Hi Tony,
Let's look at what you are doing.? Firstly, I do a lot of FM tuner alignment, and I have an ST1000A.? I don't have a great deal of luck using the double sweep feature, and it isn't a sweep as much as high modulation levels.? Your deviation is 150 KHz to 200 KHz only, and a sweeper covers far more bandwidth.? I use a spectrum analyser when I want to do that.
Some times you must follow the manufactures procedure in the manual.? One method that works best is to modulate 75 KHz in mono, then align for minimum distortion.? That even makes sense!? The THD analyser would measure 0.03% for the very best tuner, many sit around 0.15% THD.? So you could use an HP 333A or 334A or better, like a 339A.? Even a Leader THD meter would be fine.? I use an 8656A, you could use an 8657A as well.? You do want an accurate frequency, which the ST1000A cannot provide.? Other signal generators might only send a signal out on odd frequencies, like the Sencore SG80, which you will quickly find not suitable for tracking alignments.? I do use that one for distortion and stereo alignment work.
To do really good alignment work, you do need a good generator or two (I use two to avoid constantly changing frequency), and the same instrument will provide a low distortion modulated signal that will allow you do adjust for minimum distortion.? There are other techniques used as well, so training is critical as well.? The ST1000A is not a magic bullet and isn't always suitable.? You definitely need another generator if you intend to use an ST1000A.? In order to get accurate signal levels I bought a Keysight N9310A - they ain't cheap!? But if you get an HP 8656A or B calibrated and correct for impedance (from 50R to 75R) you should be close.? I also use an RF power meter.? There is no end to stuff you could use to do a better job!
I hope that helps, Chris
