Re: Tek 7623A (or 7000 series in general) - Poor man's choice to Signal Standardizer

Fabio Trevisan

Thanks Harvey for your additional comments.

I have a PG506 that does well. For the PG506, you set an internal
switch to turn off the square wave output, and then check the
calibration voltages with a good DMM.
I fully agree (in calibrating against the DMM). I wish I had a PG506 (and a leveled sine-wave generator, and a Tunnel-Diode pulser...)

Other than risetime checks, that's about it.
Yep... and even for the 100MHz system at hand, PG506's <=1ns is good enough

Tek apparently feels that if you have the
DC down right, the AC will follow.
I`m not sure what you meant. To me it's been always clear that DC performance and AC/Step response performance are treated separately and, usually, you first calibrate the scope for DC, and then you do the AC/Step response calibration.

The standardizer plugins provide a stairstep waveform that allows you
to check linearity, as well as a leveled AC output (within a frequency
limit) that allows you to pretend that you have an SG502/3/4 when you
I wish I had either... The stairstep feature is a nice, and I think relatively easy to replicate (in my intent to have/build a poor man's choice)... Nowadays even easier with a small uC.

1.0 volts in is 1.0 volts in for everything. Works for me.
Fully agree.. as I mentioned (but failed to emphasize in the original post) is that my main problem is finding cheap and fool proof ways of getting the AC / Step response right, because we can't just take for granted the edge and the tops of a square wave coming from an unproven source.
You can only fine tune the step response when you're sure of a clean input, otherwise it's impossible to know of a bump you're seeing, if it's coming from the signal source or from improper adjustment.
For non modular scopes, the pulser from Leo Bodnar seems to be a perfect bet (relatively cheap, calibration free and hell fast at < 40ps)... I don't own one, but I already considered having it. But now for the 7000s, one need a balanced output (besides being fast and clean).

Firstly, there's DC responses, setting the gain factors, then there's
the AC response, both pulse and frequency.
I think that most adjust for best pulse response, considering how most
oscilloscopes are used.
Exactly, and getting the DC right is the easiest part (if there are no thermal misbehaves).
For the AC, I think it's just trick of the trade to use a pulse, because a fast step contains so many harmonics.

The squarewave is at a low enough frequency that the pulse response
doesn't generally matter. That or you could do DC gain. Then I'd
worry about AC response (much more complicated thing).
Well, when I said square wave, I didn't mean the output of the calibrator... I meant a signal sourced from a pulse with a fast edge (< 1ns, like your PG506).
But I think I`m demised of this idea anyway... Looking more carefully to the 7B53A's AMPL signal path, the only part of it that is capable of HF, is the part that goes to the SYNC source... and that doesn't ever end up in any of the amplifiers (Hor or Vertical) it stays inside the 7B53A to trigger the TB.



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