[Top] [All Lists]

RE: Ultrasound playback setup

Subject: RE: Ultrasound playback setup
From: ONeill, William <>
Date: Fri, 14 Feb 2003 09:21:27 -0800
Regarding the question of "duplex opportunity" with the TDT RP2:  We haven't
 done it (yet), but it should be no problem. The duplex mode is often used
 for calibrating loudspeakers in our lab, but we've only done that using
 TDT's older "System 2" hardware, which uses separate A/D and D/A modules
 controlled by a central DSP card.
 The biggest limitation of the RP2 is running out of clock cycles.  Each
 "device" in software takes up clock cycles.  If you program an elaborate
 recording/playback device (e.g., with signal conditioning, temporal
 windowing, thresholding, etc) you can run out of cycles when using the
 system at it's maximum sample rate (200 kHz).  In our lab, we use the device
 mainly to generate complex ultrasonic acoustic stimuli.  If we were
 recording signals simultaneously, we would surely run out of clock cycles if
 we were using only a single RP2.  The solution is to add more RP2's to the
 setup, and split the tasks across them.
 We have been able to playback very long ultrasonic signals (lasting some
 minutes) with the RP2, but we had to roll through a double-buffered memory
 structure and use their high-speed USB interface to do it without
 Regarding dynamic loudspeakers, we've had good luck with leaf tweeters
 (e.g., Panasonic EAS 200).  They were hard to come by, heavy, and don't
 tolerate overdriving at all.  But they have excellent and broad frequency
 response (1 - 100 kHz) and a reasonably brief impulse response, and don't
 require DC bias like electrostatic speakers.
 William E. O'Neill, Ph.D.
 Bat Auditory Research Lab
 Dept. of Neurobiology & Anatomy
 Univ. of Rochester Sch. of Med. and Dent.
 Rochester, NY 14642-8603 USA
 Phone: (585) 275-4023
 FAX: (585) 756-5334
 > -----Original Message-----
 > From: Eckard Blumschein
 > [<a  href="[EMAIL PROTECTED]" rel="nofollow">[EMAIL 
 > PROTECTED]</a>]
 > Sent: Friday, February 14, 2003 4:25 AM
 > To: ONeill, William; [EMAIL PROTECTED]
 > Subject: RE: Ultrasound playback setup 
 > It is not obvious to me that TDT offers the duplex 
 > opportunity, that is,
 > sending and recording at a time as do pretty cheap sound cards. Also,
 > manufacturers rarely show the step response of their systems. 
 > Nonetheless,
 > I am sure electrostatic speakers are the best option in that 
 > respect. I
 > wonder if anybody can recommend any active electrodynamic 
 > speaker to be
 > used together with a duplex sound card. I am unhappy with a lot of
 > unacceptably oscillating step responses.
 > Eckard Blumschein
 > <a  href=""; 
 > rel="nofollow"></a>     

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the Bioacoustics-L mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU