1A4: Difference between revisions

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The 1A4 is a 1-series vertical plug-in with four input channels and 50MHz bandwidth. The four channels are grouped into two groups of two channels.  The 1A4 has a special "trace slaving" mode which, when used in a 547 mainframe, allows channels 1 and 2 to be displayed using the A time base, and channels 3 and 4 to be displayed with the B time base.  This allows high-speed and low-speed signals to be displayed together, similar to what a dual-beam scope can do, but without some of the cost and complexity.
{{Plugin Sidebar 2 |
title=Tektronix 1A4 |
summary=50 MHz quad input amplifier plugin |
image=Tek 1a4 frontx.jpg |
caption=Tektronix 1A4 front |
years=1967 - 1975 |
introduced=1967 |
discontinued=1974 |
series=[[500-series scopes]] |
manuals=
* [http://w140.com/mmm/tek-1a4.pdf Tektronix 1A4 Manual (PDF)]
* [http://bama.edebris.com/manuals/tek/1a4 1A4 manual on BAMA (offline?)]
* [[Media:Tek 1a4 fcp jan 1967.pdf‎|Tektronix 1A4 Factory Calibration Procedure, January 1967]]
}}
The '''Tektronix Type 1A4''' is a 1-series vertical plug-in for [[500-series scopes]].
It has four input channels and 50 MHz bandwidth.  


The signal path of each channel of the 1A4 is as follows.  First the signal passes through the attenuators.  Then it is clamped by two diodes and applied the the gate of a JFET source follower.  The source of the source follower is the trigger pickoff point.  From there the signal goes through an NPN emitter follower followed by an NPN differential amplifier, at which point the signal becomes differential.  Next, the signal passes through an analog multiplexer made with 1N4152 silicon switching diodes.  After the multiplexer network, the signal passes through a common base amplifier followed by 6DJ8 tube operating in common grid configuration.
Type 1A4 was [[introduced in 1967]] and lasted until the end
of the [[500-series scopes]] line.
 
The four channels are grouped into two groups of two channels. 
Type 1A4 has a special "trace slaving" mode which,
when used in a [[547]] mainframe,
allows channels 1 and 2 to be displayed using the A time base,
and channels 3 and 4 to be displayed with the B time base. 
This allows high-speed and low-speed signals to be displayed together,
similar to what a dual-beam scope can do, but without some of the cost and complexity. 
 
Like the Type [[1A2]] and unlike the Type [[1A1]],
the Type 1A4 has a Trigger Output selector that controls
which channel provides triggering when the mainframe trigger is in Plug-In mode,
for scopes having this feature ([[544]], [[546]], [[547]], [[549]], [[556]], late [[555]]).
 
==Specifications==
[[Category:Specifications needed]] ''please add''
 
Maximum channel sensitivity is 10 mV/div,
but a Signal Out jack makes it possible to cascade two channels
for approximately 200 μV/div AC with about 20 Hz - 1 MHz bandwidth. 
 
==Internals==
The signal path of each channel of the 1A4 is as follows.   
First the signal passes through the attenuators.   
Then it is clamped by two diodes and applied to the gate of a JFET source follower.   
The source of the source follower is the trigger pickoff point.   
From there the vertical signal path goes through an NPN emitter follower  
followed by an NPN differential amplifier,  
at which point the signal becomes differential.   
Next, the signal passes through an analog multiplexer  
made with [[1N4152]] silicon switching diodes.   
After the multiplexer network, the signal passes through a common base amplifier  
followed by [[6DJ8]] tube operating in common grid configuration.
 
==Pictures==
<gallery>
Tek 1a4 front n1.jpg
Tek 1a4 left n1.jpg
Tek 1a4 top n1.jpg
Tek 1a4 right n1.jpg
Tek 1a4 bottom n1.jpg
Tek 1a4 rear n1.jpg
Tek 1a4 frontclose n1.jpg
1a4 front.jpg
1a4 right2.jpg
1a4 top.jpg
1a4 bottom.jpg
</gallery>
 
[[Category:500 series plugins]]

Revision as of 14:33, 8 June 2019

Template:Plugin Sidebar 2 The Tektronix Type 1A4 is a 1-series vertical plug-in for 500-series scopes. It has four input channels and 50 MHz bandwidth.

Type 1A4 was introduced in 1967 and lasted until the end of the 500-series scopes line.

The four channels are grouped into two groups of two channels. Type 1A4 has a special "trace slaving" mode which, when used in a 547 mainframe, allows channels 1 and 2 to be displayed using the A time base, and channels 3 and 4 to be displayed with the B time base. This allows high-speed and low-speed signals to be displayed together, similar to what a dual-beam scope can do, but without some of the cost and complexity.

Like the Type 1A2 and unlike the Type 1A1, the Type 1A4 has a Trigger Output selector that controls which channel provides triggering when the mainframe trigger is in Plug-In mode, for scopes having this feature (544, 546, 547, 549, 556, late 555).

Specifications

please add

Maximum channel sensitivity is 10 mV/div, but a Signal Out jack makes it possible to cascade two channels for approximately 200 μV/div AC with about 20 Hz - 1 MHz bandwidth.

Internals

The signal path of each channel of the 1A4 is as follows. First the signal passes through the attenuators. Then it is clamped by two diodes and applied to the gate of a JFET source follower. The source of the source follower is the trigger pickoff point. From there the vertical signal path goes through an NPN emitter follower followed by an NPN differential amplifier, at which point the signal becomes differential. Next, the signal passes through an analog multiplexer made with 1N4152 silicon switching diodes. After the multiplexer network, the signal passes through a common base amplifier followed by 6DJ8 tube operating in common grid configuration.

Pictures