Symbol rate, Bandwidth and Bit rate Calculation
In satellite communication bandwidth (BW), symbol rate and bit rate are
the most vital fact for proper signal transmission. There are many
commercial software for BW, Symbol rate and bit rate calculation for TV
signal transmission. But the equations of these parameter calculation
are as follows.
BW= (1+Roll of factor)* Symbol rate
In general Roll of factor is 35%
Symbol Rate =BW / (1+Roll of factor)
and Bit Rate = Symbol rate * Modulation* FEC* (188/204)
[when 188 is encoder packet length]
or Bit Rate = Symbol rate * Modulation* FEC* (204/188)
[when 204 is encoder packet length]
Here,
FEC = Forward Error Correction. In general FEC is in the range from 1/2 to 7/8.
188/204 = constant
Unit
** BW= Hz, KHz, MHz, GHZ
** Symbol Rate= sps or baud, Ksps or Kbaud, Msps or Mbaud, Gsps or Gbaud
** Bit Rate= bps, Kbps, Mbps, Gbps
N.B.
# Uplink frequency - Downlink frequency = 2225 MHz [for C band]
For Example,
Uplink frequency is 5964 MHz
Downlink frequency is 3739 MHz.
Now 5964 MHz - 3739 MHz = 2225 MHz.
# L band frequency for downlink = LNB local oscillator frequency - Downlink frequency.
= 5150 - 3739 MHz
= 1411 MHz
In general LNB local oscillator frequency is 5150 MHz, 5750 MHz and 5950 MHz.
# Center frequency for uplink is uplink frequency. Here the center frequency is 5964 MHz.
# L band frequency for uplink = Uplink frequency - LNA local oscillator frequency
= 5964 MHz - 4900 MHz
= 1064 MHz
Frequency range for some frequency band
# IF frequency range is from 70 MHz to 124 MHz
# L band frequency range is from 1 GHz to 2 GHz (more specifically from 950 MHz to 2100 MHz)
BW= (1+Roll of factor)* Symbol rate
In general Roll of factor is 35%
Symbol Rate =BW / (1+Roll of factor)
and Bit Rate = Symbol rate * Modulation* FEC* (188/204)
[when 188 is encoder packet length]
or Bit Rate = Symbol rate * Modulation* FEC* (204/188)
[when 204 is encoder packet length]
Here,
FEC = Forward Error Correction. In general FEC is in the range from 1/2 to 7/8.
188/204 = constant
Unit
** BW= Hz, KHz, MHz, GHZ
** Symbol Rate= sps or baud, Ksps or Kbaud, Msps or Mbaud, Gsps or Gbaud
** Bit Rate= bps, Kbps, Mbps, Gbps
Baud: Unit
of signalling speed
Baud
rate: Number
of symbols transmitted per second (s)
Now b (bit) = s(symbol) * n (number of bit per-symbol)
N.B.
# Uplink frequency - Downlink frequency = 2225 MHz [for C band]
For Example,
Uplink frequency is 5964 MHz
Downlink frequency is 3739 MHz.
Now 5964 MHz - 3739 MHz = 2225 MHz.
# L band frequency for downlink = LNB local oscillator frequency - Downlink frequency.
= 5150 - 3739 MHz
= 1411 MHz
In general LNB local oscillator frequency is 5150 MHz, 5750 MHz and 5950 MHz.
# Center frequency for uplink is uplink frequency. Here the center frequency is 5964 MHz.
# L band frequency for uplink = Uplink frequency - LNA local oscillator frequency
= 5964 MHz - 4900 MHz
= 1064 MHz
Frequency range for some frequency band
# IF frequency range is from 70 MHz to 124 MHz
# L band frequency range is from 1 GHz to 2 GHz (more specifically from 950 MHz to 2100 MHz)
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