Homework 1 Assignment 1
1 Define modulation?
The process of putting information onto a high frequency carrier for transmission.
2 What is carrier frequency? Carrier frequency is used to designate the nominal frequency of a carrier wave and the center frequency of a frequency modulation signal.
3 Name two reasons modulation is used in communications?
The human voice ranges from 20 Hz to 3000 Hz, if these were transmitted directly as radio waves, the signal would be useless. Because of interference from each signal. Low frequency signals are hard to transmit. It would require many miles of antennas to transmit.
4 List parameters of a high frequency carrier varied by low frequency intelligence signal?
Peak value
Angular velocity
Phase angle
5 What are the frequency ranges of MF, HF, VHF, UHF, and SHF?
Medium Frequency (MF) 300kHz-3MHz
High Frequency (HF) 3MHz-30MHz
Very High Frequency (VHF) 30MHz-300MHz
Ultra High Frequency (UHF) 300MHz-3GHz
Super High Frequency (SHF) 3GHz-30GHz
7 A microwave transmitter typically requires a +8dBm level to drive an input fully. What is the actual voltage measured if +10dBm? Assume 600 ohm system. (2.45 V) = 10
9 Convert powers to dBM equivalents.
= -10 dBM
15. Define electrical noise?
Any undesired voltages or currents that ultimately end up appearing in the receiver output often called static.
16. Describe external and internal noise?
External noise is human made noises. Produced by spark mechanism such as an engine or fluorescent light. Internal noise is noise in a radio signal that has been introduced by a receiver.
23 Calculate S/N ratio for a receiver output of 4 V signal and .48 V noise both as ratio and decibel form?
27 Calculate input and output noise voltages? =1.1µV
Pg = 40dB + 8dB
Pg =48 dB
37 Define information theory?
The optimization of transmitted in formation, that uses a theoretical method of analysis.
38 What is Hartley’s Law, explain its
The process of putting information onto a high frequency carrier for transmission.
2 What is carrier frequency? Carrier frequency is used to designate the nominal frequency of a carrier wave and the center frequency of a frequency modulation signal.
3 Name two reasons modulation is used in communications?
The human voice ranges from 20 Hz to 3000 Hz, if these were transmitted directly as radio waves, the signal would be useless. Because of interference from each signal. Low frequency signals are hard to transmit. It would require many miles of antennas to transmit.
4 List parameters of a high frequency carrier varied by low frequency intelligence signal?
Peak value
Angular velocity
Phase angle
5 What are the frequency ranges of MF, HF, VHF, UHF, and SHF?
Medium Frequency (MF) 300kHz-3MHz
High Frequency (HF) 3MHz-30MHz
Very High Frequency (VHF) 30MHz-300MHz
Ultra High Frequency (UHF) 300MHz-3GHz
Super High Frequency (SHF) 3GHz-30GHz
7 A microwave transmitter typically requires a +8dBm level to drive an input fully. What is the actual voltage measured if +10dBm? Assume 600 ohm system. (2.45 V) = 10
9 Convert powers to dBM equivalents.
= -10 dBM
15. Define electrical noise?
Any undesired voltages or currents that ultimately end up appearing in the receiver output often called static.
16. Describe external and internal noise?
External noise is human made noises. Produced by spark mechanism such as an engine or fluorescent light. Internal noise is noise in a radio signal that has been introduced by a receiver.
23 Calculate S/N ratio for a receiver output of 4 V signal and .48 V noise both as ratio and decibel form?
27 Calculate input and output noise voltages? =1.1µV
Pg = 40dB + 8dB
Pg =48 dB
37 Define information theory?
The optimization of transmitted in formation, that uses a theoretical method of analysis.
38 What is Hartley’s Law, explain its