Hi. I've been looking at a "phase oscillator" with two main dials, phase and frequency. What is a phase oscillator and what is it used for? NB: I'm NOT asking about what a phase shift oscillator is (I don't think I am). Rich

 

Without make/model and/or photos answering your question is a shot in the dark.

From the sound of it, it is a signal generator that allows for adjustment of phase.

 

Phase with respect to what? A single frequency oscillator does not have a phase.

 

ChatGPT gives a lengthy answer to the question "What is a phase oscillator and what is it used for?", which sounds plausible.
Does you oscillator have two signal inputs for controlling frequency according to the phase difference between those signals?

 

You are probably talking about PLL 'Phase Locked Loop' oscillator. Google PLL or Phase Locked Loop.

 

If you don’t know what it is and what it is for, why are you looking for it? Where did you hear that term?

 

Here is the thing I'm looking at, strictly a variable phase oscillator: https://www.ebay.co.uk/itm/176893346233?_trkparms=amclksrc=ITM&aid=777008&algo=PERSONAL.TOPIC&ao=1&asc=281663&meid=d8152e90694945fc9f3cb353beaa47ef&pid=101949&rk=1&rkt=1&itm=176893346233&pmt=1&noa=1&pg=4375194&algv=RecentlyViewedItemsV2WithMLRPboosterAndUpdatedFeatures_BP&_trksid=p4375194.c101949.m162918&_trkparms=parentrq:8556f92a1950ab1dcc3e8726fffffa96|pageci:a8f02442-fe7a-11ef-adfd-6abc66827275|iid:1|vlpname:vlp_homepage

 

https://www.casa.co.nz/equipment/instruments/signal/VPO602_Feedback_Variable_Phase_Oscillator_OM.pdf

 

What a lovely piece of antique equipment!! Very nice collector’s piece.

You know that an electronics equipment is ancient when it has labels in CPS instead of Hertz.
Otoh, the manual shown by Danko is already labeled in Hz.

 

So it is NOT a "phase oscillator".
It is an oscillator with a variable phase - can be used, for example, for phase modulation.

 

Some people shorten a term used within their avenue of science.
Like laser induced phase oscillators.

When knobs are mentioned with phase it could be something old.
Something in an old radio museum could have phase knob.
Like the instruments listed above. It was more common with vacuum tube instruments setting feedback.

Because the relevant information is not given the question what it is used for is speculative.
A difference in phase angle normally measured on an oscilloscope is useful in analyzing impedance.
to adjust for loss due to load impedance sufficient feedback is supplied to improve the gain.

 

It’s not a variable phase oscillator it is a variable phase oscillator.