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(Attenuators have no DC trim, so their CMRR is poor)
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Unlike later comparators, Type Z has separate step attenuators for each input,
Unlike later comparators, Type Z has separate step attenuators for each input,
permitting the user to view the difference between signals of widely differing amplitudes.
permitting the user to view the difference between signals of widely differing amplitudes.
Unfortunately the divider resistors are fixed, so CMRR is poor except at 50mV/div.


It is also the only comparator that can handle ±100 V common mode at full sensitivity.
It is also the only comparator that can handle ±100 V common mode at full sensitivity.

Revision as of 16:01, 1 July 2021

Template:Plugin Sidebar 2 The Tektronix Type Z is a comparator plug-in for 500-series scopes, introduced in 1960 and dropped after 1968.

The Type Z has two inputs, A and B, plus a precision comparison voltage, VC, that is adjustable from 0 to ±1 V, 10 V, or 100 V via a ten-turn pot.

The following differential amplifier can be configured to display VA, −VB, VA−VB, VA−VC, or VC−VB.

This allows DC-coupled measurements of small signals with large DC offsets.

Unlike later comparators, Type Z has separate step attenuators for each input, permitting the user to view the difference between signals of widely differing amplitudes. Unfortunately the divider resistors are fixed, so CMRR is poor except at 50mV/div.

It is also the only comparator that can handle ±100 V common mode at full sensitivity.

With a pair of "Disconnect Signal" buttons, the Type Z was the first movement toward a "GND" position on the input switches.

The Type P6023 probe with R and C compensation, introduced in 1962, was specifically designed for the Type Z but also marketed for the Type G.

Specifications

Maximum sensitivity is 50 mV/div, and common-mode rejection at DC and low frequencies is 40,000 to 1.

Risetime as a general-purpose amplifier is 27 ns (13 MHz bandwidth), but it can track a common-mode risetime of 7 ns.

Internals

The Type Z uses both tubes and transistors, capitalizing on the strengths of each.

The step attenuators are turret attenuators.

Links

Pictures

Schematic