S-2: Difference between revisions

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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]] (PDF)
* [http://bama.edebris.com/download/tek/s2/s2.djvu Tektronix S-2 Manual @ BAMA] (DjVu)
* [[Media:070-3012-00.pdf|Digital Measurement System S-2 Calibration (PDF, needs OCR)]]
}}
}}
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]].  
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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.
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}}
==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==
Line 41: Line 64:
Tek s2 amp side.jpg | S-2 interior, amplifier board side
Tek s2 amp side.jpg | S-2 interior, amplifier board side
Tek s2 bridge in place.jpg | Sampling diodes in place
Tek s2 bridge in place.jpg | Sampling diodes in place
Tek s2 input term r4.jpg | Input termination resistor
Tek s2 input term r4.jpg | Input termination resistor R4
Tek s2 sampler r.jpg | Sampler board, right
Tek s2 sampler r.jpg | Sampler board, right
Tek s2 sampler l.jpg | Sampler board, left
Tek s2 sampler l.jpg | Sampler board, left

Revision as of 10:02, 13 March 2022

Tektronix S-2
Sampling Head
S-2 head

Compatible with 7000 and 3S series sampling heads

Produced from 1967 to 1989

Manuals
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

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