¿ªÔÆÌåÓý

  1. HP-Agilent-Keysight-Equipment
  2. Topics

A dirty way to get more frequency resolution out of a signal generator

 

To put simply, take a function generator such as a HP 3325B, set the output to 0dBm at 10 Mhz, plug that into the reference input of the signal generator. Then if you want a frequency of 100 Mhz just dial that into the signal generator. If you desire more precision with the frequency than what the signal generator is capable of, just make very slight adjustments to the function frequency on the generator supplying the the reference 10 Mhz.

I would think this could work somewhat however it might not scale linear at the various frequencies set on the signal generator, and the phase noise would suffer. And to determine the actual frequency a frequency counter would be needed.
 

I should point out I have not attempted this as I had no reason to, why I am sharing this is that it appears to be an unusual exploit should you desire a more fine frequency control though not without its obvious draw backs. I am anticipating there might be people in this group who wouldn't recommend this, I haven't tried it and I certainly don't encourage others other than simply being a interesting discussion.
 

This will probably work but you would need a counter to verify the output signal is what you are expecting.
There is no guaranty that a low resolution generator will be able to hold steady on digits it cannot even display.

--Victor
 

Hi,

This is pretty similar to what the 8640B signal generator does. You
can lock the oscillator to the quartz time base via the counter. Then
by changing the counter timebase you can fine tune the frequency. One
caveat is that the counter will not indicate the change as the
generator is locked to the counter. And, probably doesn't have enough
resolution anyway. So to find the 'fine tuned' frequency, one has to
use an external counter.

Szabolcs

DW <wilson2115@...> ezt ¨ªrta (id?pont: 2020. m¨¢rc. 1., V, 22:19):


To put simply, take a function generator such as a HP 3325B, set the output to 0dBm at 10 Mhz, plug that into the reference input of the signal generator. Then if you want a frequency of 100 Mhz just dial that into the signal generator. If you desire more precision with the frequency than what the signal generator is capable of, just make very slight adjustments to the function frequency on the generator supplying the the reference 10 Mhz.

I would think this could work somewhat however it might not scale linear at the various frequencies set on the signal generator, and the phase noise would suffer. And to determine the actual frequency a frequency counter would be needed.
 

Some 3325 generators have? the Option 001 OCXO, others don't.

On Sun, Mar 1, 2020 at 4:19 PM DW <wilson2115@...> wrote:
To put simply, take a function generator such as a HP 3325B, set the output to 0dBm at 10 Mhz, plug that into the reference input of the signal generator. Then if you want a frequency of 100 Mhz just dial that into the signal generator. If you desire more precision with the frequency than what the signal generator is capable of, just make very slight adjustments to the function frequency on the generator supplying the the reference 10 Mhz.

I would think this could work somewhat however it might not scale linear at the various frequencies set on the signal generator, and the phase noise would suffer. And to determine the actual frequency a frequency counter would be needed.

1 - 5 of 5