[R-390] 8640B

[2002tii]

Glenn wrote:

>You can also use it's internal counter for external measurements

Be very, very careful.  The maximum allowable input level is very 
low, and permanent damage occurs just a whisker above it.  Best thing 
to do is solder the BNC cap onto the connector so you're not tempted 
to try to use the external counter input.

>Like most HP gear, the 8640B accepts and external 10MHz reference 
>input should you care to do that

Actually, the 8640B uses a 5 MHz external reference.  At least, the 
civilian version does -- I don't remember offhand whether that is 
different for the AN/USM323 military version.  Of course, a 
comparator and a couple of flip-flops (and a filter if you want a 
sine wave) will easily make 5 MHz from a 10 MHz reference.

Best regards,

Don