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{{Plugin Sidebar 2|
{{Plugin Sidebar
title=Tektronix S-2 |
|manufacturer=Tektronix
summary=Sampling Head |
|series=7000 and 3S series sampling heads
image=Tek s2 front crop.jpg |
|type=S-2
caption=S-2 head |
|summary=Sampling Head  
series={{3S+7S}} |
|image=Tek s2 front crop.jpg  
introduced=1967 |
|caption=S-2 head  
discontinued=1989 |
|introduced=1967  
manuals=
|discontinued=1989  
* [http://bama.edebris.com/download/tek/s2/s2.djvu Tektronix S-2 Manual (DjVu)]
|designers=
* [http://w140.com/tek_s-2.pdf Tektronix S-2 Manual (PDF)]
|manuals=
* [[Media:070-0764-00.pdf|Tektronix S-2 Manual]] (OCR)
* [[Media:Tek s-2 whole foldouts.pdf|Tektronix S-2 Manual Foldouts]] (whole, color)
* [[Media:070-3012-00.pdf|Digital Measurement System S-2 Calibration]]
}}
}}
The '''Tektronix S-2 Sampling Head''' plug-in provides a single  
The '''Tektronix S-2 Sampling Head''' plug-in provides a single [[GR-874 connector|GR-874]] 50 Ω input with a 75 ps risetime.  
[[GR-874 connector|GR-874]] 50 Ω input with a 75 ps risetime.  


The S-2 can be used in the 7000 series and 3S series of [[sampling oscilloscope|sampling plug-ins]].  
The S-2 can be used in the 7000 series and 3S series of [[sampling oscilloscope|sampling plug-ins]].  
Line 18: Line 20:
Noise is specified as less than 10 mV.
Noise is specified as less than 10 mV.


When the S-2 was first introduced, the rise-time specification was 50 ps, but that
When the S-2 was first introduced, the rise-time specification was 50 ps, but that was not achieved in practice, so the rise-time specification was revised to be 75 ps.
was not achieved in practice, so the rise-time specification was revised to be 75 ps.
 
The interface between the GR-874 connector and the printed circuit board is described in US Patent 3,426,311.


{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Rise time | 75 ps }}
{{Spec | Rise time | 75 ps (50 ps initially) }}
{{Spec | Bandwidth | 4.66 GHz eq.}}
{{Spec | Bandwidth | 4.66 GHz eq.}}
{{Spec | Input voltage | -1 to +1 V (max. -5 to +5) }}
{{Spec | Operating input voltage range | −1 V to +1 V with ≤1 V<sub>p-p</sub> signals }}
{{Spec | Maximum single sample step | 200 mV}}
{{Spec | Maximum input voltage  | ±5 V<sub>DC</sub> or sine of 10 V<sub>p-p</sub> up to 10 MHz }}
{{Spec | Input impedance | 50 Ω ±1% ([[GR-874]]) }}
{{Spec | Noise  | < 10 mV }}
{{Spec | Features | trigger pickoff for internal triggering }}
{{EndSpecs}}
{{EndSpecs}}
==Links==
{{Documents|Link=S-2}}
{{PatentLinks|S-2}}
==Similarity to [[S-1]]==
The S-1 and S-2 samplers are constructed very similarly. The mechanical construction including  internal connector locations is identical, and the preamp boards are almost identical. The main difference in these boards is the value of the gain adjust trimpot R46, which is 5k for the S-1 and 30k for the S-2, to allow higher gain settings to compensate for the shorter sampling pulses of the S-2. Bipolar transistors Q41 and Q45 are different types (why?). Preamp boards can be swapped between S-1s and S-2s for testing purposes without issues.
The strobe boards use identical active components ([[avalanche transistor]] Q69 [[153-0556-00]] and [[Snap-off diode]] D61 152-0335-00), but the board layout is different to accommodate longer strobe clipping lines in the S-1.
The sampling circuit itself is almost identical, except that the dampening resistors R7B and R8B of the [[S-1]] are missing in the S-2. The [[sampling diodes]] are different, the S-2 uses a 152-0361-00 GaAs matched pair.
==Repair issues==
* The input should always be terminated when not in use because the [[sampling diodes]] are easily damaged by excessive inputs or static discharge.  See that article for possible replacements.
* The ground contact of input termination resistor R4 can become intermittent, causing the input impedance to go high or fluctuating. The cure is to disassemble the sampler incuding the sampler board covers, and then carefully bend the ground tabs of the input termination resistor outward.
==Prices==
1979: $780 (~$3,000 in 2022 Dollars)
According to an [[Media:Tek Schottky Diodes Memo rot.pdf|internal memo]], in 1979 annual sales were estimated at 321 units.


