AMPLITUDE RANGE CONTROL 



537 



TABLE II 

 Comparison of Nomenxlature for Range Controllers 



Col. (1) 

 Arbitrary ^ 



1. Vogad 



2. Vogad Combined with 



Syllabic Compressor 



3. Volume Limiter 



4. Compandor 



5. Noise Reducer 



6. Limited Range Com- 



pressor 



7. Peak Limiter 



8. Peak Chopper 



9. Crosstalk Suppressor 



10. Rooter and Inverse 

 Rooter 



n. Vodas (Singing Sup- 

 pressor Relay) 



12. SvUabic Vodas 



Col. (2)_ 

 Systematic 

 Full Range 45 db 



Volume Compressor 

 Full Range 45 db 



Volume Compressor 

 High Range 15 db 1 : 5 



Volume Compressor 

 Full Range 60 db 2 : 1 



Syllabic Compandor 

 Low Range 20 db 2 : 1 



Syllabic Expander 

 High Range 10 db 1 : 2 



Instantaneous Compressor 

 High Range 12 db 1 : 5 



Syllabic Compressor 

 Hi^h Range 6 db 1 : 100 



Instantaneous Compressor 

 Low Range 10 db 10 : 1 



Instantaneous Expandor 

 Full Range 70 db 2 : 1 



Instantaneous Compandor 



Col. (3) 

 Symbolic 

 45 F5/ 23-18 

 Compressor 

 45 F55/ 23-18 



Compressor 

 15 VS Compressor 



6052 Compandor 



2052 Expandor 



1072 Compressor 



1255 Compressor 



6/100 Compressor 



10710 Expandor 



7072 Compandor 



07 so Expandor 



05=0 Expandor 



only when the waves acting on it differ from those just received. This 

 condition sets a new requirement on the range controller which can 

 usually be met by a combination of control circuits. 



A biased controller is one which returns to a setting corresponding 

 to some fixed or biased intensity when speech is not passing and adjusts 

 itself each time speech begins. A simple compressor is biased since 

 with no input it generally takes a setting of maximum gain so as to be 

 right for the weakest waves that might be applied in its working range 

 or below the working range. It is also possible to bias a range control- 

 ler so as to have minimum gain, or any other intermediate value when 

 no waves are applied. An important secondary characteristic is the 

 rate at which the device returns to the desired "bias" point. 



Any of the devices listed in the tables might be neutral or biased in 

 either direction, thus increasing the number of possible arrangements. 



2. Behavior Outside of Range 



For inputs outside the working range of a range controller it is 

 important to provide that the amplification of these waves does not 

 cause them to be modified so as to be out of proportion to output 

 signals in the main range. In some cases this is met by choosing a 

 device which follows the same law all the way to zero current. In 

 others, the device may act as a linear transducer, i.e., with range 



