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VSAT Bandwidth vs VSAT Data rate | Difference between VSAT Bandwidth and VSAT Data rate

This page compares VSAT bandwidth vs VSAT data rate and mentions difference between VSAT bandwidth and VSAT data rate.

As we know both data rate and bandwidth are related to capacity of the transmission medium. Different mediums will have different limits of the same.

As a rule of thumb higher bandwidth means higher data rate of transmission.
Channel capacity = maximum data rate of a channel. If bandwidth is equal to W
➨Data Rate < = 2 * W

The concept of bandwidth and data rate remains same irrespective of the communication system or transmission media.

VSAT Bandwidth

The bandwidth of VSAT is referred as total frequency allocation allocated to any VSAT at RF center frequency by RF engineers. For example, if IF frequency allocated to VSAT is 71.02 MHz and there are 1 voice and 1 data channels operating at 19.2 Kbps and 9.6 kbps respectively are used. Here total VSAT Bandwidth is (19.2 + 9.6) = 27.8 KHz provided 1 bit is used per carrier (i.e. BPSK modulation is employed).

VSAT Data Rate

The rate at which information is transmited using VSAT is referred as VSAT data rate. It is the ratio of number of bits and time duration.
➨VSAT Data rate = (Information in bits)/(Duration for information transmission in sec)


Both VSAT Bandwidth and VSAT data rate are related by following equation:
➨VSAT Bandwidth = (1/modulation level) x VSAT data rate
For QPSK, modulation level = 2 as , 2 bits per carrier are used
In other words, 1 symbol = 2 bits in QPSK,
1 symbol = 4 bits in 16QAM,
1 symbol = 1 bits in BPSK or ASK or FSK or PSK,

Hence for QPSK modulation used in satellite modem of VSAT,
VSAT bandwidth becomes half compare to BPSK case for the same data rate.


Refer following sub topics related to VSAT technology:
Article on VSAT   VSAT NMS protocol  RF Terminology   Satellite Terminology  Access types  SCPC  MCPC  RF Transceiver  C band RFT  Microstrip  RF upconverter design   Power Amplifier  what is modulation  satellite Modem  Link Budget 

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