7854

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The Tektronix 7854 Waveform Processing Oscilloscope, introduced in 1980, is a 400 MHz combined analog / digital mainframe in the 7000 series that takes two vertical and two horizontal 7000-series plug-ins. In addition to a conventional analog (real time) scope, it contains an equivalent-time sampling 10-bit digitizer and a programmable waveform processor with GPIB interface. Single-shot, pretrigger acquisition is possible with the special 7B87 time base using real-time sampling. The project manager for the 7854 was Tom Rousseau. During early development, before it was given the name "7854", the product was referred to as the "Smart Scope", and the digital processing was called the "smarts".

The waveform processor can be programmed using a detachable calculator-style keyboard, using postfix operators ("reverse Polish notation" like HP calculators) that operate on entire waveforms, not just individual numbers.

Key Specifications

Bandwidth (analog) 400 MHz
Fastest cal. sweep 500 ps/Div
Sample rate 500 kHz (stores repetitive waveforms up to 400 MHz)
Resolution 10 bit
Acquisition depth 128, 256, 512 or 1024 points
Memory capacity 2048 waveform points in up to 16 waveforms (optional expansion to 5120 points and 40 waveforms)
Single shot events and pretrigger up to 50 µs/div ("2.5 µs/point") with the 7B87 Time Base
CRT 154-0644-05 (P31) or 154-0893-09 (P11); cathode −3 kV, anode +21 kV, distributed vertical deflection plates
Features
  • Signal averaging
  • Cursor measurements
  • Waveform parameter measurements
  • GPIB interface (standard)
  • Waveform calculation operators - add, multiply, square root, log, abs
  • Internal RPN programming language (Reverse Polish Notation)
  • Keystroke programming (up to 2000 keystrokes with option 2D)
  • Programmable text display on screen
Options
  • Option 02: X-Y Phase Correction
  • Option 03: EMC Modification
  • Option 78: P11 Phosphor
  • Option 2D: 4K Expanded memory storage for up to 40 waveforms and 2000 keystrokes
Power consumption 230 W
Weight 42 lbs / 19 kg

Documents

Documents Referencing 7854

Document Class Title Authors Year Links
AX-4382.pdf Application Note WP1310 Waveform Processing System 1980
AX-4425.pdf Application Note WP1310 Signal Processing System 1980
AX-4440.pdf Application Note 7854 On-board Digital Processing Refines Scope Measurements Val Garuts Jim Tallman 1980
Tek 7854-AN-SPSBasic.pdf Article Talking to the 7854 scope with TEK SPS BASIC. Bob Ramirez 1980
Tekscope 1980 V12 N2.pdf Article New Products 1980
Tekscope 1980 V12 N3.pdf Article Digital Waveform Processing in a High-Performance 7000-Series Oscilloscope Tom Rousseau Bill Cox 1980
42AX-4682.pdf Application Note Introduction to 7854 Oscilloscope Measurement and Programming Techniques 1981
7854 Application Programs.pdf Application Note 7854 Application Programs Mike Mraz Gary Kirchberger Clark Foley Roger Loop 1981
AX-4281.pdf Application Note Measurement Variety. An Engineering Challenge Featuring the 7854 1981
AX-4864.pdf Application Note 7854 Waveform Calculator Keyboard Guide 1981
42W-4416-1.pdf Application Note Using the 7854 in a GPIB configuration 1982
42W-5334.pdf Application Note Automated TDR Testing Made Easy with the 7854 Oscilloscope/7S12 Sampler Plug-In 1983
42W-5700.pdf Application Note Power Supply/Device Testing 1984
42W-5802.pdf Application Note Basic software programs for communicating between the 7854 and IBM PC 1985
42W-6732.pdf Application Note TekMAP 7854 Time and Amplitude Measurement Software 1987
42W-6767.pdf Application Note Tektronix 7854TDR and 7854MPS measurement packages 1987

Prices

Year 1981 1984 1990
Catalog price $10,500 $14,230 $17,000
In 2023 Dollars $35,500 $42,000 $39,900

