3A74: Difference between revisions
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The '''Tektronix Type 3A74''' is a four-channel vertical plug-in [[introduced in 1963]] for | The '''Tektronix Type 3A74''' is a four-channel vertical plug-in [[introduced in 1963]] for | ||
[[560-series scopes]]. The | [[560-series scopes]]. The bandwidth is DC to 2 MHz. | ||
{{BeginSpecs}} | |||
{{Spec | Bandwidth | 2 MHz}} | |||
{{Spec | Input impedance | 1 MΩ // 47 pF }} | |||
{{Spec | Deflection | 20 mV/Div to 10 V/Div in 1–2–5 sequence }} | |||
{{Spec | Features | | |||
* Invert switch per channel | |||
}} | |||
{{EndSpecs}} | |||
==Internals== | |||
Each input signal passes through | Each input signal passes through | ||
switchable input attenuators and then into a cathode-follower made from a [[7586]] | switchable input attenuators and then into a cathode-follower made from a [[7586]] | ||
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are generated by a transistor-based ring oscillator, a four-state cyclic state machine. | are generated by a transistor-based ring oscillator, a four-state cyclic state machine. | ||
This allows each of the input signals to be traced on the screen, one after another. | This allows each of the input signals to be traced on the screen, one after another. | ||
==Links== | ==Links== | ||
Revision as of 06:00, 24 October 2014
Template:Plugin Sidebar 2 The Tektronix Type 3A74 is a four-channel vertical plug-in introduced in 1963 for 560-series scopes. The bandwidth is DC to 2 MHz.
Key Specifications
| Bandwidth | 2 MHz |
|---|---|
| Input impedance | 1 MΩ // 47 pF |
| Deflection | 20 mV/Div to 10 V/Div in 1–2–5 sequence |
| Features |
|
Internals
Each input signal passes through switchable input attenuators and then into a cathode-follower made from a 7586 Nuvistor triode. That drives a PNP differential amplifier. The output of this differential amplifier, for each of the four channels, passes through a diode-based analog signal switching network (multiplexer). The output of that multiplexer drives the output amplifier, which is part transistor, part tube. The one-hot select line signals for the multiplexer are generated by a transistor-based ring oscillator, a four-state cyclic state machine. This allows each of the input signals to be traced on the screen, one after another.
