"mc" bravely wrote to "All" (02 Jan 06 00:39:09)
--- on the heady topic of "THD claims of audio signal generators"

mc From: "mc"
mc Xref: core-easynews rec.audio.tech:185968
mc sci.electronics.design:536317 sci.electronics.repair:353509


mc My ancient Heathkit audio signal generator, which uses 3 tubes and a
mc light bulb in an oscillator circuit, claims to produce sine waves with
mc a total harmonic distortion less than 0.1%.

mc My semi-ancient Hewlett-Packard HP202B oscillator only claims to
mc produce THD less than 1%.

mc I would have expected the HP instrument to have considerably better
mc performance specifications because of its much more elaborate circuit.

mc Are we simply looking at pessimistic vs. optimistic ratings?


Some designs take the output at a different location and/or extra
filtering to achieve better distortion numbers. It also depends on the
circuit design, for example using a Wein Bridge configuration instead
of multiple RC phase shifts, etc...

A*s*i*m*o*v

.... Which sparks some mnemonic circuitry.