. The Bell System technical journal . Fig. 6—-Front \icw of Transmitter Panel with Cover Reniovecl from TuningCondensers being obtained from filament drop, H battery drop and a com-bination_of these two. l_^The transmitting unit shown in Figs, (i and 7 is divided into twoparts, the transmitting circuit proper and the power amplifier. Thefirst is a circuit comprising a 101-D tube functioning as a Hartle\- 160 BELL SYSTEM TECHSICAL JOURNAL oscillator with indiulixc fied-back, a 223-A tube operating as aspeech am])lifier or modulator and a 223-A tube operating as a highfrequency anii)lifier. The
. The Bell System technical journal . Fig. 6—-Front \icw of Transmitter Panel with Cover Reniovecl from TuningCondensers being obtained from filament drop, H battery drop and a com-bination_of these two. l_^The transmitting unit shown in Figs, (i and 7 is divided into twoparts, the transmitting circuit proper and the power amplifier. Thefirst is a circuit comprising a 101-D tube functioning as a Hartle\- 160 BELL SYSTEM TECHSICAL JOURNAL oscillator with indiulixc fied-back, a 223-A tube operating as aspeech am])lifier or modulator and a 223-A tube operating as a highfrequency anii)lifier. The |)latc or constant current system of modu-lalinn is emploxed but dilTers somewhat from the usual practice in. Iig. 7—Rear View of Trdnsmiiu-r Idiiel with Co\tT Kcmovcd that the ouljiut of the high fie(|uency amplifier is modulated ralherthan the output of the oscillator itself. This scheme was found todelixer more modulated jxiwer than the usual arrangement since itis not limited to the same extent by the oxerloading of the higii fre-(|uency amplifier. This circuit has a power output of one watt, whichhas i)ro\e(l to be ample f(jr normal o|)eration (jf the carrier system. ()\y (K\ iiiaii i-oLucr. \m To providi- Inr (>|Hr,iti(iii dI tlii s\>trm wlu-n ilu- . is pro\i(lf(l. This aniplilii-r employs a 50 watt tula-1211-A) and is placed in the eircuit i)y a simple swiichinjj o() this amplifier is operated, the output of the iransitiitlinji circuitis impressed upon the j;rid of the 50 watt tuhe and ampiilud to aj)-proximately fift>
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
