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Sample Problem: Calculate the total power and the power in each side frequency for a standard AM transmission that is sinusoidally modulated to a depth of 80% if the unmodulated carrier power is 50 kW.
Self-Sufficient Guide to ECE by JASON AMPOLOQUIO1-47 Sample Problem: Calculate the amplitude and resulting side frequency if a carrier wave of frequency 10 MHz with a peak value of 10 V is amplitude modulated by a 5 kHz sine wave of amplitude 6 V. Solution: ()MHz9.995andMHz10.005fV,3V:AnswerV32100.62mVVlitude;ampForMHz9.995andMHz10.005MHz0.005MHz10fffFrequency;SideFor0.6106VVmm;ForsideSBcSBmcsidecm======±=±====Sample Problem: The output voltage of an AM transmitter is 40 V when sinusoidally modulated to a depth of 100%. Calculate the voltage at each side frequency when the modulation depth is reduced to 50%.
AMPLITUDE MODULATION 1-48 E..SUPPRESSED-CARRIER AM SYSTEM. 1.Double-Sideband Suppressed-Carrier (DSB-SC) General Solution of Double Sideband Suppressed Carrier (DSB-SC) cccmcmmVmV(t)cos2 (ff )tcos2 (ff )t22ν= −π++π−Read it till it Hertz…jmaªThe maximum bandwidth of an AM wave is twice of the maximum modulating frequency. ªThe total power in an AM signal increases with modulation, reaching a value of 50%greater than that of the unmodulated carrier at 100% modulation. ªThe extra power with modulation goes into the sidebands; the carrier power does not change with modulation. ªThe useful power, that is, the power that carries the information, is rather small reaching a maximum of one-third of the total signal power at 100% modulation.
Self-Sufficient Guide to ECE by JASON AMPOLOQUIO1-49 Parameter General Solution Transmit Power2cTm PP2=Sideband Power 2cUSBLSBm PPP4==Transmit Voltage cTmVV2=Transmit Current cTmII2=ECE Board Exam: NOV 2004 A DSB-SC system must suppress the carrier by 50 dB from its original value of 10 W. To what value must the carrier be reduced?
AMPLITUDE MODULATION 1-50 Parameter General Solution Transmit Power2cTcm PPP4=+Sideband Power 2cUSBLSBm PPor P4=Transmit Voltage 2TcmVV14=+Transmit Current 2TcmII14=+ECE Board Exam:NOV 2004 Assuming 100% modulation H3E system, what would be the transmitted power in the remaining sideband of an AM signal if the carrier power is 1000 watts?