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The Tektronix Type 181 is a time mark generator. There is a benchtop version, | {{Instrument Sidebar | ||
the 181, and a rackmount version, the RM181. | |manufacturer=Tektronix | ||
|model=181 | |||
|class=Pulse generator | |||
|series= | |||
|summary=Time mark generator | |||
|image=181_PC_ISO.jpg | |||
|caption=181, early version | |||
|introduced=1955 | |||
|discontinued=(?) | |||
|designers= | |||
|manuals= | |||
* [[Media:070-292.pdf|Tektronix 181 Manual]] (sn 6917, color schematics, PDF) | |||
* [https://w140.com/mmm/tek-181.pdf Tektronix 181 Manual (PDF)] | |||
}} | |||
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 a oven-stabilized1 MHz crystal oscillator (OCXO), the CO181 (Tek part number [[158-007]]), thereby 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". | |||
==Internals == | |||
Internally, the 181 is similar to the [[180A|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 == | |||
<gallery> | <gallery> | ||
Tek 181.jpg|181 | |||
Tek rm181.jpg|RM181 | |||
181_PC_ISO.jpg|181, early version | |||
181_PC_Front.jpg|181, early version, front | |||
181_PC_Left.jpg|181, early version, left side | |||
181_PC_Right.jpg|181, early version, right side | |||
Tek co181.jpg|CO181 oven-stabilized oscillator | |||
Tek 181 block.png|Block diagram | |||
Tek 181 oscillator and multiplier.png|oscillator and multiplier | |||
Tek 181 frequency dividers.png|frequency dividers | |||
Tek 181-switching detail.png|switching detail | |||
Tek 181 power supply.png|power supply | |||
Tek rm181 1us output2.jpg|Output waveform of RM181 set for 1 us period | |||
Tek 181 later style rounded case.jpg|Later style case, rounded corners | |||
Tek 181 left internal on.jpg|Left internal view, powered up | |||
Tek 181 late internal.jpg|Internal view, late version | |||
</gallery> | </gallery> | ||
[[Category:Time mark generators]] | |||
[[Category:Introduced in 1955]] |