at random timing of receiving a signal within said frame structure to reduce probability of changing gain during receiving a weak signal to noise impact.  
     
     
         9 . The method for controlling gain change timing according to  claim 5 , wherein said received signals are formatted in a predetermined frame structure and received without intermittence and said timing control circuit includes a device for measuring time in synchronization with said frame structure and a device for storing said frame structure and exerts control so that the programmable gain amplifier make gain change out of timing when a specific signal that is strong to noise impact by being error corrected in the frame is received to reduce the noise that is generated by discrete gain changing in said first programmable gain amplifier because of their DC offsets.  
     
     
         10 . The method for controlling gain change timing according to  claim 5 , wherein said received signals are formatted in a predetermined frame structure and received without intermittence and said timing control circuit exerts control so that the frequency of gain change by said first programmable gain amplifier that is connected to mixer at the following stage is reduced by providing said first programmable gain amplifier with a hysteresis characteristic.  
     
     
         11 . The method for controlling gain change timing according to  claim 6 , wherein said first programmable gain amplifier having the function of suppressing noise that accompanies gain change includes first and second transistors which form a differential pair, wherein the emitters of the first and second transistors are connected via a capacitor to reduce the noise that is generated by discrete gain changing in said first programmable gain amplifier because of their DC offsets.  
     
     
         12 . The method for controlling gain change timing according to  claim 11 , wherein, in said first programmable gain amplifier, the collector of said first transistor and the collector of said second transistor are connected via a capacitor to reduce the noise that is generated by discrete gain changing in said first programmable gain amplifier because of their DC offsets.