E8257D/67D, E8663D PSG Signal Generators Service Guide 165TroubleshootingRF Path Description (Frequency Generation, Level Control, and Modulation)has a frequency range of 200 to 400 MHz. A 10 MHz reference signal from theA7 Reference (or an external 10 MHz reference) can be used to phase–lock thesample clock signal of the DACs.The Burst Pulse signal from the A14 Baseband Generator goes to the A11Pulse/Analog Modulation Generator, and is used to drive the pulse modulatorson the A8 Output and A30 Modulation Filter. The Burst Pulse signal is used bythe digital modulation formats to synchronize the main RF path and ensuremaximum on/off level ratio.The I and Q output signals are the primary signals out of the A14 BasebandGenerator. They are the digital modulation signals that go to the A13 I/QMultiplexer, and are then routed to the I/Q modulators on the A8 Output andA35 I/Q Modulator.Approximate Device Gains and LossesYou can troubleshoot assemblies in the RF path by measuring gains and lossesand comparing them to Table 1-28, below. See “Troubleshooting RF PowerLevels” on page 122 for more information.Table 1-28 Approximate Device Gains and LossesItem # Device Gain/Loss Value(dB)AnalogInstrumentsVectorInstruments1 A8 Outputnon–1EA/1EU1EA/1EUN/AN/A> 17> 20X X2 A12 Opt 1E6 Pulse Mod. Loss < 3 X X3 A23 Lowband Coupler Loss < 3 X X4 A28 YO Output N/A > 11 X X5 A29 20 GHz DoublerJ1 to J2J1 to J3 and J4GainLoss> 1< 18X X6 A35 3–20 GHz I/Q Mod.Bypass mode, J5 to J13.2 to 12.8 GHz12.8 to 20 GHzGainLoss> 0< 2X
