S-6

The Tektronix S-6 Sampling Head plug-in is a 50 Ω feed-through unit with a rise-time of 30 ps and bandwidth of 11.5 GHz. It was introduced in 1971.

Manuals – Specifications – Links – Pictures

The S-6 provides two unterminated 50 Ω SMA connections in a loop-through configuration as is convenient for TDR applications. It is good practice to leave a termination resistor on the unit when unused to give some protection against electrostatic discharge. The S-6 does not provide a trigger pickoff signal.

Key Specifications

Rise time	30 ps
Bandwidth	11.5 GHz
Operating input voltage range	1 Vp-p
Maximum single sample step	250 mV for less than 5% aberration
Maximum input voltage	±5 VDC
Input impedance	50 Ω (unterminated!)
Noise	< 5 mV of noise
Features	No internal trigger pick-off signal No internal termination

Internals

The S-6 is very similar to the S-4 in that it uses a 6-diode traveling wave trapped-charge sampling gate. This gate is implemented in the 155-0053-00 hybrid. Since the S-6 is a feed-through sampling head, the blow-by compensation is implemented slightly differently using a 10 k resistor in the hybrid directly connected to the input signal. The S-6 replaces the discrete preamplifier of the S-4 with two opamps from a 155-0035-00 quad opamp chip. The two other opamps are used to buffer the gate bias voltages.

Links

• S-6 internal photo and simulation
• Repairing an S-6 head (with internal photos)
• S-6 @ amplifier.cd 7S12 page
• S-6 @ barrytech.com

Prices

1979: $1,345 (~$5,300 in 2022 Dollars)

According to an internal memo, in 1979 annual sales were estimated at 225 units.

Pictures

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  S-6 front

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  S-6, entire plugin

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  S-6 sampling head and S-52 pulse generator head in a 7S12 TDR/Sampler plugin

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  S-6 with a black face plate

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  S-6 schematic

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  S-6 internal left side

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  S-6 internal right side

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  S-6 internal right side

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  S-6 internal left side, Preamp board removed

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  S-6 internal all boards removed, 155-0053-00 hybrid remains

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  S-6 Preamp board top

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  S-6 Preamp board backside

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  S-6 Strobe board backside

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  S-6 interconnect board

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  155-0053-00 hybrid sampling diode assembly

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  155-0053-00 hybrid sampling diode assembly (internal)

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  155-0053-00 hybrid sampling diode assembly with lid

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  155-0053-00 hybrid sampling diode assembly (internal)

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  155-0053-00 hybrid sampling diode assembly (internal)

Measurements

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  Impulse taken with S6 sampling head. Every dot is equivalent to one sample taken, and combined on the CRT with a rate of app. 100 Hz. Bright dots are newer than dimmed ones.

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  Incident pulse from an S-52 (nom. < 25 ps) displayed by an S-6 head (nom. < 30 ps), both installed in a 7S12. Displayed rise time ~35 ps confirms spec.

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  "Self Portrait" of an S-6: A pulse reflected on the unterminated "through" path (approx. 120 ps one way)

Custom ICs used in the S-6