7D14

The Tektronix 7D14 is a 525 MHz frequency counter plug-in for 7000 series mainframes.

Tektronix 7D14
525 MHz frequency counter 7D14 front view Compatible with 7000-series scopes Produced from 1970 to 1980 Manuals Tektronix 7D14 Service (OCR) Tektronix 7D14 Service, SN B050000+ 7000 Series Digital Plug-In Applications (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

It uses the mainframe's readout system to display an eight-digit count on the CRT. Modes include frequency, frequency ratio and events count using manual or external gate.

When installed in a horizontal compartment, it can count the trigger pickoff from a vertical amplifier unit. This allows simultaneous viewing and counting of a signal in four-bay mainframes.

In a vertical compartment, the trigger signal (i.e. the "shaped" input) can be displayed as the module's Y output.

Key Specifications

Frequency	525 MHz (5 MHz bandwidth limiting switch available)
Sensitivity	100 mV to 10 V
Input Impedance	50 Ω or 1 MΩ // 20 pF on external input, 1.5 Div internal when set to "Trig Source"
Gate time	1 ms to 10 s
Display time	0.1 s to 5 s or infinite
Features	Gate monitor output / Ext Gate input (BSM) 1 MHz reference monitor output / Ext Ref input (BSM)

Internals

An input section using relays selects the counter signal from the internal trigger path or external input, and activates 50 Ω termination and/or attenuators.

A differential FET buffer + bipolar amplifier stage drives a counter gate that uses a 10 mA tunnel diode as the switching element.

The first counter decade is implemented as a divide-by-2 ECL flip-flop (U329) followed by a five-stage ring counter made with discrete transistor pairs (note circular layout) and some logic to BCD-encode the count result.

In early 7D14 units (board 388-1825-00), U329 was a Tek made IC, 155-0046-00, which was not used in other instruments. From SN B050000 on, a standard ECL part (156-0377-00) was used on a a redesigned high-frequency counter board (670-0993-01).

The following seven counter stages are conventional TTL decade ripple counters (N8292A).

The counter outputs are multiplexed onto a common 4-bit bus using open-collector NAND gates under control of the mainframe's readout system. The multiplexed digit value feeds a D/A converter (Tek 155-0038-01) that in turn drives the analog row and column returns to the readout system. A separate blanking logic eliminates leading zeroes and displays a ">" sign in the leftmost column if the counter overflows.

Links

Documents Referencing 7D14

Document	Class	Title	Authors	Year	Links
Tekscope 1971 V3 N1 Jan 1971.pdf	Article	Digital Counter and Multimeter		1971	7D14 • 7D13
Tekscope 1971 V3 N5 Sep 1971.pdf	Article	The 7D14 Counts Current to Minimize Circuit Loading	Emory Harry	1971	7D14 • P6041 • CT-1
Tekscope 1972 V4 N2 Mar 1972.pdf	Article	A Review of Basic Counter Principles	Ray Herzog	1972	7D14
7000 series brochure March 1973.pdf	Brochure	7000 series brochure, March 1973		1973	7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001
Tekscope 1975 V7 N5.pdf	Article	Delayed Gate Aids Oscilloscope Digital Measurements	Dave McCullough	1975	7D12 • 7D14 • 7D15 • 7B53A
7000 Series Digital Plug-In Applications.pdf	Application Note	7000 Series Digital Plug-In Applications		1977	7D10 • 7D11 • 7D12 • 7D13 • 7D14 • 7D15

Prices

Year	1973	1976	1980
Catalog Price	$1,400	$1,550	$2,075
In 2023 Dollars	$9,700	$8,400	$7,700

Pictures

7D14 front panel. The unit pictured was able to count up to 640 MHz on the external input and 532 MHz on the trigger path (7A19 in 7904).
7D14 left side
7D14 right side (later 670-0993-01 board)
7D14 detail - input amplifier
7D14 detail - counter gate
7D14 detail - 525 MHz divide-by-2 stage (later 670-0993-01 board)
7D14 detail - divide-by-5 discrete ring counter stage
7D14 screen picture - 500 MHz signal counted on trigger path (7A19 amplifier, 7B92A time base in a 7904 mainframe)

Components

Some Parts Used in the 7D14

Part	Part Number(s)	Class	Description	Used in
155-0038-01	155-0038-00 • 155-0038-01	Monolithic integrated circuit	5-bit current source D/A converter	7A42 • 7D13 • 7D14 • 7M13 • T4005
155-0046-00	155-0046-00	Monolithic integrated circuit	high-speed divider	7D14
SMTD994	152-0177-01	Discrete component	10 mA, 2 pF tunnel diode	067-0587-01 • 067-0580-00 • 3T5 • 3T6 • 485 • 5S14N • 7D14 • 7T11 • 7T11A • S-53