7A42

The Tektronix 7A42 is a four-channel 350 MHz plug-in for 7000-series scopes.

It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs.

A fifth trace, "Trigger View", displays the trigger function output or external clock input.

The input V/Div setting can only be seen in the mainframe's readout.

Tektronix recommended the P6131 10 MΩ probe, and the P6230 variable-offset 450 Ω probe for ECL circuits.

Key Specifications

Bandwidth	350 MHz
Deflection	0.1 / 0.2 / 0.5 V/Div (TTL mode) 20 / 50 / 100 mV/Div (ECL mode) each direct or through 10:1 probe
Input impedance	1MΩ or 50 Ω
Max. input voltage	at 1 MΩ: 25 V DC+peak AC below 36 MHz, down to 3 V AC at 300 MHz at 50Ω: 5 V RMS during any 1 ms interval
Trigger level	-1.27 to +1.28 V (TTL mode) in 10 mV steps -254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)
Hysteresis	40 mV (TTL), 8 mV (ECL) (or ×10)
Features	NiCd battery to preserve front-panel control status
Weight	2.8 kg / 6.2 lb

Internals

The 7A42's functions are controlled by an 8085A microprocessor.

Each of the four input attenuator circuits contains five miniature relays. The bistable relay coils are wired in a 4x5 matrix.

The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, -2 V and -5 V from the mainframe's +/-50 V rails.

Pictures

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  display - four signal traces plus trigger view

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  7A42 rear view

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  7A42 top view

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  memory backup battery

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  internal switch mode PSU for digital logic supplies

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  microprocessor board

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  amplifier board front - attenuators, amplifiers, channel switches

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  amplifier board rear - channel switches, two 15 ns delay lines

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