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G8MNY > TECH 24.09.20 06:50z 105 Lines 4454 Bytes #999 (0) @ WW
BID : 7301_GB7CIP
Read: GUEST
Subj: Systron Donner 115 Pulse Gen
Path: HB9ON<IW2OHX<UA6ADV<CX2SA<N3HYM<GB7CIP
Sent: 200924/0634Z @:GB7CIP.#32.GBR.EURO #:7301 [Caterham Surrey GBR] $:7301_GB
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 & side carrying handles.
FRONT PANEL
RATE DELAY WIDTH + Out Levels - Out
___________________________________________________________________
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 & pulse enable.
There is a 50ê 2V pulse sync output for locking up to the start of the
pulse/delay.
The two BNC 50ê outputs give +/- pulses & 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
Repeat RATE ___³___________³___________0v ___³_____________³_________
DELAY time ³ÄÄij ³ÄÄij ³ÄÄij ³ÄÄij
WIDTH time ³Ä³ ³Ä³ ³³ ³³ ³³ ³³
ÚÄ¿ ÚÄ¿+5V Ú¿ Ú¿ Ú¿ Ú¿
+ve Pulse ______³ ³_________³ ³_0v __³³__³³________³³__³³___
-ve Pulse ÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄÄ¿ ÚÄ0v ÄÄ¿ÚÄÄ¿ÚÄÄÄÄÄÄÄÄ¿ÚÄÄ¿ÚÄÄÄ
³_³ ³_³-5v ³³ ³³ ³³ ³³
INSIDE
There are 2 large PCBs filling the whole unit, one has the PSU for 3 power
rails 5V & ñ15V & all the pulse generator electronics.
heatsink
____ÞÞÞÞÞÞÞÞÞÞÞÞÞÞÞÞÞÞÞ________.-----._
³ +5V +15V -15V | DC -*³ Trans- ³
³ V* | corr- ³ former ³
³(ú)() () () |ection ³_________³ V* = set +15V
³ P S U | bias ³ '-----' ³ -* = set -ve pulse -5V ref
³ | amps ~~~~~~~~~³ 0* = set -ve pulse 0V height
³ | +* 0* ³ +* = set +ve pulse 5V height
³ Pulse Generators | +ve -ve ³ F* = set Max rep frequency
³ | Pulse Pulse ³ D* = set shortest delay time
³ F* D* W* | amp amp ³ W* = set shortest width time
³ [ ] [ ] [ ] | ³
³ ÄÅÄ ÄÅÄ ÄÅÄ | -load +load ³
³ _³_ _³_ _³_ | DC amp DC amp ³
ÀÄÄÅÄÄÄÄÅÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
The 2nd PCB has a very complex pair of current limited output amps using 16
heatsinked HF pulse transistors & 5 DC correction op-amps for each of the two
50ê outputs.
USES
Scope calibration of attenuators as the pulse shapes have very wide bandwidth.
Coax cable testing, & 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 soothing 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
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