Pulse Generator Tektronix Type 284 (067-0548) with manual

Description

The 284 comes without an enclosure but with a manual and calibration procedure plus cardboard sleeve. Unit is in good cosmetic condition. Unit powers up, and when tested, seems to work well.  However it is sold
AS-IS
The fast pulse risetime pictures are taken with a relatively slow scope: 7834, 7B10, 7A19.  This is what I have at this time.  There are two different pictures: Full Scan and Reduced scan. The reduced scan mode ups the writing rate and waveform size to give better brightness and risetime.  Check out the photos.
The
Tektronix 284
is a pulse generator
introduced in July 1967
. Its output modes include:
70 ps risetime pulse, 200 mV, 50 kHz repetition rate, 1 μs pulse duration (5% duty cycle)
Sine wave, 1 GHz or 100 MHz, 100 mV
Square wave, 10 MHz, 1 MHz or 100 kHz, 10 mV, 100 mV, or 1 V
Only one mode can be used at a time. The pulse comes out one output connector. The sine wave and square wave come out another output connector. Both outputs are 50 Ω
GR-874
.
The 284 generates a 1 GHz sinewave using a
2N3478
RF NPN transistor-based oscillator.
The 284 generates the 70 ps risetime pulse using a 20 mA, 1.5 pF tunnel diode, D180, Tektronix part number
152-0329-00
. D180 is mounted inside of a 50 Ω airline (rigid coaxial transmission line with only air between the center conductor and the shell). D180 is in series with the airline's center conductor. One end of the airline contains three resistors for biasing the tunnel diode and terminating the transmission line. The other end of the airline is the GR-874 pulse output connector. For each pulse (every 20 μs):
the biasing current is switched on, putting D180 close to its peak current
a capacitively coupled "tripper" applies a short current pulse to D180, causing it to switch to its high-voltage state
the biasing current is switched off, causing the tunnel diode to fall back to the low-voltage state
The tripper pulse is produced by a
snap-off diode
. Air gap capacitors couple the tripper pulse to the tunnel diode. These capacitors, C185 and C186, are drawn with dashed lines in the schematic because they are really just stray capacitances. One side of each capacitor is the unconnected center pin of the bulkhead-mount female
SMB connectors
in the side of the airline. The other side of the capacitor is the conductive tunnel diode mount in the core of the airline.
Limited International Shipping
NOTE: Shipping cost reflects double boxing and insurance.
Unit is sold
AS-IS
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