THE TYPE PI CARRIER SYSTEM 



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used not only in all the channel, demodulator, and signaling filters in 

 the terminal and in the directional filters at the repeater, but also in the 

 channel oscillators and other parts of the circuitry where an inexpensive, 

 adjustable element offered manufacturing or service advantages. 



4.3 Capacitors 



Most of the wide-limit capacitors used in the filters are of the com- 

 mercially available molded mica type. Where the capacitance values 

 would require large and expensive mica units both in filters and other parts 

 of the circuit, newly available foil-Mylar capacitors were used. These take 

 the form of very small pigtail units in a range of physical sizes similar 

 to those of the solid tantalum capacitors described below. The Mylar 

 capacitors have low working voltages in these miniature sizes and can 



Fig. 12 — Prototype solid tantalum capacitors for PI carrier. 



