I have added a new picture, showing the low frequency end performance:
/g/HP-Agilent-Keysight-equipment/photo/78668/1?p=Name,,,20,1,0,0
The upper trace A is the TG output near 0 dBm, up to 1 kHz. The lower B trace is the stored maximum hold, with the TG output "OFF." The line spurs are artifacts due to ground loops in the experimental test and repair setups - I'm still working on the sweep-stopping issue, etc. In earlier tests before this came up, the TG exhibited no line/PS stuff at all - only the residual line noise of the 8568 was evident, about 10 dB lower than it looks here. It should be OK once everything is buttoned up properly.
The TG/SA arrangement exhibits nearly 100 dB dynamic range, and is at the limit of on-screen capability. The near-DC (f=0) response of the 8568 at the narrowest IFBW hits the noise floor by about 100 Hz, so it's fully usable from there up. The TG output is of course, coming from the low-band (~0-500 MHz) amplifier. The original, main amplifier rolls off below around 300 kHz, so is incapable of reaching the bottom end of the 8568's frequency range.
Ed
