&
THE IF SHIFT SYSTEM ALLOWS THE ACTUAL PASSBAND TO BE MOVED HIGHER OR LOWER IN FREQUENCY COMMA ELIMINATING INTERFERENCE THAT IS ENCOUNTERED OUTSIDE THE PASSBAND COMMA WHILE LEAVING THE PITCH OF THE INCOMING SIGNAL AND THE BANDWIDTH OF THE IF PASSBAND UNCHANGED STOP YOU CAN ALSO IMPROVE RECEPTION BY CHOOSING TO NARROW THE BANDWIDTH OF THE IF WIDTH FUNCTION AND THEN VARYING THE PASSBAND WITH THE IF SHIFT STOP  +