. Elements of radio telephony . Fig. 46.—Electrodynamic type of loud speaker. signal. The coil on the transformer with the larger numberof turns is connected in place of the radio receiver, and theone with the smaller number is connected to the moving efficient operation is desired the last stage of theamplifier should contain a power tube operated atits normal plate voltage. The electrodynamic receiver iscapable of handhng an output of several watts efficiently. 96 ELEMENTS OF RADIO TELEPHONY and the signal must be amplified accordingly if maximumresponse is desired. Push-pull Ampl
. Elements of radio telephony . Fig. 46.—Electrodynamic type of loud speaker. signal. The coil on the transformer with the larger numberof turns is connected in place of the radio receiver, and theone with the smaller number is connected to the moving efficient operation is desired the last stage of theamplifier should contain a power tube operated atits normal plate voltage. The electrodynamic receiver iscapable of handhng an output of several watts efficiently. 96 ELEMENTS OF RADIO TELEPHONY and the signal must be amplified accordingly if maximumresponse is desired. Push-pull Amplifier Connection.—In order to avoid theusual serious distortion of speech and music when highamphfication is employed the push-puU circuit has beendevised. While some of the distortion may usually betraced to improperly operating loud speaking devices a con-. inputcircuit to loudSpeaker: Fig. 47.—Push-pull amplifier circuit. siderable proportion is due to the distorting effects of thetubes themselves. This connection which is illustrated inFig. 47 requires special transformers with double windingsand eliminates most of the tube distortion by increasingthe plate current in one tube while it is decreasing the platecurrent in the other, and when the effects of the two currentsare taken together they give a response exactly proportional-to the grid voltage. Where the signals are weak the ordinary RECEIVING EQUIPMENT 97 single-tube connection gives satisfactory results but afterthey have been amplified up through several stages sometype of distortionless connection must be used in the laststages if clear signals are to be obtained from the loudspeaker. CHAPTER VIITRANSMISSION Antenna and Ground Systems.—The function of thetransmitting antenna is to change the electric power pro-duced by the radio transmitter into electromagnetic wavesand to
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradio, bookyear1922