==Pictures==
==Pictures==


<gallery>
<gallery>
File:Tek s2 front.jpg
Tek s2 front.jpg
File:S-52 s-2 rt.jpg | [[S-52]] and S-2 give 76 ps rise-time together.
S-2_50ps_front.JPG | early S-2 with  tr ≤ 50ps on front
File:S2 schem1.png
S_2_old.JPG      | early S-2 with ‎overstickered tr ≤ 50ps
File:Tek s2 strobe side.jpg
S-2_eng_sample.JPG |  two S-2 engineering sample (late model)
File:Tek s2 amp side.jpg
S-52 s-2 rt.jpg | [[S-52]] and S-2 give 76 ps rise-time together
File:Tek s2 bridge in place.jpg|Sampling diodes in place.
S2 schem1.png   | schematic
File:Tek s2 input term r4.jpg|Input termination resistor.
Tek s2 strobe side.jpg | S-2 interior, strobe board side
File:Tek s2 sampler r.jpg
Tek s2 amp side.jpg | S-2 interior, amplifier board side
File:Tek s2 sampler l.jpg
Tek s2 bridge in place.jpg | Sampling diodes in place
File:Tek s2 diode removal.jpg|Diode holder slides out.
Tek s2 input term r4.jpg | Input termination resistor R4
File:Tek s2 amp under.jpg
Tek s2 sampler r.jpg | Sampler board, right
File:Tek s2 amp removed.jpg
Tek s2 sampler l.jpg | Sampler board, left
File:Tek s2 strobe under.jpg
Tek s2 diode removal.jpg | Diode holder slides out
File:Tek s2 strobe removed.jpg
Tek s2 amp under.jpg | Sampler board underside
File:Tek s2 amp side.jpg
Tek s2 amp removed.jpg | S-2 with amplifier board removed
Tek s2 strobe under.jpg | Strobe board underside
Tek s2 strobe removed.jpg | S-2 with strobe board removed
Tek s-2 rise trace.jpg|S-2 pulse response
</gallery>
</gallery>




[[Category:7000 and 3S series sampling heads]]
[[Category:7000 and 3S series sampling heads]]
[[Category:GR874]]

Latest revision as of 11:58, 19 June 2024

Tektronix S-2
Sampling Head
S-2 head

Compatible with 7000 and 3S series sampling heads

Produced from 1967 to 1989

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix S-2 Sampling Head plug-in provides a single GR-874 50 Ω input with a 75 ps risetime.

The S-2 can be used in the 7000 series and 3S series of sampling plug-ins. It provides an internal trigger pickoff signal for internal triggering. Noise is specified as less than 10 mV.

When the S-2 was first introduced, the rise-time specification was 50 ps, but that was not achieved in practice, so the rise-time specification was revised to be 75 ps.

The interface between the GR-874 connector and the printed circuit board is described in US Patent 3,426,311.

Key Specifications

Rise time 75 ps (50 ps initially)
Bandwidth 4.66 GHz eq.
Operating input voltage range −1 V to +1 V with ≤1 Vp-p signals
Maximum single sample step 200 mV
Maximum input voltage ±5 VDC or sine of 10 Vp-p up to 10 MHz
Input impedance 50 Ω ±1% (GR-874)
Noise < 10 mV
Features trigger pickoff for internal triggering

Links

Documents Referencing S-2

Document Class Title Authors Year Links
Service Scope 53 Dec 1968.pdf Article Digital Systems Come Of Age John Bowne 1968
Service scope dec 1968 ocr.pdf Article Digital Systems Come of Age John Bowne 1968
Service Scope 52 Oct 1968.pdf Article The State of the Art in Sampling Al Zimmerman 1968
42W-5850.pdf Application Note Preventing Sampling Head Overdrive and Static Damage Gary Mott 1985

Similarity to S-1

The S-1 and S-2 samplers are constructed very similarly. The mechanical construction including internal connector locations is identical, and the preamp boards are almost identical. The main difference in these boards is the value of the gain adjust trimpot R46, which is 5k for the S-1 and 30k for the S-2, to allow higher gain settings to compensate for the shorter sampling pulses of the S-2. Bipolar transistors Q41 and Q45 are different types (why?). Preamp boards can be swapped between S-1s and S-2s for testing purposes without issues.

The strobe boards use identical active components (avalanche transistor Q69 153-0556-00 and Snap-off diode D61 152-0335-00), but the board layout is different to accommodate longer strobe clipping lines in the S-1.

The sampling circuit itself is almost identical, except that the dampening resistors R7B and R8B of the S-1 are missing in the S-2. The sampling diodes are different, the S-2 uses a 152-0361-00 GaAs matched pair.

Repair issues

  • The input should always be terminated when not in use because the sampling diodes are easily damaged by excessive inputs or static discharge. See that article for possible replacements.
  • The ground contact of input termination resistor R4 can become intermittent, causing the input impedance to go high or fluctuating. The cure is to disassemble the sampler incuding the sampler board covers, and then carefully bend the ground tabs of the input termination resistor outward.

Prices

1979: $780 (~$3,000 in 2022 Dollars)

According to an internal memo, in 1979 annual sales were estimated at 321 units.

Pictures