7D14
The Tektronix 7D14 is a 525 MHz frequency counter plug-in for 7000 series mainframes.
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) |
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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 |
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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
Prices
Year | 1973 | 1976 | 1980 |
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Catalog Price | $1,400 | $1,550 | $2,075 |
In 2023 Dollars | $9,700 | $8,400 | $7,700 |
Pictures
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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).
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7D14 left side
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7D14 right side (later 670-0993-01 board)
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7D14 detail - input amplifier
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7D14 detail - counter gate
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7D14 detail - 525 MHz divide-by-2 stage (later 670-0993-01 board)
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7D14 detail - divide-by-5 discrete ring counter stage
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Components
Some Parts Used in the 7D14
Part | Part Number(s) | Class | Description | Used in |
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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 |