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mark, then subsequent indications show the degree of modulation 

 under actual operating conditions. In the interests of best operation, 

 it may be desirable, of course, to adjust the system for somewhat less 

 than complete modulation when the 100 per cent indication is reached. 

 In any event, the indications on the voltage scale always show the 

 percentage utilization of the channel. This is a decided advantage be- 

 cause everyone involved has a clear conception of a percentage indica- 

 tion. Furthermore, since the scale does not extend beyond the 100 



Fig. 15 — Type of scale used on IG and 700A volume indicators. 



per cent mark (except in the form of a red warning band) and since it 

 is impossible to obtain more than 100 per cent utilization of the 

 facilities, there is no incentive on the part of non-technical people 

 connected with program origination to request an extra loud "effect" 

 on special occasions. 



Actually, two scales, each containing both vu and voltage markings, 

 have been devised. One of these, known as the type A scale, Fig. 16, 

 emphasizes the vu markings and has an inconspicuous voltage scale. 

 The second, known as the type B, Fig. 17, reverses the emphasis on 



