. The Bell System technical journal . TUNING-STUB Fig. 13—The main wave guide of Fig. 12 removed from the rest of the equipment 60 GAS-DISCHARGE TRANS MIT-RECEIVE SWITCH 61 turn coupled to the TR cavity by another window. The input and outputwindows of the TR cavity are adjusted in size to provide an impedancematch to the line during the receiving period. Tlie window to the ATRis, however, adjusted so that it presents a high impedance, that is muchgreater than the surge impedance, during the receiving period. This highimpedance is effectively in series with the magnetron impedance. Theresultin
. The Bell System technical journal . TUNING-STUB Fig. 13—The main wave guide of Fig. 12 removed from the rest of the equipment 60 GAS-DISCHARGE TRANS MIT-RECEIVE SWITCH 61 turn coupled to the TR cavity by another window. The input and outputwindows of the TR cavity are adjusted in size to provide an impedancematch to the line during the receiving period. Tlie window to the ATRis, however, adjusted so that it presents a high impedance, that is muchgreater than the surge impedance, during the receiving period. This highimpedance is effectively in series with the magnetron impedance. Theresulting high impedance is located at an odd number of quarter wavelengthsfrom the TR and so presents a ver> low impedance in series with the receivingbranch. ATR BOX CLAMP TR BOX CLAMP ATR BOX DISMOUNTEDFROM MAIN WAVE. TR BOX OSASSEMB-ED Fig. 14—An exploded view of Fig. 13 Both the TR box and the ATR box must be tuned to resonance at themagnetron frequency. Broad-band ATR boxes using very low Q circuitshave been designed which require no adjustment over a 5% band. Suchboxes, which obviously are very advantageous in tunable systems, do notuse the copper-disc-seal tubes which form the principal subject matter of thepresent paper, and will not be discussed further. TR Box Performance The performance of a TR box can be described in terms of four parameterswhich are related to the four duplexing requirements mentioned parameters are respectively: (1) the high level loss, which is the trans-mitting power loss in the TR tube; (2) the leakage power, which is theamount of transmitter power which reaches the receiver; (3) the recoverytime, which measures the rate at which the TR box recovers its low level 62 BELL SYSTEM TECHNICAL JOURNAL behavior after the termination of the transmitting perio
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