How to check sample rate

I'd like to use an external usb soundcard with my ubuntu 13.04 for musician purpose. Unfortunately the application requires 48 kHz and jackd to be used, but whenever I select the external souncard in qjackctl I see jackd falls back from 48 to 44,1kHz. Please is there a way to do that? Or at least a way to check/set the sample rate in the genuine ubuntu sound system, just to verify the card is 48k capable. Thank you. (the audio card is Korg's Pandora PX5D, and the chip inside is Texas Instruments TAS1020B). Thank you