Working with my repaired 8644A (options 002,004,007,010) I noticed quite jitter on generator modulation audio output.
If I choose square output there is 600 ns waveform jitter present.
When using sine output there isnt any.
Same internal modulation generator (NSM OSC) PCB is used in whole 8644/64/65 generators series, can you look at it ?
Is it known bug / limitation of internal LF generator ?
My suspect is old firmware - 2.10.0 on bay I seen 8644 advertised with 4.2 (?) firmware versions.
Can you look what FW version is in your 8644A/B (showing for couple of seconds at startup)?
Anybody have firmware files newer than 2.10? more information about firmware versions ? is firmware inter changeable between 8644 and 8664/5 ?
Juris
yl3cb
p.s.
If anybody want to upgrade 8644 to 2GHz option, on bay is available doubler module for 70$, also other modules from 8644...