4S1: Difference between revisions

Latest revision as of 10:53, 20 July 2023

Tektronix 4S1
Dual channel sampling plugin 4S1 front view image Compatible with 661 Produced from 1962 to (?) Manuals Tektronix 4S1 Manual (late) Tek 661 4S1 5T1 Preliminary Manual Tektronix 4S1 Calibration Outline (OCR) (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix Type 4S1 is a dual-trace sampling unit for the 661. The 4S1 was developed in 1961 and introduced in 1962.

Each channel has a trigger pick-off, a delay line, and a sampler. Specified rise time is 350 ps. The sampling pulses for each channel are generated by a step recovery diode.

Key Specifications

Rise time	350 ps
Deflection	2 mV/Div to 200 mV/Div, 1−2−5
Input impedance	50 Ω

Please add

Description

Sampling Bridge

The sampling pulses are fed to a sampling bridge made of four GaAs diodes. These diodes are fragile and exact replacements are hard to find. They have however been successfully replaced by modern Schottky diodes, e.g. Agilent HSMS-28x series.

Dual-trace and X-Y Modes

The 4S1 has a dual-trace mode, where the A waveform and the B waveform are both displayed in the time domain at the same time with a single trigger source and a single equivalent-time sweep rate. Another mode is called "A vert/B horiz". This mode is used in conjunction with an X-Y mode switch on the panel of the 661. The signals enter the 4S1 through GR-874 connectors on the front panel.

Trigger Amplifier

The 4S1 uses an unusual trigger amplifier with two trigger signal paths. One path is for low frequencies, the other for high frequencies. (A similar approach was also used in the main vertical signal path of the 7A29 several years later.)

From serial number 101 to 1349, the low frequency path starts with a 25 kΩ resistor that DC-couples the input signal to a 2N1429 PNP emitter-follower stage. After that is a 151-103 NPN common-emitter. The high frequency path starts with a trigger pick-off transformer on the input. The pick-off signal feeds a common-base amplifier that uses a 2N700 PNP transistor. The low frequency and high frequency trigger paths meet at the trigger output of the 4S1. From there, the trigger signal passes through the 661, and into a 5T1 or 5T3.

4S1 units with serial number 1350 and up use a slightly less complex trigger amplifier circuit, with a TA2333 silicon NPN transistor amplifying the entire frequency range.

Comparison with S-1 Sampling Heads

The sampler board in the 4S1 is roughly equivalent to a pair of S-1 sampling heads. A short piece of RG-174 coax connects the 661 timing pulse coaxial connector to the SMB connector timing pulse input on the 4S1 sampler board. This signal triggers a blocking oscillator which drives a snap-off diode, D2004, which generates the fast falling edge for the channel A and B sampling bridges. The 4S1 uses 7586 nuvistor triodes as high-impedance buffers between the sampling bridge and the amplification that follows.

The 4S1 has a main chassis and sub-chassis that plug into it. A sub-chassis extension, part number 012-069, allows maintenance of the sub-chassis.

Pictures

top view of 4S1
Coaxial interconnect (using Gremar connectors) from the timing plug-in goes through the mainframe, into the 4S1, and ends here, at the sampler.
This is the sampler. The GaAs sampling diodes are arranged in a diamond shape and are directly connected to the socket from the delay line.
The delay line is a coil of coax going from the trigger pickoff to the sampler.
LF and HF trigger pickoff
trigger pickoff
trigger pickoff
Bottom wiring
Dual trace card
Dual trace card
Dual trace card
Inverter card
Inverter card
Inverter card
Memory card
Memory card
Memory card
Memory card front - solid state version
Memory card rear - solid state version
Amp card
Amp card
Amp card
Sampler card
Sampler card
Sampler card

Some Parts Used in the 4S1

Part	Part Number(s)	Class	Description	Used in
120-0304-00	120-0304-00	Discrete component	inductor	4S1 • 4S2
7308	154-0371-00	Vacuum Tube (Dual Triode)	dual triode	3S76 • 3S3 • 4S1 • 4S2A • 4S3 • S-311
7586	154-0306-00	Vacuum Tube (Triode)	Nuvistor triode	M • 1A1 • 1A2 • 1A5 • 10A2 • 10A2A • 11B1 • 11B2A • 321 • 321A • 3A1 • 3A1S • 3A3 • 3A5 • 3A6 • 3A7 • 3A8 • 3A74 • 3S76 • 3T77 • 3T77A • 3B5 • 4S1 • 4S2 • 6R1 • 6R1A • 9A1 • 9A2 • 82 • 86 • S-311

