THE VODAS 



471 



to find the relation between the delay and the sensitivity required to 

 produce given amounts of clipping of initial sounds. The results are 

 shown for a Type A vodas in Fig. 10. The curves for the syllabic 

 device are similar. The set-up was arranged so that various delays 

 could be inserted in either the transmission circuit (Delay X) or the 

 relay circuit (Delay Y). The left ends of the curves indicate that 

 when delay Y is used, that is, when the net operating time of the 

 relay is great, a point will be reached where no reasonable increase in 



CD "J 



-25 



-10 -5 5 10 



X MINUS Y IN MILLISECONDS 



Fig. 10 — Typical delay vs. sensitivity for certain clipping effects. 



sensitivity is sufficient to prevent intolerable clipping. The value of 

 20 milliseconds of delay X as compared to zero is equivalent to an 

 increase of about 5 db in sensitivity for a given amount of noticeable 

 clipping. 



A reasonable release time is of value in preventing clipping, as it 

 causes the relays to remain operated not only for trailing weak endings 

 of sounds, but also when the energy is temporarily reduced by inter- 

 mediate consonants which may be comparable with noise. Delayed 

 release is also important when it is required to maintain the blocked 

 condition while delayed echoes are being dissipated. For these 



