01
ноя
Power density is the single most important operating parameter for transmitting earth stations and probably the least understood by operators of satellite communication terminals. In this two-part article, we will define what power density is, the role it plays in the design of satellite networks and the licensing of satellite terminals, how easy it is to exceed the regulatory limit and the problems that result and, finally, what we can do to reduce these problems to an acceptable level. Most terminal operators can tell you how much power they are transmitting and what data rates they are achieving up and down.
Cross Power Spectral Density. Crosscorrelation and CPSD of Two Random Signals Plus Narrowband Interference. Measurement of Power Spectral Density. A natural idea for estimating the PSD of an ergodic stochastic. CT process is to start with the definition. This will give you the Power spectral density for your frame X. Now take the next frame and do the same, And when you reach a number of frames that you would like to plot, you stop and plot your vectors.
This is good information to know, but it is not good enough to ensure that the terminal is operating at its best and within regulatory limits. The official document issued by the satellite operator or regulatory agency that authorizes a terminal to transmit specifies its maximum allowed power density. Operating a terminal without knowing the current value of this critical parameter can lead to two very negative results: (1) self-interference due to transponder overload and (2) excessive interference with other users on the same and neighboring satellites. Either of these outcomes, especially number (2), could lead to the temporary or permanent revocation of a terminal’s license to transmit. Power density figures prominently in the license that every transmitting earth station must obtain in order to operate. Unfortunately, the license document typically offers no guidance regarding what the specified maximum power density value means in terms that operators are familiar with, such as High-Power Amplifier / Block Up-Converter (HPA/BUC) power level and signal parameters such as data rate and modulation type.
Very few terminals directly monitor or control power density, but almost all allow the operator to change it. For that reason, it is relatively easy for the operator to unintentionally turn his fully compliant and approved terminal into a very effective source of interference on his, and other, satellite communication systems.
What is Power Density? Simply put, power density describes how the transmit power in a communications signal is distributed over frequency. It is expressed in terms of power divided by a relatively small unit of bandwidth (e.g. DBW/4kHz) and is usually referenced to the input of the satellite terminal’s antenna. The unit dBW, or dB-Watts, is the universally accepted way of expressing power on a log10 scale (dBW = 10 log10 [PWatts]). Bandwidth is a factor since all satellite signals spread their power across a range of frequencies. The speed at which digital information flows is the data rate of the signal.
In general, as the data rate of a signal increases, so does the range of frequencies occupied by that signal. Assuming total power in the signal is constant; increasing the data rate will spread power over a wider range of frequencies and decrease power density. The inverse is also true. Figure 1 shows the power spectrums of several data signals.
All use the same waveform (modulation and coding). As you can see in the figure, a simple change to data rate can make a substantial change in power density and lead to operation well above or below the power density target / limit. Power density figures prominently in the design of a satellite network that must make optimal use of its assigned transponder or bandwidth (portion of a transponder) on the satellite.
Popular Posts
Power density is the single most important operating parameter for transmitting earth stations and probably the least understood by operators of satellite communication terminals. In this two-part article, we will define what power density is, the role it plays in the design of satellite networks and the licensing of satellite terminals, how easy it is to exceed the regulatory limit and the problems that result and, finally, what we can do to reduce these problems to an acceptable level. Most terminal operators can tell you how much power they are transmitting and what data rates they are achieving up and down.
Cross Power Spectral Density. Crosscorrelation and CPSD of Two Random Signals Plus Narrowband Interference. Measurement of Power Spectral Density. A natural idea for estimating the PSD of an ergodic stochastic. CT process is to start with the definition. This will give you the Power spectral density for your frame X. Now take the next frame and do the same, And when you reach a number of frames that you would like to plot, you stop and plot your vectors.
This is good information to know, but it is not good enough to ensure that the terminal is operating at its best and within regulatory limits. The official document issued by the satellite operator or regulatory agency that authorizes a terminal to transmit specifies its maximum allowed power density. Operating a terminal without knowing the current value of this critical parameter can lead to two very negative results: (1) self-interference due to transponder overload and (2) excessive interference with other users on the same and neighboring satellites. Either of these outcomes, especially number (2), could lead to the temporary or permanent revocation of a terminal’s license to transmit. Power density figures prominently in the license that every transmitting earth station must obtain in order to operate. Unfortunately, the license document typically offers no guidance regarding what the specified maximum power density value means in terms that operators are familiar with, such as High-Power Amplifier / Block Up-Converter (HPA/BUC) power level and signal parameters such as data rate and modulation type.