@@ Line 1: / Line 1: @@
-The Tektronix Type 4S1 is a dual-trace [[sampling_oscilloscope|sampling]] unit for the [[661]].
+{{Plugin Sidebar
-Each channel has a trigger pickoff, a [[delay line]], and a sampler.
+|manufacturer=Tektronix
-Specified rise time is 350ps.
+|series=661
-The sampling pulses for each channel are generated by a step recovery diode
+|type=4S1
-are are fed to a sampling bridge made with of four [[sampling diodes|GaAs diodes]].
+|summary=Dual channel sampling plugin
+|image=4S1 front.jpg
+|caption=4S1 front view image
+|introduced=1962
+|discontinued=(?)
+|designers=
+|manuals=
+* [[Media:070-329.pdf|Tektronix 4S1 Manual (late)]]
+* [https://w140.com/tek_661_4s1_5t1_preliminary.pdf Tek 661 4S1 5T1 Preliminary Manual]
+* [[Media:Tek 4s1 cal outline.pdf|Tektronix 4S1 Calibration Outline]] (OCR)
+}}
+The '''Tektronix Type 4S1''' is a dual-trace [[sampling_oscilloscope|sampling]] unit for the [[661]].
+The 4S1 was developed in 1961 and [[introduced in 1962]].
+Each channel has a trigger pick-off, a [[delay line]], and a sampler.  Specified rise time is 350 ps.
+The sampling pulses for each channel are generated by a step recovery diode.
+{{BeginSpecs}}
+{{Spec | Rise time | 350 ps }}
+{{Spec | Deflection | 2 mV/Div to 200 mV/Div, 1−2−5 }}
+{{Spec | Input impedance | 50 Ω }}
+{{EndSpecs}}
+''Please add''
+==Description==
+=== Sampling Bridge ===
+The sampling pulses are fed to a sampling bridge made of four [[sampling diodes|GaAs diodes]].
 These diodes are fragile and exact replacements are hard to find.
-People have improvised replacements using modern integrated Schottky
+They have however been successfully [[Sampling diodes|replaced by modern Schottky diodes]], e.g. Agilent HSMS-28x series.
-diodes such as those in HP/Agilent's HSMS-28x series.
-The 4S1 has a dual-trace mode, where the A waveform and the B waveform
-are both displayed in the time domain at the same time with a single
-trigger source and a single equivalent-time sweep rate.  Another mode
-is called "A vert/B horiz".  This mode is used in conjunction with
-an X-Y mode switch on the panel of the 661. The signals enter the 4S1
-through [[Connectors#GR-874|GR-874 connectors]] on the front panel.
-The 4S1 uses an unusual trigger amplifier with two trigger signal paths.  One path is for low frequencies, the other for high frequencies.
+=== Dual-trace and X-Y Modes ===
+The 4S1 has a dual-trace mode, where the A waveform and the B waveform are both displayed in the
+time domain at the same time with a single trigger source and a single equivalent-time sweep rate.
+Another mode is called "A vert/B horiz".  This mode is used in conjunction with an X-Y mode switch
+on the panel of the 661. The signals enter the 4S1 through [[GR-874 connector]]s on the front panel.
+=== Trigger Amplifier ===
+The 4S1 uses an unusual trigger amplifier with two trigger signal paths.
+One path is for low frequencies, the other for high frequencies.
 (A similar approach was also used in the main vertical signal path of the [[7A29]] several years later.)
-From serial number 101 to 1349, the low frequency path starts with a 25K resistor that DC-couples the input signal to a
-[[2N1429]] PNP emitter-follower stage.
-After that is a [[151-103]] NPN common-emitter.  The high frequency path starts
-with a trigger pickoff transformer on the input.  The pickoff signal feeds a common-base amplifier
-that uses a [[2N700]] PNP transistor.  The low frequency and high frequency trigger paths meet at the trigger output of the
-S1.  From there, the trigger signal passes through the 661, and into a [[5T1]] or [[5T3]].  4S1 units with serial number
-and up use a slightly less complex trigger amplifier circuit.  The later circuit uses a [[TA2333]] silicon NPN transistor
