Yes. But since spectrum analyzer had their price reduced and even my computer audio board can do a Fourier analysis I left my loyal kikusuy off. The spectrum analyser
is way faster and practical than the selective voltimeter
They were called distortion analyzers. Still get them on e-bay. A generator and Narrow tuned notch filter you then ran into a AC voltmeter. Yea, I just use a spectrum analyzer. So, a few grand for a rack of old HP, or a PC and a free app.