There's a lot of lore out there that, for instance, HP would put
oscillators with good long term stability in counters, but for things
like a spectrum analyzer or signal generator, you'd use an oscillator
with good close in phase noise, because absolute frequency accuracy
isn't as
I have an 8640B in the lab. Bizarre instrument.
David
On 7/13/20 2:57 PM, Richard (Rick) Karlquist wrote:
On 7/13/2020 11:34 AM, jimlux wrote:
There are also "frequency locked" devices that are not "phase locked"
- they essentially discipline an internal oscillator by adjusting its
On 7/13/20 11:27 AM, paul swed wrote:
Taka
I firmly believe the first answer to your question is cost.
Was the counter an economical unit or higher quality.
My 5335 counters have seriously cheap xtal clocks and an external reference
makes a big difference.
But the larger costly generators and
On 7/13/2020 11:34 AM, jimlux wrote:
There are also "frequency locked" devices that are not "phase locked" -
they essentially discipline an internal oscillator by adjusting its
frequency, but not with any sort of phase locked loop.
The 8640 famously worked (sort of) this way. The
Good question; answer is not so simple. Here goes:
Signal generators and spectrum analyzers have to have a low phase
noise oscillator inside to be able to generate/detect spectrally
pure signals. Unlike counters, the 10811, etc has to be standard
equipment, not an option.
Therefore, in order
On 7/13/20 9:58 AM, Taka Kamiya via time-nuts wrote:
I'm sorry to interject a newbie question I changed the title to
distinguish from rest of the conversation.
I have heard this both ways about external references - whether it's used to
phase lock internal source and used directly after
Taka
I firmly believe the first answer to your question is cost.
Was the counter an economical unit or higher quality.
My 5335 counters have seriously cheap xtal clocks and an external reference
makes a big difference.
But the larger costly generators and counters seem to use the phase lock
I'm sorry to interject a newbie question I changed the title to
distinguish from rest of the conversation.
I have heard this both ways about external references - whether it's used to
phase lock internal source and used directly after some conditioning. Both
come from people on this list
