7S12

Manuals – Specifications – Links – Pictures

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 reflection coefficient (ρ) units, X axis in time or distance.

Key Specifications

Sweep modes	Single / Repetitive / Manual / External input
With S-6 and S-52	Pulse: 200 mV into 50 Ω Rise time: < 35 ps for incident step, < 45 ps for displayed reflection Jitter: < 10 ps
With S-5 and S-54	Pulse: > 400 mV into 50 Ω Rise time: < 1.5 ns for displayed reflection of a shorted line Jitter: < 20 ps
Sweep modes	free-running, single, manual, external input
Air Dielectric Range	15 m (49 ft) 150 m (490 ft) 1500 m (4900 ft)
Weight	2.13 kg (4.7 lbs)

Links

• Tek 7S12 @ amplifier.cd
• Evaluation of 7S12 performance (video)
• 7S12 extender board by Dave Partridge

Documents Referencing 7S12

Document	Class	Title	Authors	Year	Links
7000 series brochure March 1973.pdf	Brochure	7000 series brochure, March 1973		1973	7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001
42W-5334.pdf	Application Note	Automated TDR Testing Made Easy with the 7854 Oscilloscope/7S12 Sampler Plug-In		1983	7854 • 7S12
Rochester LLE Review Volume 25.pdf	Article	Computerized, Wide-Bandwidth, Multichannel, Soft X-Ray Diode Spectrometer for High Density Plasma Diagnosis		1985	7S12 • S-52 • S-6 • LM7912 • LM7912A • 7912DPO
RISOM2873.pdf	Article	Improvement of the Bandwidth of the Transient Digitizers in the LIDAR Thomson Scattering Diagnostic on JET	Erik Kristensen	1990	7912AD • 7A29 • 7704A • 7S12 • S-6 • S-52

Patents that may apply to 7S12

Documents Referencing Time domain reflectometers

Document	Class	Title	Authors	Year	Links
Service Scope 38 Jun 1966.pdf	Article	Tektronix Type 1S2 Makes Reflectometry Easy		1966	1S2 • Time domain reflectometers
Service Scope 45 Aug 1967.pdf	Article	Time-Domain Reflectometry Theory and the Testing of Coaxial Transmission Lines		1967	1S2 • 547 • Time domain reflectometers
062-1244-00.pdf	Book	Measurement Concepts: Time-Domain Reflectometry Measurements	James A. Strickland • H. Allen Zimmerman • Gordon Long • George Frye	1969	Time domain reflectometers • 3S7 • 3T7

Pictures

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  Front view without sampling head plug-ins

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  Front view with S-6 sampling head and S-52 pulse generator

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  7S12 TDR "self portrait" in 7613 storage mainframe

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  7S12 as a sampler, displaying a 1 GHz sine using a S-6 sampling head and S-53 trigger recognizer, 2^nd channel (top) on a 7S11 with S-4 sampling head.

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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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  Rise time of a P6202 500 MHz FET probe measured on a 7S12 with S-52 and S-4 (in a 7844 mainframe), at 1 ns/Div

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  Rise time of a P6202 500 MHz FET probe measured on a 7S12 with S-52 and S-4 (in a 7844 mainframe), at 100 ps/Div

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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

As a generic sampler

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  7S11 with S-4 and 7S12 with S-6 and S-53 displaying a 1 GHz sine in normal mode without storage. Sampling is evident.

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  7S11 with S-4 and 7S12 with S-6 and S-53 displaying a 1 GHz sine in high-res mode with variable-persistence storage on a 7613.