Message 28970 in TECH.WW
From: G8MNY
Date: Sat, 29 Aug 26 07:30:00 Z
Newsgroups: TECH.WW
Subject: Systron Donner 115 Pulse Gen
Message-ID: <3607_GB7CIP>
Path: N2NOV|VE2PKT|GB7BED|EI2GYB|GB7CIP
R:260829/0733z @:N2NOV.#RICH.NY.USA.NOAM $:3607_GB7CIP
R:260829/0733Z 16675@VE2PKT.#TRV.QC.CAN.NOAM LinBPQ6.0.25
R:260829/0732Z 16706@GB7BED.#21.GBR.EU LinBPQ6.0.25
R:260829/0732Z 58238@EI2GYB.DGL.IRL.EURO LinBPQ6.0.25
R:260829/0730Z @:GB7CIP.#32.GBR.EURO #:3607 [Caterham Surrey GBR] $:3607_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Aug 20)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
I bought one of these pulse generators at a rally (it matched my RF sig gen).
It is a 19" 2U rack unit with yellow panels and side carrying handles.
FRONT PANEL
RATE DELAY WIDTH + Out Levels - Out
___________________________________________________________________
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ext Enable Sync Power Base + Comp - Base
In In Out Gnd Out Out Gnd
SPECIFICATION
It generates signals from 0.5Hz - 25MHz, 8 decade variable timebase RATE.
Pulse Delays & Pulse Widths from 100nS - 5S, 8 decade variable.
As well as fixed ratio square wave (to 25MHz).
It has 3 main controls, RATE, DELAY, & WIDTH.
There are 2 inputs for triggering and pulse enable.
There is a 50ohm 2V pulse sync output for locking up to the start of the
pulse/delay.
The two BNC 50ohm outputs give +/- pulses and can be switched to complementary
(invert pulse sense). The outputs have switched & variable high power output
attenuators (2W) to give 5V, 2V, 1V, & 0.5V terminated, as well as optional DC
offset +1 to - 5V. (e.g. offset the 0 & -5V pulse to +5V & 0V)
PULSE SHAPES
Single Pulse Mode Double Pulse Mode
Sync Pulses at +2v
INSIDE
There are 2 large PCBs filling the whole unit, one has the PSU for 3 power
heatsink
The 2nd PCB has a very complex pair of current limited output amps using 16
heatsinked HF pulse transistors and 5 DC correction op-amps for each of the two
50ohm outputs.
USES
Scope calibration of attenuators as the pulse shapes have very wide bandwidth.
Coax cable testing, and demonstrating pulse shape-spectrum on spectrum
analyser, clearly shows why digital QRM is so bad!
FAULTS
Initially it all appears to be working, although a main smoothing capacitor had
been poorly replaced. Systron Donner kit often fails with main smoothing going
open circuit (been there done that!)
The -ve output occasionally has a DC fault, eventually proved to bad PCB
soldered link throughs on the +15V rail to the DC load amp, on this complex
variable/floating output amp biasing.
See my buls on "A Versatile Pulse Tester", "Spectrum Harmonic Demo circuit".
"Variable RF Attenuator" & "Systron Donner 1702 SIG Gen".
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
← Return to Bulletin List