[Techtoolslist] O-scope Z-Channel Question

[Dave M]

Taken from the 475 manual, the Z-Axis has the following characteristics:

Sensitivity:
Positive-going signal from ground decreases intensity
5 V P-P signal causes noticeable modulation at normal intensity

Maximum Input Voltage:
100 V (DC plus peak AC)
100 V P-P AC at 1 kHz or less

Useable Frequency Range:
DC to 50 MHz.

I take the sensitivity spec to mean that you need AT LEAST 5Vp-p to see any intensity modulation.  To completely blank the trace, you need more than 5Vp-p.  I haven't used the Z-Axis on my 575 in recent memory, but it makes sense that you will need to 
(A) check the amplitude and polarity of the signal you're feeding to the Z-Axis, 
(B) amplify it to an amplitude that will give you the needed blanking level, and 
(C) invert it if necessary to give a positive-going pulse with ground reference.

Getting sufficient amplitude to completely blank the trace will likely require some experimentation, but shouldn't be difficult.  If I were doing this, I'd start with an amplifier with a gain of 2x to maybe 5x and see how that works. My guess is that it will take a pulse of around +10V to give complete blanking.

Cheers!!

Dave M