Function generator - "duty" control also changes frequency

[injb]

I have this old Kenwood function generator (FG-273). As well as a frequency control, it has a control marked "duty". I thought this was a duty cycle control, but it's behaviour is a bit puzzling to me. It changes the on time of the signal when the generator is in square wave mode. But it changes the frequency too! If I turn the pulse length up, the frequency goes down.

So I can kind of get the frequency and duty cycle I want by adjusting the duty control first, and then the frequency control, but it's very tedious this way.

Is that typical or does it sound like something is wrong with it, or with the way I'm using it?

[JohnnyMalaria]

That's the expected behavior. See page 8 of http://physics-astronomy-manuals.wwu.edu/Kenwood%20%20FG-273A%20Function%20Generator%20Manual.pdf