7S12
The Tektronix 7S12 is a Time Domain Reflectometer / Sampler plug-in for 7000-series scopes. It occupies two mainframe plug-in bays (one vertical, one horizontal).
The 7S12 has two bays for S-series plug-in modules ("heads"). The right bay accepts a pulse generator or a trigger recognizer plug-in, whereas the left bay accepts a sampling plug-in.
The typical configuration is to have an S-6 on the left and an S-52 on the right for time domain reflectometry, or a sampling head like the S-4 on the left and an S-53 on the right as a generic sampler.
The 7S12 can also control an optional 7S11 through its left side contacts, adding a second input channel.
Y axis can be scaled in voltage (mV) or distance (ρ) units, X axis in time or distance.
Key Specifications
Sweep modes | Single / Repetitive / Manual / External input |
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With S-6 and S-52 |
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Sweep modes |
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Weight | 2.13 kg (4.7 lbs) |
Links
- Tektronix 062-1244-00: Time-Domain Reflectometry Measurement Concepts, James A. Strickland, 1969. pages. PDF, OCR, 6.2 MB
- Service Scope No. 45, August 1967 - Time-Domain Reflectometry Theory
- Tek 7S12 @ amplifier.cd
- Tek 7S12 @ barrytech.com
- Evaluation of 7S12 performance (video)
- 7S12 extender board by Dave Partridge
Pictures
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Front view without sampling head plug-ins
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7S12 TDR "self portrait" in 7613 storage mainframe
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Metric dial tape
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Inside
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Left side
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Left side with cover. Side contacts to interface 7S11 are exposed.
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Right side
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Top view
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Horizontal board
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Vertical board
Measurements
TDR
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TDR "Self Portrait" — pulse reflected on S-6 "through" path (approx. 120 ps one way)
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7S12 displaying the incident pulse from an S-52 (nom. < 25 ps) through an S-6 head (nom. < 30 ps). Displayed rise time ~35 ps confirms spec.
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7S12/S-6/S-52 displaying pulse reflection from ~ 5 in semi-rigid SMA cable. Stored display of two traces. Left trace: cable only, right trace: cable plus SMA-to-BNC adapter (~ 25 mm)
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7S12/S-6/S-52 displaying reflected pulse from end of 5 in semi-rigid SMA cable. Stored display overlaying multiple traces, left to right: cable alone, SMA-to-BNC adapter added, BNC f-f adapter added, (cheap) 50 Ω terminator added.
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Full pulse pattern of a 7S12/S-52 in real time (top trace) and sampled (bottom trace) shown simultaneously on 7844. 7S12 trace at slowest possible sweep.
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S-52 pulse in real time (top trace) and sampled (bottom trace) shown simultaneously on 7844. Approximately equal time scales.
Probe rise times
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P6230 Rise time, no ground lead
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P6230 Rise time, no ground lead, enlarged – 9.2 * 20 ps = 184 ps (equiv. to 1.9 GHz bandwidth)
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P6230 with "low inductance" ground lead – rise time 400 ps, bandwidth 875 MHz