Wide-band automatic gain-controlled amplifier

Claim 1

A WIDE-BAND AUTOMATIC GAIN-CONTROLLED TRANSISTOR AMPLIFIER COMPRISING A PLURALITY OF TRANSISTOR AMPLIFYING STAGES EACH HAVING INPUT AND OUTPUT TERMINALS, A PLURALITY OF VARIABLE ATTENUATORS EACH ARRANGED BETWEEN AN ADJACENT PAIR OF SAID AMPLIFYING STAGES, EACH CONNECTED BETWEEN THE OUTPUT OF THE PRECEDING STAGE AND THE INPUT OF THE FOLLOWING STAGE, AND EACH HAVING AT LEAST ONE ARM CONTAINING A NON-LINEAR ELEMENT AND A RESISTANCE CAPACITOR NETWORK PRESENTING SUBSTANTIALLY THE SAME FREQUENCY RESPONSE AT THE MINIMUM AND MAXIMUM ATTENUATION LEVELS OF SAID ATTENUATOR; AND SIGNAL LEVEL DETECTING MEANS CONNECTED FROM THE OUTPUT OF THE LAST ONE OF SAID STAGES TO ONE SIDE OF EACH NON-LINEAR ELEMENT FOR INCREASING THE ATTENUATION OF EACH ATTENUATOR IN ACCORDANCE WITH THE OUTPUT FROM SAID LAST STAGE, THE ATTENUATION INTRODUCED BY THE ATTENUATOR LAST IN THE DIRECTION OF TRANSMISSION BEING INCREASED FROM ITS MINIMUM TO ITS MAXIMUM WITH INCREASING SIGNAL LEVEL AND THE ATTENUATION INTRODUCED BY EACH SUCCESSIVE PRECEDING ATTENUATOR BEING INCREASED FROM ITS MINIMUM TO ITS MAXIMUM WITH FURTHER INCREASE IN SIGNAL LEVEL WHEREBY AT ANY GIVEN SIGNAL LEVEL ONLY ONE OF THE ATTENUATORS IS OPERATIVE TO VARY THE GAIN.