Rational Acoustics

August 28th, 2012, 11:06 AM
Thought I would post this to assist those who might run across this. Previous to 7.4 I was used to being able to access the Generator for a Reference signal. On switching to 7.4, initially I thought this feature had been lost--and yet my previously set up signals based on that reference were still existing, but I could set up no new ones. So, started reading the help files and noted the new setting for Transfer Functions where access to multiple devices is allowed (or disallowed); to use the Generator as a reference this feature must be enabled.

Hopefully that helps.


August 29th, 2012, 06:43 PM
How exactly do you select the generator as the reference source?

I have a box that routes generator back to the reference in of my interface but this would be cleaner.

August 30th, 2012, 04:18 PM
From the Help file (please read the whole paragraph):

"Transfer Function measurements can also be referenced internally to Smaart's signal generator by enabling "Allow Multi-Device Transfer Function" option on the Transfer Function page of the main Options dialog and selecting the Generator as your reference signal source. In practice there are a few caveats to doing this, again mainly associated with delay times. For one thing, the latency of the measurement system from the output to the input becomes a factor in measuring absolute delay times. (This is generally not a factor when actively actively recording both input signals.) Another is that the latency through the measurement system may not be consistent from one measurement to the next, meaning you may need to measure the delay again each time you stop and restart the measurement and/or the signal generator. And finally if the measurement signal input and the output used to stimulate the system under test are not identically clocked, then the reference delay time will be subject to drift while measuring, and not just when restarting the measurement."