N5161A/62A/81A/82A/83A MXG Signal Generators User's Guide

Adding Real–Time Noise to a Signal (Option 403)Adding Real–Time Noise to a Dual ARB WaveformFigure 9-3 Real Time I/Q Baseband AWGN - Noise Mux Menu SoftkeysMode > Dual ARB > Arb Setup >Real-Time AWGN Setup > MoreThe Carrier BitRate softkey isonly availablewhen the Carrierto Noise softkeyis set to E b /N o .Enables diagnostic control ofadditive noise, so that only thenoise, only the carrier, or thesum of both the noise and thecarrier are output from theinternal baseband generator.With the ALC off, this featureenables direct measurement ofthe carrier or the noisecontributions independentlyfrom the total power. The systemstill behaves as if both the noiseand the carrier are present onthe output when it comes todetermining the Auto ModulationAttenuation and the RMS levelfor RMS Power Search.Figure 9-6 on page 254provides additionaldetails on these settings.For details on each key, use key helpas described on page 42.E b /N o Adjustment Softkeys for Real Time I/Q Baseband AWGNThis feature allows the AWGN C/N to be set using the E b /N o (energy per bit over noise power densityat the receiver or signal to noise ratio per bit) form. This requires the carrier bit rate to be known.Refer to Figure 9- 4, “Eb/No Carrier Bit Equation.”Figure 9-4E b /N o Carrier Bit EquationC E---------- ------ b ⎞ bitRate= ⎛ dB + 10 log ⎛----------------------------------------------- ⎞⎞⎞N ⎝N dB0 ⎠ 10⎝carrierBandwidth⎠ ⎠⎠252 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide