1180 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER, 1953 



10^ 10-2 10" 



PRODUCT OF RMS INPUT VOLTAGES (VOLTS X VOLTS) 



Fig. 5 — Performance curves of multiplier. 



of r increases in small steps from to 1.5 ms in 5/3 sec. and therefore 

 can be approximated by r = hi, where h = .0015/(5/3) = 0.0009. 

 Hence the lowest product frequency is roughly 1600 X 0.0009 = 1.44 cps. 

 The actual low frequency cutoff of the amplifier is made about 0.1 cps 

 to allow for changes in the signal components and to preserve good trans- 

 mission within the nominal band. The upper cutoff frequency is likewise 

 made somewhat higher than the nominal value of 32,000 X 0.0009 

 = 28.8 cps. 



The integration is performed by a series condenser and shunt resistance 

 at the amplifier output. A good approximation to integration is accom- 

 plished by a large time constant such that the indicial admittance 



