Topics: Radio, Frequency modulation, Amplitude modulation Pages: 3 (697 words) Published: September 10, 2011
QUIZ # 2
ECP433L1

Direction: Rewrite the following questions in Engineering Lettering before answering. This will be send by 10:30 am.. Therefore call time for papers is 4.30 in the afternoon. Scan or photos of the papers will be send in my email. Thanks

PS..

1. Determine the percent modulation of an AM for the following conditions if the unmodulated carrier is 80 V peak to peak.  | Maximum P-P carrier| Minumum P-P carrier|
(a)| 100| 60|
(b)| 125| 35|
(c)| 160| 0|
(d)| 180| 0|
(e)| 135| 35|

2. Determine the maximum sideband power if the carrier output is 1 kW and calculate the total maximum transmitted power. 3. A 500 W carrier is to be modulated to 90% level. Determine the total transmitted power. 4. An AM broadcast station operates at its maximum allowed total output power of 50 kW and at 95% modulation. How much of its transmitted power (sidebands)? 5. The antenna current of an AM transmitter is 12 A when unmodulated but increases to 13 A when modulated. Calculate the percent modulation. 6. An intelligence signal is amplified by a 70% efficient amplifier before being combined with a 10 kW carrier to generate the AM signal. If it is desired to operste at 100% modulation, what is the input power to the final intelligence amplifier? 7. A transmitter with a 10 kW carrier transmits 11.2 kW when modulated with a single sine wave. Calculate the modulation index. If the carrier is simultaneously modulated with another sine wave at 50% modulation , calculate the transmitted power. 8. An AM transmitter at 27 MHz develops 10W of carrier power into a 50 ohm load. It is modulated by a 2 KHz sine wave between 20 and 90% modulation. Determine a. Component frequencies in the AM signal

b. Maximum and minimum waveform voltage of the AM signal at 20% and 90% modulation. c. Sideband signal voltage and power at 20% and 90% modulation d. Load current at 20% and 90% modulation

9. An AM transmitter...