7D15

The Tektronix 7D15 is a 225 MHz frequency counter plug-in for 7000-series scopes. It is optimized for timing measurements, having a 100 MHz oscillator and interval measurement averaging capability. It has two inputs and can measure frequency, period or time difference.

The front panel uses SMB connectors for arming, clock in/out and reset signals.

Specifications

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Internals

The 7D15 uses a number of Tek-made custom chips. The 155-0086-00, 155-0087-00 and 155-0088-00 legend generators are specific to this plug-in. The 155-0090-00 or 155-0171-00 four decade counter/latch/DAC chips implement the lower six counter digits. For the topmost two digits, the 7D15 employs ECL counters. ECL logic requires a -5 V supply, which a switching regulator (board A8) generates from the -15 V rail.

The 5 MHz signal from the (non-ovenized) internal reference crystal oscillator is divided down to a 1 MHz master clock. Optionally, the 1 MHz can be supplied externally as well. An internal VCO, phase-locked to the 1 MHz master, produces a 100 MHz input to the counter chain for timing measurements.

Links

• Tek 7D15 page @ amplifier.cd
• Tek 7D15 page @ barrytech.com

Prices

Year	1973	1976	1980	1984	1990
Price	$1,475	$1,600	$2,200	$3,200	$4,400
2015 value	$7,840	$6,640	$6,300	$7,270	$7,950

Pictures

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  7D15 front

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  7D15 left side. Note -5 V switching regulator (board A8) on the far left.

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  7D15 right side