"Phil Allison" wrote in message
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To overcome the issue with fine frequency adjustment, I fitted 500ohm, 10
turn WW pots in series with one of the sections of each Comptom pot -
which is 2 x 15kohms. Makes it easy to set any frequency up to 50kHz, +/-
1Hz.
Stability is good enough to work with the -100dB notch filter, which at
996 Hz has a notch width of about 0.02 Hz.
Stability issues...
The Leader LAG-120A has a sync terminal for synchronisation with a high
stability frequency source, the circuitry where the synchronisation takes
place looks very similar to the corresponding part of the BDW141 schematic.
The manual has a description of the sync option (page 7/8):
http://www.slashdocs.com/kwqytp/lag-...on-manual.html
Unfortunatly, other than the original manual I have, there's no schematic
but with reference to the BDW141 schematic the sync input is simply a
resistor of 10K between the sync terminal and the R4/R5/R54/C14/C17A node.
Component values are very similar too.
For the LAG-120A in practice the sync range is better than the specified
+/-1%, about +/-2.5% at 1kHz (other freq. not measured).
I don't know about possible pitfalls of implementing such a sync input for
the BDW but maybe it's worth looking into it.
BTW, if you have access to ABSE I could post the LAG-120A schematic and/or
manual.
Gio Re