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iampaul
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" A intelligence signal is amplified by a 80% efficient amplifier before being combined with a 12kW carrier to generate the AM signal. if it is desired to operate at 100% modulation, what is the DC input power at the modulator" The choices are a: 12kW b. 7.14kW c.7.5kW d. 15kW
my solution:
For 100% modulation the modulating signal power must be one half of the carrier power.
Pm=0.5Pc=6kW
Pm is the output of the 80% efficient amplifier.
efficiency=Pout/Pin=Pm/Pin
Pin=Pm/efficiency=6kW/0.8=7.5kW
Is this right?
How do I solve problems like this? Sometimes i do the same procedure for a similar question but with different values, but I get a wrong answer. Can you suggest a good reference. I am currently using the electronics communications books by frenzel and blake
my solution:
For 100% modulation the modulating signal power must be one half of the carrier power.
Pm=0.5Pc=6kW
Pm is the output of the 80% efficient amplifier.
efficiency=Pout/Pin=Pm/Pin
Pin=Pm/efficiency=6kW/0.8=7.5kW
Is this right?
How do I solve problems like this? Sometimes i do the same procedure for a similar question but with different values, but I get a wrong answer. Can you suggest a good reference. I am currently using the electronics communications books by frenzel and blake