7A42: Difference between revisions
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The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]]. | The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]]. It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot. | ||
It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs. | 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. | |||
A | There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called ''nested triggering'', where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated. | ||
The trigger can be qualified by an external clock. A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed. A TTL-level "reset" input will inhibit the trigger if active. | |||
Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed a counter for time measurement or event counting. | |||
Tektronix recommended the [[P6131]], | The input V/Div setting can only be seen in the mainframe's readout. There is a jumper to allow the readout to work in a [[7854]] mainframe. | ||
The trigger level is set digitally and shown on a 7-segment display. | |||
Tektronix recommended the [[P6131]], 300 MHz, 10 MΩ ×10 probe, and the [[P6230]], 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits. | |||
The [[067-1155-99]] calibration fixture is specific to the 7A42. | The [[067-1155-99]] calibration fixture is specific to the 7A42. | ||
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There is a [[7A42/Repairs|NiCd backup battery]] that allows the unit to retain its last configuration. | There is a [[7A42/Repairs|NiCd backup battery]] that allows the unit to retain its last configuration. | ||
A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper. | |||
==See also== | ==See also== | ||
Revision as of 08:57, 6 January 2024
The Tektronix 7A42 is a four-channel 350 MHz plug-in for 7000-series scopes. It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot.
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.
There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called nested triggering, where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated. The trigger can be qualified by an external clock. A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed. A TTL-level "reset" input will inhibit the trigger if active.
Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed a counter for time measurement or event counting.
The input V/Div setting can only be seen in the mainframe's readout. There is a jumper to allow the readout to work in a 7854 mainframe. The trigger level is set digitally and shown on a 7-segment display.
Tektronix recommended the P6131, 300 MHz, 10 MΩ ×10 probe, and the P6230, 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits.
The 067-1155-99 calibration fixture is specific to the 7A42.
Key Specifications
| Bandwidth | 350 MHz |
|---|---|
| Deflection |
|
| Input impedance | 1 MΩ // 15 pF or 50 Ω |
| Max. input voltage |
|
| Trigger level |
|
| Hysteresis | 40 mV (TTL), 8 mV (ECL) (or ×10) |
| Features |
|
| Weight | 2.8 kg / 6.2 lb |
Internals
The 7A42's functions are controlled by an Intel 8085A microprocessor, with code in three 2764 EPROMs (a fourth ROM socket is unused). The front-panel pushbuttons are handled by an Intel 8279 keyboard controller.
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.
There is a NiCd backup battery that allows the unit to retain its last configuration.
A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper.
See also
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
Internal
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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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Components
Some Parts Used in the 7A42
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 148-0145-00 | 148-0145-00 | Discrete component | miniature bi-stable relay actuator | 7A42 • 119-1517-00 |
| 155-0038-01 | 155-0038-00 • 155-0038-01 | Monolithic integrated circuit | 5-bit current source D/A converter | 7A42 • 7D13 • 7D14 • 7M13 • T4005 |
| 155-0078-00 | 155-0078-xx • 155-0273-00 • 155-0274-00 | Monolithic integrated circuit | broadband amplifier | 464 • 465 • 466 • 468 • 475 • 475A • 475M • 485 • 7834 • 7844 • 7854 • 7904 • R7903 • R7912 • 7912AD • 7912HB • 7104 • 7A16A • 7A16P • 7A24 • 7A26 • 7A42 • 067-0587-01 • 067-0680-00 • AM503 • PG502 • PG508 • DC510 • DC5010 • FG5010 |
| 155-0236-00 | 155-0236-00 | Hybrid integrated circuit | channel switch | 2445 • 2465 • 2467 • 7A42 |
| ICM7218 | 156-1621-00 • 156-1622-00 | Monolithic integrated circuit | 8-digit, 7-segment LED driver | 7A42 • SG5010 |
| Intel 8085A | 156-1088-00 | Monolithic integrated circuit | 8-bit microprocessor | 308 • 468 • 4025 • 7A42 • 7D02 • AFG5101 • AFG5102 • PFG5105 |
| Intel 8279 | 156-1535-00 | Monolithic integrated circuit | keyboard controller | 7A42 • AFG5101 • DM5010 • FG5010 • PFG5105 |
| SG3524 | 156-0933-00 • 156-0933-01 • 156-1585-00 • 156-1585-01 | Monolithic integrated circuit | PWM switch-mode controller | 067-1011-00 • 1502B • 1502C • 1503B • 1503C • 7A42 • DP100 |