Charles wrote:

Then it says somewhat cryptically:

"Harmonic distortion measurements are useful and significant up to
mudulation frequencies of approximately 1000 cps. At higher
frequencies the de-emphasis characteristic of the tuner will
attenuate
the higher distortion products severely and give rise to

considerable

errors in measurement."

Bob Fitzgerald wrote:

What they meant above 1KHz was the generator had to apply pre-
emphasis, or all the harmonics would be rolled off by the tuners de-
emphasis.

No.

Take it at face value.

"Harmonic distortion measurements are useful and significant up to
mudulation frequencies of approximately 1000 cps.

Exactly so.

Now if the generator uses preemphasis and is distortionless including
the sine stimuli wed still have the fact that the distortion of the
analogue parts after the detector will have its distortion deemphased at
a rate of 6 dB/octave.

".......This equipment may measure each frequency component
individually or may measure all frequency components
collectively......."

I suspect this is saying that either a THD or THD+N measurement was
OK, just call it "distortion."

No.

They say either use a wave analyser to measure each individual harmonic
or use a thd analyzer.

It later proscribes using for the IM test 15,000 and 14,600 Hz at
identical frequencies at 100% modulation and measuring the 400Hz
referenced to 400 Hz at 100% modulation.

Right this measurement tells a LOT.

IM is a good test, but it still is ignoring all the spurs and
garbage of the cheap bad old THD+N test,

No the two tone CCIF test makes for even WORSE figures than simple 15
kHz stimuli will do.

AND ohhh yessss the spurs and garbage will be even greater with TWO HF
tones than one...............


--
Best,

Goran Finnberg
The Mastering Room AB
Goteborg
Sweden

E-mail: mastering@...

Learn from the mistakes of others, you can never live long enough to
make them all yourself. - John Luther