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7D14: Difference between revisions
circuit details
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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 | ||