7854: Difference between revisions

Jump to navigation Jump to search
190 bytes added ,  9 August 2021
no edit summary
m (→‎top: clean up, replaced: {{Oscilloscope Sidebar → {{Oscilloscope Sidebar |manufacturer=Tektronix |designers=, title=Tektronix → model=)
No edit summary
Line 1: Line 1:
{{Oscilloscope Sidebar |manufacturer=Tektronix |designers=|
{{Oscilloscope Sidebar  
model= 7854|
|manufacturer=Tektronix  
image=tek7854.jpg|
|series=7000-series scopes
caption=Tektronix 7854 on a [[K213]] cart|
|model=7854
introduced=1980 |
|image=tek7854.jpg
discontinued=1990 |
|caption=Tektronix 7854 on a [[K213]] cart
summary=400 MHz waveform-processing scope|
|introduced=1980  
manuals=
|discontinued=1990  
|summary=400 MHz waveform-processing scope
|designers=Tom Rouseau;Les Larson;Jack Collins;Ellen Deleganes;Jim Schlegel;Gary Fladstol;Val Garuts;Tim Holte;Burt Johnson;Bruce Kingsland;Wes Kosta;Jim Tallman;Kirk Wimmer
|manuals=
* [http://w140.com/070-2874-01.pdf Tektronix 7854 Manual (PDF, OCR)]
* [http://w140.com/070-2874-01.pdf Tektronix 7854 Manual (PDF, OCR)]
* [http://w140.com/7854_manual_change_info_d.pdf Tektronix 7854 Manual Change Information (PDF)]
* [http://w140.com/7854_manual_change_info_d.pdf Tektronix 7854 Manual Change Information (PDF)]
Line 66: Line 69:
==Internals==
==Internals==
The acquisition system uses what Tektronix termed a "display-oriented random sampling digitizing technique".
The acquisition system uses what Tektronix termed a "display-oriented random sampling digitizing technique".
It simultaneously digitizes a pair of X and Y signal values at a rate of 3.5 µs/point, using Schottky diode bridge
It simultaneously digitizes a pair of X and Y signal values at a rate of 3.5 µs/point, using Schottky diode bridge based sample/hold circuits and a single 10-bit successive-approximation ADC.   
based sample/hold circuits and a single 10-bit successive-approximation ADC.  The Y sample value is then  
The Y sample value is then written into the memory location addressed by the X value, using DMA.  
written into the memory location addressed by the X value, using DMA.  


The CPU in the 7854 is a [https://en.wikipedia.org/wiki/Texas_Instruments_TMS9900 Texas Instruments TMS9900 16-bit microprocessor],
The CPU in the 7854 is a [https://en.wikipedia.org/wiki/Texas_Instruments_TMS9900 Texas Instruments TMS9900 16-bit microprocessor], known from the infamous TI-99/4 home computer of the late 70s, with 32+6KByte ROM and 8KByte RAM.
known from the infamous TI-99/4 home computer of the late 70s, with 32+6KByte ROM and 8KByte RAM.


The firmware consists of mask ROMs, an FPLA, and patch EPROMs.  These ROMs (particularly the early ones from Mostek) are a common point-of-failure. Several remedies exist, [[7854rom|outlined here]].
The firmware consists of mask ROMs, an FPLA, and patch EPROMs.  These ROMs (particularly the early ones from Mostek) are a common point-of-failure. Several remedies exist, [[7854rom|outlined here]].

Navigation menu