-to amplify the entire frequency range.
-* [http://w140.com/kurt/4s1.pdf 4S1 manual without schematics]
+From serial number 101 to 1349, the low frequency path starts with a 25 kΩ resistor that DC-couples the input signal to a [[2N1429]] PNP emitter-follower stage.
-* [http://w140.com/kurt/4s1/ 4S1 schematics]
+After that is a [[151-103]] NPN common-emitter.  The high frequency path starts with a trigger pick-off transformer on the input.
-* [http://w140.com/tek_4s1_late.pdf Late Issue Tektronix 4S1 Manual (PDF)]
+The pick-off signal feeds a common-base amplifier that uses a [[2N700]] PNP transistor.
+The low frequency and high frequency trigger paths meet at the trigger output of the 4S1.
+From there, the trigger signal passes through the 661, and into a [[5T1]] or [[5T3]].
+S1 units with serial number 1350 and up use a slightly less complex trigger amplifier circuit, with a [[TA2333]] silicon NPN transistor amplifying the entire frequency range.
+=== Comparison with S-1 Sampling Heads ===
+The sampler board in the 4S1 is roughly equivalent to a pair of [[S-1|S-1 sampling heads]].
+A short piece of RG-174 coax connects the 661 timing pulse coaxial connector to the [[SMB connector]] timing pulse input on the 4S1 sampler board.
+This signal triggers a blocking oscillator which drives a [[snap-off diode]], D2004, which generates the fast falling edge for the channel A and B sampling bridges.
+The 4S1 uses [[7586|7586 nuvistor triodes]] as high-impedance buffers between the sampling bridge and the amplification that follows.
+The 4S1 has a main chassis and sub-chassis that plug into it.
+A sub-chassis extension, part number [[012-069]], allows maintenance of the sub-chassis.
+==Pictures==
 <gallery>
-Image:4s1_top.jpg|top view of 4S1
+Tek 4s1 front.jpeg
-Image:4s1_timing_pulse_connection.jpg|Coaxial interconnect from timing plug-in goes through the mainframe, into the 4S1, and ends here, at the sampler.
+s1_top.jpg|top view of 4S1
-Image:4s1_sampling_bridge.jpg|This is the sampler.  The GaAs sampling diodes are arranged in a diamond shape and are directly connected to the socket from the delay line.
+s1_timing_pulse_connection.jpg|Coaxial interconnect (using [[Gremar connector]]s) from the timing plug-in goes through the mainframe, into the 4S1, and ends here, at the sampler.
-Image:4s1_delay_connection.jpg|The delay line is a coil of coax going from the trigger pickoff to the sampler.
+s1_sampling_bridge.jpg|This is the sampler.  The GaAs sampling diodes are arranged in a diamond shape and are directly connected to the socket from the delay line.
+s1_delay_connection.jpg|The delay line is a coil of coax going from the trigger pickoff to the sampler.
+Tek 4s1 trigger takeoff.png|LF and HF trigger pickoff
+Tek 661 pickoff 1.jpg|trigger pickoff
+Tek 661 pickoff 2.jpg|trigger pickoff
+Tek 4s1 bottom wiring.jpg|Bottom wiring
+Tek 4s1 dual trace card top.jpg|Dual trace card
+Tek 4s1 dual trace card front.jpg|Dual trace card
+Tek 4s1 dual trace card rear.jpg|Dual trace card
+Tek 4s1 inverter card top.jpg|Inverter card
+Tek 4s1 inverter card front.jpg|Inverter card
+Tek 4s1 inverter card rear.jpg|Inverter card
+Tek 4s1 memory card top.jpg|Memory card
+Tek 4s1 memory card front.jpg|Memory card
+Tek 4s1 memory card rear.jpg|Memory card
+S1 memory card front.jpg|Memory card front - solid state version
+S1 memory card back.jpg|Memory card rear - solid state version
+Tek 4s1 amp card top.jpg|Amp card
+Tek 4s1 amp card front.jpg|Amp card
+Tek 4s1 amp card rear.jpg|Amp card
+Tek 4s1 sampler top.jpg|Sampler card
+Tek 4s1 sampling card.jpg|Sampler card
+Tek 4s1 sampler rear.jpg|Sampler card
+</gallery>
-</gallery>
+{{Parts|4S1}}
+[[Category:661 plugins]]
+[[Category:Sampling plugins]]
+[[Category:GR874]]