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181 - TekWiki

Tektronix 181
Time-mark generator
181, early version

Produced from 1955 to (?)

Manuals

(All manuals in PDF format unless noted otherwise)

The Tektronix Type 181 is a time-mark generator introduced in 1955. There is a benchtop version, the 181, and a rackmount version, the RM181.

MOD 110 substitutes an oven-stabilized 1 MHz crystal oscillator (OCXO), the CO181 (Tek part number 158-007), achieving 2 parts per million frequency stability in a 24 hour period, the same stability as the 180A. A 181 with the OCXO mod is a "181 S1".

Links

Documents Referencing 181

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Internals

Internally, the 181 is similar to the 180.

The oscillator drives a chain of synchronized monostable multivibrators. Each multivibrator is triggered by the output of the previous stage, and cannot be triggered again for the duration of its pulse width. In the 181, the pulse width ratio of one stage to the next is 1:10, i.e. when a stage triggers on a pulse at its input, it propagates that event to its output, but inhibits the next nine pulses (by time, not by counting).

The 181 also provides a 10 MHz output. This is generated by a 10 MHz resonator that is driven by an amplified and waveshaped copy of the 1 MHz crystal oscillator output. Since it is a harmonic, the 10 MHz output has same relative frequency accuracy as the reference oscillator.

The power supply of the 181 produces +300 V and −150 V regulated voltages and +400 V, −8 V, and −25 V unregulated. The voltage reference is a 5651 tube. The output tubes for both regulators are 12B4 and the feedback amplifier tubes are 6AU6. The 181 does not contain a fan or a thermal cutoff.

Pictures

  • 181

    181

  • RM181

    RM181

  • 181, early version

    181, early version

  • 181, early version, front

    181, early version, front

  • 181, early version, left side

    181, early version, left side

  • 181, early version, right side

    181, early version, right side

  • CO181 oven-stabilized oscillator

    CO181 oven-stabilized oscillator

  • Block diagram

    Block diagram

  • oscillator and multiplier

    oscillator and multiplier

  • frequency dividers

    frequency dividers

  • switching detail

    switching detail

  • power supply

    power supply

  • Output waveform of RM181 set for 1 us period

    Output waveform of RM181 set for 1 us period

  • Later style case, rounded corners

    Later style case, rounded corners

  • Left internal view, powered up

    Left internal view, powered up

  • Internal view, late version

    Internal view, late version

Components

Some Parts Used in the 181

Part Part Number(s) Class Description Used in
12AU7 154-041 • 154-0041-00 • 154-0287-00 Vacuum Tube (Dual Triode) dual medium-μ triode 104 • 104A • 122 • 160 • 161 • 162 • 181 • 190 • 310 • 310A • 316 • 317 • 3C66 • 502 • 502A • 507 • 511A • 512 • 516 • 517 • 517A • 524 • 526 • 535 • 536 • 545 • 545A • 545B • 547 • 549 • 555 • 561 • 564 • 570 • 575 • 581 • 581A • 585 • 585A • C • D • E • N • Q • Hickok 1825 • Keithley 660A • Pentrix L20 • Pentrix L30
6AL5 154-016 • 154-0016-00 • 154-0038-00 Vacuum Tube (Dual Diode) high-perveance dual diode 163 • 181 • 190 • 1M1 • 310 • 310A • 315 • 316 • 317 • 3B1 • 3B1S • 3B2 • 3B3 • 3B5 • 502 • 502A • 503 • 511 • 511A • 512 • 516 • 517 • 517A • 524 • 526 • 535 • 535A • 545 • 545A • 549 • 551 • 565 • 570 • 581 • 581A • 585 • 585A • C • T • Telequipment D52 • Telequipment D56 • Telequipment S52
6AU6 154-0022-00 • 157-0073-00 • 157-0059-00 • 154-0284-00 Vacuum Tube (Pentode) RF pentode 107 • 129 • 160 • 181 • 190 • 60 • 2A60 • 72 • 3A72 • 3C66 • 310 • 310A • 316 • 317 • 360 • 502 • 502A • 506 • 511 • 511A • 512 • 513 • 516 • 517 • 517A • 524 • 526 • 529 • RM529 • 531 • 531A • 535 • 536 • 545 • 545A • 546 • 547 • 549 • 555 • 561 • 561A • 561S • 564 • 565 • 567 • 570 • 575 • 581 • 581A • 585 • 585A • 80 • C • CA • Q
6BQ7A 154-028 • 154-0028-00 • 157-0003-00 • 157-0022-00 Vacuum Tube (Dual Triode) dual triode 107 • 163 • 181 • 310 • 315 • 316 • 360 • 524 • 531 • 532 • 535 • 536 • 541 • 545 • 570 • T
6X4 154-035 • 154-0035-00 Vacuum Tube (Dual Rectifier) dual rectifier 128 • 130 • 181 • 511A • 512 • 517 • 517A • 570