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 9-6Carrier to Noise Ratio ComponentsCarrier Bandwidth (CBW) is typically theoccupied bandwidth of the carrier and the NoiseBandwidth is the flat noise bandwidth (NBW).Carrier BW(CBW)RMS(total carrier power)Noise BW(NBW) =flat noisebandwidthCarrier BW(CBW)The carrier now appearslarger because of theadded noise power.CarrierCNoiseNExampleUse the following steps to modulate a 1 GHz, –10 dBm carrier with the factory–supplied waveformSINE_TEST_WFM, and then apply noise with a 45 MHz bandwidth signal that has a 30 dBcarrier–to–noise ratio across a 40 MHz carrier bandwidth.1. Preset the signal generator and set the following:• Frequency: 1 GHz• Amplitude: −10 dBm• RF output: on2. Select the factory–supplied waveform SINE_TEST_WFM:a. Press Mode > Dual ARB > Select Waveform.b. Highlight SINE_TEST_WFM and press Select Waveform.3. Turn on the dual ARB player: press ARB Off On to highlight On.4. Set the ARB sample clock to 50 MHz: Press ARB Setup > ARB Sample Clock > 50 > MHz.5. Press Real–time Noise Setup and set the following:• Carrier to Noise Ratio: 30 dB• Carrier Bandwidth: 40 MHz• Noise Bandwidth: 45 MHz• Real–time Noise: onThe signal generator’s displayed power level (–10 dBm) includes the noise power.254 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide