7D14: Difference between revisions
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title=Tektronix 7D14| | title=Tektronix 7D14| | ||
summary=525 MHz frequency counter| | summary=525 MHz frequency counter| | ||
image= | image=7d14-front.jpg | | ||
caption=7D14 front view (manual)| | caption=7D14 front view (manual)| | ||
introduced=1971 | | introduced=1971 | | ||
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{{EndSpecs}} | {{EndSpecs}} | ||
==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 decade is implemented as a divide-by-2 ECL flip-flop followed by a 5-stage ring counter made with discrete transistor pairs (note circular layout) and some logic to BCD-encode the count result. | |||
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 [[7000 series readout system|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== | ==Links== | ||
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==Pictures== | ==Pictures== | ||
<gallery> | <gallery> | ||
File:Tek 7d14 1.jpg | File:7d14-front.jpg | 7D14 front panel | ||
File:7d14-left.jpg | 7D14 left side | |||
File:7d14-right.jpg | 7D14 right side | |||
File:7d14-input-amp.jpg | 7D14 detail - input amplifier. Own photo. | |||
File:7d14-gate.jpg | 7D14 detail - counter gate | |||
File:7d14-div2.jpg | 7D14 detail - 525 MHz divide-by-2 stage | |||
File:7d14-div5.jpg | 7D14 detail - divide-by-5 discrete ring counter stage | |||
File:7d14-screen.jpg | 7D14 screen picture - 500 MHz signal counted on trigger path ([[7A19]] amplifier, [[7B92A]] time base in a [[7904]] mainframe) | |||
File:Tek 7d14 1.jpg | |||
File:Tek 7d14 2.jpg | File:Tek 7d14 2.jpg | ||
File:Tek 7d14 3.jpg | File:Tek 7d14 3.jpg | ||
Revision as of 05:30, 3 October 2014
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.
Specifications
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 |
|
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 decade is implemented as a divide-by-2 ECL flip-flop followed by a 5-stage ring counter made with discrete transistor pairs (note circular layout) and some logic to BCD-encode the count result.
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
Pictures
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7D14 front panel
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7D14 left side
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7D14 right side
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7D14 detail - input amplifier. Own photo.
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7D14 detail - counter gate
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7D14 detail - 525 MHz divide-by-2 stage
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7D14 detail - divide-by-5 discrete ring counter stage
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