Comtech EF Data DMD-2050E Installation And Operation Manual page 92

DMD2050E Universal Satellite Modem
Leased bandwidth
Almost all satellite operators charge for the Leased Bandwidth (LBW). Leased Bandwidth or
Leased Resource is the greater of the Allocated Bandwidth and Power Equivalent Bandwidth.
For example, if a carrier requires 3 MHz of Allocated BW and 4.5 MHz of PEB, the Leased
Bandwidth is 4.5 MHz
Power Spectral Density (PSD)
Power Spectral Density (PSD) is the signal power per unit bandwidth: dBW / Hz
For example:
PSD Ratio
PSD ratio is the ratio of power spectral density of the interfering carrier and the desired carrier. If
looking at the 2 carriers side-by-side on a spectrum analyzer:
Eb/No
Ratio of Energy per bit (Eb) to Noise density (No): Unit is dB
C/N
Carrier Power (C) to Noise (N) ratio: Unit is dB
C/No
Carrier Power (C) to Noise Density (N
Co+No/No
Carrier Density (C
MN-DMD2050E Revision 2
Signal power = 20 dBm
Signal bandwidth = 500 kHz
PSD = 20 – 10 *log (500 * 1000)
= -36.99 dBm / Hz
) ratio: Unit is dBHz
o
) + Noise (N ) to Noise Density (N
o o
) ratio: Unit is dB
o
Theory of Operation
or
dBm / Hz
3–50