Diagnostic Test Interfaces

Extender Boards

  • 067-0913-00 Extender Board 44-Pin (used with the A30-GPIB and A31-ROM Boards)
  • 067-0914-00 Extender Board 80-Pin (used with the A27-MPU and A28-RAM Boards)
  • 067-0915-00 Extender Board 124-Pin (used with the A26-Control Logic and A29-Display Boards)

Software

Links

Internals

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 sample/hold circuits based on Schottky diode bridges, and a single 10-bit successive-approximation ADC. The Y sample value is then written into the memory location addressed by the X value, using DMA (direct memory access, i.e. bypassing the CPU).

The CPU in the 7854 is a 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.

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, see the Repairs page.

Pictures

Memory Maps

Devices with separated ROM and RAM boards (SN < B100000)

Address Range Size ICs Purpose
0000...3FFE 8k U100, U110 ROM
4000...7FFE 8k U200, U210 ROM
8000...8FFE 2k U300, U310 PATCH ROM “for future use”
9000...9FFE 2k U400,U410 PATCH + ROM
2k RAM 4k RAM 8k RAM
A000...A7FE 1k U510,U520,U530,U540 x x x
A800...AFFE 1k U610,U620,U630,U640 x x
B000...B7FE 1k U710,U720,U730,U740 x
B800...BFFE 1k U810,U820,U830,U840 x
C000...C7FE 1k U110,U120,U130,U140 x
C800...CFFE 1k U210,U220,U230,U240 x
D000...D7FE 1k U310,U320,U330,U340 x x
D800...DFFE 1k U410,U420,U430,U440 x x x
E000...E37E GPIB, Keyboards, Digitizer,...
E380...FFFE Reserved for Diagnostic Interface

Devices with combined RAM+ROM Board (SN >= B100000)

Address Range Size ICs Purpose
0000...7FFE 16k U220,U320 ROM
8000...9FFE 4k U200,U300 ROM for future use
A000...DFFE 8k U400,U410 RAM
E000...E37E 4k GPIB, Keyboards, Digitizer,...
E380...FFFE Reserved for Diagnostic Interface

Devices with installed Diagnostic Boards (all serial numbers)

Address Range Size ICs Purpose
0000...0FFE 2k U430,U330 ROM
1000...1FFE 2k U410,U310 ROM
2000...2FFE 2k U200,U100 ROM
3000...3FFE 2k U220,U120 ROM
4000...4FFE 2k U420,U320 ROM
5000...5FFE 2k U400,U300 ROM
6000...6FFE 2K U210,U110 ROM
7000...7FFE 2K ROM for future use
8000...7FFE 4k Not used
9800...9FFE RAM in Microlab I, disabled when standard ROM is in 7854
A000...DFFE 2...8k RAM – see tables above
E000...E37E GPIB, Keyboards, Digitizer,...
E380...E39E BKREGCS Breakpoint address register chip select
E3A0...E3BE CTREGCS control register chip select
E3C0...E3DE BKDATA breakpoint data latch
E3E0 F/P Display Data
E3E2 F/P Display Data
E3E4 F/P Keyboard Data
E3E6 F/P Keyboard flag reset
E3E8 Terminal I/O Control
E3EA Terminal I/O Data
E3EC Cassette I/O Control
E3EE Cassette I/O Data
E3F0 Modem I/O Control
E3F2 Modem I/O Data
E3F4...E3FE ONBDIO on board input/output to microlab I
E400...E7FE RAM in Microlab I
E800...EFFE U120,U225 ROM - bank switched by PROMBK
F000...FFFE U220,U320 ROM - bank switched by PROMBK