Very few terminals directly monitor or control power density, but almost all allow the operator to change it. For that reason, it is relatively easy for the operator to unintentionally turn his fully compliant and approved terminal into a very effective source of interference on his, and other, satellite communication systems.
What is Power Density? Simply put, power density describes how the transmit power in a communications signal is distributed over frequency. It is expressed in terms of power divided by a relatively small unit of bandwidth (e.g. DBW/4kHz) and is usually referenced to the input of the satellite terminal’s antenna. The unit dBW, or dB-Watts, is the universally accepted way of expressing power on a log10 scale (dBW = 10 log10 [PWatts]). Bandwidth is a factor since all satellite signals spread their power across a range of frequencies.
The speed at which digital information flows is the data rate of the signal.
In general, as the data rate of a signal increases, so does the range of frequencies occupied by that signal. Assuming total power in the signal is constant; increasing the data rate will spread power over a wider range of frequencies and decrease power density. The inverse is also true. Figure 1 shows the power spectrums of several data signals.
All use the same waveform (modulation and coding). As you can see in the figure, a simple change to data rate can make a substantial change in power density and lead to operation well above or below the power density target / limit. Power density figures prominently in the design of a satellite network that must make optimal use of its assigned transponder or bandwidth (portion of a transponder) on the satellite.
...'>C Program For Power Spectral Density(01.11.2018)Power density is the single most important operating parameter for transmitting earth stations and probably the least understood by operators of satellite communication terminals. In this two-part article, we will define what power density is, the role it plays in the design of satellite networks and the licensing of satellite terminals, how easy it is to exceed the regulatory limit and the problems that result and, finally, what we can do to reduce these problems to an acceptable level. Most terminal operators can tell you how much power they are transmitting and what data rates they are achieving up and down.
Cross Power Spectral Density. Crosscorrelation and CPSD of Two Random Signals Plus Narrowband Interference. Measurement of Power Spectral Density. A natural idea for estimating the PSD of an ergodic stochastic. CT process is to start with the definition. This will give you the Power spectral density for your frame X. Now take the next frame and do the same, And when you reach a number of frames that you would like to plot, you stop and plot your vectors.
This is good information to know, but it is not good enough to ensure that the terminal is operating at its best and within regulatory limits. The official document issued by the satellite operator or regulatory agency that authorizes a terminal to transmit specifies its maximum allowed power density. Operating a terminal without knowing the current value of this critical parameter can lead to two very negative results: (1) self-interference due to transponder overload and (2) excessive interference with other users on the same and neighboring satellites. Either of these outcomes, especially number (2), could lead to the temporary or permanent revocation of a terminal’s license to transmit. Power density figures prominently in the license that every transmitting earth station must obtain in order to operate. Unfortunately, the license document typically offers no guidance regarding what the specified maximum power density value means in terms that operators are familiar with, such as High-Power Amplifier / Block Up-Converter (HPA/BUC) power level and signal parameters such as data rate and modulation type.
Very few terminals directly monitor or control power density, but almost all allow the operator to change it. For that reason, it is relatively easy for the operator to unintentionally turn his fully compliant and approved terminal into a very effective source of interference on his, and other, satellite communication systems.
What is Power Density? Simply put, power density describes how the transmit power in a communications signal is distributed over frequency. It is expressed in terms of power divided by a relatively small unit of bandwidth (e.g. DBW/4kHz) and is usually referenced to the input of the satellite terminal’s antenna. The unit dBW, or dB-Watts, is the universally accepted way of expressing power on a log10 scale (dBW = 10 log10 [PWatts]). Bandwidth is a factor since all satellite signals spread their power across a range of frequencies.
In general, as the data rate of a signal increases, so does the range of frequencies occupied by that signal. Assuming total power in the signal is constant; increasing the data rate will spread power over a wider range of frequencies and decrease power density. The inverse is also true. Figure 1 shows the power spectrums of several data signals.
All use the same waveform (modulation and coding). As you can see in the figure, a simple change to data rate can make a substantial change in power density and lead to operation well above or below the power density target / limit. Power density figures prominently in the design of a satellite network that must make optimal use of its assigned transponder or bandwidth (portion of a transponder) on the satellite.
...'>C Program For Power Spectral Density(01.11.2018)