What is input backoff in satellite communication?

What is input backoff in satellite communication?

Input Back-Off: In a power amplifier, a measure of how far you must reduce the input power in order to receive the desired output linearity and power. Stated differently, the ratio between the input power that delivers maximum power to the input power that delivers the desired linearity.

What is input back off?

Input Back-Off (IPBO) is the power level at the input of RF amplifier relative to input power which produces maximum output power. In a satellite link calculation, input backoff is calculated by taking difference between actual flux density and the saturated flux density.

At what value of output back off in dB does the satellite operate?

The transponder is operating at 12 dB Input Back Off. The satellite power amplifier characteristics specify that for every dB of Input back-off the Output Back-off changes by 0.5 dB.

How is satellite downlink EIRP calculated?

For a leased 2 MHz slot, out of a transponder bandwidth of 36 MHz, the available downlink EIRP will be +37.5 -10 log(36/2) = +25 dBW . This assumes that the total power is more or less evenly divided according to bandwidth.

What is back off in RF?

Power Backoff in an amplifier is a power level below the saturation point at which the amplifier will continue to operate in the linear region even if there is a slight increase in the input power level. The amount by which we lower the power level is called Power Backoff.

What are the limitations of FDMA satellite access?

Disadvantages of FDMA :

• Due to the simultaneous transmission of a large number of frequencies, there is a possibility of inter modulation distortion at the transponder.
• It is suitable only for analog signals.
• Storage, enhancement of signals is not possible.
• The large bandwidth requirement for transponders.

When a large number of carriers are simultaneously present in a TWTA the operating point must be backed off to the linear portion of the transfer characteristics to reduce intermodulation This is called as?

Welcome back. When a number of carriers are present simultaneously in a TWTA, the operating point must be backed off to a linear portion of the transfer characteristic to reduce the effects of intermodulation distortion. Such multiple carrier operation occurs with frequency division multiple access (FDMA).

What are different losses in downlink analysis?

The total path loss in the downlink comprises of several components, including spreading (1/r2) loss, free space loss (Ls), ionospheric scintillations, climatic attenuation, sun outage factors etc.

Why FM is used in satellite communication?

As the advance in technology and limitation of analogue modulation it is now most of the satellite using digital modulation techniques and providing some advantages over analogue modulation like better performance, error detection and correction efficiency, signal to noise ratio etc.

What does a link budget for satellite communication include?

It includes the transmit and receive antenna gain, the free space path loss and additional losses and gains, assuming line of sight between the transmitter and receiver. The wavelength (or frequency) term is part of the free space loss part of the link budget.

What does input back off mean in satellite EIRP?

Input back-offThe input back-off is the difference in decibels between the carrier input at the operating point, and saturation input that would be required for single carrier operation. 5. Output back offWhere in put back off is employed corresponding output back off must be allowed for the satellite EIRP.

How is input backoff and output backoff calculated?

In a satellite link calculation, input backoff is calculated by taking difference between actual flux density and the saturated flux density. Also calculated Output backoff help calculated actual EIRP of the satellite.

What’s the difference between output and input back off in a RF amplifier?

Output Back-Off (OPBO) is the power level at the output of RF amplifier relative to maximum output level possible using the RF amplifier. Input Back-Off (IPBO) is the power level at the input of RF amplifier relative to input power which produces maximum output power.

What’s the difference between output and input backoff in a TWTA?

Both the Output backoff(OPBO) and Input Backoff(IPBO) are used to determine the operating power levels required in a satellite transponder TWTA or RF Power Amplifier to function in linear region. Output Back-Off (OPBO) is the power level at the output of RF amplifier relative to maximum output level possible using the RF amplifier. EXAMPLE: