SysCalc calculates sensitivity based on the system MDS , additional losses (see Input Parameters) and the required S/N for the specified modulation scheme. The S/N value can be directly entered by the user or, in the case of digital modulation, be calculated automatically for the specified BER. SysCalc can perform the BER-S/N conversions for the following kinds of modulation:
BIPOLAR (Baseband Signaling)
BPSK (Binary Phase Shift Keying, coherent)
DPSK (Differential Phase Shift Keying, non-coherent)
FSK (Frequency Shift Keying, coherent/non-coherent)
MSK (Minimum Shift Keying, coherent)
OOK (On/Off Keying, coherent/non-coherent)
PAM (M-level Amplitude Modulation, coherent, rectangular constellation)
POLAR (Baseband Signaling)
PI/4 DQPSK (Quadrature Phase Shift Keying, differentially coherent)
QAM (M-level Quadrature Amplitude Modulation, coherent, rectangular constellation)
QPSK (Quadrature Phase Shift Keying, coherent)
UNIPOLAR (Baseband Signaling)
The following equations are used to determine BER/SNR conversions. Ideal detection conditions are assumed (matched filter, no Inter-Symbol Interference). It is also assumed that the symbol rate and system bandwidth are the same; thus, in each of the equations
Where,
S = Signal power (Watts)
N = Noise power in a bandwidth equal to the symbol rate of the modulator (Watts)
Eb = Average bit energy, No = Single-sided noise power density (Watts/Hz)
, for general M-ary signaling
(PAM, QAM)
M = 2, for binary signaling
M = 4, for QPSK and PI/4 DQPSK
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Applies to the following relationships |
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Bipolar |
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Polar |
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Unipolar |
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Coherent Detection |
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Non-coherent Detection |
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BPSK |
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Not provided |
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DPSK |
Not provided |
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FSK |
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MSK |
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N/A |
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OOK |
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QPSK |
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N/A |
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PI/4 DQPSK
Where,
M-ary Signaling
PAM
Where,
QAM
Where,
