Good evening all. The Precise RF Co. has a model TTG1 two tone audio generator for a steep asking price. My question: Other than trying to build my own, are there other sources with a better price break for a 2 tone test generator? This of course is to be used to check transmitter linearity etc. Thanks, Ron
Many people think any way we generate a two-tone results in a good test, and even that a good two-tone test means a system has good bandwidth. A two-tone test is far better than no test, but does not check overshoot or dynamic regulation. It only tests RF dynamics at the tone spacing. For example if tone spacing is 1 kHz, a 600 Hz and 1.6 kHz audio tone, the IF and RF stages, ALC, and power supplies are all tested at a 1 kHz load change rate.
That, of course, is nothing like speech. Of course it is much better than no test, but it really doesn't tell us we don't have a problem. It only tells us if could be clean, not if it is clean, but that can still be worthwhile compared to nothing.
The problem is always obtaining a signifcantly cleaner two-tone signal than the system beyond the generator, but fortunately most radios and amplifiers are not especially pure.
I use two or three good audio generators, each through a very high attenuation pad, as an audio tone generator.