Components

Some Parts Used in the 7854

Part Part Number(s) Class Description Used in
154-0644-00 154-0644-00 154-0644-04 154-0644-05 154-0644-09 CRT CRT with distributed deflection plates 7704A 7854 7904 7904A R7903
155-0009-00 155-0009-00 Monolithic integrated circuit horizontal lockout logic 7504 7514 7704 7704A R7704 7834 7844 7854 7904 R7903 7904A 7934 7104
155-0010-00 155-0010-00 Monolithic integrated circuit chop divider and blanking 7504 7514 7704 R7704 7704A 7834 7854 7904 R7903 7904A 7934 7104
155-0011-00 155-0011-00 Monolithic integrated circuit clock and chop blanking 485 7313 7403N R7403N 7503 7504 7514 7603 AN/USM-281C 7613 7623 7623A 7633 7704 R7704 7704A 7834 7844 7854 7904 7904A R7903 R7912 7912AD 7912HB 7934 7104 R7103 AN/USM-281C
155-0012-00 155-0012-00 Monolithic integrated circuit Z Axis Logic 485 7504 7514 7704 R7704 7704A 7834 7844 7854 7904 R7903 7904A R7912 7934 7912AD 7912HB 7104 R7103
155-0013-00 155-0013-00 155-0013-01 Monolithic integrated circuit horizontal chop and alt. binary 7504 7514 7704 R7704 7704A 7834 7854 7904 7904A R7903 7934 7104
155-0014-01 155-0014-00 155-0014-01 Monolithic integrated circuit A/D converter 7000 series readout system 7854 7934 7J20 7L5 P7001
155-0015-01 155-0015-00 155-0015-01 Monolithic integrated circuit analog data switch 7000 series readout system 7854 7934
155-0017-00 155-0017-00 Monolithic integrated circuit 5 MHz decade counter 7000 series readout system 7854 7934
155-0021-00 155-0021-00 155-0021-01 Monolithic integrated circuit timing generator 7000 series readout system 7854 7934
155-0022-00 155-0022-00 155-0022-01 Monolithic integrated circuit analog multiplexer 147 148 149 335 468 1430 1441 1461 1900 1910 2220 2221 2230 5223 5403 5440 5441 5443 5444 5A38 7313 7403N 7503 7504 7514 7603 AN/USM-281C 7613 7623 7623A 7633 7704 R7704 7704A 7834 7844 7854 R7912 7912AD 7912HB 7904 R7903 7904A 7934 7A12 7A18 7A18A 7A18N 7B52 7B53N 7D10 7D11 7D12 NT-7000 P7001
155-0059-00 155-0059-00 Monolithic integrated circuit HF amplifier 7834 7844 7854 7904 R7903 R7912 7912AD
155-0064-00 155-0064-00 Hybrid integrated circuit vertical output amplifier 7834 7854 7904 R7903 7912AD 485 PG502
155-0067-02 155-0067-00 155-0067-02 155-0067-03 Monolithic integrated circuit SMPS controller 7704A 7834 7844 7854 7904 R7903 7904 7904A 7934 R7912 7912AD 7912HB 7934 7104 R7103 308 434 485 690 P7001
155-0078-00 155-0078-xx 155-0273-00 155-0274-00 Monolithic integrated circuit broadband amplifier 464 465 466 468 475 475A 475M 485 7834 7844 7854 7904 R7903 R7912 7912AD 7912HB 7104 7A16A 7A16P 7A24 7A26 7A42 067-0587-01 067-0680-00 AM503 PG502 PG508 DC510 DC5010 FG5010
155-0167-01 155-0167-01 Hybrid integrated circuit 4-bit D/A converter 7854 ADC820T
155-0187-00 155-0187-00 Monolithic integrated circuit ft doubler amplifier 7854
155-0206-00 155-0206-00 Hybrid integrated circuit channel switch 7854
MC3448 156-1133-02 Monolithic integrated circuit GPIB bus driver 7854
MC68488 156-1246-00 Monolithic integrated circuit GPIB controller 7854 CG551AP
Mostek MK36000 Monolithic integrated circuit 8k×8 mask-programmable ROM 468 7854
Texas Instruments TMS9900 Monolithic integrated circuit 16-bit microprocessor 1980 7854